Hardness Of Matrix Research Articles

Microstructure evolution and fatigue crack initiation life prediction of actual failed bearings under GRCF conditions

During the operation of bearings under alternating stress, contact fatigue failure often occurs, primarily due to non-metallic inclusions in bearing steel (GCr15). Based on actual fatigue-failed bearings, this study used Aspex scanning electron microscopy to analyze the inclusion distribution in bearing steels produced by two processes: electroslag remelting and vacuum refining. FIB-TEM technology was employed to characterize the microstructural evolution characteristics at the fatigue failure source area. Finally, considering the depth, area, and matrix hardness of the inclusions, a fatigue life prediction model based on gigacycle rolling contact fatigue (GRCF) was proposed. The prediction results closely matched the fatigue data of actual failed bearings.

Enhancing dry sliding wear resistance of high-Mn austenitic steel by adding N

In this study, the wear resistance of two high-Mn austenitic steels, i.e., Fe−18.5Mn−7Cr−0.6C and Fe−18.5Mn−7Cr−0.6C−0.21N was tested in dry sliding friction on a disc friction and wear testing machine (MMU-5G). The wear behavior and microstructure evolution of the two tested steels were investigated. The results revealed that adding N enhanced the wear resistance of high-Mn austenitic steel due to the synergistic effects of hardness, wear hardening, and oxide layer. Interstitial N atoms increased the matrix hardness and decreased the stacking fault energy (SFE). The lower SFE facilitated wear hardening, and the active mechanical twins along with the higher dislocation density induced the formation of a thicker nanocrystalline layer with finer grains. The nanocrystalline layer with higher surface activity promoted the adsorption of a protective oxide layer. These factors decreased the surface roughness, coefficient of friction (COF), and wear rate of N-alloyed high-Mn austenitic steel. This study provided valuable insights into the application of N-alloyed high-Mn austenitic steels under dry sliding friction conditions.

Cryogenic rapid quenching simultaneously enhances the strength and ductility of steel–Aluminum composite plates

Roll-bonded steel–aluminum composite plates exhibit poor plasticity due to work hardening induced by severe plastic deformation. In this study, the mechanisms for improving the plasticity of steel–aluminum composite plates were investigated through liquid-nitrogen quenching from both material science and mechanical perspectives. From a materials science perspective, rapid cryogenic quenching forms numerous dislocation walls and cells within the Al matrix. These dislocation configurations effectively limit dislocation movement during tensile deformation. Additionally, the difference in thermal expansion properties between the steel and aluminum matrices generate significant microstrain near the interface, enhancing the back stress-induced strengthening effect. From a mechanical perspective, rapid cryogenic quenching increases the hardness and tensile strength of the aluminum matrix. A stronger aluminum matrix restricts the deformation of the steel matrix during tensile loading, delaying the onset of necking in the steel matrix. Additionally, the significant hardening of the aluminum matrix can cause the tensile specimen to bend, creating two potential necking points that divide the tensile strain, thereby significantly increasing the pre-necking deformation of the composite plate. Compared with untreated specimens, the tensile elongation and tensile strength of the specimens treated with rapid cryogenic quenching increased by 49.1% and 10.8%, respectively. This study provides a novel approach to simultaneously enhance the strength and plasticity of composite plates.

Effect of SiC addition on the microstructure and properties of Ti6Al4V by selective laser melting

The fine crystalline behavior of SiC/Ti6Al4V is revealed in this study. Titanium matrix composites (TMCs) with different types, amounts, and morphologies of second phases were prepared in situ by adding different contents of SiC. The grain refinement mechanism of multi-phase synergistic was analyzed, and the synergistic contribution of the in-situ second phases (TiC, Ti5Si3, and Ti3Si) as well as the fine grain organization to the strengthening of the materials was quantitatively evaluated. The results show that the quasi-continuous network structure formed by the in situ TiC and Ti5Si3 phases inhibits grain growth and completes the equiaxed transformation of β-grains. Meanwhile, the TiC phase provides a large number of nucleation sites for the α-Ti phase, which promotes the nucleation of the matrix phase. Finally, the aspect ratio of the α phase was reduced from 5.8 to 3.1, while the β grain size was refined from 20.0 to 1.7 µm. The matrix hardness (6.3 GPa) and compressive yield strength (1692 MPa) of TMC were increased by 37 % and 67.4 % respectively compared with Ti6Al4V. Fine grain strengthening accounted for 71.2 % of the total strengthening increase. The load-bearing strengthening caused by TiC, Ti5Si3 and Ti3Si accounted for 6.0 %, 11.6 % and 3.0 % of the total strengthening increase, respectively.

Evolution of mechanical properties of organic-rich shale during thermal maturation

Accurate assessment of the mechanical properties of organic matter, clay matrix, and bulk shale during maturation remains a challenge. Here, we aim to assess the mechanical properties of organic-rich shale during maturation using a combination of nanoindentation methods and various geochemical analyses, i.e., mineral composition, mass loss rate, chemical structure of organic matter, and Rock-Eval analyses. Results show that the evolution of mechanical properties of organic matter in shale during maturation can be divided into: the main oil-generation stage, and the condensate oil and gas generation stage. The stiffening of organic matter in the shale is mainly due to increased aromaticity and condensation of aromatic groups. The clay matrix experiences a slight decrease in hardness and Young’s modulus at low maturity levels due to the generation of liquid hydrocarbons. However, overall, the clay matrix becomes stiffer as the shale matures due to shale dehydration, expulsion or cracking of liquid hydrocarbons, transformation of clay minerals, and hardening of organic matter. The Young’s modulus and hardness of bulk shale generally increase with increasing maturity. This is closely related to the hardening of organic matter and clay matrix, as well as the development of the more compact and dense microstructure in the shale.

Modulation of structure and mechanical properties in metallic glass composites reinforced with B2 phase by microalloying

This study investigated the impact of Ta on the structure and properties of Zr46Cu46Al4Ti4)100-xTax (x = 0, 1, 1.5, 2 at%) bulk metallic glass composites (BMGCs). The addition of Ta led to a gradual increase in the glass transition temperature, while the crystallization onset temperature remained nearly constant. This resulted in a decrease in the supercooled liquid phase region and a reduction in the glass-forming ability (GFA). The room temperature uniaxial compression tests revealed that the addition of Ta initially increased the plasticity of the alloys, followed by a subsequent decrease. The alloy with 1.5 at% Ta exhibited superior properties, including the highest fracture strength (2033 MPa) and plasticity (8.1 %). The Vickers hardness tests revealed that the addition of Ta led to an increase of the hardness in the glass matrix region of alloys from 512.8 HV to 550.9 HV. In conclusion, a moderate amount of Ta element can enhance both the fracture strength and plasticity of Zr-based BMGCs, as well as improve the hardness of the alloy glass matrix.

Development of an advanced hydride reorientation model for Zircaloy cladding and its experimental validation

Hydride reorientation, which occurs under hoop stress during cooling, stands out as a primary mechanism for material degradation in spent fuel management. The radial hydride fraction (RHF) is strongly involved in the mechanical integrity of cladding, highlighting the necessity for a robust modeling framework for quantitative analysis. However, the predictability of previous thermodynamic models for hydride reorientation in reactor-grade Cold Worked Stress Relieved (CWSR) Zircaloy has been hindered due to the intricate nature of hydride reorientation and the difficulties in characterizing microstructures. Recent successful EBSD characterization of reactor-grade CWSR Zircaloy has revealed valuable insights into microstructural characteristics of hydrides, enabling advancements in the modeling framework of hydride reorientation. This study aims to develop a thermodynamic model specifically focused on predicting the RHF. The developed thermodynamic model, based on classical nucleation theory, integrates aforementioned microstructural findings, combined with the Hydride-Nucleation-Growth-Dissolution (HNGD) model to capture transient precipitation behavior during cooling. Extensive experimental validations demonstrate enhanced predictability of the model. Additionally, the study examines the sensitivities of hydride reorientation to hydrogen concentration, applied stress, and cooling rate. It also provides predictions on reorientation behavior for engineering implications such as extension of wet storage, matrix hardening, recrystallization, and thermal cycling, supported by plausible explanations rooted in the underlying physical mechanisms elucidated through the model.

Tribological and mechanical behaviors of Fe3O4NPs reinforced UHMWPE biocomposite

Ultra high molecular weight polyethylene (UHMWPE) filled with diverse contents of magnetite nanoparticles (Fe3O4NPs) were produced via hot compression molding. The effect of Fe3O4NPs on the tribological and mechanical properties of the UHMWPE matrix was studied. Wear and friction behaviors were studied using a reciprocating pin-on-disc tribometer under a sliding speed of 0.03 m.s−1 and an applied normal load of 20N. Mechanical behavior was investigated using tensile and hardness tests. SEM technique was used to explore the surface morphology and to investigate wear mechanisms. Results showed that reinforcement with Fe3O4NPs improved UHMWPE matrix hardness and wear resistance. A maximum hardness and wear resistance in addition to a good mechanical behavior in traction were obtained when adding 1 wt% of magnetite nanofiller. Reinforcement increased the coefficient of friction but there is no obvious correlation between nanofiller contents and friction. SEM analysis showed that the reinforcing rate of UHMWPE influences wear mechanisms.

Effect of graphene on microstructure, strain hardening and corrosion behaviour of dual phase Mg-Li matrix processed through liquid metallurgy route

The significance of this study lies in the potential enhancement of magnesium (Mg)-based materials through the addition of graphene, aiming to improve their mechanical properties and corrosion resistance. This research investigates the development of graphene-Mg composites, employing a liquid metallurgy route to fabricate a dual-phase structured Mg-8Li composite. Mg-Li dual-phase composites are of interest due to their lightweight nature and promising mechanical properties, making them suitable for applications in aerospace, automotive, and structural engineering. Graphene was incorporated into the Mg matrix at varying percentages (0.2, 0.4 and 0.6 wt.%), and the resulting materials were subjected to microstructural, mechanical, and corrosion analyses. Microstructural characterization results reveals that the increase in graphene content results in decrement in grain size of α-Mg and β-Li up to ∼33 and ∼11.5% respectively. Likewise, additions of graphene improvise tensile and yield strength of base matrix up to ∼47 and ∼44% respectively. Strain hardening exponent (n) values of base material decrease from 0.21 to 0.17 with respect to graphene addition which confirms the effect of graphene that acts as effective barrier to slip that decreases the deformation. Corrosion analysis revealed a decrease in corrosion rate and increased pitting resistance with the addition of graphene, indicating improved corrosion resistance. Electrochemical impedance spectroscopy results depict that the composite with 0.4 wt.% graphene exhibits larger semi conducting loop with higher charge transfer resistance ( Rct) value of 128 Ω cm2.

The Effect of Heat Treatment on the Plasma Nitriding of Hot-rolled 17–7 PH Stainless Steel

17–7 PH stainless steel is a highly versatile material with a multitude of applications in a diverse range of fields, including aerospace, chemistry and petrochemistry, and medicine. The material’s exceptional mechanical properties and corrosion resistance render it the optimal selection for numerous components and instruments. Nevertheless, the surface properties of 17–7 PH stainless steel are inadequate for applications requiring high hardness and wear resistance in certain extreme environments. Due to its excellent mechanical properties and corrosion resistance, it can be utilized in the manufacturing of pharmaceutical equipment components. However, certain specialized environments still require surface nitriding treatment. Considering the complex heat treatment process required for this material, this paper reports a detailed study of the surface performance changes of 17–7 PH steel before and after ion nitriding following aging heat treatment. The study employs rolled 17–7 PH stainless steel as the subject material. The impact of heat treatment on plasma nitriding of stainless steel is investigated by comparing and analyzing the influence of martensite content and dislocation density within the martensite of the material prior to and following heat treatment on the hardness, thickness, and corrosion resistance of the nitrided layer on the surface of the steel after nitriding. The results demonstrate that 17–7 PH stainless steel, which does not undergo heat treatment, exhibits a high internal dislocation density, a high nitriding efficiency, and consequently, a high surface hardness. Following the application of a heat treatment, there is an increase in the martensite content of 17–7 PH stainless steel, a decrease in the dislocation content, and an increase in the matrix hardness.

The study on 4D culture system of squamous cell carcinoma of tongue

Traditional cell culture methods often fail to accurately replicate the intricate microenvironments crucial for studying specific cell growth patterns. In our study, we developed a 4D cell culture model-a precision instrument comprising an electromagnet, a force transducer, and a cantilever bracket. The experimental setup involves placing a Petri dish above the electromagnet, where gel beads encapsulating magnetic nanoparticles and tongue cancer cells are positioned. In this model, a magnetic force is generated on the magnetic nanoparticles in the culture medium to drive the gel to move and deform when the magnet is energized, thereby exerting an external force on the cells. This setup can mimic the microenvironment of tongue squamous cell carcinoma CAL-27 cells under mechanical stress induced by tongue movements. Electron microscopy and rheological analysis were performed on the hydrogels to confirm the porosity of alginate and its favorable viscoelastic properties. Additionally, Calcein-AM/PI staining was conducted to verify the biosafety of the hydrogel culture system. It mimics the microenvironment where tongue squamous cell carcinoma CAL-27 cells are stimulated by mechanical stress during tongue movement. Electron microscopy and rheological analysis experiments were conducted on hydrogels to assess the porosity of alginate and its viscoelastic properties. Calcein-AM/PI staining was performed to evaluate the biosafety of the hydrogel culture system. We confirmed that the proliferation of CAL-27 tongue squamous cells significantly increased with increased matrix stiffness after 5 d as assessed by MTT. After 15 d of incubation, the tumor spheroid diameter of the 1%-4D group was larger than that of the hydrogel-only culture. The Transwell assay demonstrated that mechanical stress stimulation and increased matrix stiffness could enhance cell aggressiveness. Flow cytometry experiments revealed a decrease in the number of cells in the resting or growth phase (G0/G1 phase), coupled with an increase in the proportion of cells in the preparation-for-division phase (G2/M phase). RT-PCR confirmed decreased expression levels of P53 and integrinβ3 RNA in the 1%-4D group after 21 d of 4D culture, alongside significant increases in the expression levels of Kindlin-2 and integrinαv. Immunofluorescence assays confirmed that 4D culture enhances tissue oxygenation and diminishes nuclear aggregation of HIF-1α. This device mimics the microenvironment of tongue cancer cells under mechanical force and increased matrix hardness during tongue movement, faithfully reproducing cell growthin vivo, and offering a solid foundation for further research on the pathogenic matrix of tongue cancer and drug treatments.

A systematic study on wear behavior of TiCrNbTaWx refractory high-entropy alloy: Inducing amorphization to achieve anti-wear

Refractory high-entropy alloys (RHEAs) possess exceptional properties at elevated temperatures. However, their limited wear resistance at room temperature (RT) hinders their widespread application. In this work, based on compositional modulation and surface engineering strategies, two TiCrNbTaWx (x = 0, 0.5) RHEAs were prepared using spark plasma sintering. The results show that the addition of W can effectively improve the hardness (10.3 GPa) and deformation resistance of the BCC matrix, alleviating the severe adhesion and the fracture behavior. In addition, the friction-induced oxidized amorphous layer with high hardness (12.3 GPa) can further improve the anti-wear properties. Because of these, the TiCrNbTaW0.5 alloy has a low wear rate of 9 × 10−5 mm−3·N−1·m−1, which is 67 % lower than the pristine TiCrNbTa alloy. In conclusion, our design strategy provides a new idea for designing RT wear-resistant RHEAs.

Microstructure evolution and enhanced mechanical performance of multilayer MXene-reinforced silver matrix composites

In this study, multilayer MXenes were first incorporated into an Ag matrix through a hetero-agglomeration process followed by spark plasma sintering (SPS), with the microstructural evolution of MXenes during composite fabrication characterized using transmission electron microscopy. The partial decomposition of MXene and transformation into rutile-TiO2 nanoparticles occurred during SPS, facilitating the generation of submicron Ag grains through effective pinning. As revealed by the Vickers hardness measurements and tensile tests, the addition of 3 vol% MXene increased the hardness and yield strength of the Ag matrix from 57.7 HV and 97.5 MPa to 116.0 HV and 129.1 MPa, representing increases of 101 % and 32 %, respectively. Quantitative calculations suggested that the improved mechanical properties of the MXene/Ag composites were primarily due to grain refinement strengthening. Meanwhile, the electrical and thermal conductivities of the 3 vol% MXene/Ag composite decreased by 9 % and 11 %, respectively. However, the ultimate tensile strength and ductility of the composites were lower than those of pure Ag, attributed to the weak MXene-Ag interfacial bonding and fracture surface observations, as well as the presence of accordion-like structures in MXene. Compared with conventional Ag matrix composites, MXene/Ag composites demonstrate a superior balance of mechanical and physical properties, making them highly suitable for applications in electrical devices. This work enhances our understanding of the interface phenomena between MXenes and metals, providing new insights for designing novel Ag matrix composites for use in conductive devices.

Adapting high-speed indentation mapping for investigating microstructure-property correlations in chromium carbide-nickel alloy coatings: Challenges and solutions

This study investigates the microstructural and mechanical characteristics of chromium carbide‑nickel rich alloy coatings produced through laser cladding, detonation spraying, and plasma spraying techniques. While all three processing techniques used the same feedstock powder, each method yields coatings with unique microstructures encompassing varying compositions and length scales. Employing Field Emission Scanning Electron Microscopy (FE-SEM) in combination with Energy Dispersive Spectroscopy (EDS) and nanoindentation mapping, local microstructure and mechanical properties were assessed at the micrometre length scale. Laser-clad coatings exhibit a typical metal matrix composite microstructure with high carbide content, distinct (MoNb)C2 phases, and Fe in the metallic matrix, while the thermal sprayed coatings showed carbides of varying sizes and metallic matrix with varying degrees of chromium dissolved in it. The instrumented indentation technique helped precisely record the microstructural features in all the coatings. Chromium carbide consistently emerges as the hardest phase across all coatings, with variations in metallic matrix hardness. Higher matrix hardness in thermal sprayed coatings correlates with increased Cr content, attributed to extended solid solubility of Cr and the presence of Mo and Nb. Energy dispersive spectroscopy and transmission electron microscopy provided clearer insight into the microstructure. This study highlights a direct one-to-one correlation between microstructure and mechanical properties mapped using instrumented indentation techniques in chromium carbide‑nickel rich coatings across different deposition methods.

Unveiling the self-healing behavior of marine exposed concrete: Nondestructive ultrasonic detection and Vickers hardness characterization

Cracking is a widespread phenomenon throughout the service of concrete structures for marine and offshore engineering. In this paper, the effect of sulfate ions and related cations on the crack closure behavior of cracked mortar in chloride-containing environments was studied. To this end, the mortars are cracked before transferring to the pure chloride solution as well as composite chloride and sulfate solutions (CNS and CMS series). The self-healing behavior is assessed by the evolution of crack width, water absorption, and nondestructive ultrasonic detection. The Vickers hardness test is applied to evaluate the micro-hardness of self-healing products generated in the crack gaps. Thermodynamic modeling of the phase volume expansion from the mortar matrix to the crack surface is conducted using Gibb’s free energy theory to explore the self-healing mechanisms. Experiment results suggest that the existence of sulfate ions in chloride-containing solutions is beneficial for crack closure, and self-healing could be more obvious if the cations that bind to sulfate are magnesium ions. The distributions of Vickers hardness on the mortar surface across the crack reveal that the brucite layer diminishes the overall Vickers hardness of the mortar matrix, whereas it is favorable for the micro-hardness enhancement of self-healing products in the CMS series. Thermodynamic modeling interprets the expansion rates relative to the original unhydrated cement under the action of different soaking solutions.

Analysis of abrasive impact wear of the Mn8/SS400 bimetal composite using a newly designed wear testing rig

In this study, the abrasive impact wear behaviour of a bimetal composite made of medium manganese steels (MMSs) and low carbon steels (LCSs), i.e., the Mn8/SS400 bimetal composite, was investigated using a newly designed wear-testing rig. The need for a new rig arose from the difficulty in replicating real-world wear conditions. Our rig allows for precise control and measurement of wear, simulating harsh environments more accurately than other wear-testing rigs. The bimetal composite Mn8/SS400 demonstrated superior wear resistance, showing an improvement of up to 2.8 times compared to benchmark steels, attributed to its enhanced work hardening sensitivity. Scanning electron microscopy (SEM), X-ray diffractometer (XRD), and electron backscatter diffraction (EBSD) analyses were employed to elucidate the wear mechanisms. After 300 h of abrasive impact wear, the subsurface microhardness of Mn8 reached 601.31 HV, significantly higher than that of the matrix hardness of 292.24 HV, indicating a substantial work hardening effect. The wear mechanism of the Mn8/SS400 bimetal composite was found to be a synergistic effect of grain refinement strengthening, dislocation strengthening, and twin strengthening. Initially, twin strengthening was the dominant mechanism up to 200 h of wear testing. However, after 300 h, contributions from all three mechanisms became increasingly significant, enhancing the overall wear resistance of the composite.

Mechanical and ballistic studies of boron carbide filler reinforced glass fiber composites

AbstractOwing to the outstanding properties of boron carbide (B4C) particles, material researchers have shown potential in filler‐reinforced polymer composites. The present work studied the implication of B4C fillers on the mechanical and ballistic properties of glass fiber epoxy reinforced composites. Two different weight percentages of 2 and 4 wt% B4C fillers were used to modify the epoxy resin. The composite samples with glass fabric woven were made through compression molding. The results show that the tensile, flexural, interlaminar, impact strength and hardness of glass fiber composite were improved by addition of 2 wt% of B4C. The high‐velocity ballistic tests were conducted on the unfilled and B4C filler‐reinforced composites using a 9 mm parabellum projectile with an initial striking of 372 ± 15 m/s. The least back face signature (BFS) and highest specific energy absorption (SEA) were observed for 2 wt% B4C filler composite. Adding B4C filler enhanced matrix toughening and interfacial bonding between fiber and matrix. Matrix cracking and fiber breakage result in the least ballistic resistance for unfilled composite. Fracture behavior was studied on tensile, impact, and ballistic‐tested samples using scanning electron microscopy. The fractured surfaces of filler‐reinforced composite demonstrated good interfacial bonding, matrix hardening, and fiber pullouts.Highlights The addition of B4C with epoxy up to 2 wt% improves the mechanical and ballistic properties of the composites. The least back face signature and highest specific energy absorption were observed for 2 wt% B4C filler composite. B4C filler enhanced matrix toughening and interfacial bonding between fiber and matrix. Failure of unfilled glass fiber composites is a combination of matrix cracking, fiber pullout, and interface debonding.

Microstructure and oxidation of a Ni–Al based intermetallic coating formation on a Monel-400 alloy

Abstract The purpose of this work was to examine how the microstructure and oxidation characteristics of Monel 400 Alloy were affected by the low-temperature aluminizing method. Monel 400 alloy was subjected to a low-temperature aluminizing procedure for 2 and 4 h at 600, 650, and 700 °C. Pure aluminum powder was used as the source of aluminum deposition to prepare the packs for the process. The activator and inert filler utilized were ammonium chloride (NH4Cl) and Al2O3 powder, respectively. The coating surfaces were characterized using energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM), as well as X-ray diffraction (XRD) analysis. It was discovered that the through-thickness variance in the layer microstructure varied between 4 and 30 µm, and that it increased with greater process temperatures and times. The coating layer hardness grew to 800 HV after the deposition process, whereas the matrix hardness remained at 200 HVN. Furthermore, the sample that was coated at 600 °C for 4 h was exposed to oxidation at 750–800 and 850 °C. It was found that the oxidation kinetics were 176 kJ/mol.

Enhanced sintering resistance in LaYbZr2O7 system through HfO2 doping for thermal insulation ceramic materials

AbstractThe increase in operating temperature contributes to improving the performance and fuel utilization efficiency of gas turbines. However, it also places thermal barrier coatings (TBCs) in a more demanding working environment, requiring higher sintering resistance and better mechanical properties. In the present study, HfO2 was introduced into the dual‐phase LaYbZr2O7 system as a doping oxide to form the LaYb(HfxZr1−x)2O7 system. The research concentrated on its phase composition, mechanical properties, and thermophysical properties. The results show that substituting Hf for Zr does not alter the dual‐phase structure of the system. The mutual inhibition between the two phases and the inherent material‐binding capability of Hf further reduce the grain size compared to pure LYZO. Additionally, the presence of Hf reduces the tendency of Frenkel defect formation and cation migration frequency, effectively inhibiting ion diffusion and thereby suppressing the densification and shrinkage trends of the material. The system retains relatively high hardness, fracture toughness, and low elastic modulus of the LYZO matrix, with a decrease in thermal conductivity and an increase in infrared reflectivity. These results suggest that Hf doping enhances the sintering resistance of LYZO material, making them promising for high‐temperature TBCs. Our study presents a viable approach to enhance the sintering resistance of LYZO, and this methodology can be extrapolated to other rare‐earth zirconates.

Effect of sintering temperature on the properties of titanium matrix composites reinforced with Al0·5CoCrFeNi high-entropy alloy particles

In this study, the organization and mechanical properties of the composites were analyzed at different sintering temperatures, and it was found that the local high-temperature phenomenon of discharge plasma sintering led to rapid melting and element diffusion at the junction of the high-entropy alloy particles and the Ti matrix, resulting in the formation of the interfacial layer. The increase in sintering temperature promoted close bonding between particles and element diffusion, caused lattice distortion and new phase formation, and increased the thickness of the interface layer and precipitated phase at the grain boundary. Most of the high-entropy alloy particles were dissolved when the sintering temperature reached 1050 °C. The composites were characterized by a high sintering temperature. The comprehensive mechanical properties of the composites first increased and then decreased when the sintering temperature increased, and they were optimized at 850 °C. The nanoindentation results show that the increase in sintering temperature leads to a decrease in the hardness of the high-entropy alloy particles, an increase in the hardness of the titanium matrix, and a higher hardness of the interfacial layer than that of the high-entropy alloy particles and the titanium matrix.