(1. 山東大學(xué) 材料液態(tài)結(jié)構(gòu)及其遺傳性教育部重點(diǎn)實驗室，濟(jì)南 250061；
2. 濟(jì)鋼集團(tuán)山東冶金設(shè)備制造公司，濟(jì)南 250101；
3. 山東大學(xué) 材料科學(xué)與工程學(xué)院，濟(jì)南 250061)
摘 要: 利用金相顯微鏡、DIL402C高溫膨脹儀等對Al-Si合金的線膨脹進(jìn)行了研究。結(jié)果表明：對于Al-Si合金，硅含量越高，其線膨脹系數(shù)越小，隨溫度變化幅度減小；隨著溫度升高，磷變質(zhì)比鍶變質(zhì)的線膨脹系數(shù)變化幅度小，合金更加穩(wěn)定；此外，T6熱處理也顯著降低Al-Si合金的線膨脹系數(shù)。通過對合金線膨脹系數(shù)和微觀組織的對比觀察發(fā)現(xiàn)：硅相的形態(tài)和體積分?jǐn)?shù)對Al-Si合金的線膨脹系數(shù)產(chǎn)生重要影響。初晶硅體積分?jǐn)?shù)的增加和初晶硅的析出能夠顯著降低Al-Si合金的線膨脹系數(shù)，共晶硅的形態(tài)對合金線膨脹系數(shù)也有一定的影響，共晶硅為短棒狀、顆粒狀時(尤其經(jīng)熱處理后)，合金的線膨脹系數(shù)也顯著降低。
關(guān)鍵字: Al-Si合金；線膨脹系數(shù)；熱處理；變質(zhì)處理
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
