Fabrication and stability of ultrafine ZrC nanoparticles dispersion strengthened sub-micrometer grained W alloy

Abstract An ultrafine ZrC nanoparticles dispersion strengthened sub-micrometer grained W-0.5 wt% ZrC alloy (W-ZrC) were fabricated by an improved ball milling and spark plasma sintering (SPS) process. The as prepared W-ZrC has an average grain size of ∼0.86 μm with an average second-phase particle size of 24 nm. The thermal stability and thermal shock resistance of this W-ZrC alloy were investigated systemically by comparison with the reported rolled specimens. For this W-ZrC alloy, the evolution of microstructure with annealing temperature indicates that the occurrence temperature of grain growth is up to 1400 °C–1500 °C, which is higher than that of the as-rolled one (∼1350 °C). Moreover, the crack threshold (100 shots) at room temperature is in the range of 0.22−0.33 GW/m2, which is similar to that of most carbide dispersion strengthening tungsten alloys. In addition, a quantitative relationship between Vickers micro-hardness and grain size of sintered W-based alloys has been proposed.