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Biodegradable Mater-Bi (MB) composites reinforced with hazelnut shell (HS) powder were prepared in a co-rotating twin-screw extruder followed by compression molding and injection molding. The effects of reinforcement on the morphology, static and dynamic mechanical properties, and thermal and rheological properties of MB/HS biocomposites were studied. Rheological tests showed that the incorporation of HS significantly increased the viscosity of composites with non-Newtonian behavior at low frequencies. On the other hand, a scanning electron microscope (SEM) examination revealed poor interfacial adhesion between the matrix and the filler. The thermal property results indicated that HS could act as a nucleating agent to promote the crystallization properties of biocomposites. Furthermore, the experimental results indicated that the addition of HS led to a significant improvement in the thermomechanical stability of the composites. This paper demonstrates that the incorporation of a low-cost waste product, such as hazelnut shells, is a practical way to produce low-cost biocomposites with good properties. With a content of HS of 10%, a remarkable improvement in the elastic modulus and impact strength was observed in both compression and injection-molded samples. With a higher content of HS, however, the processability in injection molding was strongly worsened. [ABSTRACT FROM AUTHOR]

Industrial solid waste red mud discharge has caused serious environmental problems. This study utilized red mud as an additive to loessial silt being used for roadway subgrade material. In this study, unconfined compressive test, direct shear test, electrical resistivity test, and hydraulic conductivity test were conducted on red mud stabilized loessial silt (RMLS) with different red mud dosage (DR) to investigate DR effect on mechanical-electrical-hydro properties. Scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses were carried out to reveal the mechanism from micro perspective. The results showed addition of appropriate amount of red mud (30–42%) effectively improved unconfined compressive strength of treated loessial silt but reduced resistivity and hydraulic conductivity. Significant correlation between resistivity and strength performance of RMLS mixture was developed. Microscopic analysis indicates red mud addition will promote generation of hydration products such as calcium silicate hydrations (C-S-H), calcium silicate aluminates hydrations (C-A-S-H), and ettringite (Aft), which will tightly connect surrounding particles of loessial silt and hydrates. Red mud particles adhere to surface of soil particles and fill in pores between them improving a compact and stable structure. This study demonstrated the feasibility of using red mud as a stabilization material for roadway subgrade and proved that resistivity measurement is a nondestructive testing method to evaluate mechanical properties for RMLS mixture. [ABSTRACT FROM AUTHOR]

This article addresses the effect of nanocrystalline cellulose (NCC) on the mechanical and thermal properties of polypropylene (PP). A new approach was adopted to produce mechanically improved and thermally stable PP-NCC nanocomposite. This approach involved producing optimized PP-NCC nanocomposite by adding NCC nanoparticles to PP matrix at different concentrations by means of injection molding process. The aim of this work was to find the optimum NCC concentration to enhance the mechanical and thermal properties of the PP matrix. The mechanical and thermal behavior of PP-NCC nanocomposite was studied by performing three-point bend, nanoindentation, differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and Fourier transform infrared (FTIR) spectroscopy tests. The results showed that the mechanical properties of strength, modulus, and hardness of the nanocomposites increased with the addition of NCC by 6.5%, 19%, and 150%, respectively. DSC results showed that the addition of NCC to PP does not affect the thermal stability (melting temperature). However, TGA showed that upon inclusion of NCC nanoparticles, the thermal stability of the samples improved compared to pure PP except for the 5% added NCC. This is attributed to the presence of NCC rod-like particles that dissipated heat by generating tortuous paths, as depicted in the SEM results and verified by FTIR results. [ABSTRACT FROM AUTHOR]

In the present work, we studied the formation of sunflower oil nanoemulsion using ultrasound techniques. Later, we investigated the development of active films based on a mixture of whey protein containing sunflower oil base nanoemulsion with different concentrations (10, 25, and 50% of total whey protein). The prepared film was by analyzing using the Fourier transform infrared (FTIR), X‐ray diffraction (XRD), and field‐emission scanning electron microscope (FE‐SEM). The film shows no changes in its integrity and crystallinity compared to the virgin film. The presence of nanoemulsion improves the mechanical properties from 2.75 MPa to 3.52 MPa while it decreases the water vapor permeability from 3.4 × 10–10 to 1.3 × 10−10g/m.s.Pa for concentrations NE (50% of Whey protein). The antioxidant activity for Tween 20 nanoemulsion is 38.7% compared to 36.1% for Tween 80 nanoemulsion. The antimicrobial activity of the film contains sunflower nanoemulsion higher than virgin films. The results showed the potential of blend film of whey protein with nanoemulsion for active films for novel food protection. [ABSTRACT FROM AUTHOR]

This paper reports the synthesis and properties of WC-Co-Ti(C0.5, N0.5)-Mo cemented carbides with various compositions by employing powder metallurgy processing technology. The effect of adding Mo to cemented carbides on their microstructure and mechanical properties is investigated. The volume shrinkage, porosity, microstructure characteristics, hardness, and indentation toughness are examined by analytical balance, indentation method, scanning electron microscope, and X-ray diffractometer, respectively. By adding 0.5 weight percent Mo to cemented carbides, the density and hardness can be increased to 14.12 g/cm3 and 1804.56 kgf/mm2, respectively, while the indentation fracture toughness remains at a tolerable level of approximately 7.6 MPa·m1/2. Furthermore, the addition of Mo to the WC-Co-Ti(C0.5, N0.5) cemented carbides can effectively inhibit Co loss, reduce microdefects in the systems, and improve the microstructure. [ABSTRACT FROM AUTHOR]

In the current work, mild steel used in shipbuilding applications was friction-stir-welded (FSWed) with the aim of investigating the microstructure and mechanical properties of the FSWed joints. Mild steel of 5 mm thickness was friction-stir-welded at a constant tool rotation rate of 500 rpm and two different welding speeds of 20 mm/min and 50 mm/min and 3° tool tilt angle. The microstructure of the joints was investigated using optical and scanning electron microscopes. Additionally, the grain structure and crystallographic texture of the nugget (NG) zone of the FSWed joints was investigated using electron backscattering diffraction (EBSD). Furthermore, the mechanical properties were investigated using both tensile testing and hardness testing. The microstructure of the low-welding-speed joint was found to consist of fine-grain ferrite and bainite (acicular ferrite) with an average grain size of 3 µm, which indicates that the temperature experienced above A1, where a ferrite and austenite mixture is formed, and upon cooling, the austenite transformed into bainite. The joint produced using high welding speed resulted in a microstructure consisting mainly of polygonal ferrite and pearlite. This could be due to the temperature far below A1 experienced during FSW. In terms of joint efficiency expressed in terms of relative ultimate tensile, the stress of the joint to the base material was found to be around 92% for the low-speed joint and 83% for the high-welding-speed joint. A reduction in welding was attributed to the microstructure, as well as the microtunnel defect formed near the advancing side of the joint. The tensile strain was preserved at 18% for low welding speed and increased to 24% for the high welding speed. This can be attributed to the NG zone microstructural constituents. In terms of crystallographic texture, it is dominated by a simple shear texture, with increased intensity achieved by increasing the welding speed. In both joints, the hardness was found to be significantly increased in the NG zone of the joints, with a greater increase in the case of the low-welding-speed joint. This hardness increase is mainly attributed to the fine-grained structure formed after FSW. [ABSTRACT FROM AUTHOR]

The present work aims to investigate the effect of nanofiller, lead oxide on the mechanical, thermal, and water intake behavior of luffa fiber-reinforced epoxy polymer matrix composites. Filler material PbO of 20 nm was added in different weight proportions along with luffa fiber to the matrix and the compression molding technique was used for the fabrication of the composite laminates. Tensile, flexural, and impact properties were studied on the prepared samples. The influence of lead oxide on glass transient temperature (Tg) and the curing of epoxy were also studied using the Differential scanning calorimeter. The optimum mechanical and thermal properties were observed on the addition of 1.25 wt. % of nanofiller. The morphological images show various defects like interfacial behavior, fiber pulls outs, voids, and internal cracks, and these were examined using a scanning electron microscope. Hence the present investigation showed that the addition of nanofiller could enhance the mechanical strength of the natural fiber composite. Further, it enhanced the moisture resistance and thus could find potential structural and packaging applications. [ABSTRACT FROM AUTHOR]

This paper reports an experimental study of the influence of elevated temperature on alkali activated slag (AAS) and slag‐metakaolin (MK) systems. The residual compressive and flexural tensile strengths, ultrasonic pulse velocity (UPV) and porosity and water absorption ratios of AAS and AAS‐MK composites after subjected to elevated temperatures of 200, 400, 600, 800, and 1000°C were investigated. Two different procedures were applied for cooling the specimens. The changes in the microstructure of the composites after subjected to high temperature were examined with scanning electron microscope and X‐ray diffraction. Test results reveal that depending on the increasing temperature, the residual compressive strength, flexural tensile strength, and UPV values of the specimens decreased, and porosity and water absorption ratios increased. The minimum strength results of AAS and AAS‐MK specimens were observed at 800 and 600°C, respectively. In particular, there have been significant changes in the internal structure of AAS and AAS‐MK specimens exposed to 1000°C and new reaction products were observed. Test results have shown that AAS specimens are a new alternative that can be developed for use in environments exposed to high temperatures. Since this new composite contains only slag binder and slag aggregate, it can be an economical product that use fully recycled material and these properties can increase the application areas of environmentally friendly material. [ABSTRACT FROM AUTHOR]

As a rapidly developing additive manufacturing technology, fused deposition modeling (FDM) has become widespread in many industry fields. It can fabricate complicated geometries using filament of thermoplastic materials such as PP, polylactic acid, acrylonitrile butadiene styrene, etc. However, poor mechanical properties of raw materials limit their application. Poly-ether-ether-ketone is a type of special engineering plastic with high performance, which could be further reinforced by adding carbon fibers (CFs). During FDM process, the mechanical properties of printed parts are largely subject to careful selection of process parameters. To improve the mechanical properties of PEEK and CF/PEEK 3D-printed parts, the effects of various process parameters including building orientation, raster angle, nozzle temperature, platform temperature, ambient temperature, printing speed, layer thickness, infill density, and number of printed parts on mechanical properties were investigated. The tensile fracture interfaces of printed parts were observed by scanning electron microscope (SEM) to explain the influence mechanism of process parameters. In the single factor experiments, flat and on-edge specimens show the best tensile and flexural strength, respectively; the specimens with raster angle ±45° and 0° show the best tensile and flexural strength, respectively. When the nozzle temperature at 500°C, platform temperature at 200°C, ambient temperature at 150°C, printing speed is 20 mm/s, layer thickness is 0.2 mm, and infill density is 100%, the printed parts exhibit the best mechanical properties. [ABSTRACT FROM AUTHOR]

Additive manufacturing is one of the key technologies for the future production of complex and individualised components. One of the most challenging questions to minimize the production cost is the reuse of the powder leftover after the building process. This study investigates the influence on the mechanical properties when reusing the leftover powder out of the process chamber up to four times. Tensile test specimens are produced and investigated. The results show a decreasing in the ultimate tensile strength with repeated reuse of the leftover powder. After four times of reuse the strength increases again. This cannot be explained by the literature and has to be verified in further investigations. The investigations reveal a high mechanical anisotropy as the strength highly depends on the component orientation in the process chamber. The particle shape does not show any differences between virgin and aged powder under the scanning electron microscope. [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]

Purpose: This study aims to develop a biodegradable linear low-density polyethylene (LLDPE)/starch blends with improved mechanical and flow characteristics and evaluate the probability of using essential oils such as Moringa oleifira and castor oils as green plasticizers and compatibilizers to avoid using harmful chemicals. Design/methodology/approach: Corn starch was blended with LLDPE through the melt blending technique. The corn starch content was varied from 5 to 40 phr in LLDPE. To enhance poor mechanical characteristic of the LLDPE/starch, essential oils such as M. oleifira and castor oils were incorporated into the composites with different concentrations starting from 1 to 7 phr. The essential oils' effect on mechanical, flow character, thermal stability and electrical properties of the LLDPE/starch was also investigated. The morphology of LLDPE/starch containing essential oils was also investigated by scanning electron microscope (SEM). Findings: The results revealed that increasing the corn starch content had an adverse effect on mechanical and flow characteristics of the composites, whereas incorporation of essential oils had increased the flow and mechanical characteristics of the composites. Also, dielectric measurements revealed that permittivity and dielectric loss increased by increasing oil content. Moreover, the values of the blends containing castor oil are higher compared to that containing M. oleifira. The SEM micrographs illustrated that the presence of essential oils in LLDPE/starch enhanced the distribution and the homogeneity of the composites, and the particle size of starch granules became smaller in LLDPE matrix. Originality/value: This study aims to introduce green plasticizer and compatibilizer to avoid using harmful chemicals in packaging industry. [ABSTRACT FROM AUTHOR]

Kota stone dust (KSD) and fly ash (FA) are the wastes generated from the construction industry and thermal power plant, respectively. In the present work, a novel hybrid composite is developed to utilize KSD and FA as reinforcing phases in the epoxy matrix. The hand lay‐up method is adopted for the fabrication of 12 sets of samples. Four sets are prepared with single filler KSD and eight samples are prepared with a hybrid combination of KSD and FA. The prepared samples are undergone physical and mechanical tests. To understand the compatibility between filler‐matrix and visualize the dispersion of fillers in epoxy, micrographs are taken using the scanning electron microscope. The density and void contents of the material increases with an increase in filler content. The maximum water absorption measured is 0.96% for the combination of epoxy with 40 wt% KSD and 10 wt% FA. From mechanical testing, maximum tensile strength and flexural strength obtained is 34.4 MPa and 65.4 MPa, respectively, for a combination of epoxy with 20 wt% KSD and 5 wt% FA. Compressive strength and hardness increase with either of the content of the filler and reaches 116.28 MPa and 104 Shore D number, respectively, with 40 wt% KSD and 10 wt% FA. From experimentation, it was found that mechanical properties of the hybrid composites are better as compared to that of single filler composites though physical properties are slightly compromised by hybridization of fillers. [ABSTRACT FROM AUTHOR]

In order to understand the evolution of the structure–property relationship between the crosslink density and mechanical properties of polyurethane-urea/sodium silicate (PU/SS) hybrid composites, a series of PU/SS composites with 2.5 wt% organofunctional silanes and pure PU/SS composites are investigated at different curing time. Mechanical properties, the fracture surface morphology, and thermo-mechanical properties of these PU/SS composites are characterized by electron omnipotence experiment machine, scanning electron microscope, and dynamic mechanical analysis (DMA), respectively. The mechanical test results show the strength and fracture toughness of the PU/SS composites first increase and then stabilize during cure, and the modification leads to PU/SS composites with significantly higher mechanical properties. Further, the morphology of fractured samples also reveals that the longer curing time and the modification of the PU/SS composites means a higher curing degree. Moreover, the increase in the crosslink density calculated from the DMA tests quantitatively confirmed the positive influence of the curing time and the modification in enhancing mechanical properties. In addition, it is also found that the mechanical properties of the PU/SS composites not only depend on the crosslink density but also on the well-dispersed hybrid PU/SS system. [ABSTRACT FROM AUTHOR]

The poor interface bonding between graphene and copper matrix significantly impair the strengthening effect of graphene, but it can be improved by graphene modification. In this work, the Ni-rGO compound powders were synthesized via hydrothermal method, and the Cu matrix bulk composites reinforced by Ni-rGO and rGO were prepared by the molecular-level mixing method along with spark plasma sintering, respectively. The sintered bulk materials were examined by transmission electron microscope, scanning electron microscope, Raman spectroscope and X-ray diffractometer, and the mechanical and electrical properties were tested as well. The results indicated that the incorporation of Ni-rGO exhibits a more obvious strengthening effect. As compared to the 0.1wt.%rGO/Cu composite material, the yield strength, tensile strength and elongation of the 0.1wt.%Ni-rGO/Cu composite material are increased by 10.9, 13.5 and 23.9%, respectively. This can be ascribed to the modified structure of graphene along with the improved interface bonding by the incorporation of Ni nanoparticles in rGO. [ABSTRACT FROM AUTHOR]

Hybrid laminates made using natural fibers have been finding applications in diverse fields such as automotive parts, building structures and sports goods. These laminates incorporate the benefits of the reinforcements used in constructions. The present work deals with the fabrication of hybrid laminate comprising of the natural fibers areca and kenaf in varying stacking sequences through the hand layup method. Epoxy resin (LY556) and hardener (HY951) are mixed in the ratio of 10:1 to prepare the matrix material. Six different hybrid laminates having five layers of areca and kenaf in different stacking sequences are produced. Two more laminates having either kenaf or areca in all the five layers and are produced to act as reference laminate. The prepared laminates are cut as per ASTM standards and subjected to tensile, compressive, flexural, impact and hardness tests in order to identify the properties of the fabricated laminates. The result shows that composite made with kenaf fiber as skin material and areca as core materials exhibit better tensile, flexural and hardness properties. Likewise, composites with outer layers of areca and core layers of kenaf fibers have high compressive and impact strength. The fractured surfaces after the mechanical tests are investigated through the Scanning Electron Microscope (SEM). [ABSTRACT FROM AUTHOR]

A characteristic study on the phenol formaldehyde (PF) composite is carried out based on the micro level bio waste particles such as wood sawdust (WSd) and coir pith (CP). Composite is characterized by mechanical properties such as tensile, flexural and impact at different percentages of particles (0-50% by weight) to find out the optimum percentage of particle loading to get the maximum properties. the WSd/CP/PF hybrid composite is also prepared by two different methods i.e., one: one (1:1) ratio and rule of mixture. The first method (1:1) is used to find out the optimum level of hybrid particles loading to get the maximum properties. But, the second method is followed to find out the weight percentages of particles influencing the properties of resulting composite. The results show that the mechanical properties of WSd/PF are higher than CP/PF composite in the entire particle loading. The optimum particle loading to get the maximum properties is 40 wt.% in CP/PF composite, whereas for WSd/PF composite are at 30 wt.%. the hybrid composite (1:1) also gives the maximum properties at 30 wt.%. moreover, the hybrid composite (20WSd/10CP) prepared by rule of mixture showed the highest mechanical properties compared to the other particle loading. It is identified that the WSd particles are most influencing the properties of PF composites than the CP particles. Fractographic study was performed using scanning electron microscope to examine the failure mechanism of the composite specimens. [ABSTRACT FROM AUTHOR]

Liquid metallurgy method based aluminum matrix composites (AMCs) are extensively utilized in diverse engineering applications including shipbuilding, structural, nonstructural, automotive, and aerospace owing to their superior strength, weightless, low density, excellent corrosion, and wear resistance. In the present investigation, liquid state technique was employed to prepare the LM4/aluminum nitride (AlN) composites containing four different mass proportion of AlN filler particles content. The weight proportion of filler particles from 0 to 12 wt% at 4 wt% intervals. Scanning electron microscope (SEM) images demonstrated a even dispersal of filler particles in the matrix. The test outcomes discovered that the LM4/12 wt% AlN AMCs had revealed extreme hardness, tensile, compression strength than the nonreinforced base matrix alloy. A considerable enrichment in the tensile strength is associated with the incorporation of AlN particles into LM4 matrix. The manufactured composites reveal high mechanical properties when compared with the alloy without reinforcement. The improvement of those lightweight AMCs with superior mechanical characteristics has a extreme potential to be employed for aircraft, structural and automobile applications. [ABSTRACT FROM AUTHOR]

Al–5.7Si–2Cu–0.3Mg alloy was subjected to a thixoforming process. The impact behaviour of the thixoforming process on microstructure characterisation and mechanical properties was investigated. A cooling slope (CS) technique was applied here to get thixoforming feedstock material at three different pouring temperatures of 640 °C, 650 °C and 660 °C, plate lengths 300 mm, 400 mm and 500 mm and constant CS angle 60°. Some samples of thixoformed were treated using T6 heat treatment. These samples were characterised via optical microscopy, scanning electron microscope, energy dispersive spectrometer and X-ray diffraction investigations, tensile and hardness tests. Consequently, the optimum conditions of CS casting process were 650 °C pouring temperature and 400mm plate length. The thixoformed alloys observed fine globular α-Al phase microstructure surrounded by uniformly distributed Si particle, minimum of porosity and refined fragmented intermetallic phase. The hardness of the thixoformed-T6 sample was roughly twice as much as-cast sample. The tensile and yield strength of thixoformed-T6 samples were enhanced by 45% and 39%, respectively, compared to as-cast samples. The thixoformed-T6 samples observed the highest value of tensile elongation to fracture of 4.8 ± 0.4%. The tensile fractures surface of thixoformed-T6 samples exhibited decline in each of tensile strength and ductility, due to occurrence of Fe-rich intermetallic on the samples. [ABSTRACT FROM AUTHOR]

This article investigates the effect of fabrication techniques on the physical, mechanical, and erosion wear properties of glass fiber reinforced dolomite dust‐filled epoxy composites. The composites were fabricated by hand layup and vacuum‐assisted resin transfer molding (VRTM) techniques with fixed glass fiber (20 wt%) and varying dolomite dust (0 to 15 wt%) with epoxy resin. In physical properties, the experimental density consistently increased with the increase in the dolomite hand layup and the VRTM process; in opposite the voids content increased in the hand layup process and decreased in the VRTM process. In mechanical properties, the hardness, impact energy, and interlaminar shear strength increases while tensile and flexural strength consistently decreases with dolomite dust content. Using Taguchi's optimization technique, the erosion wear of the fabricated composites was also evaluated at different impingement angles, impact velocities, and erodent sizes. Erosion test results indicate that the VRTM process fabricated composite has minimum erosion wear compared to the hand layup process. The eroded surfaces were studied using a scanning electron microscope to understand the erosion behavior of particulate‐filled fiber reinforced polymer composites. [ABSTRACT FROM AUTHOR]

In this work, a comparative assessment of the mechanical properties of chopped glass-carbon-aramid fiber reinforced polypropylene (PP) composites was carried out. Reinforcement and matrix materials were mixed with the extrusion method, and then composite materials were produced in the form of plates with the press molding technique. The composites' tensile, 3-point bending, and drop weight tests were carried out and the surface morphology of the fractured surfaces was examined by Scanning Electron Microscope (SEM). The tests' results indicate that the mechanical properties increase significantly in the presence of fiber. On the other hand, it is observed that the effect in percentage decreases as the fiber content increases. Moreover, It was observed that some of the fiber materials were pulled out from the matrix as a result of stress. ANOVA analysis using S/N values, and F-Test were performed to observe the effectiveness of each test factor (fiber type, and fiber additive content) on the test results. Finally, an optimization study was carried out to obtain the mathematical expression by fitting the experimental data. [ABSTRACT FROM AUTHOR]

The main objective of this research was to study the influence of an enzymatic treatment process of date palm fibers on their chemical and morphological properties as well as the physical and mechanical characteristics of composites filled with raw and treated fibers. To this end, three extraction approaches were considered (a combination of xylanase and pectinase enzymes, xylanase enzymes followed by a pectinase one and pectinase enzyme followed by xylanase). Chemical and morphological analyses were performed on raw and treated fibers. The tensile test of the manufactured composites was achieved, using extrusion and injection molding process. These composites were also subjected to water absorption tests. The results showed that non-cellulosic components decreased after enzymatic treatments while the cellulose content increased significantly. The scanning electron microscope morphological analyses showed that the extraction with the combination of these enzymes is very effective as a fibrillation phenomenon. Composites with high rigidity were observed in the case of enzymatically treated fibers. These composites reveal a better moisture resistance compared to the untreated fibers. Graphical Abstract [ABSTRACT FROM AUTHOR]

In the present work, the composite materials were prepared from coconut shell powder, palm kernel powder, and epoxy resin. The addition of coconut shell powder was considered when preparing the composite samples, and mechanical properties such as tensile strength, hardness, impact, bending strength, physical behavior water absorption, as well as morphological tests, were conducted using Fourier Transform Infrared Spectroscopy, Scanning Electron Microscope, and Thermogravimetric Analysis for both the prepared composite material boards and chipboard. The minimal variation of tensile stress and percentage of elongation between the 50 % coconut shell powder composite material and the wooden chipboard material is 4,44 MPa and 1,00 %, respectively, according to the findings of experimental tests.The lowest compressive stress and hardness variations between coconut shell powder composite material and wooden chipboard are found to be 0,14 MPa and 3,2 MPa, respectively. It is determined that the composite materials made from waste shell powders and epoxy resin are suitable for applications such as panel boards, automotive interior dashboards, roof sheets, and doors. [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]

This article deals with the effect of selected machining parameter values in hard turning of tested OCHN3MFA steel in terms of SEM microstructural analysis of workpiece material, cutting forces, long-term tests, and SEM observations of flank wear VB and crater wear KT of used changeable coated cemented carbide cutting inserts in the processes of performed experiments. OCHN3MFA steel was selected as an experimental (workpiece) material. The selected experimental steel was analyzed prior to hard turning tests to check the initial microstructure of bulk material and subsurface microstructure after hard turning and chemical composition. Study of workpiece material's microstructure and worn cemented carbide cutting inserts was performed with Tescan Vega TS 5135 scanning electron microscope (SEM) with the X-Ray microanalyzer Noran Six/300. The chemical composition of workpiece material was analyzed with Tasman Q4 surface analyzer. All hard turning experiments of the used specimens were performed under the selected machining parameters in the SU 50A machine tool with the 8th selected individual geometry of coated cementite carbide cutting inserts clamped in the appropriate DCLNR 2525M12-M type of cutting tool holder. During the hard turning technological process of the individual tested samples made of OCHN3MFA steel, cutting forces were measured with a Kistler 9257B piezoelectric dynamometer, with their subsequent evaluation using Dynoware software. After the long-term testing, other experiments and results were also realized, evaluating the influence of selected machining parameters with different cutting insert geometry on the achieved surface quality. [ABSTRACT FROM AUTHOR]

In this study, composite was made by the addition of 10 wt% SiC particles in the LM25 matrix through gravity casting and thixocasting processes. Thixocasting temperature was varied to investigate its effect on the microstructure, mechanical and thermal properties. Properties of thixocast samples were also compared with gravity cast ones. XRD analysis was done to analyse the phases present in the samples. Optical microscope and scanning electron microscope were used to record the microstructures of gravity cast as well as thixocast samples. Tensile, compressive and flexural tests were performed on universal testing machine with the prepared composite samples according to the ASTM standards. Thermal diffusivity tests of gravity cast and thixocast samples were done on laser flash diffusivity instrument. Results reveal that thixocast samples are sounder than the gravity cast samples. The microstructure of α-Al phase transformed from dendritic to globular shape due to the thixocasting. Also, volume fraction of eutectic phase in the sample increased with the increment of thixocast temperature. Tensile strength, compressive strength and flexural strength were found higher in the case of thixocast samples as compared to gravity cast. Thermal diffusivity considerably increased due to thixocasting, while its value slightly reduced with increment of thixocast temperature. [ABSTRACT FROM AUTHOR]

Rubber powder is widely used to modify base asphalt binder to improve the low-temperature performance and crack resistance of asphalt mixtures. This paper investigates the aging mechanism and performance evolution of rubber-modified asphalt in terms of three levels: rubber powder, rubber-modified asphalt, and rubber-modified asphalt mixture. The multilevel analysis results show that mass loss, phase transition, and melting occur during the process of rubber powder aging, and scanning electron microscope images indicate that the surface morphology of the rubber powder becomes smoother. The aging of base asphalt leads to the volatilization and oxidation of light components, resulting in the production of carbonyl and sulfoxide groups and a reduction in the swelling between the rubber powder and aged base asphalt. The aging of rubber powder leads directly to a significant decrease in the modification effect of the rubber; thus, rubber powder aging plays a more decisive role in the degradation of rubber-modified asphalt than base asphalt aging. By contrast, the performance indicators of aged rubber-modified asphalt are able to reach their highest values due to the effective blending between the rubber powder and base asphalt, which results in an enhanced antiaging capability. The sensitivity of all performance indicators of rubber-modified asphalt to the aging temperature is relatively low, except for the 5°C ductility index. Therefore, the mixing temperature needs to be strictly controlled to a specified value when rubber-modified asphalt is applied in cold areas that require low-temperature stability of the mixture. As for the aged rubber-modified asphalt mixture, the dynamic stability improved significantly, the ultimate tensile strain at low temperature decreased, and the antifatigue performance decreased to different extents under different stress ratios. [ABSTRACT FROM AUTHOR]

Zirconium nitride films are deposited onto stainless steel AISI 316L and silicon (100) by radio frequency magnetron sputtering at different nitrogen flow ratios [N2/(Ar+N2)] varied between 0 and 0.25). Scanning electron microscope, atomic force microscopy, X‐ray diffraction (XRD), and Raman are used to investigate the surface morphology and microstructure of the thin films. The mechanical and electrochemical properties of all coatings are evaluated and compared with the uncoated AISI 316L to explore the efficiency of surface modification. The XRD and Raman analysis show that all the films are crystalline. This shows that the increased nitrogen content leads to a transformation from hexagonal α‐Zr phase to cubic c‐Zr and then to mixed α‐Zr and face centered cubic c‐ZrN phases. The films deposited with nitrogen flow ratio of 0.2 show the highest hardness of 32.2 GPa. Using the potentiodynamic polarization method, the corrosion behavior of the films is studied in Hank's solution. The comparison between uncoated and coated substrates shows a decrease in corrosion current density for all coated samples. [ABSTRACT FROM AUTHOR]

Thermal, electrical, as well as mechanical behavior of blends of polyamide 6/polystyrene (PA6/PS) (50/50 wt/wt%) loaded with different concentrations of lead dioxide (PbO2) were investigated for X-ray shielding. Thermal stability and hardness (shore D) of these composites are studied. Addition of PbO2 decreases the thermal stability of the prepared composites. Stability of thermal properties confirmed by determining the activation energy for the thermal decomposition of unfilled PA6/PS and filled composites according to the Horowitz and Metzger method. Dielectric properties of bulk PbO2 have been investigated as a function of frequency and temperature in the frequency range from 40 Hz to 5 × 106 Hz and in the temperature range from 293 K to 423 K. The characterization of the prepared composites is done using scanning electron microscope. With PbO2-loaded PA6/PS blends composites, the dielectric properties were significantly influenced by γ-irradiation effects that ε ′ and ε ″ values increase with radiation dose up to 100 kGy for samples loaded with PbO2. Linear attenuation coefficient μ and half-value layer (HVL) of all composites strongly depend on the concentration of the filler used and the applied voltage of X-ray machine. HVL of the obtained composites that loaded with 100 wt/wt% of PbO2 nearly 3 mm can be used as X-ray tube housing, equipment housings and castings, electronic devices protection, and so on. [ABSTRACT FROM AUTHOR]

This paper emphasis the improvement of mechanical properties of AA7075‐T651 using friction stir processing through localized surface modification by adding nano boron carbide particles. The reinforcement techniques such as the groove and blind hole methods were used by changing reinforcements of nano boron carbide and a matrix of AA7075‐T651 surface composites volume percentages (2 %, 4 %, and 6 %) along with tool rotational speed and processing speeds. Optical microscopy, scanning electron microscope and x‐ray diffraction analysis were used to examine the particle dispersion for the surface composites and to correlate with the enhanced mechanical properties. Results revealed that high input parameters have given grain coarsening and precipitate agglomeration and low input parameters provide poor nugget metal consolidation and no vertical material flow. The L9 orthogonal Array designed and optimized the process parameters for enhancing the surface properties of processed samples. Mechanical properties like ultimate tensile strength, yield strength, hardness, percentage of elongation and impact strength were evaluated for the groove friction stir processing method and blind‐hole friction stir processing methods. From the results, it has been observed that the blind‐hole technique resulted in higher hardness and the homogenous dispersion of nano boron carbide particles in the stir zone than the groove method. Consequently, for blind‐hole friction stir processing, grey relational analysis (GRA) and particle swarm optimization (PSO) approaches were proposed to optimise process parameters. From the compared optimization results between grey relational analysis and particle swarm optimization, particle swarm optimization approach was shown the best optimization results. Successively, the optimum condition in the respective experimentation is accomplished. Based on these observation and results, final validation tests were carried by changing the volume percentages of reinforcement keeping tool rotation speed and tool processing speed as constant. It is apparent that dynamic recrystallization in aluminium alloy at the processed zone due to presence of heterogeneous nucleation sites with nano boron carbide particles. [ABSTRACT FROM AUTHOR]

Fluorine rubber (FKM) is often used in bearing seals, bearing seal will be affected by high temperature in the process of use and performance decline. Therefore, in this paper, the effect of CeO2 on the high temperature composite properties of FKM was studied by filling CeO2 nanoparticles into FKM. 5% CeO2/FKM composites were prepared by mechanical blending and hot-pressing process after nano CeO2 was treated with silane coupling agent KH-570. After mechanical and high temperature friction tests of CeO2/FKM composites, the morphology of CeO2/FKM composites was characterized by three-dimensional topography instrument and scanning electron microscope. The mechanical strengthening mechanism and anti-wear and anti-friction mechanism of CeO2 on FKM were expounded. The results showed that the microstructure of Fluor elastomer with CeO2 particles was reinforced, and the defects of fluorine rubber itself were filled. Specifically, compared with the original FKM, the strength of CeO2/FKM composite was improved, in which the tensile strength reached 20.75 MPa, increased by 18.5%, and the tear strength reached 43.44 N/mm, increased by 3.5%. CeO2/FKM composites show outstanding anti-wear and low friction coefficient properties at high temperature (200 °C). The main mechanism is that nano-CeO2 keeps high hardness of FKM, and CeO2/FKM composites have high crosslinking density. [ABSTRACT FROM AUTHOR]

The present research focuses on studying the physical, mechanical, and abrasive wear behavior of the hemp/nettle natural fiber woven mat reinforced with the polyester matrix. The hemp and nettle fibers woven mats were reinforced into the polyester matrix by simple hand‐layup, and after that compression molding process was used to fabricate the composites. The water absorption, tensile, flexural, and impact properties were studied using a hemp/nettle hybrid composite. This study found that increasing the amount of hemp and nettle fiber in polyester from 3 to 9 wt% increased the mechanical properties of hybrid composites. The higher weight percentage (9 wt%) of hemp/nettle fiber in polyester hybrid composites exhibited the highest tensile (42.41 MPa), flexural (78.52 MPa), impact (22.72 kJ/m2) strength, and a higher hardness value of 46.7 HV. Finite element analysis simulation is conducted on mechanical properties (tensile, flexural, and impact strength). The minimum abrasive specific wear rate of hybrid composites is 0.00827 mm3/Nm found in the 9 wt% of hemp/nettle fiber composite at 10 N of normal load and 200 RPM, through Taguchi's approach (L9 orthogonal array). The contribution of control factors in a hybrid composite is studied by analysis of variance. The surface morphological studies were performed to examine the abraded worn surface by abrasive wear to study the behavior of the wear mechanism using the scanning electron microscope. [ABSTRACT FROM AUTHOR]

Additive manufacturing technology can help us to produce complex components/parts easily. It can be used to develop the parts with multi‐material structures consisting of thermoplastic, thermosetting plastic, and ceramic fibers. This multi‐material structure enhances the performance of lightweight polymer‐based components. In this research work, poly‐lactic acid (PLA) lattice (mono‐material structure), PLA lattice filled with epoxy (bi‐material structure), and PLA lattice incorporated with embedded milled glass fibers (MGFs) in an epoxy matrix (tri‐material structure, TMS) were designed and developed by fused filament fabrication and solution casting methods. PLA lattice of 50% volume was fixed in all structures and 50% volume was filled with epoxy and MGFs. The dispersed MGFs in epoxy matrix were varied from 0, 2.5, 5, and 7.5 vol%. The mechanical properties were carried out by compression test, three‐point bending test, and tensile test. The results revealed that 5 vol% of MGFs in the epoxy sample (TMS) exhibited improved mechanical performances compared to other samples. The cone‐beam CT scan results confirmed the voids/porous free surfaces in the developed materials. The high‐resolution scanning electron microscope microstructural evolutions in‐terms of topography and fractured regions were also examined and reported. [ABSTRACT FROM AUTHOR]

Bacterial cellulose is one of the widely discussed biomaterials due to its unique physical, mechanical and chemical characteristics. In this research, bacterial cellulosic film (BCF) was developed using Acetobacter xylinum strain in green tea as a source of carbon under static culture conditions. The developed BCF was evaluated for their morphological properties using a scanning electron microscope and the approximate fiber diameter noted as 38–40 nm. The purity of the cellulose evaluated through an X-ray diffraction method identified that the developed cellulose is Iα rich – triclinic type with 89.61% of crystallinity. The thermal behavior of the BCF was evaluated using TGA and DSC. The results indicated that the major weight loss occurred from 250 to 500°C. The glass transition temperature (Tg) of the developed BCF was very high and it was 165°C. Concerning the mechanical properties, the BCF had lower tensile strength (13.82 Kgf/Cm2), Elongation (10.13 mm) and air (19.72 cm3/cm2/sec) and water vapor permeability value (151 g/m2/day) than the woven cotton fabric. However, the water absorbency (0.7 s) and water holding capacity (320%) are superior to the cotton fabric. The contact angle of the BCF was noted around 28.53°, which is an indication of the higher hydrophilic nature of the BCF. These results provide an insight into the potential applications of bacterial cellulosic material in the apparel and textile sector. [ABSTRACT FROM AUTHOR]

In this paper, SiC coating was prepared using the polymer‐derived ceramic method; then the effect of nano‐alumina as a filler material was studied. First of all, polycarbosilane(PCS) was dissolved in xylene; after that, different amounts of nano‐alumina particles were added to the solution. The coating was deposited on the alumina substrate using the dip‐coating method; this was followed by sintering at 1200℃. The phase content and microstructure of the samples were studied by X‐ray diffraction and scanning electron microscope methods, respectively. Nanohardness, Young's modulus, and coating adhesion were investigated by a nanoindentation method. The sheet resistance was evaluated using the four‐point probe technique; also, the wear resistance of the coating was studied by applying the pin‐on‐disk method. It was found that the addition of the nano‐alumina filler up to 20 wt% drastically improved the adhesion and wear resistance of the SiC coating. [ABSTRACT FROM AUTHOR]

Present work explores the utilization of forest waste (pine cone) and plastic waste (recycled HDPE) to fabricate wood plastic composites (WPCs) using microwave-assisted compression molding. The developed WPCs were experimentally subjected to physical, thermal, and mechanical characterization. Physical properties deteriorated when the filler loading level was maximized over the weight percentages due to poor wettability. The thermal study revealed that the melting point of the composites was influenced by filler weight percentage. The composites reinforced with 20 Wt.% filler exhibited the highest tensile, flexural, and impact strength of 20.01 MPa, 20.98 MPa, and 15.79 kJ/m2, respectively. Scanning electron microscope (SEM) micrographs revealed voids, microcracks, and poor filler dispersion were dominantly responsible for composites failure with increased filler weight fraction. [ABSTRACT FROM AUTHOR]

This research work investigates the influence of hybrid particulate fillers, Mg–Al layered double hydroxide (LDH), and nanoclay (NC), on the mechanical properties and formability of glass laminate AA5052 epoxy composites (GLARE). The composite laminates were prepared by varying the weight percentage (i.e., 3, 4, and 5 wt%) of the hybrid fillers in the epoxy resin. The conventional hand layup technique was utilized for the fabrication of the laminates. The tensile test samples were prepared in different orientations with respect to the rolling direction (i.e., 0°, 45°, and 90°) to address their anisotropic nature. The flexural, impact, lap shear, and formability tests were conducted as per ASTM and IS standards. The Erichsen cupping test was performed to study the formability of the composite laminates. For each test, the results were compared with that of the laminates containing individual LDH filler, NC filler, and no filler material. The results showed that the composite laminate with 5 wt% of LDH + NC hybrid filler exhibited enhanced tensile properties, impact energy, and lap shear strength while the laminate of 4 wt% LDH + NC filler possessed better flexural properties. The formability of the composite laminates with hybrid LDH + NC fillers was observed to be lower than that of the laminates with individual filler materials and laminate without any filler. The variation observed in the test results was justified by investigating the failure mechanism of the composite laminates using a scanning electron microscope. [ABSTRACT FROM AUTHOR]

The aim of this research is to investigate the thickness influence on the efficiency of multiwalled carbon nanotubes (MWCNTs) in glass/epoxy composite laminates under the high‐velocity impact. Combining 0.25 wt% of MWCNTs in the 4‐layer and 8‐layer specimens and 0.1 wt% of MWCNTs in the 16‐layer specimen led to the maximum rise in the energy absorption and specific perforation energy compared with the unreinforced laminates. The significant growth in energy absorption in the 4‐layer, 8‐layer, and 16‐layer specimens was 5.8, 8.3, and 14.4 J, respectively. The number of agglomerations (dislocations) in the matrix was consequently increased as a function of thickness, which led to the better performance of MWCNTs with lower weight percentages in the composite laminates containing more layers. The scanning electron microscope was used to observe the dispersion and agglomeration of MWCNTs in the resin epoxy, and there was also an improvement in the fiber–resin bonding. [ABSTRACT FROM AUTHOR]

Stir casting method has become prominent for fabrication of metal matrix composites in recent years. This method can be adjusted for casting around space holding particles to obtain cellular composite materials. In this study, a specific method which is a combination of stir casting and space holder techniques were used to produce open-celled A360 aluminium-B4C composite foams with regular sized and distributed pores. Weight ratios of reinforcement particles determined as 0.5, 1, 1.5 and 2%. The influences of particle reinforcement on the microstructure and the mechanical behaviour of composite foams were investigated. Microstructures were analysed with optical microscope (OM), scanning electron microscope (SEM). Compression and hardness tests were carried out to observe the effects of reinforcement on mechanical properties. Compression strength properties and hardness of composites increased with the ceramic reinforcement, however the plastic strength of the composite foams showed worsening trend after a certain reinforcement ratio (0.5 wt.%). Energy absorption properties of the composite foams showed parallel trends with compressive strength properties. [ABSTRACT FROM AUTHOR]

Service life of concrete structures depends on the structure design, construction management, and the durability of concrete in aggressive exposure conditions. The old Fengman Dam is an 80-year-old gravity dam, and due to design and construction defects, it has worked with leakage and freeze-thawing problems for more than 70 years. In this study, the durability of the dam concrete is investigated, and a coring program is conducted. The static and dynamic mechanical properties of aging dam concrete (ADC) are tested and the micropores are also observed by scanning electron microscope. Young laboratory concrete (LC) with similar compression strength of the ADC is prepared for comparison. The experimental results show that despite the harsh working conditions, the ADC exhibits good mechanical characteristics in terms of static and dynamic strength and microporosity of interfacial transition zones. The dam concrete is proved to exhibit good durability, and the service life of old Fengman Dam was limited by the poor construction management. [ABSTRACT FROM AUTHOR]