中文摘要：

The effects of slight electromagnetic stirring on morphology of primary phase in semisolid A356 prepared by low superheat pouring and slight electromagnetic stirring were researched,and some characteristic parameters characterized the morphology and grain size of the primary phase were calculated.The results indicate that the stirring power has an important effect on the morphology and the grain size.The characteristics of the morphology could be characterized by the fractal dimensions and the shape factors.The fractal dimension and the shape factor change when the morphology changes with processing conditions.Both increase with the increase of the stirring power,but the fractal dimension is still affected by the grain size.The increase of stirring power could obviously improve the grain size,fractal dimension and shape factor of the primary phase.