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The Nb-16Si-24Ti-2Al-2Cr alloy was prepared by plasma rotating electrode process (PREP) technology and the hot-pressing (HP) method, and the effects of sintering temperature on the microstructure, mechanical properties and fracture behavior were investigated. The HP alloys sintered at temperatures below 1400 °C are composed of Nbss (Nb solid solution), Nb3Si and Nb5Si3 phases. When the sintering temperature reaches 1450 °C, the Nb3Si phase is completely decomposed into Nbss and Nb5Si3 phases. Meanwhile, the microstructure coarsens significantly. Compared with the cast alloy, the HP alloy shows better mechanical properties. The fracture toughness of the alloy sintered at 1400 °C reaches 20.2 MPa·m1/2, which exceeds the application threshold. The main reason for the highest fracture toughness is attributed to the decomposition of large-sized brittle Nb3Si phase and the formation of a fine microstructure, which greatly increases the number of phase interfaces and improves the chance of crack deflection. In addition, the reduction in the size and content of silicides also reduces their plastic constraints on the ductile Nbss phase. [ABSTRACT FROM AUTHOR]

Graphene/copper composites are promising in electronic and energy fields due to their superior conductivity, but microstructure control during thermal mechanical processing (TMP) remains a crucial issue for the manufacturing of high-performance graphene/copper composites. In this study, the hot deformation behavior of graphene/copper composites was investigated by isothermal compression tests at deformation temperatures of 700~850 °C and strain rates of 0.01~10 s−1, and a constitutive equation based on the Arrhenius model and hot processing map was established. Results demonstrate that the deformation mechanism of the graphene/copper composites mainly involves dynamic recrystallization (DRX), and such DRX-mediated deformation behavior can be accurately described by the established Arrhenius model. In addition, it was found that the strain rate has a stronger impact on the DRX grain size than the deformation temperature. The optimum deformation temperature and strain rate were determined to be 800 °C and 1 s−1, respectively, with which a uniform microstructure with fine grains can be obtained. [ABSTRACT FROM AUTHOR]

FeCrNi medium entropy alloy (MEA) has been widely regarded for its excellent mechanical properties and corrosion resistance. However, insufficient strength limits its industrial application. Intermetallic particle dispersion strengthening is considered to be an effective method to improve strength, which is expected to solve this problem. In this work, microstructural evolution and mechanical behavior of FeCrNi MEA with different Si content were investigated. We found that the precipitation of fine σ particles can be formed in situ by thermomechanical treatment of Si doping FeCrNi MEAs. The FeCrNiSi0.15 MEA exhibits a good combination of strength and ductility, with yield strength and tensile elongation of 1050 MPa and 7.84%, respectively. The yield strength is almost five times that of the as-cast FeCrNi MEA. The strength enhancement is mainly attributed to the grain-boundary strengthening and precipitation strengthening caused by fine σ particles. [ABSTRACT FROM AUTHOR]

High-activity spherical TaNbTiZr refractory high-entropy alloy (REHA) powders were successfully prepared by electrode induction melting gas atomization (EIGA) and plasma rotating electrode process (PREP) methods. Both the EIGAed and PREPed TaNbTiZr RHEA powders have a single-phase body-centered cubic (BCC) structure and low oxygen content. Compared with the EIGAed powders, the PREPed powders exhibit higher sphericity and smoother surface, but larger particle size. The average particle sizes of the EIGAed and PREPed powders are 51.8 and 65.9 μm, respectively. In addition, both the coarse EIGAed and PREPed powders have dendritic structure, and the dendrite size of the EIGAed powders is larger than that of the PREPed powders. Theoretical calculation indicates that the cooling rate of the PREPed powders is one order of magnitude higher than that of the EIGAed powders during the solidification process, and the dendritic structure has more time to grow during EIGA, which is the main reason for the coarser dendrite size of the EIGAed powders. [ABSTRACT FROM AUTHOR]

[Display omitted] • A cobalt-free fcc FeCrNi MEA was manufactured by powder metallurgy method. • The alloy maintains high structural stability even at a high irradiation fluence of 5 × 1016 Au ions/cm2. • The alloy shows excellent irradiation-hardening resistance. • Microstructural evolution under high-fluence irradiation was revealed by molecular dynamics simulation. A cobalt-free FeCrNi MEA was successfully synthesized and irradiated with 7.5 MeV Au ions at room temperature over a wide fluence from 5 × 1015 to 5 × 1016 Au ions/cm2. Microstructural characterization shows that the FeCrNi MEA exhibits low structural damage and high phase stability under high-fluence ion irradiation, and diffuse dislocations and defect clusters, especially dislocation loops and stacking-faults (SFs), are the main microstructural feature after irradiation. Limited elemental segregation at grain-boundaries and nanoscale Au clusters can be observed only in the specimen irradiated at the highest fluence. Meanwhile, void formation and phase instability are absent in any irradiation condition. Cascade-collision simulation reveals that large-size vacancy cluster collapses into the stacking fault tetrahedrons (SFTs) and abundant dislocation structures, especially the high-fraction movable Shockley dislocations at the high-energy ion irradiation, contributing to the absence of voids and the easily activated dislocation networks. Owing to these microstructural features, the irradiated specimens only exhibit a slight hardness increase (26 % at 210 dpa), indicating a superior resistance to irradiation hardening. Overall, this work supports that the FeCrNi MEA possesses an outstanding irradiation tolerance especially under high-fluence ion irradiation, thereby having good application prospects in the field of advanced nuclear reactors. [ABSTRACT FROM AUTHOR]

Fine cellular substructures are typical microstructure feature of high entropy alloys (HEAs) produced via selective laser melting (SLM), playing a pivotal role in improving the mechanical properties. Nonetheless, the controlling of cellular substructure and its impact on the mechanical properties remains ambiguous. This study investigates the effect of energy densities on the cellular substructure evolution and mechanical properties of the FeCoCrNiMo 0.2 HEA. It is found the increase in energy density causes a decrease in temperature gradient (G) and solidification rate (R) in molten pool, consequently leading to the increase of cellular substructure size and the intensification of Mo segregation at cellular substructure boundaries. The cellular substructure size (d) can be described by formula d = 80 (GR) − 1 / 3 , in which G and R can be obtained from discrete element method - computational fluid dynamics (DEM-CFD) simulation. The strength of the FeCoCrNiMo 0.2 HEA is significantly affected by dislocation strengthening (σ d) and segregation strengthening (σ s), which are further determined by the cellular substructure size and the Mo segregation, respectively. The increase of cellular substructure size leads to the decrease of σ d , while the intensification of Mo segregation results in the increase of σ s. The competition between these two strengthening effects leads to an optimized and excellent tensile property of 707 MPa in yield strength, 947 MPa in ultimate tensile strength and 34 % in fracture elongation at a moderate energy density of 47 J/mm3. The findings provide guidance towards the advancement of high-performance high entropy alloys fabricated by SLM in terms of cellular substructure controlling. [ABSTRACT FROM AUTHOR]

A single-phase FeCrNi medium-entropy alloy (MEA) with a face-centered cubic structure was successfully fabricated by selected laser melting (SLM). The SLMed FeCrNi MEA exhibits hierarchical microstructures, including molten pools, coarse columnar grains, submicron cellular structures and high-density dislocations, and shows an excellent strength-ductility combination. Notably, the SLMed FeCrNi MEA has ultra-high yield strength and ultimate tensile strength of 1.1 GPa and 1.5 GPa, respectively, at 77 K, which are almost 1.5 times higher than those at room temperature, while still maintaining a high fracture elongation of 49%. It was also found that the SLMed FeCrNi MEA deformed at 77 K could produce more nanotwins compared with that deformed at room temperature. The twinning-prone matrix can produce more significant twinning-induced plasticity effects, which contributes to a high plasticity. Additionally, the high-density cellular substructure can effectively hinder dislocation motion, which is the main reason for the high strength. • FeCrNi MEA with hierarchical microstructure was fabricated by SLM. • Tensile properties at 77 K are significantly improved compared to room temperature. • A remarkable combination of strength (σ y = 1.1 GPa, σ UTS = 1.5 GPa) and ductility (ε f = 48%) is obtained at 77 K. • Highly activated twinning behavior and high-density cellular substructure are responsible for the high ductility and strength, respectively. [ABSTRACT FROM AUTHOR]

The single-phase face-centered cubic (FCC) structured FeCrNi medium entropy alloys (MEAs) exhibit high ductility but insufficient strength, which limits their engineering applications. Introducing hard intermetallic particles is an effective way to solve this problem. In this work, we found that the highly dispersed σ particles can be in-situ formed in the Mo-doping FeCrNi MEA by thermomechanical treatment, which can substantially increase the strength. The achieved FeCrNiMo 0.1 MEA has a high yield strength of 1.1 GPa and ultimate tensile strength of 1.3 GPa together with moderate elongation of 6.2%. The yield strength is almost five times that of the as-cast FeCrNi MEA. The fine σ particles can refine the grain size and hinder dislocation motion, which is the main reason for the significant increase in strength. • Highly dispersed σ particles are in-situ formed in the Mo-doping FeCrNi MEA by thermomechanical treatment. • The FeCrNiMo 0.1 MEA has a high yield tensile strength of 1.1 GPa and ultimate tensile strength of 1.3 GPa. • The high strength is attributed to the heterogeneous precipitation of the submicron-sized σ particles. [ABSTRACT FROM AUTHOR]

A novel non-equiatomic Al 15.85 Fe 11.15 Co 32.11 Cr 10.76 Ni 30.13 high entropy alloy (HEA) was fabricated via powder metallurgy (P/M) method. The Al 15.85 Fe 11.15 Co 32.11 Cr 10.76 Ni 30.13 HEA exhibits dual-phase microstructure consisting of face-centered-cubic (FCC) and body-center cubic (BCC) phases. The Al 15.85 Fe 11.15 Co 32.11 Cr 10.76 Ni 30.13 HEA has high compressive yield strength of 938 MPa and fracture strength of 3360 MPa, and still maintains moderate fracture strain higher than 40%. Also, the Al 15.85 Fe 11.15 Co 32.11 Cr 10.76 Ni 30.13 HEA has high strength of 518 MPa at the temperature of 600 °C. Microstructural characterization shows that a large number of L1 2 and B2 nanoprecipitates are uniformly dispersed in the FCC and BCC phases, respectively, contributing to the enhancement of the strength of the two phases. The effective combination of FCC and BCC phases eventually leads to the high strength of the Al 15.85 Fe 11.15 Co 32.11 Cr 10.76 Ni 30.13 HEA. This finding provides novel guidance for the development of high-performance structural materials with superior balance of strength and ductility for future industrial applications. • Novel Al 15.85 Fe 11.15 Co 32.11 Cr 10.76 Ni 30.13 HEA was prepared through powder metallurgy method. • The HEA exhibits dual-phase (FCC + BCC) microstructure. • Massive L1 2 and B 2 nanoprecipitates are embedded in the FCC and BCC phases, respectively. • The HEA exhibits high compressive yield strength of 938 MPa at room temperature. • The high strength is attributed to the hierarchically heterogeneous microstructure. [ABSTRACT FROM AUTHOR]

The equiatomic CoCrFeMnNi high entropy alloy, which crystallizes in the face-centered cubic (FCC) crystal structure, was prepared by the spark plasma sintering technique. Dynamic compressive tests of the CoCrFeMnNi high entropy alloy were deformed at varying strain rates ranging from 1 × 10 to 3 × 10 s using a split-Hopkinson pressure bar (SHPB) system. The dynamic yield strength of the CoCrFeMnNi high entropy alloy increases with increasing strain rate. The Zerilli-Armstrong (Z-A) plastic model was applied to model the dynamic flow behavior of the CoCrFeMnNi high entropy alloy, and the constitutive relationship was obtained. Serration behavior during plastic deformation was observed in the stress-strain curves. The mechanism for serration behavior of the alloy deformed at high strain rate is proposed. [ABSTRACT FROM AUTHOR]

• Novel TiNbTaZrHf based composite was synthesized through powder metallurgy method. • The composite exhibits ultra-high compression yield strength of 2620 MPa at room temperature. • The composite maintains high strength of 508 MPa at 1000 °C. • The strength improvement is attributed to the in-situ formed carbides. • Effect mechanism of carbides on high-temperature fracture behavior was revealed. Refractory high entropy alloys (RHEAs) have broad prospects in the field of high-temperature structural materials because of their outstanding mechanical properties at high temperatures. In this work, a novel TiNbTaZrHf based composite was fabricated by powder metallurgy in-situ method. By introducing carbides, the TiNbTaZrHf based composite exhibits an ultra-high yield strength of 2620 MPa at room temperature. Meanwhile, the composite still maintains a high strength of 508 MPa at 1000 °C. The significant strength improvement can be attributed to the load-bearing effect caused by the dispersed carbides with high volume fraction, while the intergranular fracture of carbides is responsible for the plastic instability. When the temperature rises to 1200 °C, the yield strength decreases significantly. The weakening of load-bearing effect and the activation of grain boundary sliding are the main reason for the strength reduction, while interfacial debonding between the matrix and carbides becomes the main failure behavior. [ABSTRACT FROM AUTHOR]

A series of novel lightweight TaNbVTi-based refractory high entropy alloys (RHEA) were fabricated through ball-milling and spark plasma sintering (SPS). The reinforced phase of TiO precipitates were in-situ formed due to the introduction of Al2O3 ceramic particles. The RHEA with 15% Al2O3 exhibits a high compressive yield strength (1837 MPa) and a low density (7.75 g/cm3) with an adequate ductility retention. The yield strength and density are 32% higher and 15% lower, respectively, compared to the RHEA without Al2O3 addition. The specific yield strength (237 MPa cm3/g) of the RHEAs is much higher than that of other reported RHEAs, and is mainly ascribed to the introduction of high volume fraction of Al2O3 additives, resulting in solid solution strengthening and precipitation strengthening. Meanwhile, the ductile matrix is responsible for the good compressive plasticity. [ABSTRACT FROM AUTHOR]

• Novel oxide dispersion strengthened FeCrNi alloys were fabricated by powder metallurgy technique. • The optimized combination of yield strength (1024 MPa) and fracture elongation (12.4%) is obtained. • Dispersed oxide nanoparticles and ultrafine-grained grains are responsible for the high yield strength. A series of oxide dispersion strengthened (ODS) FeCrNi medium entropy alloys (MEAs) were fabricated via mechanical alloying and spark sintering plasma (SPS). The ODS FeCrNi MEAs are mainly composed of fcc matrix, in which Y-Ti-O typed nanoparticles are uniformly distributed. Effects of TiH 2 and YH 3 additions on the mechanical properties were investigated. Increasing the addition of TiH 2 and YH 3 leads to the significantly enhanced strength while slightly decreased ductility. The optimized combination of yield strength (1024 MPa) and fracture elongation (12.4%) is obtained in the alloys with the addition of 0.2 wt% TiH 2 and 0.2 wt% YH 3. The high strength is mainly ascribed to the highly dispersed oxide nanoparticles and ultrafine-grained grains. [ABSTRACT FROM AUTHOR]

A series of TaNbVTiAlx (x = 0, 0.2, 0.4, 0.6, 0.8, and 1.0) refractory high-entropy alloys (RHEAs) with high specific strength and reasonable plasticity were prepared using powder metallurgy (P/M) technology. This paper studied their microstructure and compression properties. The results show that all the TaNbVTiAlx RHEAs exhibited a single BCC solid solution microstructure with no elemental segregation. The P/M TaNbVTiAlx RHEAs showed excellent room-temperature specific strength (207.11 MPa*cm3/g) and high-temperature specific strength (88.37 MPa*cm3/g at 900 °C and 16.03 MPa*cm3/g at 1200 °C), with reasonable plasticity, suggesting that these RHEAs have potential to be applied at temperatures >1200 °C. The reasons for the excellent mechanical properties of P/M TaNbVTiAl0.2 RHEA were the uniform microstructure and solid solution strengthening effect. [ABSTRACT FROM AUTHOR]

A novel metal matrix composite based on the NbMoCrTiAl high entropy alloy (HEA) was designed by the in-situ formation method. The microstructure, phase evolution, and compression mechanical properties at room temperature of the composite are investigated in detail. The results confirmed that the composite was primarily composed of body-centered cubic solid solution with a small amount of titanium carbides and alumina. With the presence of approximately 7.0 vol. % Al2O3 and 32.2 vol. % TiC reinforced particles, the compressive fracture strength of the composite (1542 MPa) was increased by approximately 50% compared with that of the as-cast NbMoCrTiAl HEA. In consideration of the superior oxidation resistance, the P/M NbMoCrTiAl high entropy alloy composite could be considered as a promising high temperature structural material. [ABSTRACT FROM AUTHOR]

The equiatomic CoCrFeMnNi high entropy alloy prepared by powder metallurgy has homogenous chemical composition and microstructure. The mechanical properties of the CoCrFeMnNi high entropy alloy at the strain rates (1 × 10 −4 s −1 to 0.1 s −1 and 1 × 10 3 s −1 to 3 × 10 3 s −1 ) and the temperature (298 K, 673 K and 1073 K) were investigated. Results indicate that the yield strength of the CoCrFeMnNi high entropy alloy is in the range of 350–700 MPa, increasing sensitively with increasing the strain rates, especially at a high strain rate (larger than 1 × 10 3 s −1 ). The serration behavior of the high entropy alloy is observed on the flow stress curves of the alloy deformed at a low strain rate of 1 × 10 −3 s −1 and the high strain rates (1 × 10 3 s −1 to 3 × 10 3 s −1 ). Influences of the strain rate and the temperature on the serration behavior of the CoCrFeMnNi high entropy alloy are discussed. [ABSTRACT FROM AUTHOR]

Strength-ductility trade-off is a difficult challenge for structural materials. In this work, a precipitate-gradient Ti W alloy with simultaneous high strength and high ductility was prepared by powder metallurgy and subsequent heat treatment. The precipitate-gradient structure was achieved by controlling the diffusion of W phase. The diffusion of W phase on microstructural evolution and strengthening mechanisms was investigated. The precipitate-gradient titanium alloy exhibits high strength, high ductility, and superior strain hardening capability. It was found that the high strength was mainly caused by the solid strengthening of W atoms and the precipitation strengthening of α '/ α "phases. Furthermore, the gradient structure could generate strong hetero-deformation induced (HDI) stress, which further enhanced the strength of the titanium alloy. The good ductility and superior strain hardening capability were attributed to the activation of multiple deformation modes around the gradient interface during plastic deformation, including planar dislocation sliding, stress-induced twinning (TWIP), and stress-induced martensite phase transformation (TRIP). • Ti-W alloy with gradient precipitate structure is prepared by powder metallurgy. • Gradient Ti-W alloy exhibits high strength and superior strain hardening capability. • HDI hardening effect caused by the gradient structure can enhance the strength. • Dislocation slip, TWIP, and TRIP contribute to strain hardening capability and plasticity. [ABSTRACT FROM AUTHOR]

Oxide dispersion strengthened (ODS) ferrite steel is a competitive candidate structural material for the Generation IV fission reactors. In this work, a novel ODS ferrite steel reinforced with ultra-fine Y 2 (Zr 0.6 , Ti 0.4) 2 O 7 particles was prepared by powder metallurgy method, which exhibit superior mechanical properties at elevated temperatures. Creep tests of the ODS ferrite steel at 800 °C was conducted to reveal its high-temperature creep failure mechanism. This ODS steel has an average grain size of 1.31 μm, and the mean size and number density of the ultra-fine oxide particles are 5.48 nm and 4.85 × 1023 m−3, respectively. When the applied creep stress is 100 MPa, the creep rupture time of the ODS steel is 2448.5 h, and the minimum creep rate is only 1.05 × 10−7 s−1. Under the similar creep stress at 800 °C, the creep rate of this ODS steel is at least one order of magnitude lower than that of other typical ODS steels reported in the literatures, showing excellent creep properties. By fitting the data of minimum creep rate, applied stress and effective stress normalized by shear modulus, the creep threshold stress of the ODS steel was determined as 56.2 MPa, and the true stress exponent was calculated as 4.5 ± 1.0, which indicates that the creep mechanism is dominated by dislocation. Orowan bypass mechanism and dislocation climb over the particle mechanism play a major role in this dislocation mediated creep behavior. Due to the strong hindering effect of dislocation motion caused by the ultra-fine and dispersed Y 2 (Zr 0.6 , Ti 0.4) 2 O 7 particles, the novel ODS ferrite steel thereby achieved excellent creep properties. • A novel ODS ferrite steel reinforced by ultra-fine particles was fabricated by powder metallurgy method. • Microstructures involve nanoscale Y 2 (Zr 0.6 , Ti 0.4) 2 O 7 particles, and ultrafine grains. • ODS ferrite steel reinforced with Y 2 (Zr 0.6 , Ti 0.4) 2 O 7 particles has superior creep property at 800 °C. • Pinning effect of ultra-fine particles on the dislocations is the main reason for the excellent creep performance. [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) strengthened by dispersed oxide nanoparticles are considered potential structural materials used in advanced nuclear reactors. Herein, a novel Y-Si-O nanoparticle-strengthened near-equiatomic FeNiMnCr HEA was prepared via the powder metallurgy method. Microstructural characterizations revealed that the oxide dispersion-strengthened (ODS) FeNiMnCr HEA consisted of the face-centered cubic (FCC) matrix and high-density Y-Si-O nanoparticles (Y 2 SiO 5 and Y 2 Si 2 O 7). The average diameter and volume fraction of the nanoparticles were counted to be 21.3 nm and 1.02%, respectively. The grain size was reduced from 10.13 μm of the FeNiMnCr HEA to 0.79 μm of the ODS FeNiMnCr HEA. The ODS FeNiMnCr HEA showed a yield strength of 1125 MPa, an ultimate tensile strength of 1137 MPa, and a moderate elongation of 8.3% at room temperature. At 500°C, the ODS FeNiMnCr HEA also had a high yield strength of 662 MPa. Theoretical calculation showed that the high strength of the ODS FeNiMnCr HEA was mainly due to the grain boundary strengthening, dislocation strengthening, and precipitation strengthening. ● A newly designed ODS FeNiMnCr HEA with enhanced strength-ductility combination was fabricated by a powder metallurgy method. ● The alloy contained nano-sized grain structure and nano-oxide particles including Y 2 SiO 5 and Y 2 Si 2 O 7. ● The grain boundary strengthening, dislocation strengthening, and precipitation strengthening were the main reasons for the high mechanical strength of the ODS FeNiMnCr HEA. [ABSTRACT FROM AUTHOR]

Nb Si based alloy is a promising structural material due to its low density and remarkable high-temperature strength, while the poor oxidation resistance comes to a critical factor for its application. In this study, hot pressing (HP) method has been utilized to produce Nb Si based alloys with fine microstructure to improve the high-temperature oxidation resistance. The effects of sintering temperature on the microstructural evolution and oxidation resistance of the Nb-16Si-24Ti-2Al-2Cr (at. %) alloys were investigated. Results show that, as the sintering temperature increased, the microstructure was refined at first and then coarsened. Correspondingly, the oxidation resistance of the alloy was enhanced at first and then decreased. The alloy sintered at 1400 °C had the best oxidation resistance. In comparison to the as-cast alloy with relatively coarse microstructure, the current 1400 °C sintered alloy exhibited lower weight gain (150.74 mg/cm2) after oxidation at 1250 °C for 50 h, and the oxidation rate constant was decreased by ∼53.3%. The primary reason for the improving oxidation resistance was attributed to the refined microstructure, which facilitated the formation of a more continuous and protective glassy SiO 2 layer, thus safeguarding the alloy substrate from oxidation. This study provides new idea for the preparation of Nb Si based alloys with high oxidation resistance in terms of microstructure refinement. • Microstructure of Nb Si based alloy is refined by appropriate sintering temperature (1400 °C). • Oxidation resistance of Nb Si based alloy is improved by microstructure refinement. • Microstructure refinement promoted the formation of the protective glassy SiO 2 layer. [ABSTRACT FROM AUTHOR]

TiC particle reinforced titanium matrix composites show excellent mechanical properties, which are widely regarded as promising high-performance structural materials. Here, we fabricated in-situ TiC enhanced Ti Ta based composites through mechanical alloying of elemental Ti and Ta powders and subsequently followed by spark plasma sintering and hot rolling. The stearic acid was utilized as both process control agent and carbon source. Experimental results show that Ti-enriched area, Ta-enriched area and TiC particles can be observed after sintering, and TiC particles are all distributed inside Ti-enriched area. After hot rolling, Ti-enriched areas and Ta-enriched areas are elongated along the rolling direction. The tensile strength increases and the ductility decreases with increasing content of in-situ formed TiC particles. The yield strength, the ultimate tensile strength of Ti Ta composite with 8 wt% TiC reach up to 1035 MPa and 1287 MPa, respectively, with a ductility of 1.6%. The enhanced strength is due to dislocation hardening, solid solution between Ti and Ta, grain boundary hardening and TiC particulate reinforcement. Besides, the solid solution of O element and the heterogeneous structure of Ti Ta composites may also improve the strength. This method provides an efficient way to fabricate in-situ TiC particle enhanced titanium based composite with improved strength. • The Ti-Ta composites presented heterogeneous structure with Ti-enriched, Ta-enriched and diffusional regions. • TiC particles were generated through in-situ reaction between Ti matrix and stearic acid. • The strength enhanced by in-situ formed TiC particles is higher than 200 MPa. • The strengthen mechanisms were determined to simulate the strength of Ti-Ta composites. [ABSTRACT FROM AUTHOR]