Microstructure evolution and tensile behavior of balanced Al-Mg-Si alloy with various homogenization parameters

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. © 2024 The Nonferrous Metals Society of China