Grain size effects of tungsten powder on the micro-structure and mechanical properties of tungsten-based alloys

Abstract

Bulk W-0.5 wt% ZrC (WZC) plates were fabricated using tungsten powders with different powder grain sizes of 0.2 μm, 0.5 μm and 2.8 μm, respectively. The different grain sizes resulted in completely different micro-structures and mechanical properties of as-rolled WZC plates. For the tungsten plate prepared from the initial powder with grain size of 0.5 μm (0.5WZC), more excellent mechanical properties were achieved than those of plates made of powders with grain sizes of 0.2 μm (0.2WZC) and 2.8 μm (2.8WZC). In the as-rolled 0.5WZC, the ductile-brittle transition temperature is as low as 150 °C and ultimate tensile strength is as high as 932 MPa at 150 °C, respectively. Moreover, the 0.5WZC plate has the most outstanding high-temperature stability with a recrystallization temperature of 1500 °C. Micro-structure analysis indicates that the second-phase particles are uniformly distributed in the 0.5WZC, but serious particle aggregation occur in the 2.8WZC. The possible micro-mechanisms have been proposed.