(1. 山东大学 材料液态结构及其遗传性教育部重点实验室,济南 250061;
2. 济钢集团山东冶金设备制造公司,济南 250101;
3. 山东大学 材料科学与工程学院,济南 250061)
摘 要: 利用金相显微镜、DIL402C高温膨胀仪等对Al-Si合金的线膨胀进行了研究。结果表明:对于Al-Si合金,硅含量越高,其线膨胀系数越小,随温度变化幅度减小;随着温度升高,磷变质比锶变质的线膨胀系数变化幅度小,合金更加稳定;此外,T6热处理也显著降低Al-Si合金的线膨胀系数。通过对合金线膨胀系数和微观组织的对比观察发现:硅相的形态和体积分数对Al-Si合金的线膨胀系数产生重要影响。初晶硅体积分数的增加和初晶硅的析出能够显著降低Al-Si合金的线膨胀系数,共晶硅的形态对合金线膨胀系数也有一定的影响,共晶硅为短棒状、颗粒状时(尤其经热处理后),合金的线膨胀系数也显著降低。
关键字: Al-Si合金;线膨胀系数;热处理;变质处理
phase on TE of Al-Si alloys
(1. Key Laboratory of Materials Liquid Structure and Heredity, Ministry of Education,
Shandong University,Ji’nan 250061, China;
2. Jigang Group Shandong Metallurgy Equipment Manufacture Corporation, Ji’nan 250061, China;
3. School of Material Science and Engineering,Shandong University, Ji’nan 250061, China)
Abstract:The linear coefficient of thermal expansion (CTE) of Al-Si alloys was studied by using Hi-scope video microscope and DIL 402C high temperature dilatometer. The results reveal that the CTE of Al-Si alloys decreases with increasing Si level. Compared with Sr modification, the Al-Si alloy modified with P has a lower CTE and is more stabilized. Moreover, T6 heat treatment can also decrease the CTE of Al-Si alloys,and improve the stability during heating-up. According to the contrasts above and combined with microstructure observation, it is found that Si phase has important influence on CTE of Al-Si alloys. The increase of volume fraction and precipitation of primary Si both can decrease the CTE. Also, eutectic Si exerts certain influence on the CTE of Al-Si alloys, i.e. the CTE decreases when eutectic Si exhibits morphology of short-bar shape and small particles, especially after heat treatment.
Key words: Al-Si alloys; stability; CTE; heat treatment; modification