Effect of heat treatment and stress relaxation in 7075 aluminum alloy

Aluminum 7075 alloy annealed at 413 °C for 2 1/2 h is used to study stress relaxation over the entire stress strain curve at room temperature. It is observed that the phenomenon of stress relaxation is accompanied by some hardening process, the latter being dominant over the former at rather low tensile strains. The intrinsic height of the energy barrier to the movement of relaxing dislocation is found to be 2.3 eV, which is of the order of magnitude required for recovery processes.