Journal of Materials Research and Technology (May 2023)
Novel titanium matrix composites reinforced by NiCoCr medium entropy particles
Abstract
Titanium matrix composites (TMCs) reinforced with 2–8.3 wt.% NiCoCr medium-entropy alloy particles (NiCoCrp/Ti) were synthesized through an in-situ reaction between NiCoCr and Ti powders during a spark plasma sintering process at 850 °C and 1000 °C. At 850 °C, there are obvious interdiffusion layers with Ti3(Ni, Co) intermetallic around NiCoCr particles. At 1000 °C, the sufficient diffusion of Ni, Co and Cr away from the prior NiCoCr particles results in clusters of granular intermetallic (Ti3(Ni, Co) and Ti2(Ni, Co)) in the Ti matrix. Besides, the addition of NiCoCr particles leads to a significant improvement in tensile strength and hardness. Ti-2wt.%NiCoCr sintered at 1000 °C has a combination of high tensile strength (788 MPa) and good ductility (23.4%). Furthermore, the mechanical properties are mainly correlated to the amount and distribution of the intermetallic compounds in TMCs.