Abstract: Small amount Of antimony addition to the Mg-9Al-0.8Zn-0.2Mn (AZ91) alloy resulted in the obvious increase of tensile strengths at both ambient and elevated temperatures.The creep resistance at the temperatures ap to 200℃ was also improved significantly by antimony addition. Mcrostructurul observations revealed that the addition of antimony modified morphology of the α(Mg17Al12) phase and caused the formation of some rod-shaped precipitates Mg3b2 at grain boundaries. These precipitates have high thermal stability and play an important role for strengthening groin boundaries at elevated temperutures.

Key words: magnesium alloy, antimony, creep