Abstract: Mg-9Al-xRE magnesium alloys were studied,where x is0,0.4,0.8,1.2and 1.6(in weight percent,wt),respectively.Influence of rare earths(RE) on microstructure and strength in both T4(solute heat treatment)and T6(solute heat treatment and artificial ageing treatment)were investigated.Strength of specimen was tested at am-bient temperature.The microstructure was analyzed by optical microscopy,scanning electron microscopy(SEM)and X-ray diffreation analysis.RE additions improved T4 tensile strength of the treated alloys.Small addition (0.4wt) of RE greatly im-proved the strength of ageing treated(T6)Mg-9Al alloy,but further additions caused decreasing.

Key words: Mg-Al alloy, rare earth (RE), heat treatment,