With the increase of the cooling rate, both the grain size and secondary dendrite arm spacing of A357 alloy decrease, and the distribution of Si phase is changed from a chain to a short strip or short bar.

• 随着冷却速率的提高,A357合金的晶粒尺寸和二次枝晶间距减小,Si相由链状分布变为短条状或短棒状分布。