Analysis of the creep response of the AE44 magnesium alloy between 100 and 150°C

The creep response of the AE44 magnesium alloy was investigated by means of constant load creep tests carried out between 100 and 150 degrees C. The minimum creep rate dependence on applied stress was described by a conventional power law, with a stress exponent n larger than 30 at the highest temperature. The minimum creep rate in the low stress regime was thus about two orders of magnitude lower in AE44 than in AM50. This large difference in creep response has been attributed to the presence and evolution of rare earths (RE) intermetallic phases mainly distributed in the grain boundary zone in form of an almost continuous network of dispersoids, that were observed by means of optical and scanning electron microscopy.