Mechanically driven b.c.c. TiCr alloy and its hydrogen solubility

Abstract

In this study, Ti–Cr binary mixtures were prepared by mechanical alloying and the phase structure and corresponding hydrogen solubility were discussed. According to the binary equilibrium phase diagram, solubility of Ti in Cr at room temperature is very limited. This is because Ti is in equilibrium with the extremely stable Laves phase (TiCr 2) existing in the middle of the phase diagram. In this study, it was demonstrated that mechanically alloying yielded formation of Ti–Cr b.c.c. phase at room temperature. It was discussed how the excess energy derived during mechanical alloying works on the formation of Ti–Cr b.c.c. phase. P – C isotherms of the synthesized Ti–Cr alloy powders show the capability of hydrogen absorption and desorption. Especially, the Ti 80Cr 20 hydride should be very stable so that the high hydrogen content around 2 wt.% even at 10 −4 MPa was shown. In addition, the Ti 80Cr 20 hydride was identified as f.c.c. structure with hydrogen content was 3.4 wt.% at 5.5 MPa and 313 K.