Effects of mechanical vibration parameters

such as amplitude

frequency

pouring temperature and preheating temperature of mold

on solidification structure of ignition-proof magnesium alloy AZ91D-3Ca were investigated. The results show that solidification structures of ignition-proof magnesium alloy AZ91D-3Ca can be refined by controlling mechanical vibration parameters and solidification conditions. Primary grain in the alloy is refined gradually with the increase of amplitude within 0～1.7 mm. When frequency is 1Hz

refinement effect of primary grain appears. With frequency in range of 50～100 Hz

change of microstructure refinement can be ignored. With the increase of pouring temperature （610～700 ℃）or preheating temperature of the mold （room temperature to 600 ℃）

primary grain of the alloy is coarsened gradually by mechanical vibration.