Microstructure evolution and tensile behavior of balanced Al-Mg-Si alloy with various homogenization parameters
(1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. State Key Laboratory of Advanced Power Transmission Technology, State Grid Smart Grid Research Institute Co., Ltd., Beijing 102209, China;
3. State Grid Liaoning Electric Power Supply Co., Ltd., Shenyang 110042, China;
4. Jiangsu Zhongtian Technology Co., Ltd., Nantong 226010, China;
5. China Electric Power Research Institute Co., Ltd., Beijing 100192, China)
2. State Key Laboratory of Advanced Power Transmission Technology, State Grid Smart Grid Research Institute Co., Ltd., Beijing 102209, China;
3. State Grid Liaoning Electric Power Supply Co., Ltd., Shenyang 110042, China;
4. Jiangsu Zhongtian Technology Co., Ltd., Nantong 226010, China;
5. China Electric Power Research Institute Co., Ltd., Beijing 100192, China)
Abstract: The effects of homogenization parameters on the microstructure evolution and tensile behavior of a balanced Al-Mg-Si alloy were investigated using the optical microscope, scanning electron microscope, X-ray diffraction, electron probe microanalyzer, differential scanning calorimetry, electrical conductivity test, and tensile test. The results show that Mg2Si and β-AlFeSi are the main intermetallic compounds in the as-cast structure, and Mg solute microsegregation is predominant inside the dendrite cell. The prediction of the full dissolution time of Mg2Si by a kinetic model is consistent with the experiment. The β-AlFeSi in the alloy exhibits high thermal stability and mainly undergoes dissolution and coarsening during homogenization at 560 °C, and only a small portion is converted to α-AlFeSi. The optimal homogenization parameters are determined as 560 °C and 360 min, when considering the evolution of microstructure and resource savings. Both the strength and ductility of the alloy increased after homogenization.
Key words: Al-Mg-Si alloy; homogenization; kinetic model; Fe-bearing phase; tensile behavior