Influence of punch diameter on impression creep behaviour of AZ91 magnesium alloy

The influence of punch diameter on impression creep behaviour of the AZ91 alloy in the cast and wrought conditions was studied. The stress exponents of 5.3–7.8 and 1.8–2.6 were found, respectively, for the cast and wrought alloy, and the activation energy is close to the lattice diffusion of magnesium for both conditions. The punch diameter has no influence on the deformation mechanisms and the obtained creep data introduce lattice diffusion-controlled dislocation climb and grain boundary sliding, which are the dominant deformation mechanisms during creep of the cast and wrought alloys, respectively. The punch diameter affected the impression creep behaviour of the alloys so that with an increase in the punch diameter, the steady-state impression rate in both deformation mechanisms was increased exponentially.