Effects of segregated Ga on an Al grain boundary: A first-principles computational tensile test

We perform a first-principles computational tensile test (FPCTT) to investigate the effect of segregated Ga (substitutional) on an Al grain boundary (GB). We show that isolated Ga segregation has little effect on the tensile strength of the Al GB, but greatly reduces the toughness and the Griffith fracture energy. The interfacial Al-Ga bond with some ionic character is suggested to be responsible for the nearly unchanged tensile strength and the toughness reduction. Based on the bond length evolution result, we further demonstrate that GB fracture is directly associated with interfacial Al-Ga bonds.