Effects of solution treatment time on microstructure and mechanical properties of thixoformed AZ63Magnesium alloy at 430℃ were investigated.The results indicate that the eutecticβphase in secondarily solidified structures is dissolved into the primaryαphase after solution treatment.The solution treatment of thixoformed AZ63magnesium alloy can be divided into three stages:dissolution of eutectic βphase and coarsening of the particles（

<

0.5h）

normal growth of the particles（1h

1

2h）

and rapid growth of the particles（24h

3

6h）.In the initial stage of solution treatment

the tensile strength and elongation of the alloy are increased rapidly.As increasing in the solution treatment time

the tensile strength and elongation of the thixo-formed AZ63are increased firstly and then decreased.The tensile strength and elongation reach the maximum values of 341MPa and 17.8%

respectively

with solid solution at 430℃for 12h.The solution treatment process of permanent mold casting is slower than that of thixoforming.