【摘要】 通过光学显微镜、扫描电镜和差示扫描量热仪等技术手段研究了Al-0.7Mg-0.9Si合金在550℃均匀化退火过程中的显微组织演变。结果表明，合金的铸态组织存在严重偏析，晶界析出长条状Al（Fe, Mn）Si相和短棒状Mg₂Si相，晶内析出球状Q-AlCuMgSi相；随着均匀化退火时间的延长，枝晶偏析消失，Q-AlCuMgSi相和Mg₂Si相逐步回溶于基体，Al（Fe, Mn）Si相发生断续化转变。合金导电率呈先降低后缓慢升高的趋势。结合均匀化动力学计算，确定Al-Mg-Si合金合理的均匀化退火制度为550℃8 h。更多还原

【Abstract】 The microstructure evolution of Al-0.7Mg-0.9Si alloy during homogenization at 550 ℃ was investigated by optical microscopy, scanning electron microscopy and differential scanning calorimetry.The results show that serious dendritic segregation exists in as-cast alloy, with the long-strip Al（Fe, Mn）Si phase and short-bar Mg₂Si phase at grain boundaries, and the spherical Q-AlCuMgSi phase in the grain; with the increase of the homogenization time, the dendritic segregation disappears, and the Q-AlCuMgSi and Mg₂Si phases dissolve back to the matrix step by step, and the intermittent transformation of the Al（Fe, Mn）Si phase occurs. The electrical conductivity of the alloy shows a tendency of decreasing and then slowly increasing. Combined with the calculation of homogenization kinetics, a reasonable homogenization heat treatment system for Al-Mg-Si alloy is determined as 550 ℃8 h.更多还原