Effects of homogenized temperature and time on microstructures and mechanical properties of as-cast Mg-4Sn-1Zn alloy during homogenization were investigated.The results show that serious dendrite is segregated at the strain boundaries and dendrites boundaries

and there exist a large amount of thick Mg2 Sn and MgSnZn eutectic phases.The temperature exhibits a more important effect during homogenization compared to the time.The eutectic phases can be dissolved into the matrix totally at 410℃for 12 h

and the dendrite segregation is eliminated

where the micro-hardness of Mg-4Sn-1Zn alloy reach 60 HV.The optimized annealing process of Mg-4Sn-1Zn alloy is homogenized at 410 ℃for 12 h.