摘要
在不同温度和不同保温时间条件下对2524铸态合金进行均匀化处理,利用扫描电镜(SEM)、透射电镜(TEM)、差示扫描量热法(DSC)和金相显微镜(OM)等,研究2524铸态合金在均匀化过程中微观组织的变化,并分析在不同的均匀化处理状态下T相(即Al20Cu2Mn3相)的析出情况。结果表明:2524铸态合金中存在严重的枝晶偏析,大量的非平衡共晶相连续地沿晶界分布,主要的第二相为Al2Cu和Al2Cu Mg;主要合金元素不同程度地富集在晶界,富集程度为Cu>Mg>Mn;最佳的均匀化处理制度为500℃/48 h,均匀化处理后,Al2Cu和Al2Cu Mg基本回溶至基体,只余少量难溶的Al Cu Fe Mn相散布在晶界,该均匀化制度与均匀化动力学方程的计算结果基本一致;随均匀化处理温度升高,T相粒子的尺寸逐渐增大而数目逐渐减少。
Microstructural evolution of as-cast AA2524 alloy during homogenization at different temperature and holding time was investigated using scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, optical microscopy （OM）, energy dispersive spectrometry （EDS） and differential scanning calorimeter （DSC）. The precipitation of A120Cu2Mn3 phase in different homogenization conditions was also studied. The results show that, large amounts of non-equilibrium phase distribute along grain boundaries and dendritic segregation exists in as-cast alloy. The main elements of as-cast alloy are enriched in grain boundaries and the segregation degree is in the order of Cu, Mg and Mn. The main secondary phases are A12Cu and A12CuMg. During homogenization, these intermetallic phases gradually dissolve into matrix and only insoluble phase A1CuFeMn exists in grain boundaries. There is a significant increase in particle size and a modest reduction in number density of T phase （A120Cu2Mn3） with increasing homogenization temperature. The suitable homogenization parameter is 500 ℃/48 h, which agrees with the results of homogenization kinetic analysis.
出处
《粉末冶金材料科学与工程》
北大核心
2017年第2期151-158,共8页
Materials Science and Engineering of Powder Metallurgy
基金
国家自然科学基金资助项目(51171209)
