Effects of pressure and punching head speed on microstructure and mechanical properties of thixoformed AZ63H magnesium alloy were investigated.The results indicate that with increasing in pressure

the grain size AZ63 Halloy is increased firstly and then decreased

and the tensile strength is increased firstly and then decreased

where the maximum value can be obtained with 140 MPa.With the increase of the punching head speed

the microstructure compactness is enhanced as result of the improvements of mold-filling capacity and feeding ability

resulting in the increase of mechanical properties.However

when the punching head speed is more than 140 mm/s

the number and the size of the pores are increased

which is harmful for the mechanical properties.In view of the microstructure compactness and mechanical properties

the optimized thixoformed process of AZ63H magnesium is presented as follows:apunching head speed of 140 mm/s and a pressure of 140 MPa.