Sr变质对亚共晶铝硅合金中共晶硅形貌的影响

Effect of Sr Modification on Eutectic Silicon Morphology in Hypoeutectic Al-Si Alloy

研究了添加0~0.08wt%的Sr变质剂对铸态和热处理态亚共晶铝硅合金中共晶硅形貌的影响。结果表明,随Sr含量的增加,在铸态时共晶硅的形貌由粗大的长针状变为短小的针片状,最终变成分布均匀、细小的蠕虫状。经过热处理后,合金中共晶硅的形貌由粗大的棒状逐渐变短,最后转变成细小的圆点状。当Sr添加量增大到0.06wt%时,合金的拉伸断口组织良好,韧窝增多。

The effects of 0-0.08 wt% Sr modifier addition on the eutectic silicon morphologies in cast and heat treated hypoeutectic Al-Si alloy were studied. The results show that with the increase of Sr content, the morphology of eutectic silicon changes from coarse long needle shape to short needle shape in as-cast state, and finally to evenly distributed small worm shape. After the heat treatment, the morphology of eutectic silicon in the alloy gradually shortens from thick rod shape, and finally is converted into fine dot shape. When the content of Sr increases to 0.06 wt%, the tensile fracture microstructure of the alloy is good, the dimple content increases.