High Entropy Alloy Matrix Composites Research Articles

Mechanical properties and corrosion behavior of SiC reinforced high entropy alloy (Ni-Co-Fe-Ti) matrix composites produced by microwave and conventional sintering techniques

Abstract The aim of this work is to synthesize SiC reinforced Ni-Co-Fe-Ti composite using powder metallurgy (PM) method. Two sintering methods, conventional sintering (CS) using a tubular furnace and microwave sintering (MWS), are employed to synthesize three different weight percentages of SiC (3 wt.%, 6 wt.%, and 9 wt.%) within a Ni-Co-Fe-Ti matrix. The densification behavior of synthesized Ni-Co-Fe-Ti-SiC composites are studied using sinterability function. The highest sinterability of 0.89 was achieved for Ni-Co-Fe-Ti-0 wt.wt.% SiC alloy. The densification rate was found to be higher in MW sintered composites compared to those sintered conventionally. 3.5 wt.% NaCl solution was considered for corrosion examination and it was determined that Ni-Co-Fe-Ti- 9 wt.% SiC MW sintered composite exhibit highest corrosion resistance. Ni-Co-Fe-Ti-9 wt.%SiC MW sintered composite exhibits higher compressive strength of 1050 MPa than conventional sintered Ni-Co-Fe-Ti-9 wt.%SiC (625MPa). Ni-Co-Fe-Ti-6wt.% SiC MW sintered composite possess highest hardness of 58 HRC among other prepared composites. Interestingly, decreasing trend in hardness was observed for further inclusion of SiC with Ni-Co-Ti-Fe matrix. Scanning electron microscopy (SEM) and microstructural characterization technique shows the formation of pores in the conventional sintered composites. But, there is no formation of pores in the MW sintered composite of all the composition. Tribological studies were conducted using pin on disc method. Worn surface morphology was analyzed and it shows that severe pullout was observed in the worn surface of conventional sintered Ni-Co-Fe-Ti- 6wt.%SiC.The best optimum set of parameters (Sliding Speed 1146 rpm, SiC inclusion 6 wt.%, Applied Load 20 N) were found out using Taguchi method.

Revealing the Microstructure Evolution and Mechanical Properties of Al2O3-Reinforced FCC-CoCrFeMnNi Matrix Composites Fabricated via Gas Atomization and Spark Plasma Sintering

In the present work, novel Al2O3 particles were used to reinforce heterogeneous CoCrFeMnNi high-entropy alloy (HEA) matrix composites with nano- (5.0 wt.%) and nano- + micro- (5.0 wt.% + 10.0 wt.%) specimens. Al2O3 particles were fabricated via gas atomization and spark plasma sintering. The microstructure evolution and properties, i.e., density, hardness, and room temperature compression, were systematically investigated. The results indicate that the concentration of the Cr element in the pure CoCrFeMnNi HEA and the HEA matrix composite can be effectively reduced by using a gas-atomized HEA powder as the matrix. The formation of an impurity phase can also be inhibited, while the distribution uniformity of matrix elements can be improved. The composites prepared via gas-atomized powders formed a network microstructure composed of continuous Al2O3-rich regions and isolated Al2O3-poor regions, exhibiting good plasticity and improved density. The relative densities of the pure HEA, nano- (5.0 wt.%), and nano- + micro- (5.0 wt.% + 10.0 wt.%) composites were 98.9%, 97%, and 94.1%, respectively. The results demonstrate a significant improvement in the relative densities compared to the values (97.2%, 95.7%, and 93.8%) of the composites prepared via mechanical alloying. In addition, compared to the compressive fracture strains of nano- (5.0 wt.%) and nano- + micro- (5.0 wt.% + 10.0 wt.%) composites based on the mechanically alloyed HEA powder, the values of the nano- (5.0 wt.%) and nano- + micro- (5.0 wt.% + 10.0 wt.%) specimens prepared via gas atomization and spark plasma sintering increased by 80% and 67%, respectively.

Steam oxidation properties of graphene reinforced bioinspired laminated CoCrFeNiMn high-entropy alloy matrix composites at 1000 ℃

Laminated CoCrFeNiMn high-entropy alloy (HEA) matrix composites reinforced with 1.0 wt% graphene nanoplatelets (GNPs) were fabricated by mechanical ball milling and flake powder metallurgy, and were isothermal oxidized at 1000 ℃ for 100 h. Vacuum hot-pressure sintering (VHPS) shows a distinct nacre structure with the microstructure composed of FCC matrix phase, Cr23C6, CrMn1.5O4 precipitated phases, numerous dislocations and twins. High-temperature oxidation tests showed that the composites had mass gains at 12 h intervals from 12 to 100 h respectively. The oxidation kinetic curve changes from a linear pattern in the early stages to an exponential pattern in the later stages, which demonstrates better long-term oxidation resistance. The anisotropy of the laminated structure results in excellent resistance to high-temperature steam oxidation in the vertical lamellar direction. Observation of the cross-section reveals that although Cr2O3 (inner layer) is present, (Mn, Cr)3O4 and Mn3O4 are the dominant oxides (outer layer). Elemental depletion zones for Mn and Cr exist in the region of the matrix near the oxide scales. The results show that the oxidation resistance of the laminated GNPs/CoCrFeNiMn composites is mainly influenced by the diffusion of Mn and Cr elements, the microstructure of the laminations and the internal oxidation.

In-situ development of Ti(C, N) and their effect on microstructure，wear and corrosion properties of CoCrFeNiTi high-entropy alloy matrix composites

In situ Ti(C, N) reinforced high-entropy alloy (HEA) matrix composites were fabricated spark plasma sintering (SPS). The effects of Ti(C, N) on the microstructure, wear and corrosion behaviour of the composites were systematically investigated in this study. The Ti(C, N) particles were uniformly distributed and well bonded to the HEA interface. Hardness analysis revealed that the addition of Ti(C, N) significantly increased the hardness of the composites from 776Hv to 1256.3Hv. Additionally, when Ti(C, N) was incorporated, the wear mechanisms of High Entropy Alloys (HEA) changed from adhesive wear, oxidative wear, and delamination to abrasive and oxidative wear. The Ti(C, N)/HEA composite showed the highest nano-hardness, resulting in the wear rate of the composites was significantly lower than that of the HEA. In H2SO4 solution, pitting corrosion mainly occurs in HEA. However, the introduction of Ti(C, N) resulted in finer grains and the formation of a denser and more stable passivation film on the composite surface. This inhibited pitting, leading to lower corrosion current density and higher polarization impedance compared to HEA Alloy.

Study on Microstructure and Properties of WC Particle-Reinforced FeCoCrNi-Matrix High Entropy Alloy Composites

In recent years, high entropy alloy (HEA) matrix composites have undergone rapid development. In this work, the effects of different WC contents (10 wt.%, 20 wt.%, and 30 wt.%) on the microstructure, mechanical properties, and wear resistance of FeCoCrNi HEA matrix composites prepared by spark plasma sintering (SPS) were studied. The results show that the WC–HEA composites are mainly composed of an FCC matrix phase (Ni, Fe) and carbide phases (Cr7C3, Co3W3C, WC, etc.). The hardness of the 30 WC–HEA composites was the highest at 459.2 HV, which is 71.2% higher than the 268.3 HV of the pure matrix material. Similarly, the compressive yield strength of the 30 WC–HEA composite was the largest, reaching 1315.1 MPa, which is 112.1% higher than that of the pure matrix material. However, the compression deformation rate of the 30 WC–HEA composite significantly decreased to 16.6%. Under the same dry friction conditions, the addition of an appropriate amount of WC particles can reduce the friction coefficient of the HEA matrix. The wear volume of the composites decreased rapidly with the increase of WC content. The wear volume of 30 WC–HEA was the lowest, only 3.17% of that of the pure matrix material.

Preparation of graphene film reinforced CoCrFeNiMn high-entropy alloy matrix composites with strength-plasticity synergy via flake powder metallurgy method

Inspired by the design principle of pearl structure, a bottom-up flake powder self-assembly arrangement strategy, flake powder metallurgy, is used to prepare graphene films (GFs) reinforced CoCrFeNiMn high-entropy alloy (HEA) matrix composites with a pearl laminated structure. Flaky HEA powder was prepared by ball milling method and homogeneously mixed with Ni plated GFs. Vacuum hot-press sintering (VHPS) technique was carried out to solidify the mixed powders to obtain composites with uniform distribution of GFs(Ni) and flaky HEA. The results show that the bottom-up preparation strategy can effectively fabricate bionic laminated HEA matrix composites, and the composites have a distinct pearly laminated structure. The tensile strength of the composites with 5 vol% GFs(Ni) content reached 834.04 MPa, and the elongation reached 26.58 %. The compressive strength in parallel and perpendicular laminar directions reached 2069.66 MPa and 2418.45 MPa at 50 % strain, respectively. The laminated GFs(Ni)/HEA matrix composites possessed excellent strength and maintained good plasticity. In this study, the strengthening and toughening mechanism of the laminated GFs(Ni)/HEA matrix composites is discussed in detail, and the results show that the laminated structure and GFs(Ni) are favorable for the hardening and strengthening of the HEA matrix.

Insight of novel CoCrFeMnNi–Al2O3p high entropy alloy matrix composites by mechanical alloying and spark plasma sintering

In the present work, novel nano-Al2O3p reinforced heterogeneous CoCrFeMnNi matrix composites with 0–7.5 wt% Al2O3p were fabricated by mechanical alloying (MA) and spark plasma sintering (SPS) method. The microstructure evolution and properties, i.e., density, hardness and room temperature compression were systematically studied. The results show that different degrees of heterogeneous matrix organization occurred in the composites. The CoCrFeMnNi-2.5 wt%Al2O3p composite consists of CG region and UFG region of uniformly distributed nano-Al2O3p. And the addition of nano-Al2O3p can effectively refine the matrix grains. Compared to pure HEA, the grain size of CoCrFeMnNi-5.0 wt%Al2O3p composite is refined by 48.5%. With the increase of nano-Al2O3 content, the hardness values of the composites increased by 23.6%–56.7% than those of pure HEA. Among the nanocomposites, the CoCrFeMnNi-5.0 wt%Al2O3p composite exhibits the best strengthening effect, while the CoCrFeMnNi-2.5 wt%Al2O3p composite shows a superior strong-plastic synergistic effect with yield strength, ultimate compressive strength and fracture strain of 913 MPa, 1935 MPa and 38%, respectively. However, with the Al2O3p content further increases to 7.5 wt%, both the strength and plasticity of the composite decrease due to the serious agglomeration of nanoparticles.

Graphene enables equiatomic FeNiCrCoCu high-entropy alloy with improved TWIP and TRIP effects under shock compression

Graphene (Gr) reinforced high-entropy alloy (HEA) matrix composites are expected as potential candidates for next-generation structural applications in light of outstanding mechanical properties. A deep comprehension of the underlying deformation mechanisms under extreme shock loading is of paramount importance, however, remains lacking due to experimentally technical limitations in existence. In the present study, by means of nonequilibrium molecular dynamics simulations, dynamic deformation behaviors and corresponding mechanisms in equiatomic FeNiCrCoCu HEA/Gr composite systems were investigated in terms of various shock velocities. The resistance to dislocation propagation imparted by Gr was corroborated to encourage the elevated local stress level by increasing the likelihood of dislocation interplays, which facilitated the onset of twins and hexagonal close-packed (HCP) martensite laths. Meanwhile, the advent of Gr was demonstrated to endow the HEA with an additional twinning pathway that induced a structural conversion from HCP to parent face-centered cubic (FCC) inside HCP martensite laths, different from the classical one that necessitated undergoing the intermediate procedure of extrinsic stacking fault (ESF) evolution. More than that, by virtue of an increase in flow stress, the transformation-induced plasticity (TRIP) effect was validated to be additionally evoked as the predominant strain accommodation mechanism at higher strains on the one hand, but which only assisted plasticity in pure systems, and on the other hand, can also act as an auxiliary regulation mode together with the twinning-induced plasticity (TWIP) effect under intermediate strains, but with enhanced contributions relative to pure systems. One may expect that TRIP and TWIP effects promoted by introducing Gr would considerably inspire a synergistic effect between strength and ductility, contributing to the exceptional shock-resistant performance of FeNiCrCoCu HEAs under extreme regimes.

Cracking behavior of newly-developed high strength eutectic high entropy alloy matrix composites manufactured by laser powder bed fusion

A novel AlCoCrFeNi2.1 eutectic high entropy alloy (EHEA) composite doped with SiC particles was designed and fabricated by laser powder bed fusion (LPBF). Its microstructure characteristic, tensile properties, and metallurgical defects, with an emphasis on cracking behavior, have been investigated. The results showed that the addition of SiC particles into the AlCoCrFeNi2.1 matrix enabled the development of a {100} texture and highly elongated columnar grains, which were the main contributors to mechanical behavior anisotropy. The ultimate tensile strength of 1466 ± 26 MPa and elongation of 9% ± 3% achieved in the as-deposited EHEA composite surpassed those of advanced metal alloys subjected to additive manufacturing processes. Unfortunately, severe horizontal and longitudinal cracks, as well as a few micro-cracks were observed in the as-deposited bulk samples. Micro-cracks were verified to be associated with the aggregation of carbon and oxide particles. They formed in the final stage of solidification owing to insufficient liquid feeding ability and solidification contraction. The formation of macroscopic cracking was induced by the tensile stress accumulations at sample edges, and the stress concentration areas where microcracks and pores were located were the predominant propagation location. This work provides guidelines for defect control in SiC-reinforced EHEA, assisting in the high-performance design and integrated manufacturing of EHEA composite components.

Investigations on Silicon Carbide Reinforced High Entropy Alloy (CoCrNiMnFe) matrix Composites Produced by Powder Metallurgy Process

Investigations on Silicon Carbide Reinforced High Entropy Alloy (CoCrNiMnFe) matrix Composites Produced by Powder Metallurgy Process

A novel NbC/CrMnFeCoNi0.8 high entropy alloy matrix composites with ultrastrength and ductility: Experiments and density function theory

In this work, NbC particle-reinforced CrMnFeCoNi0.8 high-entropy alloys (HEAs) matrix composites were prepared by induction melting method. With increasing NbC content, the strength of the composites increases first and decreases afterwards, while the ductility decreases monotonically. The composite with 5 vol% NbC exhibits an excellent combination of yield strength (458.9 MPa), ultimate tensile strength (917.9 MPa), and ductility (29.0% elongation). The enhanced strength of the composite can be attributed to the synergy of various strengthening mechanisms, including dislocation strengthening, Orowan strengthening and load-bearing effect. Density functional theory (DFT) calculations revealed that the addition of NbC particles increases the value at Fermi level for individual elements in the HEA matrix, which provides support for improving mechanical properties of the NbC-reinforced composites.

The effect of different Ag addition on microstructure, mechanical properties and tribological behavior of CoCrFeNiMn-Cr3C2 composite

CoCrFeNiMn high entropy alloy (HEA) matrix composites with Cr3C2 reinforcement (10 wt%) and different mass friction of Ag lubricant (10, 15 and 20 wt%) were produced by spark plasma sintering. The composites consist of HEA’s FCC phase, Cr7C3 phase and Ag phase, and the microstructures of composites are dense and uniform. The ultimate plasticity strain and fracture toughness improve with the addition of Ag increasing at room temperature. The composites exhibit excellent self-lubricating and wear resistance below 400 °C, and the composite with 20 wt% Ag content has the lower friction coefficient and wear rate. The Ag addition exhibits positive role in improving the wear behavior at medium-low temperatures. The main wear mechanisms of the composites are micro-cutting and abrasive wear at low temperatures. At high temperatures, the oxide tribo-layer generates on the wear surface and deeply torn. Oxide wear and surface deformation are the main wear mechanisms.

Microstructure and mechanical properties of bioinspired laminated CoCrFeNiMn high entropy alloy matrix composites reinforced with graphene

Due to the hierarchical structure and associated multi-scale toughening mechanisms of biological materials such as shells in nature, they often have unique properties that differ from the synthetic materials. Inspired by the ultra-tough nacre structure, the laminated CoCrFeNiMn high entropy alloy (HEA) and the laminated graphene nanoplatelets (GNPs) reinforced CoCrFeNiMn HEA matrix composites were fabricated by flake powder metallurgy and vacuum hot-pressure sintering (VHPS) to create a "brick-mortar" structure of nacre based on HEAs. Tensile and compression tests were used to test the mechanical properties, the results showed that the laminated HEA and composites yielded tensile strengths of 673.49 MPa and 826.39 MPa while maintaining good elongation of 21.22% and 16.31% respectively, whose compressive strengths achieved 2177.47 MPa and 2530.13 MPa at 50% elongation. The laminate structure leads to crack deflection and microstructure has numerous dislocations and twins, which further increase strength with good plasticity, leading to excellent strength-plasticity synergy. The strengthening and toughening mechanisms are discussed based on the fracture morphology and microstructure of the SEM and TEM images. Bioinspired laminated HEA have been an innovative direction in recent years. This study provides a relatively simple method for the development of HEAs in combination with nacreous lamellar structure.

Achieving superior strength-ductility synergy by constructing network microstructure in Ti-based high-entropy alloy matrix composites

In-situ (Ti,Nb)B whiskers ((Ti,Nb)Bw) reinforced Ti-based high-entropy alloy (HEA) matrix composites ((Ti,Nb)Bw/Ti1.5ZrNbAl0.3) with a quasi-continuous network microstructure were successfully fabricated via low energy milling (LEM) and hot-pressed sintering (HPS). The results show that the in-situ (Ti,Nb)Bw reinforcements were distributed around Ti1.5ZrNbAl0.3 matrix particle forming a special network architecture. This microstructure resulted in remarkable grain refinement of Ti-based HEA matrix, which contributed to the superior strength-ductility synergy. Consequently, the as-sintered (Ti,Nb)Bw/Ti1.5ZrNbAl0.3 composites exhibited a high yield strength (σYS = 1015 MPa) while maintaining superior ductility (ϵe = 17.5%), which were simultaneously increased by 11.5% and 96.6% compared with the monolithic Ti1.5ZrNbAl0.3 alloy. The network microstructure design of HEA-based composites could be therefore exploited to overcome the strength-ductility trade-off.

Exceptional strength-ductility combination of additively manufactured high-entropy alloy matrix composites reinforced with TiC nanoparticles at room and cryogenic temperatures

The cryogenic mechanical properties and deformation behaviour of additively manufactured (AM) medium/high-entropy alloys (MEA/HEA) and their composites are seldom studied. This work fills this gap by systematically studying the mechanical properties, deformation behaviour and strengthening mechanism of the additively manufactured CoCrFeMnNi high-entropy alloy (HEA) and 2 wt% TiC/CoCrFeMnNi composite (HEC) at room (293 K) and cryogenic (93 K) temperatures. The TiC nanoparticles promote the densification behaviour, and they are uniformly distributed around and in interior of the cellular substructures of the HEC sample. The tensile tests reveal that the strength and ductility can be simultaneously increased in both HEA and HEC samples when the temperature decreases from 293 K to 93 K. The TiC nanoparticles significantly promote a remarkable combination of strength and ductility in the HEC at both 293 K and 93 K, and the cryogenic tensile strength of HEC (1506 ± 6.6 MPa) is the highest value reported for AM-fabricated MEA/HEAs. For the HEA sample, the significant increase in strength and ductility is attributed to an additional hardening contribution induced by multiple twin systems at 93 K, which results in a steady and even increased strain hardening rate. When the temperature decreases from 293 K to 93 K, a remarkable yield strength increment (344.4 MP) is found in the HEC sample, which is significantly higher than that of HEA (229.0 MPa). The difference in the increase in yield strength between HEA and HEC sample is ascribed to the difference in dislocation strengthening and Orowan strengthening, which are related to the temperature-dependent thermal expansion coefficient and elastic modulus, respectively. However, the HEC sample has a smaller ductility increase (10.3%) than the HEA sample (26.4%), since no additional hardening mechanism is generated during the cryogenic deformation in the HEC sample. This research provides a new route to design materials with a good combination of strength and ductility for cryogenic applications.

Enhanced tensile properties of CrMnFeCoNi0.8 high entropy alloy with in-situ TiC particles

In-situ TiC particulate reinforced CrMnFeCoNi0.8 high entropy alloy (HEA) matrix composites were prepared by induction melting method. The effect of TiC content upon the microstructure and tensile properties of as-cast samples were analyzed and discussed. The HEA matrix has single-phase face-centered cubic (FCC) structure, determined by X-ray diffraction (XRD) pattern. Compared to the CrMnFeCoNi0.8 matrix, 7.5 vol%TiC/CrMnFeCoNi0.8 composite possessed remarkable yield strength (517.1 MPa vs 240.9 MPa), ultimate tensile strength (926.2 MPa vs 527.5 MPa) and excellent uniform elongation (38.0%). Strong dislocation interactions, load-bearing effect and Orowan mechanism afforded by in-situ TiC particles, together with solid-solution strengthening via C and Ti elements, are responsible for the strength enhancement.

Laser additive manufacturing of nano-TiC particles reinforced CoCrFeMnNi high-entropy alloy matrix composites with high strength and ductility

CoCrFeMnNi high-entropy alloy (HEA) matrix composites reinforced with nano-sized TiC particles were successfully fabricated by laser powder bed fusion (LPBF), which is widely used laser additive manufacturing technology. The microstructural evolution and mechanical properties of the HEA composites fabricated at various processing conditions, were investigated. The LPBF-fabricated HEA composites showed typical hierarchical microstructure characteristics including epitaxially grown columnar grains, submicron-sized cellular substructures, nano-sized precipitates, and a high density of dislocations. The rapid solidification process inherent to LPBF resulted in micro segregations of Mn and Ni along the cell walls, which contributed to a pronounced impurity-drag effect toward the present dislocations. TiC1-x with a size of 35–100 nm uniformly precipitated along the cell boundaries as well as inside the cells. Entangled dislocations easily formed around the cell walls and the nano-TiC1-x precipitates leading to a high dislocation density in the LPBF-fabricated HEA composites. The HEA composites with 1 wt% nano-TiC addition exhibited a promising mechanical performance readily characterized by a yield strength of 779 MPa, tensile strength of 940 MPa and an elongation of 30%. The advantageous combination between strength and ductility can be attributed to the prevailing subgrain boundaries, solid solution strengthening, grain refinement, nano-precipitation hardening, dislocation hardening, plasticity and storage. This work demonstrates the importance of hierarchical microstructures of HEA materials via incorporation of nano-sized TiC particles for imparting exceptional mechanical properties.

Microstructure and mechanical behaviors of in-situ SiC particle reinforced Fe2.5CoNiCu high-entropy alloy composites

The in-situ SiC particulate (5 vol% and 10 vol%) reinforced Fe2.5CoNiCu high entropy alloy (HEA) matrix composites were fabricated via vacuum inductive melting. The matrix of the HEA composites consists of single FCC phase. Both the ultimate tensile strength (UTS) and ductility of the SiC/Fe2.5CoNiCu composites were significantly improved with the increase of SiC volume fraction. The solid-solution strengthening and dispersion strengthening are the governing mechanisms responsible for the strength enhancement.

Microstructure and mechanical properties regulation and control of in-situ TiC reinforced CoCrFeNiAl0.2 high-entropy alloy matrix composites via high-gravity combustion route

In this study, CoCrFeNiAl0.2(TiC)x (x = 0,0.06,0.12,0.2) composites were prepared by high-gravity combustion synthesis (HGCS). The mixture powders of several low-cost metal oxides (Co2O3, Cr2O3, Fe2O3, NiO), Al, Ti and C were used as raw materials. In the high-gravity field, the CoCrFeNiAl0.2 high-entropy alloys (HEAs) were obtained by inducing a thermic reaction between the several low-cost metal oxides (Co2O3, Cr2O3, Fe2O3, NiO) and Al powders. Then the TiC was in-situ synthesized by Ti and C powders. The results show that the size and distribution of the in-situ synthesized TiC can be controlled by adjusting the Ti and C additions and the value of high-gravity field. When the high-gravity field rises to 1200 g, the bending strength, compressive strength and specific strength of CoCrFeNiAl0.2(TiC)0.12 composites respectively up to 1.17 GPa, 2.13 GPa, 0.3 MPa·Kg−1·m−3. Therefore, the HGCS with ‘green’ and efficiency characteristics offers an alternative pathway to control the structure and properties of the ceramic/ HEAs composites.

In-situ TiC particles strengthen and ductilize Fe1.2MnNi0.8Cr high entropy alloy

In-situTiC particles reinforced Fe1.2MnNi0.8Cr high-entropy alloy matrix composites (HEACs) were prepared by vacuum induction melting. The effects of Ti and C additions on the microstructural evolution and mechanical properties of the new composites were investigated. It was found that by adding Ti and C, not only were TiC particles produced in situ, extra solid-solution effect was also introduced to strengthen the HEA matrix. As the volume fraction of TiC increased, both the ultimate tensile strength and the percent elongation of the composites first increased then decreased while the hardness increased and remained high. The ultimate tensile strength of the composites was found to reach 856 MPa when the content of TiC was 5.9 vol %, which is 30% greater than that of the HEA base. At the same time, the percent elongation was found to be 34%, an increase by 42% as compared to the HEA matrix. Due to the combined effects of Orowan mechanism, load transfer and solid solution strengthening, the new composites have achieved an unity of high tensile strength and good plasticity.