Structural stability and hydrogen diffusion in TiH_x alloys, with x=0-2, have been studied by ab initio total energy calculations. A concentration dependent structural transformation is predicted to occur from FCC (x≤0.5) to FCT (0.75≤x≤1.50) and then again to FCC (1.75≤x≤2.0). Moreover, a concentration independent hydrogen diffusion behavior is found with activation energies of 0.50 eV in TiH_(0.75) (along the 110 direction) and 0.54 eV in TiH_(1.75) (along the 100 direction), respectively. These results are in good agreement with the recent experimental works.
展开▼
