Phase relationship and equation of state of TiH at high pressures and high temperatures

Endo, Naruki; Saito, Hiroyuki; Machida, Akihiko; Katayama, Yoshinori; Aoki, Katsutoshi

The phase diagram and the equation of state of TiH at high pressure and high temperature (HPHT) were carefully investigated in the present study using by using an synchrotron X-ray diffraction measurement for new titanium alloys hydrides development. Summary of the study is as follows: At ambient conditions, the TiH had a face-centered cubic crystal structure (FCC). At high pressure, TiH crystallized in a FCC structure above 200C. In lower temperature range, the TiH structure was not only a FCC structure but also a tetragonal structure. Since the transformation temperature of TiH was increased with increasing pressures, the thermal stability of this phase was increased by pressures. In this presentation, we will report detailed results together with the phase diagram and the equation of TiH state at HPHT.