5059高镁铝合金均匀化热处理工艺  

Homogenization heat treatment process of 5059 high Mg containing aluminum alloy

作　　者：蒋海春[1,2] 叶凌英[1,2] 张新明[1,2] 顾刚[1,2] 张盼[1,2] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083 [2]中南大学有色金属材料科学与工程教育部重点实验室,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2014年第12期4138-4144,共7页Journal of Central South University:Science and Technology

基　　金：国家重点基础研究发展规划(973计划)项目(2012CB619501)~~

摘　　要：利用光学显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)、示差扫描量热(DSC)、X线衍射(XRD)等技术研究新型高镁装甲铝合金5059的均匀化热处理工艺及其微观组织演变,并根据Shewman扩散理论及菲克扩散定律研究合金铸锭的均匀化动力学。研究结果表明:5059铝合金铸锭枝晶偏析严重,大量非平衡β(Al3Mg2)和Al6Mn共晶相在晶界处呈连续网状分布;合金经均匀化处理后,非平衡共晶发生回溶,并伴随大量弥散β(Al3Mg2)相粒子的析出;随着均匀化温度的提高和保温时间的延长,合金中的非平衡共晶相回溶效果越好,合金元素扩散越充分,合金在460℃时开始发生过烧。综合实验观测及均匀化动力学方程计算结果,得到合金的最佳均匀化热处理工艺如下:均匀化温度为450℃,保温时间为24 h。The homogenization heat treatments and the microstructure evolution of 5059 high magnesium containing armor aluminum alloy were studied by optical microscopy（OM）, scanning electron microscopy（SEM）, energy dispersive X-ray（EDX）, differential scanning calorimeter（DSC） and X-ray diffraction analysis（XRD）. And the homogenization kinetic study of the ingot was carried out based on the Shewman diffusion theory and Fick＇s law. The results show that severe dendritic segregation exists in 5059 aluminum alloy ingot. There are many eutectic phases in grain boundary and the distribution of the main elements along interdendritic region varies periodically. The main secondary phases are β（Al3Mg2） and Al6 Mn. After homogenizing treatment,the nonequilibrium eutectic dissolves into the matrix and numerous β（Al3Mg2） dispersoids precipitated. By increasing the homogenization temperature or prolonging the holding time, the residual phases are dissolved into the matrix gradually, grain boundaries become sparse and all elements become more homogenized, which can be described by a constitutive equation in exponential function. The over burnt temperature of 5059 Aluminum alloy is 460 ℃. And the proper homogenizing process is 450 ℃, 24 h, which is consistent with the results of homogenization kinetic analysis.

关 键 词：5059铝合金 均匀化热处理 枝晶偏析 显微组织 动力学方程 

分 类 号：TG146.2[一般工业技术—材料科学与工程]