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The mechanical and thermal properties of ZrC x are strongly dependent on the composition and microstructure. In the present study, densified ZrC x (x = 0.5, 0.7 and 1.0) with relative density in the range of 99.2–99.7% have been prepared by a combination of spark plasma sintering (SPS) and vacuum arc melting (VAM). Both the Young's modulus and Vickers hardness monotonically increase with increasing C/Zr ratio. The maximum Young's modulus and Vickers hardness values of 488.1 ± 13.4 GPa and 28.8 ± 1.7 GPa, respectively, for dense ZrC have been obtained. With increasing the C/Zr ratio, the thermal conductivity of ZrC x increases. The thermal conductivity ZrC ranged from 25.17 W/m/K to 43.85 W/m/K from ambient to 1200 °C. Owing to the higher density of ZrC x , the present thermal conductivities and Young's modulus of ZrC x are higher than those of the previous studies. The present results are beneficial to design and preparation of ZrC x ceramics. [ABSTRACT FROM AUTHOR]

The present work focuses on the role of NiB and ZrB 2 addition on density, structural evolution, mechanical and thermal properties of 90W-6Ni-4Co (wt%) heavy alloys. The investigated tungsten heavy alloys were sintered at 1485 °C and 1500 °C with a holding time of 75 min in H 2 atmosphere. Compared to the base alloy 90W-6Ni-4Co, the NiB-substituted alloys showed improved densification at both sintering temperatures. An in-depth study of the phase and microstructure of the 1500 °C sintered samples was carried out. X-ray diffraction analysis confirmed the presence of ZrO 2 in ZrB 2 containing WHAs. Microstructural analysis affirms that ZrB 2 incorporation attributes for grain size refinement in sintered alloys. Furthermore, the elephant foot formation in the sintered samples was avoided by incorporating NiB individually or in combination with ZrB 2 dispersoids. The distortion parameter (δ) of the samples sintered at 1500 °C was found to be decreased from 24.83 (0 wt% ZrB 2) to 6.36 (2 wt% ZrB 2). On the other hand, the combined addition of NiB and ZrB 2 provides better shape retention with δ =2.82 for the tungsten heavy alloys with 3 wt% NiB and 2 wt% ZrB 2. The maximum compressive stress of ∼2000 MPa was obtained in the 89W-6Ni-4Co-1ZrB 2 samples. The maximum and minimum bulk hardness of 432 ± 5 HV 3 and 365 ± 9 HV 3 was obtained for 88W-3Ni-3NiB-4Co-2ZrB 2 and 90W-6Ni-4Co heavy alloys. The coefficient of thermal expansion of the 90W-6Ni-4Co alloy was found to be the highest (7.65 × 10−6 /°C), which was reduced to 7.1 × 10−6 /°C and 6.8 × 10−6 /°C with the incorporation of 1 and 2 wt% ZrB 2 respectively. W-rich channels were noticed in the microstructure of 1500 °C sintered samples. Overall, W-Ni/NiB-Co-ZrB 2 alloys are very effective in enhancing the mechanical properties and distortion behavior compared to W-Ni-Co alloys. • ZrB 2 addition refines W grain size in sintered alloys. • XRD and EDS analysis confirm the partial transformation of ZrB 2 to ZrO 2. • A distinct channel like structure was noticed in NiB-substituted sample. • The liquid phase sintered W-Ni/NiB-Co-ZrB 2 alloys prevent shape distortion. • ZrB 2 -containing heavy alloys offer reduced thermal expansion coefficient. [ABSTRACT FROM AUTHOR]

This report aims to investigate the structural, mechanical, optical, thermal, and electronic properties along with hardness of CuXO 3 (X = Al, In) perovskites for the first time by using first-principles calculations within the density functional theory (DFT). The geometry of the both structures have been optimized by using Broyden-Fletcher-Goldfarb-Shanno (BFGS) minimization technique and confirmed as the cubic structure with the space group of P m ‾ 3 m (No. 221). The studied lattice parameters of CuXO 3 (X = Al, In) closely resemble with previous theoretical and experimental results. Both the compounds of CuXO 3 (X = Al, In) under investigation are mechanically stable as the calculated elastic constants satisfy the Born stability criteria. The calculated value of Pugh's ratio, Poisson's ratio and Cauchy pressure confirm strong ductility behavior in contrast to brittleness of these compounds. The elastic anisotropy calculations confirm the anisotropic nature in CuAlO 3 in contrast to isotropic nature as observed in CuInO 3. CuAlO 3 is predicted to be harder than that of CuInO 3. CuInO 3 shows the highest machinability index among studied compounds. The electronic band-structure and density of states ensure semiconducting nature in CuAlO 3 whereas, CuInO 3 reveals metallic nature. The investigation of optical properties reveals the prospective application of the entitled substances in a wide range of electronic and optoelectronic device uses. The title compounds could be used as thermal barrier coating materials (TBC) for exhibiting low thermal conductivity. [Display omitted] [ABSTRACT FROM AUTHOR]

Taking inspiration from the unique hierarchical structure of bio-materials like pearl oyster, this study employs bio-inspired composites technological route using flake powder metallurgy to prepare laminated Cu/Ti 3 SiC 2 /C composites. The prepared composites have clear laminated structure, uniform dispersion of reinforcing phase and clean interface. At a Cu-plated GNPs content of 0.5 wt%, the composites displayed tensile strength of 300.65 MPa, compressive strength of 575.32 MPa, electrical conductivity of 26.31 MS/m, and thermal conductivity of 285.87 W·m−1·K−1. The reinforcement of composites is caused by the load transfer effect of the laminated structure. During the loading process, the laminated structure creates multiple paths for deflecting cracks, which leads to the redistribution of the applied load. Moreover, the homogeneous distribution of GNPs throughout the laminated structure extends the mean free path of both free electrons and phonons within the material, consequently bolstering the electrical and thermal conductivity of the composites. [Display omitted] • Cu/Ti 3 SiC 2 /C laminated composites with balanced strength-toughness and good thermal and electrical conductivity were prepared. • The role of the lamellar structure was discussed. • The interfacial reactions and interfacial structure of Cu/Ti 3 SiC 2 /C was investigated. • The study investigated the mechanisms of interfacial thermal conductivity, interfacial electrical conductivity, and reinforced toughening. [ABSTRACT FROM AUTHOR]

Arundo donax L. is investigated in this study as a suitable reinforcing agent for PLA/PP waste blend 3D printing filament. To improve the compatibility of the fibre and polymer, the Arundo fibre was chemically modified using alkali and silane treatment. Untreated and treated fibres were extruded with Polymer blends before being 3D printed. Effect of chemical treatment on thermal, mechanical, and morphological properties of the composites was investigated. The tensile, Izod impact, and water absorption of the 3D printed specimens were also tested. The Alkali treated (ALK) and combination of alkali and silane treatment (SLN) composites displayed good results. Tensile strength and modulus of the materials increased, as well as their maintained stability in the Izod impact test, demonstrating that the incorporation of ArF did not result in a loss in performance. SEM examination supported these findings by confirming the creation of beneficial interfacial contacts between the matrix and fibre components, as demonstrated by the lack of void between the matrix and the fibre surface. Furthermore, the alkali treatment of the ArF resulted in a considerable reduction in water absorption inside the biocomposite, with a 64% reduction seen in ALK composite comparison to the untreated composite (Un). After the 43-day assessment period. • Arundo fiber was chemically treated and utilized as a filler for the PLA/PP blend. • DSC, TGA, and MFI tests were performed on the ArF/PLA/PP composites. • The 3D-printed ArF composites were analyzed using tensile and Izod impact tests. • The agents responsible for improving the strength of ArF composites are discussed. • Water absorption of the 3D printed PLA/PP/ArF samples is studied. [ABSTRACT FROM AUTHOR]

In this study, the ground state physical properties of Hg-based chalcopyrite semiconductors, HgXN 2 (X = Si, Ge and Sn), are investigated using the density functional theory (DFT), which is based on full potential linearized augmented plane wave (FP-LAPW) method. The structural, electronic, optical, mechanical and thermal properties of the body-centered tetragonal (BTC) phase, HgXN 2 (X = Si, Ge and Sn), have been calculated using the modified Becke-Johnson exchange-correlation potential (TB-mBJ). The obtained lattice parameters and volume are in good agreement with the values reported earlier, indicating that the results are reliable and reproducible. The phase stability of the titled compounds is elaborately studied and it is confirmed that all are thermodynamically, dynamically and mechanically stable. The electronic band structure demonstrated a direct band gap of 1.70 eV, 0.99 eV, and 0.94 eV for the HgXN 2 (X = Si, Ge and Sn) compounds, respectively. Both HgGeN 2 and HgSnN 2 compounds have a notably lighter carrier effective mass, resulting in higher carrier mobility and conductivity than HgSiN 2. The order of the mechanical hardness is as follows: HgSiN 2 > HgGeN 2 > HgSnN 2. The studied materials are also anisotropic in mechanically and optically. All the title compounds exhibit ductile behavior. The charge density contour plots indicates the dominant covalent nature of the bonds in HgXN 2 (X = Si, Ge and Sn). All these compounds have a high absorption coefficient and low optical reflectivity in the visible light range. Due to the favorable band gap and high absorption coefficient, these compounds could be suitable for optoelectronic or photovoltaic device applications. Moreover, the thermal expansion coefficient, thermal conductivity, melting point and fracture toughness behavior have been calculated, which also showed promise for thermal barrier coating (TBC) applications. • A comprehensive theoretical study on HgXN 2 (X = Si, Ge and Sn) compounds using DFT calculations. • The compounds are thermodynamically, dynamically and mechanically stable. • The compounds are ductile and elastically and optically anisotropic in nature. • The electronic band gap is 1.70, 0.99, and 0.94 eV for the HgXN 2 (X = Si, Ge and Sn) compounds, respectively. • The compounds can be used as potential coating materials in some specific sectors. [ABSTRACT FROM AUTHOR]

This work reports on the synthesis, mechanical, and thermal properties of in situ AlN/Al-12Si composite through laser powder bed fusion (LPBF) by blending Al-12Si powder with 5 vol% nano-sized BN particles. Incorporating nano-BN particles results in (i) formation of thermally stable AlN phase, preventing Si diffusion and breakdown of cellular structure, (ii) improvement of compressive yield strength (CYS), and (iii) reduction in coefficients of thermal expansion (CTE) and thermal conductivity. In addition, compared to Al-12Si alloy, the composite exhibits grain refinement from 38.8 to 1.2 μm in size, and the alteration of columnar grains (Al-12Si) to equiaxed grains (AlN/Al-12Si). At annealing temperatures above 573 K, the CYS of the unadulterated Al-12Si alloy had a ∼ 2.1 times greater reduction (from 285 to 200 MPa) compared to that of the composites (from 301 to 260 MPa). The formation of the AlN phase mitigates the significant reduction in CYS. The CTE of Al-12Si and AlN/Al-12Si are 27.3 × 10−6 K−1 and 24.3 × 10−6 K−1 respectively. There is good agreement between the measured CYS results and the calculated strengthening mechanisms. This work offers both theoretical insights and experimental data to support the use of LPBF AlN/Al-12Si composite in low- and moderate-temperature applications. • Novel in situ AlN/Al-12Si composite is successfully fabricated by laser powder bed fusion. • AlN phase generate from the reaction between BN particle and Al-12Si during laser melting. • AlN/Al-12Si composites have a higher compressive yield strength and lower thermal conductivity. • AlN phase leads to the grain refinement, improving the compressive yield strength. • AlN phase mitigates the reduction in coefficients of thermal expansion at medium temperature. [ABSTRACT FROM AUTHOR]

Structural, electronic, optical, mechanical and thermal properties of hexagonal TM 5 Ge 3 C (TM = Cr, Mo, W) were explored using first-principles calculation. The results demonstrated the thermodynamic and dynamic stability of TM 5 Ge 3 C (TM = Cr, Mo and W). Based on the electronic band structure, density of states (DOS), and charge density mapping (CDM), the electronic ground state was determined. The metallic properties of TM 5 Ge 3 C (TM = Cr, Mo and W) were evaluated from the DOS and optical properties. According to Poisson's ratio, G / B , C 13 - C 44 and C 12 - C 66 , it was determined that TM 5 Ge 3 C (TM = Cr, Mo and W) is ductile. The elastic anisotropy of TM 5 Ge 3 C (TM = Cr, Mo and W) was systematically analysed based on the elastic anisotropy index, three-dimensional spatial distributions and planar contours, which show that the elastic anisotropy of TM 5 Ge 3 C (TM = Cr, Mo and W) is in the order of W 5 Ge 3 C > Mo 5 Ge 3 C > Cr 5 Ge 3 C. In addition, the sound velocity, Debye temperature and thermal conductivity of TM 5 Ge 3 C (TM = Cr, Mo and W) were obtained from the elastic constants and moduli. Finally, the temperature dependence of the Helmholtz free energy, internal energy, entropy, specific heat and thermal expansion coefficient of TM 5 Ge 3 C (TM = Cr, Mo and W) were studied in detail. The thermal properties of TM 5 Ge 3 C (TM = Cr, Mo and W) were studied systematically, and it was found that the high operating temperature of these compounds makes them suitable for applications such as aero-engine turbine blades. • The results also show that the hexagonal structure TM 5 Ge 3 C (TM = Cr, Mo, and W) are dynamical and mechanical stable. • The electronic band structure and density of states indicate the metallic properties of the materials. • The results also show that TM 5 Ge 3 C (TM = Cr, Mo, and W) are dynamical and mechanical stable. • The results show that the anisotropy of TM 5 Ge 3 C is strong. [ABSTRACT FROM AUTHOR]

The present investigation is aimed at evaluating the effect of styrene butadiene rubber, glass fibre, nylon fibre and hybrid reinforcement of glass and nylon fibre with 0.5 and 1.0 wt% on the impact, flexural, and compressive properties. A total of 19 groups were formed, including one control group and 18 study groups. All specimens were fabricated according to the standards and tests were performed. The enhancement of strengths were characterised by using scanning electron micrographs, FTIR results, XRD, and DMA tests. The degradability was studied using TGA/DTA analysis. The results were analysed using one-way ANOVA and Dunnett's post hoc multiple comparison test at p ≤ 0.05. The maximum impact, flexural, and compressive strength were found to be 3.234 ± 0.202 kJ/m2, 70.07 ± 0.7 MPa, and 84.929 ± 0.85 MPa for hybrid reinforcement of 0.5 wt% nylon fiber and 0.5 wt% glass fiber with 1.0 wt% of styrene butadiene rubber (SBR) mixed PMMA denture base material. Statistical analysis shows that the maximum mean impact strength, flexural strength, and compressive strength are about 84%, 58%, and 67% higher than the pure PMMA (control group). The maximum flexural modulus and compressive modulus are 914.4 MPa and 407.847 MPa for denture base material made of 1.0 wt% SBR, 1.0 wt% nylon fiber, 0.5 wt% glass fiber, and 0.5 wt% SBR, 0.5 wt% nylon fiber, respectively. The storage moduli of 1.0 wt% SBR, 1.0 wt% nylon fiber, and 0.5 wt% glass fiber-reinforced denture base material and pure PMMA are 0.096 and 0.422 at 79 °C, respectively, which indicates significant crosslinking of fiber and PMMA. The failure surfaces are characterized by a homogeneous distribution of fiber with increased surface roughness and fiber pullout, strong bonding, and well-dispersed SBR. [ABSTRACT FROM AUTHOR]

Carbide dispersion for reinforcement is an effective strategy to enhance the performance of tungsten (W). High-entropy carbides (HECs), when compared to conventional carbides, offer superior thermal stability, hardness, mechanical strength, creep resistance, and wear resistance. This study represents the first successful incorporation of (HfNbTaZr)C as a reinforcing phase into a W matrix, resulting in the formation of a W-HEC alloy. Compared to other carbides such as ZrC, HEC demonstrates improved coherency with the W matrix, resulting in a significant increase in plasticity and enhanced high-temperature stability. This innovative approach paves the way for alloy design in high-temperature applications such as nuclear fusion, providing fresh insights into the enhancement of mechanical properties and thermal stability. • A (HfNbTaZr)C HEC has been synthesized, for the first time, incorporated as a reinforcing phase into the W matrix. • The mismatch between HEC(200) and W(110) is 0.018, smaller than the W-ZrC alloy, indicating better coherence with the W matrix. • The W-HEC demonstrates outstanding plasticity at 600 °C, displaying total elongation of 33.0%, surpassing other W alloys. • The W-HEC hardness decreases is less than the W-ZrC after annealing at 1800 °C, demonstrating superior thermal stability. [ABSTRACT FROM AUTHOR]

To address the challenges associated with significant thermal disturbance and carbon emissions resulting from the conventional stabilization of frozen soil using cement, geopolymer material is used to replace cement to stabilize frozen soil. The unconfined compressive strength (UCS) of the geopolymer stabilized soil was investigated in relation to the proportions of metakaolin (MK), calcium carbide slag (CCS), curing temperature, and curing age. Microscopic analysis was conducted to unveil the stabilized mechanism. The UCS, shear strength, thermal conductivity, hydration products and microstructure of geopolymer stabilized soil and cement soil were compared in parallel. A total of 240 experiments were conducted in this study. The outcomes indicate that the optimal content of MK and CCS is 10% and 6% respectively. The UCS of samples with the optimal content after 28d of curing at 20 °C, −2 °C, and − 10 °C are 3.783 MPa, 1.164 MPa, and 0.901 MPa respectively. The primary causes of the rise in UCS of the geopolymer stabilized soil are the production of amorphous calcium silicate hydrate and calcium aluminate hydrate gel as a result of the stimulation of MK based geopolymer with CCS. The UCS of the geopolymer stabilized soil decreases with a decrease in curing temperature. In frozen conditions, the expansion of ice crystals in the soil creates voids and promotes crack growth, leading to a decrease in the efficiency of geopolymerization reactions. After 28d of curing at room temperature and low temperature, the geopolymer stabilized soil with the optimal content exhibits higher UCS, failure strain, shear strength, cohesion, and internal friction angle compared to the cement soil. At all curing temperatures and ages, the geopolymer stabilized soil has a lower thermal conductivity than the cement soil. The geopolymer stabilized soil is less susceptible to low temperature curing than cement soil, demonstrating a larger amount of hydration products and a denser microstructure, according to experimental results from XRD and SEM. The results of this work offer a theoretical foundation for using geopolymer in place of cement to stabilize soils in permafrost regions. • The optimal mixing content of geopolymer stabilized soil during low temperature curing was investigated. • The curing temperatures and curing ages have positive effects on the compressive strength of geopolymer stabilized soil. • The mechanical and thermal properties of geopolymer stabilized soil and cement soil were compared in parallel. • The low curing temperatures significantly inhibit the hydration products. [ABSTRACT FROM AUTHOR]

Improving thermal properties of polymer-based composites by using different types of fillers most of the time also reduces material elasticity and flexural strength, which is a significant problem for application. To address this problem, we have used two types of two-dimensional materials, such as reduced graphene oxide (rGO) and hexagonal boron nitride (hBN) to achieve better thermal and mechanical properties. Great tensile strength and flexibility of both those 2D-materials combined with good thermal conductivity of hBN provided a synergistic effect for the resulting composites. Here we show the composites with 30% of hBN and 10% rGO by weight that have greatly improved flexural strength and flexural modulus as well as more than threefold increased thermal conductivity as compared to pristine polypropylene. Mechanical properties of composites only filled with hBN are significantly lower. [Display omitted] • Two types of 2D fillers such as hBN and rGO were successfully used in PP matrix. • Usage of two 2D fillers increases thermal and mechanical properties of PP. • Composite with rGO and hBN showed better mechanical properties than with only hBN. [ABSTRACT FROM AUTHOR]

In this study, the effects of applied pressure (AP) and residual heat quenching (RQ) on the mechanical properties and thermal conductivities of Al-4.6Mg-3.6Zn-0.86Mn-0.48Fe alloys were investigated based on intensively microstructure analysis by scanning electron microscope (SEM), high resolution transmission electron microscopy (HRTEM) and synchrotron X-ray tomography (SXT). The results indicated that AP and RQ did not change the type of intermetallic; instead, they reduced the length and quantity of lath-like Al 6 (Fe,Mn) and significantly refined the grain by increasing the cooling rate. Moreover, η′ precipitation particles were enriched near the grain boundaries, which was beneficial for the yield strength of the alloy; the AP + RQ sample exhibited the best mechanical properties of the ultimate tensile strength, yield strength and elongation of 269 MPa, 164 MPa and 11.4 %, respectively, which were 19 %, 17 %, and 83.8 % higher than those of the gravity cast (GC) sample. Moreover, the thermal conductivity of the AP + RQ sample did not show significant changes, which were attributed to the reduction in solid solute caused by the increased volume fraction of η′ precipitates, thus improving the thermal conductivity; however, the formation of numerous semi-coherent interfaces between η′ and the matrix led to increased lattice distortion, resulting in electron scattering. • Residual heat quenching can improve the strength of cast Al–Mg–Zn alloys. • The 3D morphology of the Fe-rich phases and pores has been significantly improved. • Mechanical properties enhanced by improvement of Al 6 (FeMn) and the presence of η'. • The semi-coherent interfaces between η′ and matrix reduced the thermal conductivity. [ABSTRACT FROM AUTHOR]

The 2.5D oxide/oxide composites become attractive for their excellent integrity and mechanical properties. The thermal shock resistance performance of the material is very important in the actual high temperature application. In this work, the evolution of microstructure and mechanical behavior of the 2.5D oxide/oxide composites from thermal shock at different temperatures and cycles was investigated experimentally mainly by optical microscope, X-ray computed tomography and macro-mechanical tests. The thermal shock resistance mechanism of oxide/oxide composites was qualitatively explored. The results showed that cracks propagation was the main manifestation of thermal shock damage in composites. Compared with 2D composites, 2.5D composites exhibited the finite domain effect on crack propagation due to its reinforcement had certain fibers in Z -direction. This directly caused the critical thermal shock temperature difference of the 2.5D composites (∼900 °C) was more than twice that of the 2D oxide/oxide composites (∼400 °C). In addition, the finite domain effect also significantly reduced the damage growth rate of the 2.5D composites from cyclic thermal shock, highlighting its excellent thermal shock damage resistance. [ABSTRACT FROM AUTHOR]

Enhancing the mechanical properties and thermal stability of phthalonitrile polymers by hybrid modification holds significant importance in broadening their thermal-structural applications within high-temperature environments. Herein, fumed silica nanoparticles were considered as modifiers for a class of phenolic-type phthalonitrile resin, i.e., PN75, and their effects on mechanical properties and thermal stability were explored. First, contact angle tests (CA) were employed to show that the PN75 melt had good wettability on hydrophilic fumed silica (FS) and poor wettability on hydrophobic fumed silica (RFS). FS had a relatively satisfactory dispersion within PN75, which was indicated by scanning electron microscope (SEM), followed by FS/PN75 nanocomposites were prepared by melt blending under vacuum, with maximum FS addition 3 wt% of PN75. Second, the flexural strength and modulus of nanocomposites were increased by 23.5% and 11.9%. Finally, thermal stability of the FS/PN75 was promoted from 21.6% to 25.6% in char residue at 800 °C in the air atmosphere by the thermogravimetric analysis (TGA), which was contributed by the high heat-resistance and the shielding effect of FS. This work would inspire in-depth studies on modification and design of phthalonitrile-based hybrid composites for extreme thermal environment. [Display omitted] • Hydrophilic fumed silica exhibited well wettability with phenolic-type phthalonitrile resin. • Vacuum melt blending was proven as an efficient process achieving well dispersion of fumed silica nanoparticles. • Addition of fumed silica into phthalonitrile polymers improved the flexural strength and the char residue. [ABSTRACT FROM AUTHOR]

This study investigated the effect of graphene oxide nanosheet (GON) size, and initial temperature (IT) on the mechanical properties (MP), and thermal properties (TP) of epoxy/GO structure using the molecular dynamics simulation (MDS). The stress-strain curve, Young's modulus (YM), the atomic order parameter (AOP), and the thermal expansion coefficient (length changes) of simulated structures were studied. The results show that increasing GO length improved the simulated structure's MP. As the GO length increased to 20 Å, YM increased from 2.96 to 4.04 GPa. Furthermore, by changing the length of simulated GONs, the amount of van der Waals force applied from each plate to the atoms present in the atomic matrix changes; so, as the size of GONs increased, AOP in the structures increased. Increasing the size of simulated GONs reduced the expansion of structure. This behavior showed higher thermal resistance, and consequently, atomic stability in the samples as the nanosheets became larger. In general, increasing IT led to increasing the atomic fluctuations. Consequently, the attraction energy among the atoms decreased by increasing the atomic oscillations. Therefore, increasing the IT to 350 K led to a decrease in the YM of samples. Therefore, the MP of samples was reduced by increasing IT. Moreover, increasing IT decreased the amount of AOP in the samples. Finally, increasing IT increased the oscillation amplitude, and the distance of atoms from each other, which caused the expansion in the structure under study. • Molecular dynamics method was implemented. • Effects of graphene oxide nanosheet on the mechanical properties of epoxy/graphene oxide structure. • Increasing the nanosheets' length improves the simulated structure's mechanical properties. • As The length increases to 20 Å, Young's modulus increases from 2.96 to 4.04 GPa. • Increasing the size of the simulated nanosheets reduces the expansion of the structure. [ABSTRACT FROM AUTHOR]

Mechanical properties and thermal conductivity are the key parameters for Mg alloys used as the structural components for heat dissipation, balancing good mechanical properties and high thermal conductivity is still a long-term challenge. Here, we investigated the influence of Y contents on the microstructure and mechanical properties of the as-cast Mg–4Al–4Zn–(4– x)RE– x Y (x : 0, 1, 2, 3, 4 wt%), where RE was the Ce-rich misch metal. Compared with Mg–4Al–4Zn–4RE alloy, the strength and ductility were significantly enhanced due to the well-optimized microstructure by the suitable substitution of Y for Ce-rich RE. Especially, the ultimate tensile strength and elongation were significantly improved from 201 MPa to 244 MPa and 8.0% to 16.8%, respectively, when the Y content was increased from 0 to 3.0 wt%. Meanwhile, the thermal conductivity still kept a high level within the range of 84.2–89.6 W(m·K)−1. The significantly improved elongation was mainly attributed to the reduction and refinement of coarse lamellar Al 11 RE 3 intermetallic phases with increasing Y contents. The as-cast Mg–4Al–4Zn–1RE–3Y alloy exhibited high performance with a combination of high tensile properties and good thermal conductivity. [Display omitted] • The substitution of Y for Ce-rich RE tailored microstructure and enhanced tensile properties of the as-cast AZE444 alloy. • The tensile strength and elongation were significantly improved by the suitable substitution. • The as-cast Mg–4Al–4Zn–(4– x)RE– x Y also possessed high thermal conductivity within range of 84.2–89.6 W(m·K)−1. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bio-based copolyesters involving 2,6-pyridine structure with isosorbide as a second diol were synthesized. • Incorporation of isosorbide enhanced thermal properties of the pyridine-based polyesters. • Isosorbide significantly improved the mechanical properties of the pyridine-based polyesters. • The copolyesters showed high gas barrier properties. Driven by sustainable development and low-carbon policies, many high-performance bio-based polyesters are produced. Our previous work uncovered the high barrier but low thermal and mechanical properties of a renewable 2,6-pyridinedicarboxylic-based polyester. In this article, the copolymerization with isosorbide as a second diol is considered to ameliorate these properties. The chemical structures of copolyesters and the successful introduction of isosorbide were confirmed by FT-IR and 1H NMR. The 1H NMR spectra also allowed the calculation of isosorbide ratio in polymers. GPC revealed a decrease in molar masses with the increase of isosorbide ratio. Contact angle and water/gas permeation measurements disclosed an increase in hydrophilicity and water/gas permeability with the introduction of isosorbide. TGA and DSC analyses demonstrated an enhancement in thermal stability: 8 mol% of isosorbide to the total diol ratio increased the 5 % weight loss temperature (T 5%) by 9 °C, the maximum weight loss temperature (T max) by 8 °C and the glass transition temperature (T g) by 6 °C. DSC investigation showed that the incorporation of isosorbide significantly influenced the crystallization properties, particularly from the melt, by decreasing the crystallinity. XRD patterns indicated the presence of similar crystallization units in these polyesters. Tensile test revealed that incorporating 8 mol% of isosorbide greatly improved the mechanical properties by doubling Young's modulus and tripling the strength at break. Such enhancement in thermal and mechanical properties is important for high gas barrier food packaging applications of these polyesters. [ABSTRACT FROM AUTHOR]

Invar 36 alloy manufactured via the laser powder bed fusion (LPBF) process have attracted interest for their excellent low expansion properties. The properties of Invar 36 alloy, particularly thermal expansion, are highly sensitive to variations in process parameters. However, the effect of process parameters on microstructure and properties has not been systematically studied. This study examines the microstructure, mechanical properties, and coefficient of thermal expansion (CTE) of Invar 36 alloy under various processing parameters with different volumetric energy densities (VED). The results demonstrate that VED variations significantly impact the microstructure, mechanical properties, and CTE. Increasing VED leads to larger grain size and higher high angle grain boundaries, while geometric dislocation density and Taylor factor do not exhibit a linear relationship. At 89.29 J/mm3 VED, the Invar 36 alloy displays the optimal yield strength (405.4 MPa), tensile strength (489.3 MPa), and elongation (43.3%). The CTE meets the ASTM F1684 standard for all specimens. Lower relative density corresponds to smaller CTE, with the lowest CTE achieved at VED of 41.67 J/mm3. Furthermore, the influence of porosity on CTE diminishes with rising temperature. This research opens up the possibility of process parameters optimization for improved CTE and mechanical properties in as-printed Invar parts. [ABSTRACT FROM AUTHOR]

Seashells accumulate rapidly, particularly in coastal areas and in countries that consume a lot of seafood. In order to be recycled and used in ordinary building materials, we have carried out a study into the feasibility of using the seashells in plaster as a substitute and additive. Two cases of incorporation were carried out, the first involving the substitution of plaster by seashell powder in percentages (4%, 8%, 12%, 16% and 20% by mass), the second consisting of the use of the powder as an additive in percentages (2%, 4%, 6%, 8% and 10%). The compressive and flexural strength values are close to those of the control gypsum. However, the use of powder as a substitute can improve the thermal insulation and durability of the gypsum composite. [ABSTRACT FROM AUTHOR]

The development of non-toxic, glycidol-free chain extenders is essential for enabling the recycling and reuse of both bottle-grade PET (PET-B) and thermoform PET (PET-T) in the packaging industry without the need for separation, thereby addressing the health concerns associated with commercial glycidol-based extenders. Herein, two novel series of novel glycidol-free chain extenders for bottle-grade recycled polyethylene terephthalate (PET-B) and thermoform-grade PET (PET-T) blends are reported. Blends of PET-B with up to 20 wt% of PET-T were incorporated into novel epoxy acrylate chain extenders with terminal (PEAT-BA) and internal (PEAI-BA) epoxy groups. These chain extenders are glycidol-free and improve the mechanical, rheological, and thermal properties of the PET-B/PET-T blends, offering better performance enhancements than are provided by commercial chain extender Joncryl ADR (J). The results showed significant improvements in intrinsic viscosity and mechanical properties by around 10 and 15 %, respectively, without affecting thermal properties. These findings can play a role in enabling the recycling and re-use of PET-B and PET-T blends without requiring separation while offering glycidol-free solutions. [Display omitted] [ABSTRACT FROM AUTHOR]

First-principles computations are used to investigate the structural, stability, mechanical, optical, thermal, and electronic characteristics of perovskite material. A novel RbBa 2 Ti 3 O 10 perovskite material is studied by using the generalized gradient approximation (GGA) suggested by Perdew, Burke, and Ernzerhof (PBE) approach in the CASTEP code. According to findings, the compound structure is tetragonal in nature with a space group of 123 (p4/mmm), a lattice parameter, and a volume. RbBa 2 Ti 3 O 10 exhibits indirect bandgap semiconductor behavior, according to its electronic characteristics. The Kramer-Kroning (KK) relations are used for determining optical properties to observe light-matter interaction. Perovskites' mechanical attributes, including their ductility, compressibility, elastic anisotropy, modulus, and mechanical index, were assessed and assigned. The thermal properties of the compound are examined, including its density, minimum thermal conductivity, melting temperature, and Debye temperature. Our investigation shows that RbBa 2 Ti 3 O 10 has potential use in photocatalytic applications. • The compound structure is tetragonal with a space group of 123 (p4/mmm). • RbBa 2 Ti 3 O 10 exhibits indirect bandgap (1.66 eV) semiconductor behavior. • Perovskites' mechanical attributes, like compressibility, anisotropy, modulus, and mechanical index, were assessed. • The thermal properties are examined, including its minimum thermal conductivity, melting temperature, and Debye temperature. • RbBa 2 Ti 3 O 10 has potential use in photocatalytic applications to separate water for H 2 and O 2 production. [ABSTRACT FROM AUTHOR]

High-strength thermal insulation mortar, with its excellent mechanical properties and thermal insulation performance, is commonly used in building structure insulation and reinforcement renovations. In this study, vitrified microbeads and expanded perlite (EP) were used as thermal insulation materials to create high-strength thermal insulation mortar. The effects of the replacement percentage of these materials (50%, 65%, 75%, and 80%) on the density, water absorption, porosity, compressive and flexural strength, and thermal conductivity of the mortar were studied. The results show that increased replacement percentages of vitrified microbead (EP) led to a decrease in the density of the mortar and an increase in the water absorption rate and porosity. Furthermore, when the replacement percentages were increased, the compressive and flexural strength and the thermal conductivity of the mortar were reduced. Comparative analysis of the pore structure of high-strength thermal insulation mortar using scanning electron microscopy and digital microscope revealed the influence of vitrified microbead (EP) on the internal pore structure of high-strength thermal insulation mortar. The influence coefficient (η s) of volume replacement percentage of insulation materials was introduced using the Hamilton and Crosser models. Furthermore, the prediction model of thermal conductivity of high-strength thermal insulation mortar was established under different volume replacement percentages of vitrified microbead (EP). The calculated values of the model matched well with the measured values, with the ratios of the calculated values of the model to the experimental ones ranging from 0.85 to 1.15. • The physical, mechanical, and thermal conductive properties of mortar are found to be influenced by the amount of insulation. • The prediction model of thermal conductivity of high-strength thermal insulation mortar is established. [ABSTRACT FROM AUTHOR]

Drawing inspiration from the robustness and resilience of spider silk, this study harnessed a combination of polydopamine (PDA), cellulose nanofibers (CNFs), polyvinyl alcohol (PVA), and aminated carbon nanotubes (CNTs) to create a synergistic network through hydrogen and covalent bonding on the surface of carbon fibers (CFs). This strategy significantly bolstered the interfacial properties of the resulting composites. The enhancements in flexural strength, flexural modulus, interlaminar shear strength (ILSS), tensile strength, and interfacial shear strength (IFSS) were measured at 47.8 %, 75.2 %, 54.3 %, 55.6 %, and 51.8 %, respectively. These improvements are attributed to the formation of robust covalent and hydrogen bonds among PDA, CNF, PVA, and aminated CNTs. Furthermore, the thermal conductivity of the CF composites saw a 59.7 % increase, owing to the CNFs and CNTs. These nanofillers are instrumental in forming an efficient thermal conductivity pathway within the resin matrix, which contributes to the improved thermal conductivity. This study introduces a straightforward, eco-friendly, and innovative approach for the production of high-performance CF composites. [Display omitted] [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]

• SiC p /Al composites were prepared based on Fused Deposition Modelling (FDM) • Higher SiC volume fraction were obtained compared to other additive manufacturing methods. • complex-structure composites were prepared with excellent properties. SiC p /Al composites are widely used in space vehicles, electronic packaging, automobiles, rail vehicles and other fields due to their excellent mechanical and thermal properties. Complex-shaped SiC p /Al parts are usually manufactured by mechanical processing, which is expensive and time-consuming due to the high hardness of SiC phase. As a highly effective 3D molding method, Fused Deposition Modelling (FDM) of the complex-structure SiC p /Al composites was reported for the first time in this paper. SiC p /Al composites was densified by pressureless infiltration after FDM, and as-acquired bulk possessed high densification of 92.67 % and the SiC volume fraction of 43.2 %. Moreover, excellent performances were also presented, including flexural strength of 211 MPa, thermal conductivity of 112(W/m·K), and the thermal expansion coefficient of 8.67 × 10-6K−1. [ABSTRACT FROM AUTHOR]

To pursue superior yield strength and low thermal expansion characteristic of Fe-36Ni Invar alloy, Fe-36Ni Invar alloys containing various cerium (Ce) contents (0 wt%, 0.0050 wt%, 0.0170 wt%, and 0.0360 wt%) were prepared by vacuum induction melting, followed by the heat treatment process. With increasing Ce content, the evolution of the second-phase particles followed the sequence: MnO-MnS (0% Ce) → MnO-MnS + Ce 2 O 3 (0.0050% Ce) → Ce 2 O 3 + Ce 2 O 2 S (0.0170% Ce) → Ce 2 O 3 + Ce 2 O 2 S + Ni 5 Ce (0.0360% Ce). The results indicated that the grain size and the fraction of annealing twins (f AT) were fairly sensitive to the Ce content. The smallest average grain size (d ¯) and the highest f AT were obtained by adding 0.0170% Ce. The small addition of Ce was beneficial to the improvement of strength and low thermal expansion behavior. In particular, 0.0170% Ce alloy achieved the optimal combination properties. However, the excessive addition of Ce (0.0360%) induced a sharp decrease in mechanical performance and an undesirable increase in the coefficient of thermal expansion (CTE). The Ni 5 Ce phase was unfavorable to the enhancement of mechanical properties and low thermal expansion behavior. Last but not least, 0.0170 wt% Ce content was advised for Fe-36Ni Invar alloy by considering the balance of strength and thermal expansion behavior. • An approach for Fe-36Ni Invar alloy by Ce treatment was proposed. • The grain size and fraction of annealing twins were sensitive to the Ce content. • Improved mechanical properties were obtained by proper Ce addition. • The proper addition of Ce decreased the coefficient of thermal expansion. • The optimum Ce content of Fe-36Ni Invar alloy was 0.0170%. [ABSTRACT FROM AUTHOR]

In contemporary developments across automotive, aerospace, and military industries, there is an ever-growing demand for lightweight and robust polymer composites. In this study, a ductile epoxy resin, carbon nanotubes (CNTs), cellulose nanofibers (CNFs), and silica nanoparticles were used to fabricate nano-fillers/epoxy composites and nano-fillers/silk fibers/epoxy hybrid composites through solution casting and hot pressing. Their mechanical properties and thermal characteristics were analyzed and compared, which show that: these nano-fillers can dramatically enhance the strength and stiffness of the ductile epoxy resin; however, this is achieved at the expense of its toughness and extensibility. CNT/silk fiber/epoxy hybrid composite has the highest tensile strength (81.10 MPa), Young's modulus (3.76 GPa) and impact strength (103.7 kJ/m2), while the CNFs-reinforced one exhibits the highest breaking energy (9.96 MJ/m3). These nano-fillers almost do not affect the thermal stability of the epoxy resin and silk fiber composites. In addition, the fracture modes of their reinforced composites were revealed by macroscopic and microscopic observations. • Reveal how different nano-fillers affect the mechanical behaviors of ductile polymer matrix. • Explore the optimal content of these nano-fillers in the polymer matrix. • Indicate nano-fillers do not affect the thermal stability of their reinforced composites. • Elucidate the composites' fracture modes introduced by silk fibers and different nano-fillers. [ABSTRACT FROM AUTHOR]

[Display omitted] • The material properties discount calculation method based on fiber distribution was proposed; • The node heat transfer judgment and coupling technique based on the fiber diameter was proposed; • The number of meshes required for composite modeling can be significantly reduced based on the MPDCM and NGTJCT; • The modulus, strengths, and thermal conductivities of 3D SCf/UHTCMCs were evaluated. Conducting precise and consistent research into the mechanical and thermal properties of 3D short fiber-reinforced ultra-high temperature ceramic matrix composites (SC f /UHTCMCs) is essential for the lightweight design optimization of structures operating under extreme loads. While the current use of one-dimensional elements to simplify fiber solids addresses the mesh quantity and quality issues stemming from the demand for periodic cell size, it fails to accurately predict the mechanical and thermal properties of SC f /UHTCMCs. This research developed material models featuring fiber volume fractions ranging from 0 to 15%, derived from statistical data on the aspect ratio distribution of short fibers. Addressing the unique characteristics of SC f /UHTCMCs, we proposed the Material Properties Discount Calculation Method (MPDCM), which leverages fiber distribution to calculate the mechanical properties and thermal conductivity of composite materials. Furthermore, we introduced the Node Heat Transfer Judgment and Coupling Technique (NGTJCT), rooted in fiber diameter, to address the issue of unrealistic heat transfer between fiber nodes and matrix nodes in numerical assessments. Utilizing both MPDCM and NGTJCT allows for a substantial reduction in the required mesh count for composite modeling, while adhering to the dimensional needs of periodic cells and facilitating rapid and precise numerical analysis of 3D short fiber-reinforced composites. The outcomes of this research have the potential to overcome the existing bottleneck in the numerical analysis of SC f /UHTCMCs, minimize the necessity for complex experimental procedures in material performance studies, and lay the groundwork for engineering optimization design. [ABSTRACT FROM AUTHOR]

Al 2 O 3 /B 2 O 3 powder mixtures prepared at various ratios from 10.7 to 54.1 wt% B 2 O 3 were used to synthesize Al 18 B 4 O 33 powders by solid state calcination at 1300 °C for 1 h. Al 18 B 4 O 33 formation was completed at 44 wt% B 2 O 3 instead of stoichiometric ratio of 13.17 wt% B 2 O 3. In other words, B 2 O 3 -rich liquid phase accelerated Al 18 B 4 O 33 crystallization. Al 18 B 4 O 33 particles were not acicular in shape when first formed, but they were fully acicular for the 44 wt% and the 54.1 wt% B 2 O 3 mixtures. Anorthite-based glass and CaO were selected to induce liquid phase sintering. CaO considerably improved densification to 95.4 % relative density at 1350 °C. Both glass and mullite also enhanced densification to 94.8 %. Epitaxial nucleation of mullite on Al 18 B 4 O 33 particles resulted in a solid solution as well. Dielectric, mechanical and thermal properties of the samples were investigated and evaluated for possible applications. [ABSTRACT FROM AUTHOR]

In this study, we designed four groups of A-substituted medium-entropy perovskites, synthesized (Ba 0.4 Sr 0.4 Ca 0.1 La 0.1)ZrO 3 , a non-equimolar medium-entropy perovskite, and studied its microstructural uniformity. The medium entropy of these perovskites imparts unique mechanical and thermal properties. Compared to pure BaZrO 3 , the cold moduli of rupture of the four samples improved by 164.29%, 121.22%, 91.49%, and 81.87%, respectively, and the relative density increased from 69.47% to over 90%. The thermal conductivities of these materials were lower than those of conventional low-thermal-conductivity perovskite materials, with a minimum value of 1.513 W/(m·K). The high strengths and low thermal conductivities of these novel perovskite materials could provide vast opportunities for various future applications. [ABSTRACT FROM AUTHOR]

This study focuses on enhancing thermal properties of aramid copolymer nanocomposites by integrating hexagonal boron nitride (hBN). Pristine hBN (P -hBN) is first subjected to oxidative heat treatment at 900 °C, producing thermally treated hBN (T-hBN), which significantly improves thermal conductivity while also increasing the tensile properties of composites. The study further explores the effect of different diamine co-monomers, 3,4′- and 4,4′-oxydianiline (ODA), on the nanocomposite properties. Both types of ODA-based composite films show improvement in various properties containing T-hBN. With 20 wt% of T-hBN, the 3,4′-ODA and 4,4′-ODA-based films exhibit 33.2 % and 290 % increase in tensile strength and thermal conductivity, respectively. The functionalization of hBN by heat treatment enhances the interaction between aramid copolymer and hBN and prevents the aggregation of hBN. The rough interface was shown in fractured images for films with T-hBN, suggesting that the composite films with T-hBN withstand higher external forces. In addition, it was observed that T-hBN exhibits better dispersion compared to P -hBN. This is supported by molecular dynamics (MD) simulation, and, in addition, it also provides the underlying mechanism for the property differences between both types of co-monomers. [Display omitted] [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA), as a green functional polymer, has been useful in various coating applications. However, due to the low mechanical strength and thermal stability of PLA, it needs to be improved in order to expand its application areas. In this work, a series of polylactic acid (PLA) nanocomposite films were prepared through introducing polydopamine-modified mica (PDA@MICA) as a self-assemble nanofiller to enhance its mechanical and thermal properties. The results demonstrated that PLA/PDA@MICA shows excellent mechanical properties. Tensile tests showed that PLA/PDA@MICA exhibits a 58.3 % increase in tensile strength and a 16.8 % increase in Young's modulus compared to pure PLA. Meanwhile, thermal performance testing shown the introduction of PDA@MICA led to an increase in crystallinities (Xc = 24.78 %). And the thermal decomposition temperature of PLA/PDA@MICA film (374 °C) was slightly higher than that of PLA film (367 °C). The simultaneous improvement of the mechanical and thermal properties was attributed to the formation of hydrogen bonds between PLA and PDA@MICA. In addition, the parallel arrangement of PDA@MICA and PLA macromolecular chains forms a unique "brick and mortar" structure in the coating, which enhances the mechanical properties of PLA/PDA@MICA composite coatings. This study reports a successful approach to simultaneously address the drawbacks of PLA, specifically its low thermal stability and mechanical strength, thereby promoting its widespread application in the coatings industry. [ABSTRACT FROM AUTHOR]

• Microencapsulation of PCM with SiO 2 by Sol-gel process. • PCM@SiO2 incorporation effectively reduced concrete pavement surface temperatures, crucial for urban heat management. • Up to 30% PCM@SiO2 replacement maintained concrete strength within Indian standards, suitable for construction use. • Enhanced thermal energy storage capabilities were observed with increased PCM@SiO2 content. This study investigates the potential of enhancing thermal performance in pavement concrete by integrating microencapsulated phase change materials (PCM@SiO 2) using a Sol-gel process for encapsulation. With a concentration range from 0% to 20% in 5% increments, the effects of PCM@SiO 2 on both the mechanical strength and thermal performance of concrete were evaluated. Although the addition of PCM@SiO 2 resulted in a compromise in mechanical strength, significant improvements in thermal performance were observed, demonstrating a promising approach to mitigating temperature stresses and the urban heat island effect in pavement construction. This balance between mechanical and thermal properties underscores the potential of PCM incorporation as a strategic material choice for innovative urban development. [ABSTRACT FROM AUTHOR]

In this study, La-doped BaZrO 3 -based composite ceramics Ba 1-x La x Zr 1-0.25x O 3 (x = 0–0.2) were successfully fabricated. The structure, phase composition, sintering behavior, and mechanical and thermal properties of the materials were investigated, and their thermodynamic stability was evaluated. The results revealed that the doping of La facilitated the formation of solid solution (Ba,La)ZrO 3 , and La 2 Zr 2 O 7 , leading to grain refinement and enhanced structural densification as well as grain boundary bonding of the samples. As La doping x ranging from 0 to 0.20, the average grain size of the specimens decreased from 6.14 μm to a minimum of 2.58 μm, the cold modulus of rupture increased significantly from 84.1 to 155.6 MPa. Moreover, the apparent porosity decreased from 11.2% to a minimum of 1.7% with a thermal conductivity gradually decreased from 5.501 W/mK to 2.802 W/mK. Additionally, thermodynamic calculations indicated the potential application of La-doped BaZrO 3 ceramics in the field of highly reactive alloy melting. [ABSTRACT FROM AUTHOR]

In this work, we delve into the investigation of mechanical and thermal properties of antiferromagnetic UX 2 (X=P, As, Sb), which are structured in the unique anti-Cu 2 Sb-type tetragonal form. The study's principal findings revolve around the revelation of distinctive compressibility patterns and an observed preference for shear deformation in these compounds. These patterns are notably marked by a lower compressibility along the [100] direction than the [001] one, and the ease of shear deformation on the (100) plane compared to the (001) one. Intriguingly, our findings identify these compounds as residing on the brink of the brittle/ductile borderline as per Pugh's ratio and Poisson's ratio. Furthermore, the mechanical strength in these materials is significantly influenced by shear deformation, a fact indicated by the values of bulk and Young's modulus. Among the UX 2 (X=P, As, Sb) compounds, our analysis of the Debye temperature singles out UP 2 as an outstanding performer due to its higher Debye temperature. A noteworthy aspect of this study is the quicker propagation of longitudinal waves over transverse waves, as indicated by the wave velocity and anisotropy calculations. We bring forth an enriched understanding of the anisotropic behavior of these materials in terms of bulk modulus, Young's modulus, shear modulus, and Poisson's ratio. The predicted high melting temperatures of the UX 2 (X=P, As, Sb) compounds, coupled with the computed heat capacities aligning well with existing experimental data, point towards their potential applicability in high-temperature settings. Collectively, our study not only validates the methodologies employed but also brings to light fascinating new insights into the mechanical and thermal properties of these compounds, deepening our understanding of the intricate interplay between their atomic constitution and physical properties. • Unveiling comprehensive elastic properties of UX 2 (X=P, As, Sb) compounds. • Decoding the acoustic velocity and its anisotropy in UX 2 materials. • Charting intricate thermal properties of UX 2 , including Debye temperature and heat capacity. • Highlighting UX 2 's suitability for high-temperature applications. [ABSTRACT FROM AUTHOR]

The current work presents a theoretical study of the physical properties of several FePt 2 ordered structures through first-principles calculations, including structural, magnetic, electronic, mechanical, phonon and thermal properties. The structural stabilities are certified by the enthalpies of formation, elastic constants, and phonon dispersion relationships. The tetragonal I 4/ mmm structure is energetically favorable compared to other types FePt 2 structures including Cmcm , Immm , P 6 3 / mmc and P 4/ nmm structures. The electronic density of states and the contributions of each d -orbital electron to the magnetic moment are analyzed to understand their magnetism. The bulk modulus B values of these FePt 2 structures are similar, but the Young's modulus E and shear modulus G as well as the elastic anisotropy are quite different. The thermal properties at finite temperature are estimated by the quasi-harmonic approximation. The I 4/ mmm structure has higher isothermal bulk modulus, lower thermal expansion coefficient and weaker thermal expansion anisotropy, which is more suitable for high temperature applications than other structures. Also, the sequence of thermal expansion anisotropy is P 4/ nmm > Immm > Cmcm > I 4/ mmm (≈ P 6 3 / mmc). [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) is a promising, sustainable alternative to conventional petroleum-based polymers, but its mechanical and thermal properties limit its applications. This study introduces bamboo powders (BP) and montmorillonite clay particles (MMT) into the PLA matrix to prepare novel bio-based polymer hybrid composites using a unique combination of weight percentages of BP and MMT without chemical solvents through a stir casting process under optimised input parameters followed by compression moulding. Polymer hybrid composites were fabricated with different weight combinations, and their mechanical, morphological, and thermal properties were analysed. Tensile, flexural, and impact tests were performed to examine the mechanical performance, while thermogravimetric analysis and differential scanning calorimetry were used to assess thermal stability and characteristics. Microscopy observations showed a strong interaction between the bamboo, clay, and PLA matrix. The results revealed that the maximum tensile strength and modulus increased by 26.1 % and 40.8 %, respectively, with 10 wt% BP and 4 wt% clay content. Impact strength increased by 48 % with 15 wt% BP and 4 wt% clay content. Moreover, the thermal decomposition temperature, glass transition temperature (T g), crystallisation temperature (T c), and melting temperature (T m) of the hybrid composites improved considerably with 10 wt% BP and 4 wt% clay content, increasing by 4 °C, 2 °C, and 8 °C, respectively. Based on the findings of this study, the controlled processing parameters were optimised to fabricate the bio-based composite with significantly improved mechanical and thermal properties. These properties make the composite suitable for various automotive and structural applications. [Display omitted] • Polymer hybrid composites made by stir casting without solvents show enhanced mechanical properties. • Good interaction has been identified between matrix and reinforcement. • Bamboo and clay particles enhanced the mechanical performance of the composite. • Clay particles influence the thermal stability of the composite. [ABSTRACT FROM AUTHOR]

The rapid development of micro-electronics has a growing demand on the heat dissipation performance of devices, especially thermal management materials. However, recent researches focus on the improvement of single ability, such as thermal or mechanical properties. Herein, a strategy that simultaneously improves thermal and mechanical performance of thermal manager material was proposed, which was achieved by preparing Cu-SiC w composites via the co-electrodeposition technology. The influence of electroplating parameters, such as temperature, current density and reinforcement contents, on the microstructure evolution, mechanical and thermal conductivity were investigated systematically. The fabricated SiC w composite displayed excellent shear strength up to 420 MPa, which is resulted from the Orowan strengthening and load transferring. Additionally, the thermal conductivity of 340 W/(m·K) was obtained, owing to the uniform distribution of whiskers and good interface between the Cu matrix and whiskers. Therefore, the presented work provided an effective method for fabricating comprehensive thermal-mechanical properties and homogeneous heat dissipation capacity Cu-SiC w composites and paved the way for the practical application in the field of the connector between the power devices and heat sinks. [ABSTRACT FROM AUTHOR]

While studies on the incorporation of metal particles into the epoxy matrix are quite common, this research introduces a novel approach by incorporating electroless Ni-coated Cu particles with functional features into the epoxy matrix. Thus, it presents an innovative investigation of epoxy composites with enhanced both thermal and mechanical properties. Therefore, three samples of pure epoxy, dendritic Cu particle reinforced (20 wt%), and electroless Ni-coated dendritic Cu particle reinforced (20 wt%) epoxy composites were fabricated by mixing followed by casting into the mold. The epoxy and composite specimens underwent phase analysis through XRD, and morphological examinations were conducted using SEM equipped with an EDS analyzer, respectively. The hardness, tensile, and bending tests were conducted for mechanical characterization. To evaluate the thermal properties, DSC and TGA tests were employed to assess the impact of the Cu and the electroless Ni-coated Cu particles on the thermal stability of the composites. The mechanical analysis results showed that the pure epoxy sample had tensile and flexural strengths of 23.2 MPa and 43 MPa, respectively. These values increased significantly by 90 % and 311 % in the presence of Ni-coated dendritic Cu particles, reaching 54 MPa and 177 MPa, respectively. Thermal analysis results indicated that the Tg increased with the incorporation of dendritic Cu particles and Ni-coated dendritic Cu particles. Furthermore, the highest thermal conductivity was observed in the Cu-reinforced composites. [Display omitted] • More uniform particle distribution owing to electroless Ni interface in epoxy-Cu composites • The strong bonding of the electroless Ni interface in the epoxy-Cu composites • Increasing the flexural strength of the epoxy by 4× with the electroless Ni-coated Cu particle • Enhancing the thermal conductivity of the epoxy by 2× with the electroless Ni-coated Cu particle • Epoxy composites with both thermal and mechanical properties improved by interface development [ABSTRACT FROM AUTHOR]

[Display omitted] • Mechanical and tribological properties of PAA/EP composites were enhanced by HSiNH 2. • Compatibility of PAA and EP was improved by using HSiNH 2 as "bridging structure". • PAA was prepared by ball milling method based on the friction chemistry principle. Despite the great application potential of epoxy resin (EP) modified with polyamic acid (PAA), the large amount of high-boiling-point non-protonic polar solvents used to promote their compatibility cannot be completely eliminated, which affects the fabrication and application of epoxy composites in practical engineering. Herein, PAA was prepared by solvent-free ball milling method, and then the primary amine hyperbranched polysiloxane (HSiNH 2) was prepared by "one-pot" method as the "bridging structure" to improve the compatibility between PAA and EP. Compared to neat EP, the flexural, impact and tensile shear strength of the epoxy composite are increased by 22.2 %, 30.0 % and 23.2 %, while the average friction coefficient and volume wear rate are reduced by 26.5% and 20.6% under the contents of PAA and HSiNH 2 are 1.50 wt% and 2.0 wt%, respectively. Moreover, the material exhibits excellent thermal properties. By comprehensively analyzing the structure and properties of the epoxy composite, it is mainly ascribed to the fact that HSiNH 2 with a large number of reactive groups acted as a "bridging structure" to enhance the compatibility of PAA and EP, which results in the epoxy composite having excellent mechanical, tribological and thermal properties. This research also lays the theoretical foundation for the development of high-performance epoxy composites in aerospace. [ABSTRACT FROM AUTHOR]

New bioactive materials were introduced to not only restore the lost dental hard tissue but also to release fluoride that inhibits demineralization and occurrence of secondary caries. The current study thus aims to assess Fluoride release as well as the mechanical and physical properties of two new commercially available bioactive restorative materials. Two materials, Cention® Forte (CF) (Ivoclar Vivadent), Surefil one™ (SO) (Denstply Sirona), were evaluated in terms of fracture toughness (FT), flexural strength (FS), flexural modulus (FM) (ISO 4049), compressive strength (CS), and Vickers hardness (VH). In addition, thermogravimetric analysis (TGA) was performed, as well as pH measurements and quantification of Fluoride release after immersion in distilled water at times of 0, 7, 14 and 21 days. The sealing ability was evaluated using silver nitrate dye penetration on natural teeth. Finally, Energy-Dispersive X-Ray Spectroscopy (EDX) was used to investigate the surface composition of the two studied material surfaces. The data were statistically analyzed using Independent T-Tests; the chosen significance level was α = 0.05. CF had significantly higher FT values compared to SO (p = 0.001). Also the FS results showed that CF had significantly higher values (90.11 MPa), followed by SO (22.15 MPa). The CS values showed the same order with significantly higher values for CF (231.79 MPa). While the FM and VH showed the reverse order with SO having significantly higher values than CF. pH measurements showed that CF evolved towards significantly higher pH values after 3 weeks in distilled water, while thermal properties showed more stability and higher resistance to degradation for CF compared to SO. The silver nitrate penetration results showed significantly better sealing ability for CF compared to the self-adhesive SO. Finally, EDX surface analysis results were consistent with the release profiles and confirmed the composition of the two tested materials. Both materials, demonstrated enhanced Fluoride release ability, and hence good remineralisation potential in vitro that could prevent recurrent carious lesions in vivo. The composition based on acrylic polymerization showed better mechanical resistance to bending and fracture, and higher sealing ability than those based on acid base reaction. [ABSTRACT FROM AUTHOR]

Due to its versatile properties polyvinyl chloride (PVC) based materials are employed in several applications. At high temperatures and in acidic media PVC is prone to release toxic materials into the environment. Several reports are available in the literature about the modification of PVC to minimize such problems. Herein, an attempt is made to prepare PVC/Halloysite nanotube (HNT) nanocomposites with a fixed amount of compatibilizer, OPTIM GE 344 (maleic anhydride modified very low-density polyethylene (VLDPE)) and characterize the composites with respect to thermal stability, mechanical properties, and structural aspects. Both tensile and flexural strength showed appreciable improvement for the 4 wt% loading of the nanofiller. Thermogravimetric analysis (TGA) showed that the maximum degradation temperature improved by approximately 24 °C for 4 wt% filled composites. PVC thermomat measurements of the samples were used to study the thermal stability of the composites. PVC without HNT showed 36 min as the stability time and it increased to 398 min for 4 wt% of HNT loading. To complement the thermal properties of the composites, the mass loss measurement and contact angle behavior of the composite surfaces were also done. The decrease in contact angle values denoted better surface wettability properties. The mass loss measurements showed a decrease with respect to the filler loading of HNT, indicating a better interaction between the polymer matrix and HNT. [ABSTRACT FROM AUTHOR]

Interest in utilizing industrial waste and by-products in construction materials is growing, given recent concerns about sustainable practices aligning with the principles of the circular economy. Within this context, compressed earth blocks (CEBs) are emerging as an alternative to traditional building materials, offering cost-effectiveness, energy efficiency, and reduced environmental impact. This systematic review comprehensively explores the incorporation of industrial waste and by-products, including construction and demolition waste (CDW), in the production of CEBs. An approach based on the PRISMA model is adopted to analyze the outcomes from primary scientific databases, namely Scopus and Web of Science. The advantages and limitations of incorporating industrial waste and by-products into CEBs are thoroughly discussed. The results show that these waste materials can improve the mechanical, durability, and thermal insulation properties of CEBs. However, careful selection and processing are necessary for compatibility with CEB production. Factors like particle size distribution, chemical composition, and processing techniques significantly influence block performance. This research highlights the potential for more sustainable practices in CEB production while enhancing the mechanical and functional properties of this building product. The findings contribute to advancing knowledge in the field, benefiting researchers, practitioners, and policymakers interested in sustainable construction practices. • Incorporating industrial waste/by-products into compressed earth block is reviewed. • Mechanical, thermal and durability properties of waste-based CEBs are analyzed. • Industrial waste and by-products can improve the functional performance of CEBs. • Research gaps include compatibility issues and manufacturing standardization. • In-depth studies on environmental impact assessment are encouraged. [ABSTRACT FROM AUTHOR]

[Display omitted] • In-situ polymerization of graphene-based polyamide 66 nanocomposites. • Strong enhancement in mechanical properties and thermal properties. • Synergistic effect of chemical and physical interfacial interactions. In this work, two types of graphene-based polyamide 66 (PA66) nanocomposites were prepared by in-situ polymerization. The effect of the surface functional groups of graphene oxide (GO) and the chemically modified GO (GO-DDA) on the structure and the properties of the nanocomposites were investigated. The nanocomposites achieved excellent enhancement in the properties. Compared to PA66/GO nanocomposites, PA66/GO-DDA nanocomposite showed higher Young's modulus, tensile strength and thermal decomposition temperature at all the filler content. For example, at the filler content of 0.3 wt%, PA66/GO-DDA nanocomposite exhibited 92 % increase in the Young's modulus, while PA66/GO nanocomposite exhibited 42 % increase. The thermal decomposition temperature was improved from 357 °C to 388 °C and to 383 °C by the incorporation of only 0.5 wt% of GO-DDA and GO, respectively. These results indicate the synergy reinforcement effect brought by the chemical interactions and the physical interactions between PA66 and GO-DDA. [ABSTRACT FROM AUTHOR]

Geopolymer has excellent mechanical properties at elevated temperatures, but geopolymer concrete may not be so because of the large difference in thermal properties between geopolymer and aggregate which could lead to substantial thermal stresses when they are in a high temperature environment. In this paper we present an experimental investigation on the mechanical properties of GGBS-FA-SF blended geopolymer concrete with and without steel fibres at elevated temperatures. The influences of exposure temperature, coarse aggregate and steel fibre on the failure mode, compressive strength, elastic modulus, peak strain, and ductility of the geopolymer mortar and geopolymer concrete are examined. Based on the experimentally obtained data, empirical temperature-dependent stress-strain constitutive equations are also proposed, which can be used for the fire safety analysis and design of geopolymer concrete with and without steel fibres. [ABSTRACT FROM AUTHOR]

This study introduced the synthesis of a novel phosphorus-containing ionic liquid flame retardant called DOPA-MZ, which was used to develop epoxy resin (EP) composites with transparency, exceptional mechanical properties, and flame retardancy. Results indicate that adding 3% DOPA-MZ to the EP composite increases the Limiting Oxygen Index (LOI) to 30.3%, achieving a UL-94 V-0 rating. Differential Scanning Calorimetry (DSC) tests showed that DOPA-MZ promotes curing reactions, significantly raising the EP composite's glass transition temperature (Tg). Additionally, compared to pure EP, EP/8% DOPA-MZ reduced total smoke production (TSP) and total heat release (THR) by 23.8% and 5.9%, respectively. Thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were employed to analyze the flame-retardant mechanisms. These analyses revealed that DOPA-MZ primarily inhibits flames in the gas phase and enhanced flame retardation in the condensed phase. Furthermore, DOPA-MZ contains tertiary amine groups, which participated in the curing reactions between epoxy resin and curing agents. This tightens the integration of DOPA-MZ molecules with the cross-linked network formed during the epoxy resin curing process, leading to a 22.0% increase in tensile strength and a 17.0% increase in bending strength in EP/3% DOPA-MZ composite materials. [Display omitted] • Synthesized ionic liquid DOPA-MZ through the neutralization reaction of DOPO-derived acid and 1-MZ. • DOPA-MZ flame retardant exhibits excellent compatibility with epoxy resin and accelerates epoxy resin curing. • DOPA-MZ significantly enhances the fire safety of EP with only 0.13 wt% of phosphorus. • EP composites enhances mechanical and thermal properties while maintaining transparency. [ABSTRACT FROM AUTHOR]

• We provide correlations among structural, thermal, and mechanical properties of medical device polymers following gamma, X-ray, and electron beam irradiation. • For most of the polymers investigated, little to no variation in properties was observed among the various radiation sources at a given dose. • This study supports medical product polymer selection for sterilization radiation resistance in view of product design and function. Stemming from security threats and shortages in supply, a recent push has emerged to expand alternatives to radioisotope Cobalt-60 gamma radiation for sterilization of polymeric medical products, including electron beam (E-beam) and X-ray machine-based sources. However, before large-scale implementation, the effects of these non-isotope-based methods must be thoroughly investigated from several perspectives, involving their potential detrimental effects on the structural, thermal, and mechanical properties of polymers in medical devices. This paper investigates such effects in commonly used medical device polymers, including polypropylene homopolymer (PPH), polyolefin elastomer (POE), low-density polyethylene (LDPE), acrylonitrile butadiene styrene (ABS), and chlorobutyl rubber (CIIR). To connect radiation-driven changes in polymer structural and thermal properties and corresponding changes in mechanical properties, several characterization techniques were utilized, including gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC). We found that the tensile strength of X-ray irradiated PPH, as well as X-ray, E-beam, and gamma irradiated CIIR decreases due to chain scission, which is corroborated by GPC and DMA. The GPC results of LDPE suggest chain scission, but interestingly without a corresponding decline in tensile strength. By comparison, POE and ABS appear to undergo further crosslinking with increasing irradiation dose, which generally strengthens them. Importantly, in the vast majority of the cases, there were small to no changes in properties upon changing radiation technologies (at a given dose), i.e., no radiation source dependence. However, in a few specific cases, radiation method dependencies did arise, for instance, in terms of the molecular weight of PPH being significantly increased upon X-ray irradiation, while the melting temperature, glass transition temperature, and elongation at break reduced compared to gamma. Overall, this study provides valuable insight into radiation-driven chemical and structural changes in polymers that produce changes in physical and functional properties. [ABSTRACT FROM AUTHOR]