不同冷却条件下Al-Si/SiC颗粒系统二维凝固过程数值模拟

NUMERICAL SIMULATION OF Al-Si/SiC PARTICLE SYSTEM TWO DIMENSION SOLIDIFICATION PROCESSING ON DIFFERENT COOLING CONDITIONS

本文采用多相流模型对不同冷却条件下Al-Si/SiC系统二维凝固过程进行了数值模拟,对顶面冷却、底面冷却、侧面冷却和四面冷却条件下,无颗粒、小颗粒和大颗粒的情况进行了研究。溶质分布表明:对于分凝系数小于1的合金,先凝固的地方出现负偏析,后凝固的地方出现正偏析。顶面冷却和底面冷却时会出现A型偏析,侧面冷却和四面冷却时出现V型偏析。共晶分布验证了Scheil方程,共晶的产生会受到宏观偏析的影响,而且大颗粒的堆积会抑止共晶的产生。

A multiphase model has been developed and applied to the two dimension solidification processing of Al-7 wet pct Si/SiC particle functionally graded material on different cooling conditions. The solidification processes of no particle, small particle and large particle by cooling on the top, the bottom, side face and four sides are researched. It is approved that there is negative macrosegregation on the field solidified first and there is positive macrosegregation on the field solidified later. There is macrosegregation of pattern A by cooling on the top and the bottom and there is macrosegregation of pattern V by cooling on the side face and four sides. The Scheil equation is approved. The creation of eutectic is affected by species macrosegregation, and the accumulation of large particles restrains the creation of eutectic.