中文摘要：

考察了Sr变质及固溶时效对铝硅合金组织和性能的影响。结果表明，随Sr量的增加，铝硅合金中共品硅的形貌由粗大的板片状经过针片状，最后转变成了细小的纤维状。当加人0．04％Sr变质时，合金抗拉强度达到最大值183MPa；固溶时效处理使得经Sr变质及AlTiB细化处理的铝合金中的共晶硅相发生了粒化，变成更加圆整的形态，并随保温时间延长而粗化。铸造铝硅合金经固溶时效处理后的硬度比铸态有显著提高。535℃×6h固溶＋170℃×10h时效时，铝硅合金的硬度值最高可达84．4HBS。

英文摘要：

The effects of Sr modification and solution and aging treatment on microstructure and properties of A1-Si alloy were studied. The results show that the morphology of eutectic silicon changes from thick and big plate to needle like shape and finally to fine fibrous shape with the increase of Sr content. The tensile strength reaches the maximum of 183 MPa, as a result of 0.04% Sr modification. Solution and aging treatment can make the eutectic silicon phase granulated, and the eutectic silicon phase is coarsened with the holding time prolonging. The hardness of AI-Si cast alloy increases significantly after solution and aging treatment. The alloy has the maximum hardness of 84.4 HBS with 535 ℃×6h solution and then 170 ℃×1 Ohaging process.