High-temperature mechanical properties and deformation behavior of carbides reinforced TiNbTaZrHf composite

Abstract 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.