Research on microstructure in as-cast 7A55 aluminum alloy and its evolution during homogenization

作     者：LV Xinyu GUO Erjun LI Zhihui WANG Guojun 

作者机构：The School of Materials Science and Engineering Harbin University of Science and Technology Harbin 150080 China Northeast light alloy Co. Ltd. Harbin 150060 China State Key Laboratory of Nonferrous Metals and Processes General Research Institute for Nonferrous Metals Beijing 100088 China 

出 版 物：《Rare Metals》 (稀有金属（英文版）)

年 卷 期：2011年第30卷第6期

页      面：664-668页

核心收录：

学科分类：07[理学] 0806[工学-冶金工程] 070205[理学-凝聚态物理] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 0702[理学-物理学] 

基　　金：financially supported by the National Key Technologies R&D Program of China (No.2007BAE38B06) the National Natural Science Foundation of China (No.50904010) 

主　　题：7A55 aluminum alloy as-cast constituents homogenization 

摘      要：The microstructure of the as-cast 7A55 aluminum alloy and its evolution during homogenization were investigated by means of optical microscopy （OM）, scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, X-ray diffraction （XRD）, and differential scanning calorimetry （DSC） analysis. The results indicate that the microstructure of the as-cast 7A55 aluminum alloy mainly consists of the dendritic network of aluminum solid solution, Al/AIZnMgCu eutectic phases, and intermetaUic compounds MgZn2, Al2CuMg, Al7Cu2Fe, and Al23CuFe4. After homogenization at 470℃ for 48 h, Al/AlZnMgCu eutectic phases are dissolved into the matrix, and a small amount of high melting-point secondary phases were formed, which results in an increasing of the starting melting temperature of 7A55 aluminum alloy The high melting-point secondary phases were eliminated mostly when the homogenization time achieved to 72 h. Therefore, the reasonable homogenization heat treatment process for 7A55 aluminum alloy ingots was chosen as 470℃/72 h.