Microstructural characterization of as-cast and homogenized 2D70 aluminum alloy

Guo-jun Wang1,2), Bai-qing Xiong1), Yong-an Zhang1), Zhi-hui Li1), and Pei-yue Li1) 1) State Key Laboratory for Fabrication and Processing of Nonferrous Metals, General Research Institute for Nonferrous Metals, Beijing 100088, China 2) Northeast Light Alloy Co., Ltd., Harbin 150060, China

摘 要：The microstructure of the as-cast 2D70 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 2D70 aluminum alloy mainly consists of the dendritic network of aluminum solid solution and intermetallic compounds （Al2CuMg, Al2Cu, Al9FeNi, Cu2FeAl7, and Al7Cu4Ni）. After conventional homogenization, Al/Al2CuMg eutectic phases are dissolved into the matrix, and a small amount of high melting-point eutectic Al/Al2Cu phases exist in the matrix, resulting in an increase in the starting melting temperature. Under double homogenization, the high melting point Al/Al2Cu phases are dissolved, and no obvious change is observed for the size and morphology of Al9FeNi, Cu2FeAl7, and Al7Cu4Ni compounds.

关键词：