Effects of ZrC content on the mechanical properties and microstructures of hot-rolled W–ZrC composites

Abstract

In this paper, bulk W-0.2 wt% ZrC and W-0.8 wt% ZrC (hereafter abbreviated as WZC02, WZC08, respectively) plates were fabricated by ball milling, sintering and multi-step hot rolling technology. The microstructure, mechanical properties and thermal stability were studied to demonstrate the influence of ZrC contents. The results of Vickers hardness and tensile tests show that the WZC08 alloy has a higher hardness, larger tensile strength but lower ductility than that of the WZC02 alloy. The ductile brittle transition temperature (DBTT) of both WZC02 and WZC08 alloys are about 300 °C. The recrystallization temperature of the as-rolled WZC08 is between 1500 °C and 1600 °C, which is 200 °C higher than that of the as-rolled WZC02. The EBSD results indicate that there are strong [101] texture in both rolled WZC02 and WZC08 alloys. Microstructural analysis shows that the ZrC dispersion particles in as-rolled WZC02 have smaller particle sizes and uniform distributions but lower number densities than that in WZC08. By comparing with the pure W and WZC05, an optimal ZrC content is proposed to achieve a better comprehensive property including high tensile strength, good ductility and high thermal stability. Key words: Tungsten, ZrC content, Microstructure, Mechanical property, Thermal stability