Microstructure and mechanical properties of HfC reinforced W matrix composites regulated by trace Zr

In this study, the W-HfC-Zr composites with various Zr content were fabricated via plasma activated sintering. The relative density, microstructure, microhardness , as well as mechanical properties of these composites were investigated. The W-HfC-Zr composite with 1.0 wt% Zr content had high relative density of 97.56%, exhibited the higher microhardness of 614 Hv, compressive yield strength of 1.85 GPa and bending strength of 880 MPa, which attributing to Zr captured impurity oxygen and generated solid-solution oxide (Hf, Zr)O. The enhancement mechanisms of trace Zr addition on microstructure and mechanical properties were proposed.