Effects of rolling reduction on microstructural evolution and mechanical properties of W-0.5wt%ZrC alloys

Abstract

The effects of hot rolling reduction on microstructures and mechanical properties of W-0.5 wt%ZrC (WZC) materials were investigated. Four WZC specimens with rolling reductions of 46%, 69%, 77%, and 96% were prepared by multi-step rolling processes. Metallographic observation, SEM, EBSD, and TEM characterization were conducted to obtain information on the microstructures of the materials. The metallography and EBSD results indicate that W grains were refined to 0.4–0.5 μm in the 96%-rolled WZC01 specimen. In addition, Vickers microhardness measurements at room temperature (RT) and tensile tests at various temperatures from RT to 500 °C were conducted. The results indicate that hardness and strength increase with the increase in rolling reduction. The 96%-rolled 1-mm thick WZC plate exhibits an ultra-high tensile strength of 1450 MPa at 100 °C. The 77%-rolled 6-mm thick WZC bulk material demonstrates both high tensile strength with an ultimate tensile strength of 620 MPa and good ductility with a tensile elongation of 21% at 400 °C, which are superior to those of most reported bulk W materials. The relationships between microstructure, mechanical properties, and rolling reduction were investigated and discussed systematically.