Hydrogen-induced phase transformation

Hydrogen-induced amorphization (HIA) of intermetallic compounds was simulat ed by the molecular dynamics (MD) method using pairwise potentials. The mic roscopic mechanism of HIA in AB(2) C15 Laves phase compound is discussed. T he hydrogenation causes elastic softening in the bulk modulus and induces e lastic instability. A phase transformation by elastic instability follows p aths with minimal activation barriers, and nonequilibrium transformations i ncluding amorphization can be realized. The HIA can be considered as a case . The key to induce HIA is the expansion of the B atoms in a Laves phase; i t facilitates the instability of the sublattice of B atoms. If the amount o f hydrogen exceeds a critical value, HIA occurs. The HIA is a potential-dri ven phase transformation, and the resultant amorphous structure is potentia lly favored over the hydrogenated crystal. We also report the fracture proc ess by isotropic loading and compare it to HIA.