The effect of precipitation on the mechanical properties of extruded AZ80

The effect of ageing temperature and time on precipitates in AZ80 magnesium alloy were studied by optical microscopy to investigate the influence on mechanical properties. The results show the precipitation is distributed as bands along the extrusion direction, with no twinning. After ageing, the precipitation becomes dispersed uniformly. When ageing at 423 K, discontinuous precipitated phase increases the yield and tensile strength but reduces the ductility of the material. For ageing at 573 K, with increasing the ageing time, static ductility first increases and then decreases. This means that recrystallization induced by continuous precipitation is beneficial to both the strength and ductility. However, the effect of age hardening under 573 K is not better than 423 K. And {1012} < 1011 > twinning was also activated in compression much more than in tensile samples, which is consistent with the behaviour of AZ31.