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One of the challenges of storing hydrogen in saline aquifers is the possible geochemical reactions between host rock, formation solution, and hydrogen. This study investigated the effect of hydrogen treatment on the mechanical properties of sandstone samples from Hulett member of Sundance Formation, a potential underground hydrogen storage host in Wyoming, USA. Cylindrical specimens were treated with brine, brine+50%H 2, and brine+100%H 2 for two weeks at a pressure of 15 MPa and a temperature of 83 °C. X-ray diffraction (XRD), scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET), uniaxial compression, and triaxial compression tests were conducted on specimens. Results showed that specimens treated with brine+50%H 2 and brine+100%H 2 , on average, exhibited 24 and 41% lower peak strength, respectively, compared to that of specimens treated with the brine. XRD results showed a decrease in dolomite and clay content of specimens after exposure to hydrogen, causing degradation of the mechanical and elastic properties of the specimens. • The effect of hydrogen on the mechanical properties of Hulett sandstone was investigated. • Dolomite and clay dissolution was observed after the treatment with hydrogen. • Specimens treated with hydrogen on average showed 41% lower strength. • An average 43% decrease in elastic modulus was observed after hydrogen treatment. [ABSTRACT FROM AUTHOR]

The aim of the present work was to evaluate six commercially available abutment screws by characterising roughness parameters, microstructure and mechanical properties. Six abutment screws from each implant system, were used. The surface roughness parameters (S a , S q , S sk , S ku , S pk , S k and S vk) were identified by an optical interferometric profiler. Microstructural observations and crystallographic analysis were performed using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectroscopy (EDX) device for elemental analysis and an X-ray diffractometer (XRD), respectively. The Martens Hardness (HM), Indentation Modulus (E IT), elastic index (η IT) and Vickers hardness (HV) of all specimens were determined by instrumented indentation testing (IIT). The results were analyzed by one-way ANOVA and Tukey multiple-comparison tests (a=0.05). EDX and XRD showed the abutment screws to be mixed α- and β-phase titanium alloys. Microstructural analysis revealed a fine homogeneous microstructure without porosity, consisting of fine dispersoid rods of β-phase embedded in a continuous α-phase matrix. Statistically significant differences were found among the mechanical properies and surface roughness parameters apart from S q , S pk and S vk. The tested abutment screws showed significant differences in the probed properties, and, thus, differences in their clinical behaviour are anticipated. [ABSTRACT FROM AUTHOR]

High-entropy MAX phase (Ti 0.5 Nb 0.15 Zr 0.1 Mo 0.1 Ta 0.1 W 0.05) 2 AlC was synthesized via current-assisted sintering using Ti/Al/NbC/ZrC/MoC/TaC/WC as the raw material. The phase composition, microstructure, and elemental distribution are analyzed by X-ray diffraction, scanning electron microscope and transmission electron microscope with energy-dispersive spectrometer elemental analysis. The results obtained indicate that the as-synthesized bulk exhibits high purity with minimal elemental segregation at the grain boundary. The doped atoms caused numerous dislocations and severe lattice distortions in the crystal structure. By means of mechanical properties tests, the hardness, flexural strength, and fracture toughness of (Ti 0.5 Nb 0.15 Zr 0.1 Mo 0.1 Ta 0.1 W 0.05) 2 AlC are determined to be 9.3 ± 0.2 GPa, 433 ± 27 GPa, and 8.9 ± 0.3 MPa m1/2, respectively. These findings demonstrate notable enhancements in terms of hardening, strengthening, and toughening effects compared to the Ti 2 AlC phase. [ABSTRACT FROM AUTHOR]

In this study, the primary factors affecting the performance of PcBN (Polycrystalline cubic boron nitride) tool materials were investigated by high temperature/high pressure sintering through the variation of TiB 2 -Sialon volume ratio, the strength of TiB 2 -Sialon binder itself, as well as the matching of the average coefficient of thermal expansion (CTE) with cBN (Cubic boron nitride). The effects of TiB 2 -Sialon on the phase composition, microstructure, and mechanical properties of PcBN composites were studied by X-ray diffraction (XRD), universal testing machine, scanning electron microscope (SEM) and transmission electron microscope (TEM). The results show that the properties of TiB 2 -Sialon binder are analogous to those of the corresponding composites. The phase composition of PcBN composite is not affected by the change of volume ratio. It was found that prepared composite, have TiB 2 rod crystals growing along the (100) plane and Sialon rod crystals growing on the (001) plane. The influence of the volume ratio of TiB 2 -Sialon on the mechanical properties of the composites is principally concerned with the density, mechanical properties, and thermal expansion coefficient of the used binder. The extent to which the binder matches the coefficient of thermal expansion is favorable to the strength of the composite. When the volume ratio of TiB 2 to Sialon was 1:3, the hardness (25.21 GPa, 37.44 GPa) and toughness (7.09 Pa m1/2 and 7.48 Pa m1/2) of TiB 2 -Sialon binder/TiB 2 -Sialon-cBN composites reached the maximum value, and the optimal impact resistance was also achieved. The density of the binder and the composite material was maximized when the volume ratio is 1:4. The average thermal expansion coefficient of the binder hoc tempore matches comparatively with cBN, and the interface bonding is better, displaying the best flexural strength (805.30 MPa and 1059.60 MPa) and wear ratio (2005). Therefore, adjusting the volume ratio of TiB 2 -Sialon within a certain range is beneficial to further enhance the binder's strength and mechanical properties. [ABSTRACT FROM AUTHOR]

• Innovative latex nanodispersions were employed for the consolidation of porous stone. • Their effectiveness to improve mechanical properties of Prague sandstone was proved. • Consolidation can be tuned according to type of applied latex and its concentration. This investigation aims at assessing the potential of polyacrylate latex nanodispersions as consolidation agents for sandstones. Four different latex types, implementing polymer fluorination and chemical crosslinking, have been synthesized at the scope and fully characterized. The Prague sandstone employed in this study has been selected as an example of highly porous stones used as building materials for many historical monuments. Two different concentration levels of nanodispersions have been adopted. The consolidated stone samples have been tested using a combination of physical-mechanical tests and microscopic observations. Compared to the non-treated samples, significant increments of mechanical properties (e.g. up to 3.3 times higher bending strength) have been detected after the consolidation treatment with concentrated products. Moreover, when 10 times diluted latex nanodispersions have been applied, the improvement of mechanical properties has still been significant, while moisture transport properties, such as water absorption, have been found to be comparable with those of the untreated sample. Fluorinated polymers imparted better hydrophobic properties with a contact angle above 100°. Observations using a scanning electron microscope revealed the good filling and bridging capacity of the applied consolidation agents. As demonstrated, by acting on the polymer structure, that is, by tuning the degree of crosslinking, polymer fluorination and gel content, the properties of these novel polyacrylate latex nanodispersions can be tailored to the specific stone and type of decay in order to improve the effectiveness of the treatments and obtain the desired final properties. The flexibility of their chemistry offers new opportunities for preserving objects of cultural heritage that are also at risk due to the ongoing climate change. [ABSTRACT FROM AUTHOR]

The ceramic composites were designed through the regulation of the composition and temperature in the in-situ oxidized SiC/Al–Mg–Si composites process. The evolutions of the phase and microstructure were studied by X-ray Diffraction(XRD), Scanning Electron Microscope (SEM), and Transmission Electron Microscope(TEM) in different alloy addition and heating temperature. The products of in-situ oxidized SiC/Al–Mg–Si composites showed similar compositions due to high oxidation resistance on SiC since the heated temperature was below 1500 °C. Alloy addition dislodges the oxide shell on SiC. It promoted the oxidation of SiC, providing the sustained-release Si source to form the cordierite, mullite, and forsterite. Moissanite/spinel, mullite/spinel, and cordierite/spinel were obtained by controlling temperature or adding alloy. The mullite rods formed in 20% alloy addition samples at 1350 °C was detected. The step-like microstructure revealed that grains abide by a layer growth mechanism. The bending strength was enhanced from 13.83 ± 3.6 MPa to 22.32 ± 4.3 MPa by eutectic melting, which increased with the alloy addition and elevated temperature. [ABSTRACT FROM AUTHOR]

This research investigates the combined effect of steel and natural fibre on the mechanical properties and spalling resistance of ultra-high performance concrete (UHPC) before and after exposure to elevated temperatures. The effects of two parameters, namely temperature (ambient temperature, 200 °C, 400 °C and 600 °C) and fibre type (solely macro end hooked steel fibre (MHS) and hybrid of micro straight steel fibre (MSS), macro end hooked steel (MHS) fibre and micro jute (MJ) fibre) on the mechanical properties, spalling resistance and mass loss of UHPC were studied. Micrographs from scanning electron microscope (SEM) test were utilized to appraise the steel fibre and jute fibre before and after exposure to elevated temperatures. The test results exhibited that the residual tensile strength and flexural strength were significantly declined after exposure to high temperatures for UHPC specimens reinforced with macro steel fibre only. Moreover, explosive thermal spalling occurred for this group of specimens under 600 °C. Whereas the combined use of jute fibre and micro-macro steel fibre was an effective approach to prevent the explosive thermal spalling under 600 °C and improve the residual tensile strength, flexural strength and toughness of UHPC. Furthermore, preliminary empirical expressions have been developed in this study to predict the residual mechanical properties of UHPC as a function of natural fibre content, steel fibre content and temperature. [ABSTRACT FROM AUTHOR]

During the extraction of geothermal heat, the changes in temperature and pressure environments can alter the mechanical and hydraulic behavior of fractured rock masses, affecting the overall transmissivity and heat extraction efficiency accordingly. This study carried out a series of experiments, including X-ray diffraction (XRD), scanning electron microscope (SEM), uniaxial compression tests, and surface morphological scanning, to explore the influence of reservoir temperature on the mechanical behavior of granite and fracture surface topography. The results indicate that as the temperature increases, the uniaxial compressive strength, elastic modulus, and Poisson's ratio of granite show similar variation patterns that increase as the temperature approaches 200 °C and then decrease. In addition, with the increase in temperature, the overall surface elevation and roughness parameters generally decrease due to surface asperity degradation, with the maximum mean mechanical aperture found at 200 °C. Flow simulations were conducted to further explore the influence of temperature and pressure environments on fracture transmissivity and flow fields. It is found that the normalized equivalent hydraulic aperture B N of the tested fractures decreases progressively as the stress increases, and more scattered distributions of B N are observed under higher compressive stresses. Moreover, with the continuous increase in temperature, the average B N slowly increases to its peak of ~0.78 at 200 °C, then it decreases to ~0.76 at 300 °C and remains nearly constant. These findings can be important for assessing heat production performances during the geothermal extraction process with spatially and temporally varying reservoir temperatures and pressures. • Temperature and pressure effect on granite properties are analyzed. • Surface roughness decreases due to heat-induced asperity degradation. • UCS and transmissivity reach their maximum at 200 °C with increasing temperature. [ABSTRACT FROM AUTHOR]

For the present investigation, Tungsten heavy alloys (WHAs), (90-x)W-6Ni-4Cu-xLa 2 O 3 are synthesized using the powder metallurgy route by liquid phase sintering at 1400 °C for 1 h in hydrogen atmosphere. The effect of variation of La 2 O 3 (Lanthanum oxide) dispersion in W-Ni-Cu alloy (0, 0.1, 0.5, 1.0, 1.5, and 2.0 wt%) on microstructural evolution was investigated using a scanning electron microscope (SEM) and transmission electron microscopy (TEM). The distribution of the tungsten, matrix, and La 2 O 3 were analyzed using X-ray energy dispersive spectroscopy (EDS). The influence of La 2 O 3 content on the densification behavior was also determined. The stereological quantifications were done on particle size and contiguity. The lowest W particle size was observed in sample of 2.0 wt% La 2 O 3 added WHA. However, this sample was found to have more porosity. The W particle size was reduced by about 30% with 2.0 wt% addition of La 2 O 3. The maximum value of bulk hardness of about 320 HV 5 was observed in 1.0 wt% La 2 O 3 content WHA. The three-point bend test was performed to determine the bending behavior of these alloys. The alloy with 1.0 wt% La 2 O 3 showed the maximum compressive strength of 1481 MPa and bending strength of 1021 MPa. Fractography revealed W-W interface de-cohesion fracture mechanism to operate pre-dominantly. W particle cleavage fracture mode was observed to increase with the addition of La 2 O 3 up to 1.0 wt% in the WHAs. • W-Ni-Cu alloys with La 2 O 3 processed via powder metallurgy LPS at 1400 °C. • With 2.0 wt% La 2 O 3 in W-Ni-Cu alloy reduces W particle size by 30 %. • The addition of 1.0 wt% La 2 O 3 turns out to give the best mechanical property. • Quantification of operational fracture modes attempted. [ABSTRACT FROM AUTHOR]

Magnesium oxychloride cement (MOC) as a green cement has superior mechanical properties such as high strength and quick gain of early strength, however the inherent brittleness has limited its applications where ductility is crucial. To enhance the strength and ductility, a novel hybrid fibre-reinforced MOC-based composite (FRMOC) is developed for the first time using polyethylene (PE) fibres and basalt fibres (BF) to reinforce the MOC. A systematic investigation of the effect of fibre dosage on the flowability, rheological properties, compressive strength, and tensile properties of the developed FRMOC is conducted in this study. The results revealed that the addition of fibre reduces flowability while increasing the yield stress and plastic viscosity. The 1-day compressive strength of the FRMOC reached 68.2–85.4% of the corresponding value at 28 days, demonstrating its high early strength characteristic. The mix with 1.25% PE and 0.75% BF exhibited the maximum compressive strength at all curing ages. All the mixes consistently demonstrated excellent tensile strength and tensile strain capability (ductility), with the tensile strength and tensile strain capacity of 10.95 MPa and 4.41% achieved for the mix of 2% PE fibre, and 8.49 MPa and 2.43% for the mix of 1.25% PE and 0.75% BF respectively. Moreover, a decline in strength characteristics and strain capacity was observed as BF percentages increased. Scanning electron microscope (SEM) analysis was further employed to investigate the morphological changes in the FRMOC matrix at the microscale to discover the fibre reinforcing mechanism. • Hybrid fibre reinforced MOC (FRMOC) with enhanced strength and ductility is developed. • FRMOC demonstrates high-early-strength characteristic. • Rheological, physical, and mechanical properties were evaluated. • 1.25% PE and 0.75% BF-reinforced FRMOC exhibited maximum tensile strength and strain capacity. • Microstructural analysis is performed to analyse the morphological alterations. [ABSTRACT FROM AUTHOR]

For facilitating carbon utilization and minimizing carbon emission, steel fiber was coated with polyethyleneimine and subjected to a moist condition to capture carbon dioxide, and the CO 2 captured steel fiber (CPSF) was formed, which was used to prepare ultra-high performance concrete (UHPC). After heat curing, compressive strength and splitting tensile strength of UHPC were determined. The results reveal that, compared to the UHPC with polyethyleneimine-coated steel fiber (PSF), the compressive strength and splitting tensile strength of UHPC with CPSF increased by 16.3% and 3.4%, respectively. The microstructural tests including environmental scanning electron microscope, X-ray diffraction and thermogravimetric analysis prove that, under a combined curing of 90 °C hot water and subsequent 200 °C dry-air heating, carbon dioxide chemically combined in the coating of CPSF can be released during the combined curing and react with calcium hydroxide or cement clinkers in the matrix surrounding CPSF to generate calcium carbonate and calcium-silicate-hydrate (C–S–H) gels, which is responsible for both the refinement of microstructure and enhancement of mechanical properties of UHPC. [ABSTRACT FROM AUTHOR]

Polylactide (PLA) represents one of the promising biodegradable polymers with great potential to replace petroleum-derived plastic. In the last decade, massive efforts have been devoted to overcoming the brittleness of PLA, expecting comparable mechanical properties to traditional polyolefin and polyester. Introducing oriented texture into PLA has recently been reported to be an effective approach to improve ductility without sacrificing their high strength. However, the understanding of the mechanism is absent. Herein, we study the fracture behaviors of anisotropic PLA with oriented lamellar crystal by employing operando synchrotron X-ray scattering and diffraction. It has been found that the cavities generated parallel with stress direction can restrain the fast failure of PLA. Nevertheless, the load-carrying ability of oriented PLA lamella is still limited. On this basis, we further introduce the flexible nanofibers into an oriented PLA matrix that enables crystals to effectively participate in the stress dissipation, resulting in significant enhancement of the ductility of PLA while maintaining their high strength. Combined with morphological study by scanning electron microscope, we propose a qualitative model to describe the detailed fracture behavior of PLA with oriented texture, which may provide a reliable theoretical guideline towards further optimization of the mechanical properties of PLA. [Display omitted] • Synchrotron X-ray techniques was used to study the fracture behaviors of PLA. • Cavity along orientation direction plays important role in fracture process. • A new way for enhancing the ductility of PLA while maintaining high strength. [ABSTRACT FROM AUTHOR]

(HfMoTiWZr)C high entropy carbides (HEC) were prepared from the commercial carbide powders of IVB (Hf, Ti, Zr) and VIB (Mo, W) group metals of the periodic table via high energy ball milling (HEBM) and spark plasma sintering (SPS). Metal carbide powders (HfC, TiC, ZrC, Mo 2 C and WC) were HEBM'd for 3 h in a vibratory ball mill, and then SPS'd at different temperatures (1800, 1900, 2000 and 2100 °C). The HEBM'd powders and SPS'd ceramics were characterized in composition, density and microstructure using an X-ray diffractometer (XRD), a scanning electron microscope/energy dispersive spectrometer (SEM/EDS), a particle size analyzer and a pycnometer. Also, microhardness and sliding wear tests were conducted on the SPS'd ceramics. Based on the performed characterization, a single-phase FCC structure was observed at all sintering temperatures indicating a high entropy carbide ceramic, and they all have high hardness and wear resistance values. [ABSTRACT FROM AUTHOR]

The present study examines the mechanical and morphological characteristics of a green composite reinforced with pineapple leaf fiber (PLF) under different environmental conditions. PLF underwent chemical treatment at optimal conditions, using a 1% w/v sodium carbonate solution for 6 hours, to produce an environmentally friendly pineapple leaf fiber (PLF)/polylactic acid (PLA)-based composite via injection molding. The optimal injection settings of 165℃ (melting temperature), 50 mm/sec (injection speed), and 110 bars (injection pressure) to produce the PLF/PLA composite. The PLF/PLA composite was developed with a fiber loading of 20% and a length of 3 mm. The produced PLF/PLA composites were then exposed to a variety of environmental conditions, including water, soil, refrigeration, and room temperature. The impact of these diverse conditions on the mechanical properties (tensile, flexural, compression, and shear) was scientifically observed for four-week. Additionally, the morphology of the fractured specimens was assessed using a scanning electron microscope (SEM). The contact angle measurement was conducted to assess the hydrophilic characteristics of the PLF/PLA green composite. There has been a lack of comprehensive research on the effects of different environmental conditions on the mechanical, wettability, and morphological properties of green composites derived from PLF/PLA. Thus, in this study, emphasis is given for investigating the effect of various environmental conditions on the mechanical properties of PLF/PLA injection-molded green composite. The composite material demonstrated the highest water absorption and swelling thickness at 6.45% and 5.51%, respectively, in comparison to the dry PLF/PLA samples. The green composite of PLF/PLA demonstrated excellent mechanical performance under ambient conditions compared to other environmental conditions. The PLF/PLA composite displayed a peak contact angle of 83.26° when subjected to soil burial conditions. On the contrary, the initial samples of the PLF/PLA composite displayed the minimum contact angle of 56.72°. • The mechanical behaviour was better in room temperature than refrigerating, soil burial, and water immersion conditions.. • The maximum water absorption and thickness of swelling were observed as 6.45% and 5.51% in comparison to the dry samples. • The soil buried composite samples showed maximum contact angle of 83.26°. • Morphological study showed minor damages to the samples exposed to refrigerator and room temperature conditions. [ABSTRACT FROM AUTHOR]

• Sensing capability of PLA-nanofiber reinforced PCL composite-based smart porous scaffolds for online health monitoring. • Fused filament fabrication parameters for maximizing yield stress. • Simulated return loss , specific absorption ratio, and resonance frequency for PCL and PCL composites. In the past, studies were reported on polycaprolactone (PCL) and polylactic acid (PLA) nanofibers (NF)-based scaffolds for tissue engineering applications. But hitherto, little has been reported on the sensing capability of PLA-NF reinforced PCL composite (PPNC)-based smart porous scaffolds for online health monitoring (OHM) of joint strains/ tendon tears/ contusions/ rhabdomyolysis, etc. In this study, smart porous scaffolds (SPS) were fabricated by fused filament fabrication (FFF) using PPNC for OHM (of joint strains/ tendon tears/ contusions/ rhabdomyolysis, etc.) with tuneable sensing and mechanical properties. The results suggest that FFF parameters, zigzag fill pattern, 0.20 mm layer thickness, and 80 % infill percentage are the best-predicted settings for maximum yield stress (σ ymax) of SPS. Further, a vector network analyzer was used to ascertain the sensing capability of SPS. The resonance frequency (R f) for PCL (virgin) and PPNC with minimum yield stress (σ ymin) and σ ymax were observed as 2.3021, 2.6008, and 2.4315 GHz respectively. The simulated return loss (S 11) , specific absorption ratio (SAR), and R f for PCL (−10.7593 dB, 0.977 W/kg, and 2.6450 GHz), PPNC with σ ymin (−10.5737 dB, 1.437 W/kg and 2.3400 GHz) and PPNC with σ ymax (−10.9429 dB, 1.155 W/kg and 2.5050 GHz) indicate that experimental data is in good co-relation with the observed values. The results are supported by a scanning electron microscope and differential scanning calorimetry. [ABSTRACT FROM AUTHOR]

• The proposed method improved the precision and accuracy of measurement and reduced the time in measuring the displacement. • A novel material deformation measurement method is suggested to evaluate the mechanical properties of thin films. • The method requires images during an in-situ SEM (Scanning Electron Microscope) tensile test and analyze them. • Some images of low resolution (768 x 614) during in-situ SEM tensile test of the thin film are acquired and restored to high resolution (3840 x 3072) images using the deep learning model. In this study, a novel material deformation measurement method is suggested to evaluate the mechanical properties of thin films. It is important to identify the mechanical properties of thin films in order to do a reliable design of these products. One of the methods to get the mechanical properties of thin films is to acquire images during an in-situ SEM (Scanning Electron Microscope) tensile test and analyze them. However, SEM image acquisition is mostly affected by the time varying motion of pixel positions in the consecutive images, a phenomenon called drift and distortion. In this study, some images of low resolution during in-situ SEM tensile test of the thin film are acquired in short time and restored to high resolution images using the deep learning model called Super Resolution Residual Network (SRResNet) to calculate the deformation of thin films. The proposed method increased the precision of measurement by 5 times, improved the accuracy of measurement by 20%, and reduced the measurement time by 19 times. [ABSTRACT FROM AUTHOR]

The primary purpose of this work is to study the fabrication of a flexible natural cellulosic fiber composite. In this respect, natural cellulosic fiber was obtained by modified poplar wood fiber through sodium hydroxide (NaOH) and γ-Aminopropyl Triethoxysilan. Then, the composites were fabricated by hot-pressing the modified wood fibers and polyurethane following characterization. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM) observation results confirmed that some of the hemicellulose and lignin were removed from wood fibers after NaOH modification and successfully grafted with alkoxy structures after KH550 modification. NaOH&KH550 modification improved the interfacial compatibility between poplar wood fibers and polyurethane. The flexibility of the composites was improved (the slenderness value was reduced by 113 %), allowing flexible deformations such as bending, twisting, and knotting. In addition, thermal stability, tensile strength (increased by 105 %), elongation at the break (increased by 125 %), and water resistance were increased. This flexible natural cellulosic fiber composite is expected to be applied in the veneering of curved materials and special-shaped structure furniture, providing a theoretical basis for improving the added value of wood-based composites. [ABSTRACT FROM AUTHOR]

As an environmentally friendly material, alkali-activated fly ash-slag (AAFS) is considered as a promising alternative cement because of its excellent mechanical properties and thermal stability. Nevertheless, high temperature induced damage in AAFS can potentially bring serious risks for its practical applications. This paper presents a systematic experimental study on behaviour of AAFS paste subjected to elevated temperatures up to 800 °C in terms of microstructure as well as thermal and mechanical properties. Microstructural evolution was characterised by means of Rietveld-based quantitative X-ray diffraction (QXRD), backscattered scanning electron microscope (BSEM) and X-ray microcomputed tomography (XCT), while thermal and mechanical properties were evaluated from thermogravimetric analysis (TGA), thermal deformation and compressive and flexural strengths. Results indicate that the compressive strength of AAFS paste rises by 77.5 % at 200 °C, followed by a mitigation from 200 to 600 °C and a regain at 800 °C. Different phases in AAFS paste including unreacted particles, reaction products and pores took up 30 %, 67.7 % and 2.31 % at ambient temperature, and 4.95 %, 84.8 % and 10.3 % after exposure to 800 °C, respectively, suggesting the recrystallisation with the formation of nepheline and gehlenite. In addition, the relationships between microstructural characteristics including three-dimensional (3D) pore structure features and thermal and mechanical properties of AAFS paste at elevated temperatures were explored and discussed in depth to gain insights into the underlying degradation mechanisms including pore pressure build-up, thermal gradient and phase transformation. [ABSTRACT FROM AUTHOR]

Melia dubia is a rapidly expanding tree species in southern India, but its main drawback has been limited use in wood-based panel products until recently. To address this research gap, this study aimed to develop three reinforcement materials for producing Reinforced Laminated Veneer Lumber (RLVL) using Melia dubia. Three types of reinforcement materials, chopped glass fiber mat (CGM), glass fiber mesh (GM), and bamboo mat (BM) were employed in two layers to manufacture RLVL. The investigated parameters included physical, mechanical, and bonding performance. Furthermore, morphological images were analyzed using optical and scanning electron microscopes. The research findings revealed that the highest performance was demonstrated by BM, followed by GM and CGM. These results suggest that all three reinforcements enhanced the mechanical properties and overall performance of RLVL. Arranging the reinforcement layers closer to the surface veneer layer in the assembly resulted in outstanding mechanical properties for RLVL. The performance is superior to solid wood made from the same wood species. The findings indicate that RLVL demonstrated superior mechanical properties to laminated veneer lumber (LVL) and solid wood. The modulus of rupture for LVL reinforced with CGM, GM and BM was 7.27%, 30.91%, and 32.73% greater respectively, than that of unreinforced LVL. The composite LVL reinforced with bamboo and glass matting exhibits potential for successful utilization in outdoor structural applications, including beams, rafters, and purlins. • LVL reinforced with CGM, GM, and BM exhibited excellent modulus of rupture. • RLVL demonstrated superior mechanical properties to LVL and solid wood. • LVL reinforced with GM and BM can successfully utilized in outdoor structural applications. [ABSTRACT FROM AUTHOR]

To obtain a robust diffusion-bonded joint at a relatively low temperature, Nb foil was applied as an interlayer to the diffusion bonding of Zr-4 alloy, and a wide process parameter involving the bonding temperature of 720–820 °C and holding time of 30–120 min was investigated to reveal the evolution of interfacial structure and mechanical properties of the joints. The β-(Zr, Nb) and Widmanstädter microstructure formed at the interface induced by the eutectoid transformation of the diffused Zr and Nb at the bonding temperatures over 740 °C. The phase structure and the thickness of β-(Zr, Nb) layer were not considerably influenced by the increase in diffusion parameters while the Widmanstädter zone thickened significantly. Moreover, the tensile strength and elongation of the resultant joints could be stabilized above 433 MPa and 7.8%, respectively, when the bonding temperature exceeded 760 °C with a holding time of 30 min. By extending the holding time to 60 min at 760 °C, the tensile strength and elongation could reach 454 MPa and 12.6%, respectively, comparable to those obtained at an elevated temperature of 820 °C for 30 min. Additionally, the samples fractured at the diffusion layer were characterized by the in-situ tensile test under the scanning electron microscope, and it was discovered that the crack initiation and propagation process occurred mainly between the β-(Zr, Nb) and Widmanstädter diffusion zone. • The well-bonded Zr-4 joints were achieved by the application of Nb interlayer. • The diffusion layer consisted of β-(Zr, Nb) and Widmanstädter microstructure. • The Nb addition lowered bonding temperature without weakening tensile properties. • The fracture occurred between the β-(Zr, Nb) and Widmanstädter diffusion zone. [ABSTRACT FROM AUTHOR]

To improve the low-temperature toughness of epoxy resins, in this study, an epoxy-terminated hyperbranched polysiloxane (EPTS-12) was synthesized and introduced into the epoxy resin as a toughener. The structure of EPTS-12 was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (1H NMR), and the fractured surfaces of the modified resins were observed by a scanning electron microscope (SEM). With the content of EPTS-12 at 5 wt%, under room temperature (RT) and − 72 °C, the maximum values of elongation at break were 14.19% and 16.06%, increasing by 35.66% and 74.19% respectively. The test results of dynamic mechanical analysis (DMA) also showed that the toughness of the modified epoxy resins was improved. The SEM images of the fractured surfaces of the modified resins were used to investigate the toughening mechanism of the toughener (EPTS-12). With the virtue of a simple synthesis process, low cost, and good reproducibility, this toughener can further expand the application of epoxy resins. [Display omitted] • With 5phr EPTS-12, under RT and − 72 °C, the elongation values were increased by 35.66% and 74.19% respectively. • The dynamic thermomechanical behaviors of the composites were investigated via dynamic mechanical analysis (DMA). • The working mechanism of the toughener was studied by SEM images of the fractured surfaces. • These research results can provide a reference for the design and development of epoxy tougheners. [ABSTRACT FROM AUTHOR]

The surface topography and interface characteristics play a significant role in determining the mechanical properties of carbon fiber reinforced polymer (CFRP) composites. These features are primarily influenced by the surface chemical structures and their interactions with the matrix resin. Here, we developed a rigid-flexible coating consisting of polyetheramine (PEA) and polydopamine (PDA) on the fiber surface to control the interface and improve the mechanical properties of CFRPs. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectrum (FT-IR) results validated the successful introduction of polymeric chains and fiber surface characteristics including rough surfaces, slim polymer layers and uniform dots were examined by scanning electron microscope (SEM) and transmission electron microscopy (TEM). Contact angle tests indicate that the functionalized coating noticeably enhances the interaction force between carbon fibers, promoting improved wettability by the matrix resin. The bending and interlaminar shear strength of CFRP prepared by functional carbon fiber are increased by 45.76 % and 47.63 %, respectively. The drop weight impact (DWI) test confirms the positive effect of improved interfacial properties on the out-of-plane impact resistance of CFRPs. [Display omitted] [ABSTRACT FROM AUTHOR]

The current investigation aims to choose an alternate potential replacement for the nonbiodegradable synthetic fibers used in polymer composites. This goal motivated the thorough characterization of Rosa hybrida bark (RHB) fibers. The research explored fiber characterization such as morphological, mechanical, thermal, and physical properties. The suggested fiber features a percentage of cellulose, hemicellulose molecules, and lignin of 52.99 wt%, 18.49 wt%, and 17.34 wt%, respectively according to chemical composition studies, which improves its mechanical properties. It is suitable for lightweight applications due to its decreased density (1.194 gcm−3). The purpose of the Fourier transform infrared spectroscope was to observe and record how various chemical groups were distributed throughout the surface of the fiber. The presence of 1.41 nm-sized crystalline cellulose and further XRD analysis showed a crystallinity index of 75.48 %. Scanning electron microscope studies revealed that RHB fibers have a rough surface. According to a single fiber tensile test, for gauge length (GL) 40 mm, Young's modulus and tensile strength of RHB fibers were 6.57 GPa and 352.01 MPa, respectively, and for GL 50 mm, 9.02 GPa and 311 MPa, respectively. Furthermore, thermo-gravimetric examination revealed that the isolated fibers were thermally stable up to 290 °C and the kinetic activation energy was found to be 75.32 kJ/mol. The fibers taken from the Rosa hybrida flower plants' bark exhibit qualities similar to those of currently used natural fibers, making them a highly promising replacement for synthetic fibers in polymer matrix composites. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the effect of using single and combined marble dust (MD), granite dust (GD) and nano alumina (NA) on the performance of Portland cement concrete. MD and GD were separately replaced by different percentages of cement (2, 4, 6, 8 and 10 wt%). Furthermore, NA was used as addition by different percentages (0.25, 0.5, 0.75, 1.0 and 1.25 wt%) in the individual mixtures. The optimal ratios for MD, GD and NA were used to design two concrete mixtures with combined 6%MD+ 1%NA and 6%GD+ 1%NA. The physical properties (consistency, initial and final setting times), the workability (slump cone test), the mechanical properties (compressive, splitting tensile and flexural strengths) and microstructure analysis (X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Energy-Dispersive X-ray (EDX)) were carried on the single and combined mixtures in addition to control mix. Results revealed a rise in the water quantity needed to achieve standard consistency, along with a reduction in both initial and final setting times, as the content of GD and NA increased. However, in comparison to the control mix, minor effects in the consistency or the setting times was observed when various MD contents were used. Regarding workability, its consistently decreased in all cases in correlation with the surface area of the materials utilized. The highest reduction was observed when employing NA, characterized by the largest surface area, followed by GD, and then MD, which had a marginal effect on workability. For hardened concrete, there was an improvement in strengths of samples with replacing individually MD and GD content up to 6% at all curing ages, followed by a decrease in strengths when the content reached 10% of cement replacement compared to control sample. Concrete mixtures with addition of NA showed significant improvement in strengths at all percentages of addition until reached the maximum increase in strength at 1% then slightly decreased. Concrete with combined (6%MD+1%NA) and (6%GD+1%NA) show significantly improved mechanical properties and compact microstructure enriched with C-S-H in comparison to concrete samples using 6%MD, 6%GD and 1%NA separately. • The water of consistency increased while the initial and final setting times were shortened. • The workability of concrete was significantly diminished by NA particles. • An improvement in strength was recorded for the combined use of 6% MD and 1% NA. • An enhancement of flexural and tensile strength was attributed to the individual use of MD, GD, and NA additives. • The results of EDX analysis confirmed that lower Ca/Si ratio led to higher mechanical properties. [ABSTRACT FROM AUTHOR]

Graphene-based nanomaterials possess broad applications because of their excellent multi-functional properties. In this work, a facile self-assembling method was presented for preparing one kind of graphene oxide-based paper/hollow microspheres hybrid. It was found that most of the hollow microspheres can strongly anchored on the surface of graphene oxide paper (GOP) by an in-situ scanning electron microscope peeling testing combining with molecular dynamics (MD) simulation. In addition, the uniform distribution of hollow microspheres on the surface of GOP cannot only provide a better surface wettability, but also can effectively improve the interfacial stress-transfer capability between such hybrid and polymer matrix. Our work provides a guidance for the structural designs of graphene-based nanomaterials and broaden their applications. [Display omitted] [ABSTRACT FROM AUTHOR]

To realize the application of xylan based film in food and drug packaging, the poor mechanical property and film-forming property of xylan based film must be overcome. Herein, a good oxygen barrier composite film with desired mechanical properties was prepared based on carboxymethly xylan (CMX), chitosan (CS), and graphene oxide (GO). The results of scanning electron microscope revealed the composite film had a dense and continuous structure, which will endow the composite film with excellent mechanical property. As expected, the composite film with the 0.5% mass fraction of GO exhibited best mechanical property, among which the tensile stress, tensile strain, and Young's modulus of the composite film reached 50.81 MPa, 47.61%, and 1.39 GPa, respectively. The oxygen barrier properties of the composite films significantly increased with the addition of graphene oxide due to the dense, stacked multilayer structure. In addition, these composite films exhibited good antibacterial properties. Therefore, these films show great promise in the field of food packaging and wound dressing due to their excellent mechanical, oxygen barrier and antibacterial properties. • Flexible composite films based on CMX, CS, and GO prepared by casting method. • Desired mechanical properties of the composite films were obtained by adding GO. • The composite films exhibit good oxygen barrier and antibacterial properties. [ABSTRACT FROM AUTHOR]

During the selection of materials for anti-lithium ion corrosion, magnesium aluminate spinel has been found to have good corrosion resistance and low cost. During the preparation of light-weight spinel ceramics, it is considered to be kiln body material. In this work, spinel bubbles were prepared using electrofusion injection process. Bulk density, volume density and pressure resistance of spinel bubbles in different particle sizes were counted. Light-weight spinel bubble ceramics with different densities were prepared by using electrofused spinel bubbles as light aggregates and using ρ-Al 2 O 3 and caustic burnt magnesia powder as matrix powders. The microstructure of spinel bubbles with different particle sizes and light spinel ceramics was analyzed using scanning electron microscope. Results show that the spinel bubble has complete structure, good sphericity, perfect grain crystallization, and clear edges and corners. Although there are some fine cracks and cavities, grains are tightly bound. Compressive strength and bending strength of light-weight spinel ceramics, whose density were found to lie within the range of 0.99–1.63 g cm−3, were found to be 5.19–36.33 MPa and 3.48–12.84 MPa, respectively. [ABSTRACT FROM AUTHOR]

In this work, the properties of yttria-stabilized zirconia-based ceramics, Y-TZP containing Fe 2 O 3 as coloring agent were evaluated. Nanoparticled powder of 3Y-TZP (ZrO 2 - 3 mol.% Y 2 O 3) doped with different amounts of Fe 2 O 3 (0.002–0.136 wt%) were compacted into monolithical or multilayered samples and sintered at 1475 °C - 2 h. The samples were characterized by X-ray diffraction analysis (XRD), relative density, scanning electron microscope (SEM). Hardness and fracture toughness in the color interface were investigated using the Vickers indentation method and the biaxial flexural strength was determined by the piston on 3 balls method (P–3B). Furthermore, optical parameters were measured using spectrophotometry in regard to sample thickness and Fe 2 O 3 content. The results indicated a good adhesion between layers, proven by indentation cracks randomly growing between different regions, because the powders used produced very similar morphological characteristics. The different amounts of Fe 2 O 3 studied in this work did not interfere in densification, phase composition, or microstructure of the sintered ceramics. The fracture toughness and flexural strength did not significantly change due to the addition of Fe 2 O 3 , presenting values close to 7 MPa m1/2 and 1120–1150 MPa, respectively, in all studied compositions. On the other hand, increasing Fe 2 O 3 contents lead to an increase in the hardness of the material (1280–1330 H V), and higher contrast ratios (CR) with a consequent loss of translucency. Color variation (ΔE) depended also on the thickness of the material. [ABSTRACT FROM AUTHOR]

Dynamic mechanical properties of the selected laser melting (SLM)-NiCrFeCoMo 0.2 high-entropy alloy (HEA) are further improved by controlling the molten pool structure and the generation of σ-phase precipitation particles. In this study, a split Hopkinson pressure bar (SHPB) was used for testing the dynamical mechanical properties of the quenched SLM-NiCrFeCoMo 0.2 HEA specimens. Microstructure and volume fraction of the σ precipitates were characterized by X-ray diffractometry (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and the small angle neutron scattering (SANS) technique. After heating to 800 ℃, holding for 8 h and water quenching, the molten pool boundary of the SLM-NiCrFeCoMo 0.2 HEA disappear, and the ultimate compressive strength and the impact energy of specimens reach 1970 MPa and of 217.45 MJ·m−3, respectively. Due to the segregation of Mo elements in the molten-pool boundary of the as-build SLM-NiCrFeCoMo 0.2 HEA, more σ precipitates tend to form at the residual molten pool boundary of the quenched SLM-NiCrFeCoMo 0.2 HEA. The σ precipitates play key role in strengthening of the SLM-NiCrFeCoMo 0.2 HEA. • Annealed SLM- NiCrFeCoMo 0.2 HEA has larger ultimate compressive strength and the impact energy. • Lots of σ precipitates generate at the residual molten pool boundary. • Small angle neutron scattering technique is used to analyze the volume fraction of σ precipitates. • The σ precipitates play key role in strengthening of the SLM-NiCrFeCoMo 0.2 HEA. [ABSTRACT FROM AUTHOR]

In this study, an effort was made to enhance the mechanical properties of coal-based synthetic natural gas slag (CSNGS) geopolymer with curing at ambient temperature by incorporating ground granulated blast furnace slag (GBFS). The effects of GBFS content, activator modulus and alkali content on the compressive strength of CSNGS-GBFS (CG) geopolymers were analyzed, and the microstructural characteristics and the compositional evolution of reaction products were also investigated by X-ray diffraction (XRD), scanning electron microscope-energy dispersive spectrometer (SEM/EDS), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analyzer (TG) tests. It was found that the mechanical properties of CG geopolymers was highly dependent on the of GBFS content. When the GBFS content was 50%, the 1-day and 28-day strengths of the geopolymer were 50.8 MPa and 120.2 MPa, respectively. Increasing alkali content resulted in the strength of geopolymer to increase and then decrease, whereas, the strength of geopolymer increased monotonically with a decrease in activator modulus. The results also showed that with increasing the GBFS contents, the characteristic peaks corresponding to the gels in the XRD patterns became gradually obvious with highly denser microstructures formed by a number of gels in the SEM micrographs, and the Ca/Si ratio and Ca/(Si + Al) ratio of the reaction products were increased, revealing that the gels generated in CG geopolymers was a mixture of N-A-S-H and C-(A)-S-H gels, which corroborated with the observed the stretching vibration of Si–O-T (T = Si or Al) in FT-IR spectrum shifted from 1013 cm−1 to 990 cm−1 and the corresponding temperatures of the mass loss peaks increased form 104 °C–114 °C. In addition, the dissolution of raw materials was promoted owing to the reduction of the activator modulus, but the change of activator modulus had little effect on the thermal stability of the gels. These findings suggest that CSNGS has the potential to prepare high-strength geopolymers at ambient temperature, providing an attractive avenue for reducing the environmental impact of CSNGS and conserving natural resources. [Display omitted] • A novel high-strength geopolymer based on CSNGS was developed at ambient temperature. • The effect of BGFS on the structure of N-A-S-H and C-(A)-S-H gels in geopolymerization was studied. • The thermal stability of geopolymer was improved due to the increase of the alkali content. • The influence of activator modulus on the internal structure of geopolymeric gels was discussed. [ABSTRACT FROM AUTHOR]

Microstructural characteristics and enhanced mechanical properties of 2024 aluminum alloy associated with shot-peening treatment were investigated by optical microscope (OM), scanning electron microscope (SEM), electron backscatter diffraction technology (EBSD), X-ray diffraction (XRD) and tensile test. The results showed that the shot-peening treatment induces a severe plastic deformation within the surface area of alloys and the depth of the affected area caused by the shot-peening treatment is measured to be 600 ± 20 μm. Within the affected area, the formation of twins, curved grain boundaries and the fragmentations of grains were detected. In addition, the microstrain of the shot-peened surface increased to 0.5769% (±0.00215) from 0.2181% (±0.01084) after the shot-peening treatment. Correspondingly, the yield strength, the tensile strength and the uniform elongation were improved to 410.3 MPa (increased by about 11%), 519.4 MPa (increased by about 15.8%) and 19.7% (increased by about 81%), respectively, after the shot-peening treatment. Microstructural characteristics and the variation of microstrain within the affected area mainly account for the enhanced mechanical properties of the shot-peened 2024 aluminum alloys. The results of this work indicate that the shot-peening process is one of the effective ways to simultaneously improve the strength and ductility of alloys. • Enhanced mechanical properties of 2024 aluminum alloy were obtained by a shot-peening treatment. • Shot-peening treatment resulted in a significant affected area with a depth of about 600 μm. • Microstructural change and the variation of microstrain within the affected area mainly account for the enhanced mechanical properties. [ABSTRACT FROM AUTHOR]

• A simplified approach for optimized acid-mechanical treatment of RCA is developed. • The highest quality RCA is obtained through acid-mechanical treatment. • The compressive strength of RAC is obtained around 16.06% higher than NAC. • Other physical, mechanical, or durability properties of RAC are closer to NAC. • Sorptivity of RAC is obtained almost equal to that of NAC. Present research develops an optimized acid-mechanical treatment for recycled concrete aggregate (RCA). RCA prepared in the laboratory jaw crusher is further soaked for 24 h in a mild acetic acid solution. Acid-soaked recycled aggregates (SR) are mechanically treated at a series of charges and drum revolutions using Los Angeles machines. A performance-based quality identification approach is used to compare acid-mechanically treated recycled concrete aggregates (SRij). The VIKOR indices (QI) for each SRij is calculated by applying a multi-criteria decision-making approach. Based on performance, three SRij with the lowest QI are selected for an experimental study. The present research achieves 71.27 MPa compressive strength for concrete composed of a SRij with the lowest QI. This strength is around 16.06% higher than concrete composed of parent aggregate. Flexural strength, split tensile strength, fracture energy, ultrasonic pulse velocity (UPV) values, rapid-chloride penetration test (RCPT) values, water absorption, and abrasion resistance are in the range of what is expected for parent aggregate concrete. The scanning electron microscope (SEM) image analysis shows that the well compacted and uniform surface morphology of aggregate strengthens the newly developed interfacial transition zone (NITZ) and old interfacial transition zone (OITZ). Acid treatment reduces microcrack lengths and widths and mechanical treatment reduces microcracks and pores by reducing adherent mortar optimally. X-ray diffraction (XRD) analysis shows the lower calcium hydroxide (CH) content in the mortar attached to the SR. A reduced CH content lowers the porosity in the adhered mortar. Thus, improved quality of attached mortar and its reduced porosity strengthen the old interfacial transition zone (OITZ) and lowers the sorptivity of the concrete than reported and almost equal to that of parent aggregate concrete. [ABSTRACT FROM AUTHOR]

Selective laser melting (SLM) allows for manufacturing intricate and accurate component designs that are challenging, expensive, or impossible to achieve using traditional methods. To achieve a high-quality final product with SLM, it is necessary to optimize the process parameters carefully. This optimization helps to minimize internal structural defects and control the microstructure. In this study, the optimum production parameters of Ti6Al4V alloy were determined using the Response Surface Method (RSM). The micro-CT analysis was utilized to calculate the relative densities of the samples fabricated using different production parameters. Furthermore, the influence of heat treatment, conducted below and above the β transformation temperature, on the mechanical properties was examined. The results were analyzed by considering the microstructure images obtained from Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) analysis. The optimum production parameters for the SLM method were found to be 80W laser power, 1125 mm/s scanning speed, 25 μm layer thickness, and 45 μm hatch distance. Samples created with these optimized parameters achieved 99.919% relative density, 1050 MPa ultimate tensile stress, and 13.8% elongation, surpassing the minimum standards outlined in ASTM F3001-14. Additionally, the systematic parameter reduction approach used in the study led to savings in both powder consumption and time in SLM, a method that could be applied to various metallic materials. • Ti6Al4V-ELI alloy was manufactured with selective laser melting method. • The response surface method was used to determine the optimum production parameters. • Micro-CT analysis was performed and density ratios were calculated. • Mechanical properties were improved with post processing operation. [ABSTRACT FROM AUTHOR]

• The optical and mechanical properties of pure zirconia are affected by low temperature degradation. • First and second generation 3Y-TZP subjected to autoclave aging undergoes significant t-m phase transformation. • t-m Phase transformation in ZTA composites is limited after hydrothermal aging. • ZTA's optical and mechanical properties remain stable after aging. To synthesize a zirconia toughened alumina (ZTA) composite with 70% alumina reinforced by 30% zirconia for dental applications and to characterize its microstructure and optical properties for comparison with the isolated counterpart materials and a first-generation 3Y-TZP. Disc-shaped specimens were divided in four groups (n = 70/material): (1) 3YSB-E (first generation 3Y-TZP), (2) Zpex (second generation 3Y-TZP), (3) alumina, and (4) ZTA-Zpex 70/30. After synthesis, ceramic powders were pressed, and green-body samples sintered following a predetermined protocol. Specimens were polished to obtain a mirror surface finish. Apparent density was measured by Archimedes principle. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize the crystalline content and microstructure. Reflectance tests were performed to determine the contrast-ratio (CR) and translucency-parameter (TP). Mechanical properties were assessed by biaxial flexural strength (BFS) test. All analyses were conducted before and after artificial aging (20 h, 134 °C, 2.2 bar). Optical parameters were evaluated through repeated-measures analysis of variance and Tukey tests (p < 0.05). BFS data were analyzed using Weibull statistics (95% CI). High density values (95–99%) were found for all ceramic materials and SEM images exhibited a dense microstructure. While XRD patterns revealed the preservation of crystalline content in the ZTA composite, an increase in the monoclinic peak was observed for pure zirconias after aging. Significantly higher CR and lower TP values were observed for the ZTA composite, followed by alumina, 3YSB-E, and Zpex. The highest characteristic stress was recorded for 3YSB-E, followed by intermediate values between ZTA and Zpex, and the lowest for alumina. Aging affected the optical and mechanical properties of both zirconias, while remained stable for ZTA composite and alumina. The synthesis of experimental 70−30% ZTA composite was successful and its relevance for dental applications relies on its higher masking ability, aging resistance, and strength similar to zirconia. [ABSTRACT FROM AUTHOR]

To control food contamination and meet the growing demand for high quality food, a novel and excellent starch composite film as packing material with optimized physical, mechanical properties and antimicrobial activity was produced in this paper. Starch-based composite films incorporated with salicylic acid (SA) and waxy maize starch nanoparticles/κ-carrageenan (WMSNs/KC) were used to achieve antimicrobial activity and improve the mechanical properties. WMSNs were fabricated through enzymolysis and recrystallisation method, followed by individually adding KC to form WMSNs/KC by self-assembly, and used as a nanofiller and stabilizer to be incorporated into hydroxypropyl tapioca starch-based films at a concentration of 0–9%. Characterization of macromorphology and scanning electron microscope indicated the starch composite films with WMSNs/KC were smooth, uniform, and transparent. X-ray diffraction pattern and Thermogravimetric analysis also showed strong interactions such as hydrogen bond formation among films, WMSNs/KC and SA. Compared with the pure starch-based films, the composite films reinforced by the addition of WMSNs/KC significantly increased the tensile strength, water vapor barrier and thermal stability, while the transparency and elongation at break decreased slightly. Moreover, the starch composite films showed excellent antimicrobial activity for three typical undesired microorganisms in foods, Escherichia coli , Staphylococcus aureus , and Bacillus subtilis. • Novel antibacterial and biodegradable starch composite films were proposed. • Mechanical properties, water vapor barrier of our films were reinforced by WMSNs/KC. • For the first time, starch-based films with SA achieved antimicrobial activity. • Substantial bacteriostatic effect was obtained in yogurt in contact with our films. • This product was nontoxic, edible and could extend the shelf life of food. [ABSTRACT FROM AUTHOR]

In this study, briquettes of Ti–TiB–TiB 2 composite were produced by mixing Ti and B powders, performing self-propagating high-temperature synthesis process and by applying hydrostatic pressure on the reaction products with a high-capacity press. Ti–TiB–TiB 2 was then coated to Ti 6 Al 4 V substrate by Electro-Spark Deposition (ESD) technique under two atmospheres of air and argon, single and double-layer coatings and in two energy levels of 40 W and 110 W as input powers. Coatings microstructure were examined by Scanning Electron Microscope (SEM) equipped with Energy Dispersive Spectroscopy (EDS) analyzer. Comparison of the coatings microstructure with the electrode microstructure shows that the coatings have a much finer microstructure than that of the electrode due mainly to the high solidification rate in the ESD process. Microstructural observations also revealed that the main phases in the coatings are needle-shaped TiB and particle-shaped TiB 2 in the Ti matrix. The coating microstructure was much finer due to an increase in solidification rate by reducing the input power from 110 to 40 W. In such a situation, two phases of TiB 2 and TiB with nanometer sizes were scattered in the Ti matrix. Also, due to the trapping of the gases in low input power of 40 W, a limited number of very small gas pores was created in the microstructure. Interface examination of the coating and the substrate by the Line Scan and X-ray Image show a good coherence of the coating with the substrate. Adhesion results showed that the bond strength between the coating and the substrate was higher than 50 MPa in all coatings. No crack was observed in the coatings after bending tests which were performed, in accordance with the intended standard, on the samples around a mandrel. The hardness of all coatings was increased with decreasing the input energy from 110 to 40 W. [ABSTRACT FROM AUTHOR]

The impact of the microstructural properties of alumina on its mechanical properties is examined in this study. Furthermore, a comparison of the mechanical behaviours of alumina samples obtained by two-step and existing sintering techniques is presented. The results are rationalised by evaluating the changes in the densities and grain sizes of alumina samples. Different two-step treatments were used on commercial alumina (99.7 mass%-Al 2 O 3 content, 0.73 μm average particle size) and compared with the existing sintering technique. Alumina powder was formed by uniaxial pressing, and the samples were treated using heat. Microstructural analyses of the samples were performed with a scanning electron microscope. The mean grain size was determined via the intercept method. Porosity was determined by the relationship between the apparent and theoretical densities of the sintered alumina. The bending strength test was performed based on ASTM 1161–13. Fracture toughness was measured based on the notch method. The microhardness test was performed using the Knoop technique. The results showed that mechanical properties of the samples prepared using two-step sintering were improved—the bending strength, fracture toughness, and Knoop microhardness increased from 286 to 303 MPa, 4.09–4.35 MPa m0.5, and 17.5–17.6 GPa, respectively—compared with those fabricated using the existing sintering technique, even with a higher porosity of 2.36% in samples obtained by two-step sintering and 1.80% in the existing sintering technique. Factorial analysis demonstrated that the temperature and holding time of the second step individually affect the relative density; however, the impact of temperature is more significant. Despite this, the interaction between temperature and holding time of the second step has the most significant impact on the average grain size. [ABSTRACT FROM AUTHOR]

• Acid treatment changed the pore structure of coal and increased the porosity. • Acid treatment reduces the residual energy in coal, and weakens the impact tendency. • Compared with raw coal, acidized coal is easier to form fracture network under axial load. • Acidified coal shows a special stress-strain curve. To explore the influence of acid solution with different components on the pore structure and mechanical properties of coal, nuclear magnetic resonance (NMR), scanning electron microscope (SEM), energy dispersion spectrum (EDS) and uniaxial compression experiments were used to analyze the acid-treated coal samples. The results show that acid treatment can obviously improve the connectivity of coal, increase the porosity of coal, and is conducive to the circulation and diffusion of gas, but the promotion effect of acid solutions of different components on pores with different pore sizes is different. After acid treatment, the number of mineral particles on the surface of the coal samples are obviously reduced, and the space filled with mineral particles is gradually exposed, thus increasing the density of pores and fractures of the coal samples. The energy spectrum analysis shows that acid solution added HF has a good removal effect on kaolinite minerals, iron minerals and calcite minerals. For the mechanical properties of the coal samples, acid treatment can reduce the strength and elastic modulus of coal samples, but increase its toughness. In addition, the fracture evolution of the acid-treated coal samples mainly goes through four stages: initial stage, transition stage, expansion stage and destruction stage. Because most of the energy accumulated in the acid-treated coal samples is used to damage the coal body, the acid-treated coal samples are easy to form fracture network, and is mostly broken in blocks when unstable. [ABSTRACT FROM AUTHOR]

To promote the densification and therefore the mechanical properties of boride-based ceramics, MgO was added as sintering aid into Os 0.9 Re 0.1 B 2 powders for densification by using spark plasma sintering (SPS). The Os 0.9 Re 0.1 B 2 powders were synthesized by mechanochemical method from powder mixture of Os, Re and amorphous B. The role of MgO on densification, phase composition, microstructure and mechanical properties (hardness, fracture toughness and wear behavior) were studied by using X-ray diffraction (XRD), scanning electron microscope (SEM) with energy-dispersive spectroscopy (EDS), micro indentation and ball-on-disk tribometer. The results show that, with the introduction of MgO as sintering aid, the relative density of the Os 0.9 Re 0.1 B 2 ceramic samples increased. When the MgO content reached 9 wt%, the as-sintered sample is almost fully dense. No obvious regularity was found from the samples with the addition of different content of MgO. Vickers hardness values of the samples with 0, 3 wt% and 9 wt% MgO are found to be very close with each other within the experimental error (~30 GPa), while the sample with the addition of 6 wt% MgO exhibits the highest hardness of ~35 GPa. The fracture toughness of the samples is decreased slightly with the addition of MgO. The friction coefficient and wear rate of the sample with the addition of 6 wt% MgO was also found to be the lowest among all samples, which indicate best wear resistance. As a whole, with the addition content of 6 wt% MgO, the Os 0.9 Re 0.1 B 2 ceramic sample performs relatively excellent mechanical properties among four groups of samples. [ABSTRACT FROM AUTHOR]

To enhance the fracture toughness and thermal shock resistance of the thermal barrier coatings (TBCs), detonation spraying has been used to prepare modified neodymium (Ⅲ) oxide (Nd 2 O 3)-doped yttria-stabilized zirconia (YSZ) TBCs containing 20 vol% (D1 coating) and 30 vol% (D2 coating) of boron nitride whiskers (BNws). Analyses were performed using a scanning electron microscope (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and a microhardness tester to examine the manner in which the doping content of different rare earth oxides affected the coating morphology, composition, and mechanical properties. The results denoted that the porosity of the D2 coating was 47.9% higher than that of the D1 coating; the whisker content was 30 vol% in the former and 20 vol% in the latter. The increased porosity reduced the microhardness and bond strength of the coating. However, the fracture toughness (KIC) of the D2 coating was increased to 2.67 MPa·m1/2 because the whisker content was 8.5% higher than that in the D1 coating. The thermal cycling life of the D2 coating was 245 cycles, and its thermal shock resistance was 9.9% higher when compared with that of the D1 coating. A TBC with better overall performance was obtained when BNw reached 30 vol%. [ABSTRACT FROM AUTHOR]

This study compared the physical properties of conventional and monolithic yttria-zirconia (Yz) materials after low-temperature degradation (LTD). Bar-shaped specimens (2.0 mm thick × 4.0 mm wide × 16.0 mm in length) were produced. Autoclave aging was executed at 134°C under 2 bar pressure for 5 h. The surface characteristics were assessed using a confocal laser microscope, microstructural phase alterations via an X-ray diffractometer (XRD), 3-point flexural strength using a universal testing machine, Vickers microhardness via a digital microhardness tester, and toughness using a durometer. Fractured specimens and indented surfaces was observed via a scanning electron microscope for fractography characterization. All of the data underwent specific statistical tests considering their distribution and homogeneity. Regarding topography, different Yz materials were very similar after LTD. Conventional Yz materials were smoother. The XRD data support that both materials were mainly composed of tetragonal crystals, whereas slight monoclinic peaks were detected. Monolithic Yz showed higher flexural strength than conventional Yz. All of the fractures started on surface defects at the side where tensile stress was concentrated (opposite to load application) and propagated to the opposite side. Vickers microhardness and toughness analysis found that conventional Yz had higher performance than monolithic Yz. This study has found that there are slight differences in strength, hardness, and toughness between conventional and monolithic yttria-stabilized zirconia ceramics, although both materials demonstrate adequate performance for clinical use. [ABSTRACT FROM AUTHOR]

In this study, the preparation and consolidation of nanocrystalline LaB 6 powders originating from powder blends of La 2 O 3 , B 2 O 3 and Mg were reported. A consecutive route of mechanochemical synthesis (MCS) and purification was utilized for the achievement of nano-sized LaB 6 powders. As-synthesized powders were leached out from intermediate reaction products or impurities. Then, a sequential step of cold pressing (uniaxial pressure at 800 MPa) and pressureless sintering (at 1700 °C for 5 h under Ar gas flow) were utilized for the consolidation of the purified LaB 6 powders. The type of mill (vibratory and planetary high-energy ball mills) was employed as a MCS parameter to reveal its effect on the physical, microstructural and mechanical properties of the LaB 6 powders, and their bulk structures. Compositional, physical and microstructural properties of the products after powder processing were determined via X-ray diffractometer (XRD), particle size analyzer (PSA), differential scanning calorimeter (DSC), stereomicroscope (SM), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive spectrometer (EDS) coupled with both SEM and TEM, and vibrating sample magnetometer (VSM). The bulk properties of the LaB 6 consolidated from nanocrystalline powders with a minimum 99.99% purity, and ∼62 nm (for vibratory ball mill) or ∼74 nm (for planetary ball mill) average particle size were compared according to various properties. LaB 6 powders were synthesized in planetary mill at an approximately six times longer duration than that of in vibratory mill. According to the results, density, surface area and mean particle size values of the vibratory ball-milled samples (containing paramagnetic powders) are better than those of planetary ball-milled (containing diamagnetic powders) ones. However, mechanical properties such as hardness, surface roughness, wear rate, friction coefficient, and also electrical conductivity were improved in the planetary ball-milled LaB 6 bulks. [ABSTRACT FROM AUTHOR]

Glow discharge plasma (GDP) was used to modify chitosan films to obtain desirable properties. The chitosan films were treated with GDP of 0–800 W for 1 min, respectively. The molecular structure of chitosan films changed under GDP treatment. Chitosan films showed an enhancement of crystallinity with the increasing power of GDP, and the GDP treatment provided them with higher thermal stability, manifested as the exothermic peaks shifted from 291.5 °C (0 W) to 294.1 °C (800 W). Scanning electron microscope (SEM) indicated that the surface of chitosan films got rougher with 0–600 W GDP treatment, accompanied by the increase of tensile strength (TS), and the TS did not increase with the 800 W GDP treatment. However, the water vapor permanent (WVP) became higher with GDP treatment. GDP treatment also exhibited influence on chromatic aberration of chitosan films. GDP is proved to be a promising green, pollution-free, rapid technology to modify chitosan films. [ABSTRACT FROM AUTHOR]

• Tetraethylorthosilicate sol-gel and silane combination treatment is used. • The reinforcing effect of fibers in composites is improved. • Combination treatment shows the highest interfacial shear strength. • Thermal properties of the modified fiber composites are improved. In order to prepare high performance sisal fiber reinforced polypropylene composites, this paper pays special attention to the changes of intrinsic mechanical properties of the sisal fiber so as to achieve the maximum reinforcing effect of the fiber. For achieving this aim, the sisal fibers were modified by tetraethylorthosilicate (TEOS) sol-gel method to form SiO 2 -based organic-inorganic hybrid materials. For a better result, a novel combined modification method by TEOS precursor solution and γ-aminopropyltriethoxysilane solution for the fibers was put forward and performed. Then the relevant mechanism was also analyzed in detail. The corresponding composites were prepared by melt blending with polypropylene matrix and polypropylene-graft-maleic anhydride (MAPP) compatibilizer, and the interfacial and mechanical properties of composites were studied by single fiber fragmentation test and mechanical test, respectively. The results show that the mechanical and thermal properties of the modified fiber composites are improved compared with the untreated fiber composite. The combined modification composite presents the highest interfacial shear strength, which increases by 259.49% compared with the untreated fiber composite. A good interfacial bonding is obviously observed in the combined modification composite by the analysis of scanning electron microscope (SEM). The tensile strength and modulus of the composite with the combined treatment (20 wt% fiber loading) increase by 21.72% and 28.18%; the flexural strength and modulus increase by 3.61% and 16.02%; and the impact strength increases by 21.28%. [ABSTRACT FROM AUTHOR]

This study is aimed to investigate the influence of substrate bias on mechanical properties and high temperature oxidation of sputtered TiN coating which is prepared on the surface of Zr-4 alloy. The microstructures of coatings were characterized by using scanning electron microscope (SEM) and X-ray diffractometer (XRD). The thicknesses of coatings were detected by examining the cross-sectional SEM image. The adhesion property was tested by using scratch testing. The residual stress was measured by using the XRD method. The tensile property was evaluated by standard tensile test. And the high temperature oxidation performance in air condition was also assessed. It was revealed that substrate bias has a significant influence on crystalline structure, surface micromorphology, thickness, adhesion strength, and residual stress. Nevertheless, tensile property and high temperature oxidation performance are affected by substrate bias indistinctively. From the cross-sectional SEM image, it can be found that thicker coating can be obtained in unit time with a lower substrate bias. The adhesion property does not vary monotonically with increasing negative substrate bias and the coating deposited with −100 V possesses highest critical load. The sputtered TiN coatings demonstrate a compressive residual stress and the magnitude of residual stress of coatings prepared with −200 V and −300 V is higher than that of coatings prepared with −50 V and −100 V. The tensile test reveals that there is no obvious difference between tensile properties of TiN-coated specimens prepared with different substrate bias and the Zr-4 alloy specimen. And the weight gains of high temperature oxidation of TiN-coated specimens with different substrate bias are almost the same and are lower than uncoated Zr-4 alloy specimen. The XRD and EDS results show that TiN coating is oxidized and cracked and the internal Zr-4 substrate is also oxidized when the specimen is exposed to high temperature circumstance for a long time. • Substrate bias effects on the microstructure, thickness, adhesion strength, and residual stress of TiN coatings are studied. • The tensile properties of sputtered TiN coatings prepared with different substrate bias are discussed. • The high temperature oxidation performances of sputtered TiN coatings prepared with different substrate bias are discussed. [ABSTRACT FROM AUTHOR]

In the present work, the influences of current density and post heat treatment on the morphology, phase structure, microhardness, and corrosion performance of the Ni-P-TiO 2 nanocomposite coatings were investigated. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were employed to study the morphological and microstructural features of the coatings, respectively. In addition, corrosion performance of the coatings was evaluated via electrochemical impedance spectroscopy (EIS) and Tafel polarization. Results demonstrated that the Ni 3 Ti intermetallics forms all over the microstructure of the coatings. The volume fraction and distribution uniformity of such intermetallics is examined as a function of applied current density. In general, the as-plated coatings at current density of 15 A dm−2 exhibit the superior microhardness as well as corrosion resistance originated from their higher Ni 3 Ti amount. However, the morphology of the particles accompanied by chemical composition of constituent phases did not altered with change in current density. The electrodeposited coatings were heat treated at 400 °C in an argon atmosphere of electrical furnace. XRD patterns of the heat treated coatings show Ni 3 P and Ni phases. In addition, microhardness of the coatings noticeably increased with application of heat treatment mainly due to the precipitation of hard Ni 3 P intermetallics. • Ni-P-TiO 2 coatings electrodeposited by DC method at various current densities. • Ni 3 Ti intermetallics uniformly distributed throughout the microstructure of the coatings. • The coating electrodeposited at 15 A dm-2 exhibit the superior mechanical and corrosion properties. • The microhardness of the coatings dramatically improved after post heat treatment at 400 oC. [ABSTRACT FROM AUTHOR]

Polymer as well as polymer composites are inclined to premature due to effect on mechanical and physical properties during service time. In this paper, the effect of thermal cycling (−30 to 80 °C) on the physical and tensile properties of Polypropylene (PP), Kenaf/PP, Kenaf/PP/CNTs and Kenaf/CNTs/MAPP/PP hybrid composites for the injection moulded car battery tray was investigated. Although this study had found no physical changes on the samples in terms of colour or cracking, the samples, however, had experienced warpage and dimensional changes. The dimension of samples containing CNT had increased by 20%, while the PP and PP/Kenaf samples had decreased by 3.5% and 87%, respectively. Although the process of thermal cycling was found to have rapidly decreased the hardness of Pure PP and Kenaf/PP composites, it had, however, gradually increased the hardness of composites with CNT fillers. The tensile strength, Young's modulus and elongation of the composites had also been examined in this research. Furthermore, according to the fractographic investigations using scanning electron microscope, it is perceived that the fracture morphology of the samples is strongly influensed by thermal cycling. [ABSTRACT FROM AUTHOR]

This research reported the mechanical properties of geopolymer-based ultra-high performance concrete containing ceramic ball coarse aggregates. 10 mm straight steel fibres with various contents (0, 0.6 vol-%, 1.2 vol-% and 1.8 vol-%), medium-aluminium ceramic balls with various sizes (3 mm, 6 mm and 10 mm) and contents (0, 10 vol-%, 20 vol-% and 30 vol-%) were utilised. Mechanical properties, including the slump flow, uniaxial compressive, splitting tensile and flexural strengths, were investigated via a series of material tests. Fundamental contributions arisen from the steel fibre content, ceramic ball size and content towards the mechanical properties were analysed and discussed. In the light of the flexural load-midspan deflection curves, a constitutive flexural model was established, and the flexural toughness characteristics were quantitatively assessed using two indexes. Also, empirical equations to evaluate the strength relationships were proposed. Scanning electron microscope observation was carried out on the steel fibre-matrix interface to further explain the influencing mechanism of ceramic balls on the fibre reinforcement efficiency. [ABSTRACT FROM AUTHOR]

• The feasibility of CSNGS for road base material was investigated. • The optimum ratio of CSG for road base was calculated and analyzed. • The application potential of CSG in road base materials was evaluated. • The strength mechanism of CSG mixture was revealed. The development of the Coal-based synthetic natural gas industry inevitably produced lots of slags. The application of coal-based synthetic natural gas slag (CSNGS) to road base not only effectively alleviated the accumulation and pollution of CSNGS, but also reduced the consumption of resources, which had significant economic and social benefits. However, CSNGS has a higher crushing value and water absorption, thus its mix design, mechanical properties and pavement performance must be further investigated when applied as the raw material of novel cementing material and aggregate. The purpose of this study is to investigate and comparatively analyze the optimal mixing ratio and mechanism of the strength of CSNGS applied in road base. For this, this study prepared the precursor of geopolymer by milling CSNGS into powder and mixing it with 20% cement. Then sodium hydroxide and sodium silicate were used as alkali activators to activate CSNGS, and the 7d unconfined compressive strength was used as the evaluation index to develop the optimal mix ratio of coal-based synthetic natural gas slag geopolymer (CSG). CSNGS with particle sizes ranging from 0 to 4.75 mm and 0 to 9.5 mm were used as aggregates to replace natural stones, then the cement and CSG were selected respectively to stabilize the slags-aggregates, and the relevant tests were carried out to investigate the mechanical and road properties. The results showed that the performance of CSG stabilized aggregates was lower than cement stabilized aggregates in the tests of unconfined compressive strength, splitting strength, unconfined compressive modulus of resilience, dry-wet cycles, and freeze–thaw cycles. The performance of the mixture deteriorated with the incorporation of CSNGS when the cementitious material was cement. The temperature shrinkage test found that the shrinkage of CSG stabilized specimens was less than cement stabilized specimens, which indicated that CSG had excellent anti-cracking potential. In addition, the temperature shrinkage coefficients of mixtures with different CSNGS dosages varied with temperature when the cementitious material was cement. Finally, to further verify the macroscopic test results, this study combined with scanning electron microscope (SEM) test to deeply analyze the strength formation mechanism of several mixtures. [ABSTRACT FROM AUTHOR]

(Mo 1-x Cr x) 5 Si 3 alloys were prepared by vacuum arc melting technique. The microstructure and mechanical properties of (Mo 1-x Cr x) 5 Si 3 alloys were characterized using a scanning electron microscope (SEM), X-ray diffraction (XRD) and nano-indentation tests. The tribocorrosion characteristics of the alloys were investigated using a tribocorrosion tester in 3.5 wt% NaCl solution. The results revealed that the thermal expansion anisotropy ((CTE(c)/CTE(a))) of the (Mo 1-x Cr x) 5 Si 3 alloys decreased from 2.25 to 1.45 with increasing Cr content. The Cr-alloyed (Mo 1-x Cr x) 5 Si 3 alloys exhibited a high hardness, and their fracture toughness, ratios of H3/E2 and H/E were improved. (Mo 1-x Cr x) 5 Si 3 alloys showed a strong wear-corrosion combined effect, and an opposite trend between friction coefficient and OCP values was observed during the tribocorrosion tests. The tribocorrosion resistances of (Mo 1-x Cr x) 5 Si 3 alloys were better than that of 0Cr18Ni9 stainless steel due to the formation of Cr 2 O 3 -MoO 3 -SiO x protective films. The (Mo 0.8 Cr 0.2) 5 Si 3 alloy exhibited the best tribocorrosion characteristics with a low friction coefficient and wear rate. For the 0Cr18Ni9 and Mo 5 Si 3 alloy, pure wear (V w) was dominant, nevertheless, corrosion-induced wear (V cw) was the main tribocorrosion mechanism of (Mo 0.8 Cr 0.2) 5 Si 3 alloy. • Tribocorrosion behaviors of the (Mo 1-x Cr x) 5 Si 3 alloys were investigated. • The fracture toughness of Mo 5 Si 3 alloy was improved by Cr alloying. • Oxide films (MoO 3 , Cr 2 O 3 and SiO x) enhance the tribocorrosion properties. • Tribocorrosion resistances of the alloys were better than that of 0Cr18Ni9. [ABSTRACT FROM AUTHOR]