Tensile-compressive creep asymmetry of recent die cast magnesium alloys

The tensile-compressive creep asymmetry of die cast magnesium alloys is experimentally explored and the possible deformation mechanisms are discussed. Creep tests were performed under tension and compression at 125°C and 150 °C on die cast Mg alloys AM50, AE44 and AJ62A. Higher tensile than compressive creep strengths were observed for all alloys except for low pressure die cast AM50 at a low creep stress of 35 MPa at 125 °C. An aging treatment of 250 hours at 180 °C was employed for AM50 samples to obtain an over-aged microstructure that would minimize the effects of dynamic precipitation of β-Mgl7A112 on creep. The creep data for the aged samples showed significant scatter, and the trend in tensile-compressive creep asymmetry of the aged samples is not clear for the short-term creep tests under high creep stresses.