Multiple strengthening via high-entropy alloy particle addition in titanium matrix composites fabricated by spark plasma sintering

The strong interface bonding of particle reinforced metal matrix composites has been a longstanding puzzle. Unlike the existing titanium matrix composites (TMC) processed, which are mainly reinforced by ceramic particles, this work investigates the in-situ triggered alloying via high entropy alloy (HEA) addition, which promotes multiple strengthening to the metal matrix. The effects of HEA content on the microstructure evolution, mechanical properties, void growth mechanism, sintering model and underlying strengthening mechanism were investigated. The results show that the enhanced diffusion effect in the diffusion region leads to the formation of a multiphase structure composed of an FCC solid solution and a sigma phase. In addition, with the addition of HEAs content, the yield strength and hardness values of all composites were higher than those of unreinforced Ti6Al4V (TC4). The obtained composite reinforced with 4.5 wt% HEA achieves an unprecedented tensile elongation to failure of 8.8% and a high ultimate tensile strength of 1150 MPa. The enhancement of the strength is attributed to the combined effects of grain refinement strengthening, load transfer strengthening and dislocation strengthening.

Automated summary

This study investigates the strong interface bonding of particle reinforced metal matrix composites using high entropy alloy (HEA) addition. The results show that the addition of HEAs enhances the yield strength and hardness values of the composites, achieving strengthening through multiple mechanisms.