Influence of Heat treatment on Microstructure and Mechanical Properties of Mg-Al-Ga Alloy

In order to improve the mechanical properties of Mg-Al-Ga alloy,metallurgical microscopy,scanning electron microscopy(SEM)as well as hardness,tensile properties testing at room temperature were used to study the influence of heat treatment on the microstructure and mechanical properties of Mg-8% Al-2%Ga alloy.The results show that during the solution treatment of Mg-8%Al-2%Ga alloy,the secondary β-Mg17Al12 phases dissolve at first,and then the divorced eutectic β-Mg17Al12 phases.With the solution time increasing,the grains are growing up gradually.In the following aging treatment,the precipitation mode changes gradually from the mainly discontinuous precipitation into the continuous precipitation.Hardness testing results show that at first the hardness increased with the increase of solution treatment time,but the hardness unchanged after 1 h;the hardness of the solution+aging treated sample was obviously enhanced comparing with that of the sample with only solution treatment;the hardness reached the peak after 2 h solution +16 h aging treatment,and then decreased with the solution time.Tensile test results show that the best mechanical properties of the alloy at room temperature is obtained after solution at 415 ℃ for 2 h and aging treatment at 168 ℃ for 16 h.