利用正交试验的方法对熔体温度处理细化亚共晶 Al- Si合金的凝固组织进行了研究 .结果表明 ,经过熔体温度处理后 ,凝固组织中一次枝晶尺寸明显减小 ,长的树枝晶变为短的树枝晶或等轴晶 ,并且枝晶数量明显增多 ;二次枝晶臂间距变化不明显 .从原子团簇的角度分析认为 ,这是由于高、低温熔体混合后 ,低温熔体中大的原子团簇得到细化 ,从而导致混合熔体中形核质点增殖的结果 .研究同时发现 ,高、低温熔体的混合方式对熔体温度处理效果有直接影响 ,熔体的均匀混合有利于增大熔体凝固过冷度 ,减小临界晶核半径 ,促进凝固组织的细化 The microstructure of the hypoeutectic Al-Si alloy treated by melt temperature was studied by means of orthogonal test.The results showed that the primary dendrite size in the solidified structure decreased obviously after the melt temperature treatment, The dendrites became short dendrites or equiaxed grains, and the number of dendrites increased obviously. The variation of secondary dendrite arm spacing did not change obviously. From the perspective of atomic clusters, it was considered that this was due to the high and low temperature melt mixing, low temperature The results show that the mixing modes of high and low temperature melt have a direct effect on the effect of melt temperature treatment and the uniformity of melt Mixing is conducive to increasing the degree of supercooling of the melt solidification, reducing the critical crystal nucleus radius and promoting the refinement of the solidified structure