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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]

Ceramic fibers are an important thermal insulation material that are not only widely used in extreme conditions, but also play an important role in energy conservation and energy efficiency for sustainable development. However, the practical application of conventional ceramic fibers has a high thermal conductivity in high-temperature environments, which hinders their widespread application. Here, a novel lamellar structured porous SiTiOC/C composite ceramic materials was designed and prepared with excellent thermal insulating properties. The unique microstructure endowed the porous SiTiOC/C composite ceramic materials with a high IR refractive index (93.81%) and an ultra-low thermal conductivity (0.0562 W·m−1 K−1 at 600 ℃). In addition, the porous SiTiOC/C composite ceramic materials not only exhibited excellent mechanical properties (4.46 MPa at 800 ℃), but also demonstrated impressive oxidation resistance and thermal stability. In summary, the proposed porous SiTiOC/C composite ceramic materials provide a reference for the development of high-temperature insulation with good mechanical properties. [ABSTRACT FROM AUTHOR]

In this study, a highly dense GdB 6 bulk ceramic material was fabricated using one-step in-situ reaction spark plasma sintering technology. The sample with a relative density of 96.7 % and a purity of 96.9 wt% was successfully obtained by sintering at 1800 °C for 30 min under a uniaxial pressure of 50 MPa. The Vickers hardness, elastic modulus and fracture toughness of the as-obtained GdB 6 bulk ceramics were 18.9 GPa, 209 GPa and 1.6 MPa·m1/2, respectively. The thermal conductivity of GdB 6 at room temperature was 28.68 W·m−1·K−1, 70 % of which was mainly attributed to phonon vibration, while the remaining 30 % to the electrical thermal conductivity. In addition, the as-obtained GdB 6 ceramics showed no phase transformation after heat treatment at a relatively high temperature of 2100 °C for 20 min in Ar atmosphere. The highly covalent octahedral boron framework played a critical role in maintaining the phase stability of the GdB 6 crystal lattice. This suggested that GdB 6 ceramics could be used as potential ultra-high temperature ceramics for aerospace applications and high-power vacuum electronic devices operated at high temperatures. [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]

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]

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]

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]

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]

In this study, according to the Dinger model, aqueous Si 3 N 4 slurries with a solid loading of 63 vol% and a viscosity lower than 1.0 Pa s were successfully prepared using two-grade Si 3 N 4 powders with D 50 = 7.2 μm and 9.4 μm as starting materials. These resulting slurries exhibited good rheological properties and suspension stability. Notably, the presence of β-Si 3 N 4 seeds existed in the starting materials effectively reduced the nucleation barrier by transforming homogeneous nucleation into heterogeneous nucleation. Consequently, it facilitated the reconstructive phase transformation of α-Si 3 N 4 to β-Si 3 N 4 , promoted the anisotropic growth of β-Si 3 N 4 nucleation, and resulted in the final formation of the bimodal microstructure. This unique microstructure significantly enhanced the mechanical properties of Si 3 N 4 ceramics, resulting in a high flexural strength of 1011.4 MPa and a fracture toughness of 14.8 MPa m1/2. These excellent properties were achieved through the combination of gelcasting and gas pressure sintering. Simultaneously, the Si 3 N 4 ceramics exhibited a low thermal conductivity of 47.7 W m−1 K−1, mainly owing to the low density of 95.3 %, the presence of low-thermal-conductivity silicate-based noncrystalline substances, and the possible existence of lattice oxygen in Si 3 N 4 crystals. [ABSTRACT FROM AUTHOR]

Novel high-entropy (TiTaNbZrMo X)(CN) (x = 0, 5, 10, 15, and 20 at%) carbonitride ceramics were synthesised using the carbothermal reduction-nitridation and spark plasma sintering methods. The effects of Mo doping on the microstructure, mechanical properties, and thermal characteristics of these high-entropy ceramics were investigated. The increase in Mo contents caused increased grain size, uniform distribution of elements, improved Vickers hardness and fracture toughness, and reduced thermal conductivity at the same temperature. High-entropy (TiTaNbZrMo 0.2)(CN) ceramic displayed superior Vickers hardness of 21.41 GPa and fracture toughness of 4.34 MPa·m1/2, compared with 20.51 GPa and 3.94 MPa·m1/2 for (TiTaNbZr)(CN) ceramic, respectively. Density functional theory calculations indicated that adding Mo atoms promoted the hybridisation of metal and carbon elements, thereby preferentially enhancing electron filling in the bonding orbital due to high valence electrons. This, in turn, improved the mechanical properties of (TiTaNbZrMo x)(CN) ceramics. Additionally, the increased Mo contents strengthened covalent bonding and induced lattice distortion, reducing the thermal conductivity of high-entropy ceramics. [ABSTRACT FROM AUTHOR]

Polycrystalline diamond compact (PDC) with different grain sizes were fabricated and the multi-physical behaviors, including mechanical-, thermal-, and magnetic performances, and the microscopic features were examined to study the grain size dependence of wear behavior while cutting dense granite. The results showed that the coarse grade PDC had higher impact resistance and fracture toughness. However, the fine grade PDC had higher cobalt content, hardness and thermal resistance. Among these properties, the wear resistance changed the same way as thermal expansion properties proving the strong correlation. Moreover, the crack network caused by thermal mismatch, and the peeling/fracture of metallic phases and diamond promoted fracture wear and played the critical roles in the wear of coarse grade PDC. [ABSTRACT FROM AUTHOR]

To investigate the mechanism of the influence of the sintering additive ratio on the microstructure evolution of silicon nitride (Si 3 N 4) ceramics, Si 3 N 4 ceramics were prepared by gas pressure sintering using different ratios of Y 2 O 3 /MgSiN 2 as additives. Varying the ratio of Y 2 O 3 /MgSiN 2 changed the composition of the liquid phase, thereby affecting the densification process and phase transformation rate of Si 3 N 4 ceramics, and ultimately changing their microstructure. The reduction in the Y 2 O 3 /MgSiN 2 ratio raised the N/O and Si/O ratios in the system, which increased the liquid phase viscosity. The Si 3 N 4 grain distribution varied from "normal to bimodal". In the case of increasing the proportion of MgSiN 2 and prolonging the sintering time, more of the glass phase evaporated, which reduced the content of the low thermal conductivity phase and increased the continuity of Si 3 N 4 /Si 3 N 4. Therefore, Si 3 N 4 ceramics with 1 wt% Y 2 O 3 and 5 wt% MgSiN 2 exhibited excellent properties after sintering at 1900 °C for 12 h, with thermal conductivity, bending strength, and fracture toughness of 106.7 Wm−1K−1, 776 MPa, and 11.66 MPa m1/2, respectively. [ABSTRACT FROM AUTHOR]

Magnesium aluminate (MA) spinel has shown potential as a refractory material under harsh environments, such as high temperatures and frequent temperature variations. However, understanding the mechanical and thermal properties of MA spinel is a key step towards further improvement of MA spinel refractory materials in high-temperature fields. The formation of solid solution represents a prominent strategy to improve mechanical and thermal properties. The present study develops novel (1- x)MgAl 2 O 4 - x Mg 2 TiO 4 (0≤ x ≤ 0.1) solid solutions by single-step reaction sintering method using light-burned magnesia, reactive alumina, and as-prepared Mg 2 TiO 4 (M 2 T) powders. The effects of M 2 T content on the crystal structure, mechanical properties, and thermal properties of the MgAl 2 O 4 -Mg 2 TiO 4 solid solutions (MATss) were studied. Based on XRD, TEM, and HRTEM results, MATss were highly crystallized with a cubic spinel structure. Besides, the M 2 T addition facilitated the flexural strength, hardness, and elastic modulus in the MA spinel. Among these solid solutions, the x = 0.08 sample exhibited the highest flexural strength, hardness, and elastic modulus of 219.47 MPa, 19.99 GPa, and 270.2 GPa, respectively. M 2 T additive played a solid-solution strengthening role, which enhanced the inherent resistance to microstructural damage. Additionally, the x = 0.08 sample had the highest thermal conductivity and thermal diffusivity of 12.45 W/(m·K) and 7.98 mm2/s, respectively. In comparison with pure MA spinel, the x = 0.08 sample showed a lower thermal expansion coefficient (8.63 × 10-6 K-1 at 1550 °C). These excellent mechanical properties and exceptional thermal behavior enabled its widespread application in refractory materials. [ABSTRACT FROM AUTHOR]

Carbon-metal carbide composites are a novel family of materials with potential application in heat dissipation due to the lightness and thermal-mechanical properties. Within these composites, those of graphite-chromium carbide have been still few studied. Therefore, this research focuses on both the influence of the powder preparation method (mechanical mixing (MM) and colloidal synthesis (CS)) and the spark plasma sintering (SPS) temperature (1600, 1700, 1800, 1900 and 2000 °C) in the properties of the composite graphite-7 vol. Cr. Results indicate that the composites sintered from powders processed by CS exhibit better properties, which can be explained by the better dispersion of the chromium carbide, formed during the sintering process, in the matrix of composite. Apart from the powder preparation method, sintering temperature has influence on the properties of the composite: 1900 °C is the best in the case of the route CS + SPS, while 2000 °C is the best option in the route MM + SPS. The thermal conductivity in-plane is 1.75 times greater in the CS than in the MM route, which suggests a better performance in the composite processed by colloidal route in heat dissipation applications. [ABSTRACT FROM AUTHOR]

The porous SiC-Mullite porous ceramics with different pore size were prepared by SiC particles, kaolin, Al(OH) 3 , and flake graphite, V 2 O 5 and AlF 3 were used as mineralizers, the pore size was controllable by adjusting the size of flake graphite. Then the improved empirical formula and grey theory were used to study the effect of the change in pore size on the material properties. The results showed that with the increase of mean pore size from 1.1 μm to 8.5 μm, the cold modulus of rupture and cold crushing strength decreased by 20.8 MPa and 13.7 MPa, respectively. And the thermal conductivity increased from 1.213 W⋅m−1⋅K−1 to 1.721 W⋅m−1⋅K−1 at 800 °C. The <5 μm pores were helped enhance the strength and decreased the thermal conductivity. [ABSTRACT FROM AUTHOR]

High-performance ceramics with low thermal conductivity, high mechanical properties, and idea thermal expansion coefficients have important applications in fields such as turbine blades and automotive engines. Currently, the thermal conductivity of ceramics has been significantly reduced by local doping/substitution or further high-entropy reconfiguration of the composition, but the mechanical properties, especially the fracture toughness, are insufficient and still need to be improved. In this work, based on the high-entropy titanate pyrochlore, TiO 2 was introduced for composite toughening and the high-entropy (Ho 0.2 Y 0.2 Dy 0.2 Gd 0.2 Eu 0.2) 2 Ti 2 O 7 -xTiO 2 (x = 0, 0.2, 0.4, 1.0 and 2.0) composites with high hardness (16.17 GPa), Young's modulus (289.3 GPa) and fracture toughness (3.612 MPa·m0.5), low thermal conductivity (1.22 W·m−1·K−1), and thermal expansion coefficients close to the substrate material (9.5 ×10−6/K) were successfully prepared by the solidification method. The fracture toughness of the composite toughened sample is 2.25 times higher than that before toughening, which exceeds most of the current low-thermal conductivity ceramics. • Preparation of high-entropy pyrochlore/TiO 2 composites by rapid melt solidification. • The composite toughened samples have ultrahigh fracture toughness (3.612 MPa·m0.5). • The solidified composites exhibit excellent mechanical and thermal properties. [ABSTRACT FROM AUTHOR]

In Part 1 of this study, we investigated the macrokinetic parameters and phase formation mechanism in the combustion front of Zr–Nb–B mixtures. In the second part, we produced consolidated samples of solid solutions NbB 2 -(0.100%)ZrB 2 by hot pressing the combustion-derived powders at 1900 °C. By measuring the crystallographic parameters, mechanical and thermophysical properties of the produced bulk samples, we obtained valuable insights into the behavior of the solid solutions. Our results pave the way for the application-specific fine-tuning of the mechanical properties and thermal conductivity of diboride solid solutions in the Zr–Nb–B system for ultra-high temperature applications. Our findings have significant implications for the development of advanced materials with outstanding performance in extreme environments. [ABSTRACT FROM AUTHOR]

Reactive Structural Materials (RSMs) are a new class of materials composed of two or more metallic materials with oxide-ceramic particles that are unable to ignite or explode under various types of loadings, such as thermal, mechanical, and electrical. This study aims to investigate the microstructure, thermal, physical and mechanical properties of the Al-Ni composites, as a type of RSMs, produced by mechanical alloying and subsequent hot pressing. In this research, the Al-Ni composites with various molar mass ratios of Al to Ni of 2:1, 1:1, and 1:3 were first produced. After determining the optimum molar mass ratio of Al to Ni concerning mechanical and thermal properties, Al-Ni composites were made by adding different amounts of CuO particles (2, 4, and 6 wt%), and their mechanical and thermal properties were determined. The thermal and mechanical results proved that the 1:1 molar mass ratio of Al to Ni in the Al-Ni composite exhibited optimal properties. The thermal properties of the Al-Ni-CuO composites showed that the general addition of CuO particles had a negative impact on the energy release of the Al-Ni composites. However, the combustion test showed that the presence of a low level of CuO particles (2 wt%) increased the reaction temperature from 1180 °C to 1368 °C. However, the higher content of CuO particles (4 and 6 wt%) reduced the reaction temperature of Al-Ni composites. Similar to the thermal properties, the mechanical tests proved the detrimental influence of CuO particles on the compressive strength and hardness values of Al-Ni composites. In-depth discussions on the affecting factors on the mechanical and thermal properties of the Al-Ni-CuO composites have been provided in this work. [ABSTRACT FROM AUTHOR]

Vanadium carbides (VC 1-x) exhibit stoichiometric flexibility due to the presence of various carbon vacancies, which significantly influence their fundamental physical properties. Despite this, a comprehensive understanding of how carbon vacancies affect the mechanical and thermal properties of vanadium carbides remains elusive. Previous research has primarily focused on stoichiometric VC and has yet to fully explore the impact of carbon vacancies. This study reveals that stoichiometric VC is less stable when compared to ordered substoichiometric VC 1-x and employs first-principles calculations to obtain thermodynamic, mechanical, and transport properties of VC 1-x. The ordered carbon vacancy leads to an increase in the V–V bond density and volume. Due to the anharmonic effect, the ordered carbon vacancy impairs heat capacity and thermal expansion. The hardness and toughness decrease with increasing carbon vacancy concentrations. The Boltzmann transport equation is used to calculate electrical and thermal transport properties, which shows that growing scattering effects reduce thermal transport capacity. The results provide accurate data support for vanadium carbide research and theoretical support for designing ultra-high temperature ceramic materials. [ABSTRACT FROM AUTHOR]

Rare-earth (RE) oxide-doped La 2 (Zr 0.7 Ce 0.3) 2 O 7 (LZC) has attracted great interest in thermal barrier coatings (TBCs) because of its lower thermal conductivity. However, studies on the laws governing the effect of different types of RE oxide doping on the performance of LZC ceramics are limited. Therefore, in this study, different types of RE (Sc, Y, Gd and Eu) doped LZC ceramic bulks have been prepared using solid phase reaction method. The effects of RE doping on the crystal structure, mechanical properties and thermal properties of the LZC ceramics were investigated. The results indicated that all five ceramics exhibited a single pyrochlore phase structure, whereas their lattice constants were reduced after doping, with (La 0.85 Sc 0.15) 2 (Zr 0.7 Ce 0.3) 2 O 7 having the lowest lattice constant. The effect of rare earth doping on the grain growth of LZC was not evident; however, it could significantly improve the hardness of LZC. In addition, doping with all four RE ions significantly reduced the thermal conductivity of the LZC ceramics, and the most significant reduction was observed for Gd3+ doping. [ABSTRACT FROM AUTHOR]

Dy 2 TiO 5 ceramics with small grain size range of 1.5–3 μm were successfully prepared by microwave sintering method. The phase composition, microstructure, thermal expansion, stability, corrosion resistance and neutron absorption properties of Dy 2 TiO 5 ceramics were investigated. The results show that Dy 2 TiO 5 ceramics possess high mechanical properties due to the small grain size, with a microhardness of 12.26 GPa. The addition of Mo significantly reduces the thermal expansion phenomenon of the sample. The oxide film formed on the surface of the Dy 2 TiO 5 ceramic enhances its excellent corrosion resistance. In addition, the Dy 2 TiO 5 ceramic shows excellent neutron absorption with 87.34% neutron absorption and over 94% thermal neutron absorption in 8 cm thick particles. [ABSTRACT FROM AUTHOR]

The porous silicon carbide ceramics with multilevel directional pores were prepared by chemical vapor infiltration (CVI) combined with sacrificial template method. Carbon fiber preform with specific structure was used as template, and silicon carbide was deposited by CVI process. Then, the carbon fiber template was oxidized and removed, so that the porous silicon carbide ceramics were obtained. The influence of deposition time on pore structure, mechanical properties and thermal properties was studied. Compared with the traditional pore-making process, the pores formed by sacrificial template method are more regular, which brings excellent mechanical properties and thermal insulation properties. The porosity and flexural strength of the sample deposited for 72 h can reach 66.00% and 67.52 MPa, respectively, the thermal conductivity can be kept below 1 W/(m·K) from room temperature to 1200 °C. [ABSTRACT FROM AUTHOR]

First principles calculations were conducted on (HfTiWZr)B 2 high entropy diboride (HEB) composition, which indicated a low formation energy and promising mechanical properties. The (HfTiWZr)B 2 HEBs were synthesized from the constituent borides and elemental boron powders via high energy ball milling and spark plasma sintering. X-ray diffraction analyses revealed two main phases for the sintered samples: AlB 2 structured HEB phase and W-rich secondary phase. To investigate the performance of multi-phase microstructures containing a significant percentage of the HEB phase was focused in this study. The highest microhardness, nanohardness, and lowest wear volume loss were obtained for the 10 h milled and 2050 °C sintered sample as 24.34 ± 1.99 GPa, 32.8 ± 1.9 GPa and 1.41 ± 0.07 × 10−4 mm3, respectively. Thermal conductivity measurements revealed that these multi-phase HEBs have low values varied between 15 and 23 W/mK. Thermal gravimetry measurements showed their mass gains below 2% at 1200 °C. [Display omitted] [ABSTRACT FROM AUTHOR]

Good fracture toughness can prolong the service life of thermal barrier coatings under thermomechanical loading. Yttria-stabilised zirconia (YSZ) and other novel thermal barrier coatings have low fracture toughness and are thus prone to spalling failure. High-entropy ceramics can provide coatings with excellent mechanical properties. In this study, (ZrYTaErTi)O composites were prepared via a solid-state reaction method based on the concept of high-entropy ceramics. The high-temperature phase stability and mechanical properties of the material were characterised and analysed by X-ray diffraction (XRD) and microindentation tests. The results showed that (Zr 0.544 Y 0.114 Ta 0.114 Er 0.114 Ti 0.114)O had the best fracture toughness, which is 1.5 times higher than that of YSZ, of the ceramics prepared with different composition ratios. At the same time, the effects of grain size and the introduction of a second phase on the fracture toughness of the composites were analysed. This study provides guidance for future research on improving the mechanical properties of novel thermal barrier coating materials. [ABSTRACT FROM AUTHOR]

It is an established paradigm in the emerging fields of nanoscience, nanotechnology and molecular engineering that a very important domain of fundamental research is associated with carbon-based materials. Ever since the discovery of the first member of the fullerene family (C 60) in 1985, and the subsequent discovery of the other members, fullerenes as a nanoscopic allotrope of carbon with anticipated extensive applications in all areas of nanoscience and nanotechnology (both industrial and medical), materials science and engineering, condensed matter physics and chemistry have occupied a central position in research activities across the globe. Detailed investigations, both experimental and theoretical/computational, into their morphology, mechanical, thermal, chemical, biological, electronic, optical and structural properties have led to the emergence of a well-established and independent science of fullerenes, providing very valuable information both in basic and applied sciences. A comprehensive review of these properties of fullerenes, particularly their applications in the above fields will provide valuable up-to-date and essential background information for engaging in new research in this field and also be able to develop new concepts and applications of these exotic carbon structures. For instance, a recent development is their applications in the emerging field of nanoneuroscience, a field interfacing nanoscience and neuroscience. In this extensive, albeit selective survey, related mainly to the C 60 fullerenes, the processes involving their experimental synthesis, theoretical formulation of their geometrical structures, their mechanical and thermal properties and nanomedical applications have been reviewed and summarized both within the experimental and theoretical/computational domains. Essential theoretical concepts, ranging from discrete atomistic molecular dynamics and molecular mechanics methods to continuum-based methods have been expounded in order to facilitate the pursuance of the reviewed literature and also to aid in the development of further research in this field. [ABSTRACT FROM AUTHOR]

In this study, La 1- x Nd x MgAl 11- x Sc x O 19 (x = 0.1, 0.2, 0.3; abbreviated as LNMAS-1, 2, 3) coatings which are supposed to possess better properties than LaMgAl 11 O 19 (LMA) were plasma-sprayed and their high-temperature performance were comparatively investigated. Results show that addition of Nd3+ and Sc3+ as dopants to LMA endows corresponding coatings with reduced thermal conductivity and enhanced thermal expansion coefficient, while maintaining advantageous phase stability, although still being subjected to amorphization in plasma flame and following crystallization upon high-temperature service. Furthermore, the doping could cause adherence increasing between topcoat/bondcoat, benefiting from improved melting condition, especially in LNMAS-2 and LNMAS-3 coatings, which is related to the specific powder morphology and lowered melting point. During exposure to 1350°C, mechanical performance and structure integrity of doped free-standing LNMAS coatings can be well preserved even after 400 h aging. In thermal cyclic fatigue test, LNMAS-2 and LNMAS-3 coatings undertake thermal cycling lifetime of ∼181 and 191 cycles at 1100°C, respectively, 40% durable than that of LMA coating. These preliminary results suggest that LNMAS-2, 3 might be promising candidates for advanced thermal barrier coating applications. [ABSTRACT FROM AUTHOR]

Nanocrystalline ZrC coated graphite was synthesized in mixed molten salt system, and the effect of different zirconium sources and reaction temperature on its synthesis was studied. The effects of nanocrystalline ZrC coated graphite on the microstructure, thermal shock resistance and cold mechanical properties of low-carbon Al 2 O 3 –C refractories in different atmospheres were studied. The results indicated that nanocrystalline ZrC coated graphite synthesized by Zr powder had a more uniform coating structure than ZrO 2 as a zirconium source, and increasing the reaction temperature was beneficial for the synthesis of ZrC. The sample with nanocrystalline ZrC coated graphite fired in nitrogen atmosphere had better mechanical properties, the cold modulus of rupture was 15.67% and 50.67% higher than that of the samples fired under argon atmosphere and carbon-embedded atmosphere, respectively. Meanwhile, Sialon played a significant role in improving the mechanical properties of the samples after thermal shock. In addition, the treatment in argon or carbon-embedded atmosphere was beneficial in improving the thermal shock resistance of the samples. [ABSTRACT FROM AUTHOR]

Recently, 3D-printed metamaterials have undergone rapid development; however, the preparation of most metamaterials requires the use of resin-based materials. Thus, multifunctional ceramic metamaterials, especially the introduction of other materials to optimize thermal metamaterials, must be investigated. Here, lattice structures with different units were prepared via stereolithography appearance (SLA) process. The SiC-reinforced phase was obtained by applying chemical vapor infiltration (CVI). The effects of the SiC content and unit type on the mechanical and thermal properties were studied. The results showed that the thermal expansion coefficient (CTE) of the structures decreased by 50% after one CVI cycle. Among the structures, the wave-shaped torsion flexible design reduced the instantaneous CTE to 3.67 × 10−6 K−1 at 150 °C, lower than that for the other structures. More importantly, the lattice structures strengthened with SiC whiskers exhibited outstanding mechanical performance. The compressive strengths of the triangular structure after sintering, one cycle of CVI, two cycles of CVI, and the introduction of SiC whiskers after one cycle of CVI were 3.23, 10.51, 27.38, and 39.4 MPa, respectively. The introduction of SiC increased the compressive strength of the structure by nearly 10 times, satisfying the requirements of high strength and low CTE. Thus, this method can considerably improve the thermal and mechanical properties of 3D-printed ceramic metamaterials, laying the foundation for an in-depth study on the design and preparation of thermal metamaterials. [ABSTRACT FROM AUTHOR]

Polymer nanocomposites show great potential as thermal management materials owing to their light weight and high design freedom. However, they often suffer from the inability of integrating a high thermal conductivity, satisfactory mechanical properties, and even elevated temperature resistance for real-world scenarios. Here we tailor high-performance carbon-based aramid nanofiber (ANF) nanocomposites toward highly anisotropic thermal conductivity and superior mechanical properties through a vacuum-filtration-induced self-assembly process. The as-obtained ANF nanocomposite films exhibit a unique hierarchical structure composed of horizontally stacked carbon fillers in the ANF matrix, thereby achieving a high in-plane thermal conductivity of 20.54 Wm−1K−1 at only 20 wt% graphene nanosheet loading and anisotropy factors of over 100. Further finite element simulations and proof-of-concept applications for high-power light-emitting diode chip cooling demonstrate the excellent heat dissipation performance of the resulting nanocomposite film. More importantly, the tailored ANF nanocomposite films exhibit high mechanical robustness, high flexibility, superb thermal stability, and flame retardancy, making them extremely promising for thermal management applications in various electronic devices. [Display omitted] • Carbon-based ANF nanocomposites were tailored through a vacuum-filtration-induced self-assembly process. • The ANF nanocomposite films had unique hierarchical structures and exhibited highly anisotropic thermal conductivity. • Excellent heat dissipation performance was demonstrated through finite element simulations and proof-of-concept applications. • Superior mechanical properties, thermal stability, and flame retardancy were achieved. [ABSTRACT FROM AUTHOR]

MgO–Al 2 O 3 –SiO 2 composite ceramics were prepared by spark plasma sintering (SPS). In addition, phase composition, microstructure, mechanical properties, and thermal shock properties have been systematically characterized. Introduction of Al 2 O 3 and SiO 2 significantly increased mechanical properties and thermal shock resistance of these composite ceramics. MgO–Al 2 O 3 –SiO 2 composite ceramics prepared by spark plasma sintering (SPS) exhibited fine grain size. Reduced grain size may result in extraordinary properties. Experimental results showed that MgO–Al 2 O 3 –SiO 2 composite ceramics had the highest flexural strength and hardness among all studied ceramics of 269.6 ± 9.22 MPa and 12.51 ± 0.29 GPa, respectively. Moreover, MgO–Al 2 O 3 –SiO 2 composites can reach 16 thermal cycle times. This shows that it is feasible to prepare high-performance MgO composite ceramics by SPS. Furthermore, introduction of Al 2 O 3 and SiO 2 is effective method to improve mechanical properties and thermal shock resistance of MgO composite ceramics. [ABSTRACT FROM AUTHOR]

The high-entropy formation possibility of (VNbTaMoW) 0.5 C x was first analyzed by phase diagram and then a series of single-phase (VNbTaMoW) 0.5 C x was fabricated by SPS. We investigated the mechanical properties and thermal conductivity of (VNbTaMoW) 0.5 C x as C stoichiometry is varied. As C stoichiometry is increased from 0.345 to 0.35, multi-phase evolves into a single rock-salt phase. The high entropy phase formation depends on C atoms and vacancies, which increase the total number of microscopic states, and then increases the overall configuration entropy and lattice distortion energy. A highly carbon-deficient condition (C=0.345) leads to FCC structure disintegration and drives metal rich Mo 2 C phase evolution. As the carbon stoichiometry increases from 0.35 to 0.5, the nanohardness and flexure strength of (VNbTaMoW) 0.5 C x first increase and reach the peak values of 48 GPa and 410 MPa ((VNbTaMoW) 0.5 C 0.4), then decrease. The point defects concentration in (VNbTaMoW) 0.5 C x drastically change with carbon stoichiometry, which affects the structure, mechanical properties and thermal conductivity of high-entropy (VNbTaMoW) 0.5 C x. The thermal conductivity of (VNbTaMoW)C x first decreases and then gradually increases with an increase in carbon content. Low carbon content (VNbTaMoW)C with primarily metallic bonding is electronically thermal conductivity. As the carbon content increase, the high-entropy (VNbTaMoW)C is covalent bonding and phonon contribution to thermal conductivity plays a great role. [ABSTRACT FROM AUTHOR]

A new high-entropy diboride (Hf 0.25 Zr 0.25 Ta 0.25 Sc 0.25)B 2 was designed to investigate the effect of introducing rare-earth metal diboride ScB 2 into high-entropy diborides on its structure and properties. The local mixing enthalpy predicts that (Hf 0.25 Zr 0.25 Ta 0.25 Sc 0.25)B 2 has high enthalpy driving force, which more easily allows the formation of single-phase AlB 2 -type structures between components. The experiments further demonstrate that (Hf 0.25 Zr 0.25 Ta 0.25 Sc 0.25)B 2 possesses excellent phase stability, lattice integrity and nanoscale chemical homogeneity. (Hf 0.25 Zr 0.25 Ta 0.25 Sc 0.25)B 2 showed relatively high hardness (30.7 GPa), elastic modulus (E , G , and B of 522, 231 and 233 GPa, respectively), bending strength (454 MPa), and low thermal conductivity (13.9 W·m−1·K−1). The thermal expansion of (Hf 0.25 Zr 0.25 Ta 0.25 Sc 0.25)B 2 is higher than that of ZrB 2 and HfB 2 due to weakened bonding (M d - B p and M dd bonding) and enhanced anharmonic effects. Thus, incorporating Sc into high-entropy diborides can tailor the properties associated with the bonding, which further expands the compositional space of high-entropy diborides. [ABSTRACT FROM AUTHOR]

The mining industry produces a large amount of stone waste and tailings, which poses a threat to the environment. Dumping is the most common means of disposing of this industrial waste, contributing to soil degradation and water pollution with the acquisition of valuable land. Fortunately, it can be recycled in a variety of technologies, including the promising geopolymerization technology, which turns waste into value. This review paper presents recent advances in the production of mine tailings-based geopolymer composites from industrial waste as a potential sustainable building material. This article also provides in-depth studies on the behaviors and characteristics of mine tailings composites utilized in geopolymer production, such as physical properties, mechanical properties, durability properties, microstructural properties, thermal properties, leaching behavior, and potential applications. Besides, study developments are moving towards a comprehensive understanding of the environmental footprints and economic benefits of mine tailings-based geopolymer composites for building applications utilizing mine tailings as suitable concrete material. This review paper also highlights knowledge gaps that must be overcome to progress mine tailings composites for geopolymers, as well as future study opportunities based on prior research and existing challenges. [ABSTRACT FROM AUTHOR]

Biodegradable composites were prepared from polylactic acid (PLA) and bamboo charcoal (BC) by melt blending and hot pressing. The effects of BC addition on the mechanical properties, water absorption, DMA, TGA, DSC, and CONE of BC/PLA composites were investigated. The microscopic morphology of the composites was analyzed by SEM. The results showed that for BC addition of 40 wt%, the mechanical strength, thermal properties, and flame retardant properties of the composites were improved compared with those of PLA, with a 2.24 % increase in flexural strength and a 1535 % increase (500 °C) in TG mass retention rate. The crystallinity increased by 129.66 %, the peak loss factor decreased by 31.15 %, the time required for combustion was delayed by 168 s, the peak heat release rate decreased by 29.40 %, the carbon residue rate detected by cone calorimetry increased by 48.50 %, and the peak mass loss rate decreased by 48.82 %. The addition of BC enhanced the crystallization capacity of PLA, and improved the thermal properties and flame retardant properties of the prepared composites. The results showed that materials prepared with a BC content of 40 wt% exhibited the best overall performance. • Bamboo charcoal/polylactic acid biodegradable composites were prepared by melt blending and hot pressing. • The effects of the amount of added BC on properties of composites and their mechanisms were determined. • BC/PLA composites obtained high water resistance, thermal properties, thermal stability, and flame retardant properties. • The application field of Bamboo charcoal has been expanded. [ABSTRACT FROM AUTHOR]

With the development of high-density electronics, polymer-based thermal conductive composites with excellent thermal and mechanical performance are receiving great attention. For the development of polymer-based thermal conductive composites with superior properties, it is essential to reduce the agglomeration of fillers and enhance the interfacial interactions between thermal conductive fillers and the polymer matrix. Among the several thermal conductive materials, graphene nanoplatelets (GNPs) and cellulose nanofiber (CNFs) are attracting attention. However, poor interfacial interaction between GNP and CNF leads to interfacial separation, which in turn, deteriorates its properties. Herein, we synthesized a pyranine-functionalized polyether dispersant (PyPE), which can significantly improve the interfacial interactions between GNPs and CNFs. The effect of PyPE on the dispersion behavior of GNPs and the thermomechanical properties of GNP-CNF composite were monitored. Furthermore, we also performed molecular dynamics (MD) simulations to investigate the impact of applying PyPE dispersant on the interfacial interactions between the GNPs and CNF matrix. The application of PyPE significantly enhanced the dispersibility of GNPs within the CNF matrix, resulting in a 15.5 % increase in-plane thermal diffusivity and a 24.5 % enhancement in tensile strength of the composite, demonstrating their potential applications in high power density electrical equipment and electronic devices. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, Cu-1.5 wt%Y (Cu-Y) and Cu-0.75 wt%Y-0.75 wt%La (Cu-Y-La) were prepared by mechanical alloying combined with spark plasm sintering and hot rolling, followed with annealing at different temperatures. The effects of the introduction of La and annealing temperatures on the microstructures, mechanical properties, electrical conductivity and thermal stability of Cu-Y alloys were investigated. Both Cu-Y and Cu-Y-La obtain the heterogeneous mixed grain structures composed of coarse grains and fine grains, and oxide nanoparticles are uniformly dispersed in Cu matrix. With the introduction of La, the grains and oxide nanoparticles are refined, and LaYO 3 nanoparticles with the coherent interfacial structure can be observed in Cu-Y-La. After annealing at 500 ℃, both Cu-Y and Cu-Y-La obtain the most excellent comprehensive tensile properties and highest electrical conductivity (63 %IACS for Cu-Y and 62 %IACS for Cu-Y-La). Benefited from effectively enhanced grain boundary strengthening and particle strengthening mechanisms induced by the combination effect of La and Y, Cu-Y-La shows higher strength than that of Cu-Y (after annealing at 500 ℃, 244 MPa of yield strength for Cu-Y and 300 MPa for Cu-Y-La). Meanwhile, benefited from improved dynamics stability of the Cu matrix induced by significantly refined precipitates and the formation of LaYO 3 nanoparticles with the coherent interfacial structure after introducing La, the better softening resistance is achieved by Cu-Y-La in comparsion with Cu-Y, and almost 100 ℃ improvement of the softening temperature is achieved (966 ℃ for Cu-Y-La and 870 ℃ for Cu-Y). • A novel system of Cu-Y-La alloy for the field of ITER is designed and prepared. • Effects of heat treatment on microstructure and properties of Cu alloys reinforced by rare earth elements are studied. • The significant improvement of mechanical property of Cu-Y alloy is achieved through the combination effect of Y and La. • The softening resistance of Cu-Y alloy is successfully improved through the combination effect of Y and La. [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]

Studying the effects of elevated temperatures on nanoconcrete is a complex issue due to multiple factors and conditions that affect it. A comprehensive study is necessary to determine the real behavior of nanomodified concrete at high temperatures using different nano-modifiers for various nanomaterials, including those derived from waste. This study investigated the effect of elevated temperatures (200 °C, 400 °C, 600 °C and 800 °C) on concrete containing nano-silica, nano-aluminum, and nano-glass materials as a partial replacement for cement at percentages of 1, 2, and 3 % by weight. Compressive strength test and XRD, TGA and SEM were performed to determine residual Compressive strength, chemical composition, mass loss, and microstructure, respectively. The results showed that incorporating nanomaterials into concrete boosted its residual compressive strength at elevated temperatures. Optimal percentages of nano glass and nano-silica were 1 % at room temperature and 200 °C, and 3 % at 400 °C and 600 °C, respectively. For 800 °C, 2 % nano aluminum was most effective. The findings conform with dense microstructure, particularly in ITZ because of the filling effects and higher CSH with a reduction in calcium hydroxide that was observed by XRD, as well as the correlation with lower mass loss of nano concrete. • Nano modified concrete showed optimal performance before and after exposure to elevated temperatures. • Using 3 % nano-silica, 2 % nano-aluminum, and 1 % nano-glass at elevated temperatures greatly improves the behavior of concrete. • Improvement in microstructure and weight loss were observed through TGA and SEM and analyzed by XRD when using nanomaterials. • using of nano-sized recycled glass in concrete showed good results at different temperatures. [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]

Vitrimers behave like traditional thermosets with good thermal and mechanical properties at service temperature, combined with thermoplastic behaviors above a specific temperature due to their dynamic cross-linked networks. However, there is a lack of effort in studying the mechanical properties of existing vitrimers, which are important for applying them in practical applications. The objective of this work is to experimentally investigate the tensile, compressive, flexural, torsional, and impact properties of a widely studied epoxy-based vitrimer through the various tests: tensile test, compressive test, three-point bending test, torsional test, and pendulum impact test. Since the vitrimer has the same chemical composition as conventional epoxy, all the mechanical tests mentioned above are also conducted on the epoxy for comparison. The results show that the vitrimer is comparable to the epoxy in tensile, compressive, flexural, and torsional properties, while its impact strength is substantially improved. Finally, the thermoplastic behaviors (i.e., reprocessing, recycling, reshaping) of the vitrimer are also studied. [Display omitted] • Epoxy-based vitrimer has the same chemical composition as conventional epoxy. • The vitrimer is comparable to the epoxy in tensile, compressive, flexural, and torsional properties. • The vitrimer possesses 2.7 times higher impact strength than conventional epoxy. [ABSTRACT FROM AUTHOR]

There has been a noticeable global trend in the usage of natural, ecologically conscious fibers as reinforcements in the production of inexpensive, lighter polymer composites. Specifically, the basalt natural fibers are the most intriguing due to their characteristics among the various types of natural fibers (i.e., plants, animals, or minerals) that could be utilized as reinforcement. In the composites sector, basalt fibers (BF) have garnered a lot of interest due to their exceptional mechanical and thermal capabilities, as well as their chemical stability. In comparison to carbon, glass, or other mineral fibers generally, the environmental effect of the entire complex of technical processes involved in generating and using basalt fibers is significantly lower. Within this framework, this suggested review seeks to investigate and analyze the behavior of basalt mineral materials in the forms of fiber, powder, and mats when it is reinforced with different polymer matrices. Additionally, this study discusses the basic methods of producing basalt fibers, their characteristics, composition, and the impact of surface treatment on the fibers. Further sections address the developments in 3D printing and its possible applications in a variety of industries, encompassing mechanical, thermal, tribology, and water absorption/wettability studies. It has been noted that for both structural and non-structural applications, basalt fibers are the most advantageous substitutes and prospective reinforcements in place of glass fibers. While the quantity of BF has a significant impact on mechanical durability and basalt-fiber reinforced composites' (BFRCs) performance over time, another important factor that affects how well BFRCs perform is fiber-matrix interaction. To enhance this fiber-matrix interaction, a variety of chemical treatments (acidic, basic, and plasma) on the basalt fiber are being reported by several studies. The primary drawback of this chemical treatment is that the basalt fiber is harmed by high acid or alkali concentrations. During the long-term chemical treatment, the corrosive layer thickness significantly increased, mostly due to the presence of SiO 2. The extant research clearly indicates that augmenting the volume fraction of basalt fibers improved the composite's capacity to endure impact and absorb energy. In many experiments, basalt fibers have demonstrated greater resistance to moisture conditions when compared to natural fibers derived from plants. Since the basalt is an extremely durable and rigid material, it may be used to make frictional materials to minimize wear and friction. However, increased mass manufacturing of basalt fibers will be necessary to fulfill demand before they can be widely used as reinforcing element for structural composites. This might also make basalt fibers more affordable than more conventional reinforcements like glass and carbon fibers. [Display omitted] • Basalt fibers as a sustainable and ecologically benign reinforcing element. • Basalt fibers might be used in place of naturally obtaining crops or plant fibers. • Basalt fibers improved the composite's shock resistance and energy absorption. • Electro-technical applications can benefit from basalt fibers. • Basalt fibers are useful for the transportation and storage of radioactive objects. [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]

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]

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]

Driven by a curiosity of how sulfur (S) alters the physical properties of KTaO 3 , we embarked on a computational journey using the WIEN2k code and the insights of density functional theory (DFT). We aim to unravel the influence of S-substitution on the material's structure, electronic behavior, optical responses, mechanical strength, and thermodynamic characteristics of KTaO 3. Our investigation has unveiled a remarkable structural transformation, wherein the cubic phase of KTaO 3 undergoes a shift to a tetragonal configuration for KTaO 2 S and KTaOS 2 , eventually returning to a cubic phase in KTaS 3. Significantly, the band gap values have undergone substantial alterations, presenting energy gaps of 1.808 eV, 0.264 eV, and 0.078 eV for KTaO 2 S, KTaOS 2 , and KTaS 3 , respectively, diverging from the original band gap of 3.572 eV in KTaO 3. Importantly, all these compounds have exhibited mechanical and dynamical stability. Furthermore, these compounds have displayed promising optical features characterized by high absorption coefficients (∼105 cm−1), minimal reflectivity (<30%), and robust optical conductivity within the visible spectrum, making them ideal candidates for a range of optoelectronic technologies. Our comprehensive investigation has reinforced the stability of all computed phases, showcasing exceptional electronic, optical, and thermo-mechanical properties, including semiconducting behavior, hardness, ductility, anisotropy, high absorptivity, and low reflectivity. The modified band gap and optical characteristics of KTaO 2 S indicate considerable potential for its application in solar cells, presenting promising opportunities to improve solar energy conversion efficiency. The thermal conductivity of KTaO 3 is fascinating and shows substantial promise for applications as a heat sink material. • The effect of S substitution on the physical properties of KTaO 3 has been studied. • The band gap reduced significantly from 3.572 eV (KTaO 3) to 1.808 eV, 0.264 eV, and 0.078 eV for KTaO 2 S, KTaOS 2 , and KTaS 3. • The band gap and high absorption coefficient of KTaO 2 S indicate its potential for application in solar cells. • The thermal conductivity of KTaO 3 indicates its substantial promise for applications as a heat sink material. [ABSTRACT FROM AUTHOR]

• Novel method is applied to fabricate SiC fiber-reinforced Al matrix composites. • SiC fibers with high volume fraction is introduced into the Al matrix uniformly. • SiC fiber significantly improve the mechanical properties of Al matrix composites. • Coefficient of thermal expansion decreases with increasing the SiC fibers' content. Combining the colloidal dispersion method with the squeeze melt infiltration technique, aluminum matrix composites with different volume fractions of silicon carbide fiber were fabricated at 680 °C under vacuum. Microstructure analysis found that composite presented a dense structure and fibers were homogeneously distributed in matrix. The hardness, yield strength and elastic modulus of the composite monotonically increased with increasing the volume fraction of fiber. The highest flexural strength for composite with 10 vol% SiC fiber was achieved. The improved mechanical properties could be attributed to the dispersion strengthening and enhanced load transferring ability by fibers as well as the dislocation strengthening. On the other hand, the coefficient of thermal expansion of composites was measured at temperature up to 400 °C. It was found that the uniform introduction of silicon carbide fiber could significantly low the CTE of aluminum matrix composite, which could be attributed to the low CTE of SiC fiber and good fiber–matrix interface bonding. [ABSTRACT FROM AUTHOR]