Discontinuous model combined with an atomic mechanism simulates the precipitated η′ phase effect in intergranular cracking of 7-series aluminum alloys

Abstract

A first-principles calculation reveals that the phase that is precipitated in a grain boundary weakens the cohesiveness of the grain boundary. The hydrogen atom is likely to be trapped in the Al/MgZn2 boundary when it diffuses through the grain boundaries, which further reduces the cohesive energy of grain boundaries including Al-H-MgZn2. A discontinuous peridynamic model is proposed to compensate for a deficiency of the finite element method. The peridynamic simulation results show that the cracks grow obviously along the grain boundaries containing Al-H-MgZn2.