Dynamic compression behaviour of tungsten powders consolidated by plasma pressure compaction

It has been generally believed that the ductility of tungsten can be increa sed by decreasing grain size to ultrafine levels (similar to 100 nm). Pure ultrafine grain tungsten powders of various average particle sizes (2.0, 0. 7, and 0.16 mu m) were consolidated using the rapid consolidation technique , plasma pressure compaction ((PC)-C-2), to minimise grain growth. Prelimin ary results indicate that tungsten powders can be consolidated to high dens ity without abnormal grain growth at 2000 degrees C and 50 MPa with less th an 3 min of isothermal holding time in the (PC)-C-2 process. The densities of consolidated specimens were measured using Archimedes' method, and the m icrostructure was analysed using SEM. The mechanical behaviour of the conso lidated specimens was investigated using the compression Kolsky bar. Dynami c compression properties were examined to determine the effect of grain siz e, grain structure, and density on yield stress at various strain rates.