Effect of strain on the formation of Guinier—Preston zone in Al—Cu alloys from first-principles

Using first-principles calculations, we systematically investigate the energetics of Guinier—Preston zone (GPZ) formation in response to external strain in the Al—Cu system. The results show that when the applied strain exceeds a certain threshold, the precipitation of the GPZ preferentially occurs parallel (perpendicular) to the direction of tensile (compressive) strain and the precipitation energy of the GPZ has a parabolic relationship with the magnitude of strain. The variation of precipitation energy is related to the misfit of the GPZ with the matrix, which changes the number of bonding electrons below the Fermi level.