中文摘要：

合金凝固过程的收缩会使铸件产生缩孔、缩松、热裂、应力和冷裂等缺陷．运用阿基米德原理设计了测定合金凝固收缩率的实验装置，并研究了Al-25％ Si合金凝固收缩率随熔体温度处理和合金化元素的变化规律．试验结果发现：Al-25％ Si合金凝固收缩率随过热温度的升高先减小后增大，随降温后保温时间的延长，收缩率逐渐减小；当熔体在960℃保温30 min后，又在770℃保温60 min时，凝固收缩率达到最小值0．40％．单独加入Cu、Ni和Mn元素时，凝固收缩率分别从0．87％逐渐减小到0．77％、0．75％和0．52％．但是单独加入Mg元素时，凝固收缩率从0．87％逐渐增加到0．92％．

英文摘要：

Alloy solidification shrinkage can cause defects such as shrinkage hole ,shrinkage porosity , hot cracking and cold cracking .The experimental device for measuring the alloy solidification shrinkage using Archimedes＆#39;principle is designed and the effects of melt temperature treatment and alloying elements on the solidification shrinkage of Al-25% Si alloy are investigated .It is found that the solidification shrinkage of Al-25% Si alloy decreases first and then increases with increasing superheating-temperature ,and it decreases with increasing holding-time gradually .When the melt is hold at 960 ℃ for 30min and then at 770 ℃ for 60min ,the shrinkage reaches the minimum 0 .40% .With increasing the content of the copper ,nickel and manganese ,the solidification shrinkage decreases from 0 .87% to 0 .77% ,0 .75% and 0 .52% respectively ,but with increasing the content of the magnesium it increases from 0 .87% to 0 .92% .