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 degrees C. The significant strength improvement can be attributed to the load-bearing effect caused by the dispersed carbides with high vo-lume fraction, while the intergranular fracture of carbides is responsible for the plastic instability. When the temperature rises to 1200 degrees 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. (c) 2021 Elsevier B.V. All rights reserved.
NSTL
Elsevier