Microstructures and mechanical properties of tungsten-tantalum alloys consolidated by electron beam melting, hot pressing and spark plasma sintering

摘要

The effect of consolidation process conditions and the tungsten concentration on the microstructures and mechanical properties of tantalum-tungsten alloys has been investigated.Ta-lOW(in weight percent)and Ta-20W(in weight percent)alloys have been consolidated by electron beam melting(EBM), hot pressing(HP)and spark plasma sintering(SPS)techniques.The results show that the tantalum-tungsten alloys consolidated by EBM exhibit the highest relative density while by HP or SPS exhibit smaller grain-size compared to that by EBM, which may be attributed from the lower process temperature and the existence of oxide on the grain boundary hindering the growth of grain.The alloys with fine grain size(HP or SPS)have a higher microhardness and compression’strength than that with coarse grain size(SPS)under the same tungsten concentration.It has been shown that these two alloy systems exhibit a similar general trend of strength increasing and the ductility decreasing when applying different consolidation process, while an enhanced strength-ductility synergy can be achieved for the Ta-10W alloy.