Modeling of a Crack-induced Hydride Formation at a Grain Boundary in Metals

Crack-induced hydride formation can occur in specific metallic structures, reducing their mechanical properties and facilitating failure. Grain boundaries are observed to be preferential sites for hydride formation. We present a phase-field approach describing the kinetics of crack-induced hydride formation at a grain boundary, by using the Allen-Cahn formulation and including the increase in grain boundary energy. Hydride development is found to occur at the crack tip and in the grain boundary. These regions seemingly evolve independently, except when the crack is very close to or lies in the grain boundary.