Creep deformation study of squeeze cast AZ91 magnesium alloy

Abstract

The AZ91 magnesium alloy has excellent mechanical properties; however, its application is limited by its poor creep resistance. In this study, AZ91 magnesium alloy prepared by squeeze casting technique has been tested for its creep performance at varying stresses and temperatures. The governing creep mechanism was examined in the wake of deformation. The microstructure for as-cast AZ91 alloy confirmed the massive dendritic β-Mg17Al12 phase. The creep study indicated that the governing creep mechanisms were dislocation creep and dislocation climb governed by lattice diffusion in the test regime of 50 MPa stress at 150oC to 175oC. The measured dislocation density values showed good agreement with the expected dislocation density in the power law creep mechanism.