Effects of hydrogen content on powder metallurgy characteristic of titanium hydrides

Abstract

The titanium dihydride (TiH2) powder metallurgy has been attracted a lot of attention, but TiH2 powder is difficult to press moulding. In this paper, the titanium hydride powder metallurgy including TiH2 and unsaturated titanium hydrides (TiH1.5) was investigated simultaneously compared with pure titanium metal powder metallurgy. The results indicates that the titanium hydride powder metallurgy is accompanied by the deoxidation self-purification effect during dehydrogenation process for both of TiH2 and TiH1.5, which have higher sintering density than pure titanium. There are the three stages relative to densification rate, namely the slow, rapid and full densification stages for all of three materials. The compressive yield strengths increase rapidly in the rapid densification stage and are unchangeable almost in the full densification stage after holding 2 h at 1300 °C. The titanium hydride powder metallurgy is helpful to obtain much better mechanical properties than the pure titanium metal powder metallurgy. Here the compressive yield strength of the as-sintered TiH2 compact with the maximum hydrogen content is the best but has very small difference compared with that of the as-sintered TiH1.5 compact after full sintering densification.