(1. 中南大学物理与电子学院，长沙410083；
2. 中南大学材料科学与工程学院有色金属材料科学与工程教育部重点实验室，长沙410083)
摘 要: 采用差示扫描量热分析确定Al-Zn-Mg-Zr合金均匀化处理温度和过烧温度，采用光学显微镜、扫描电镜、能谱分析和透射电镜研究合金铸锭均匀化过程中显微组织的演化，探索该合金的均匀化热处理工艺，研究铸锭均匀化动力学过程，并利用菲克定理构建均匀化动力学方程。结果表明：铸态Al-Zn-Mg-Zr合金由α(Al)固溶体、固溶了Cu元素的η-MgZn2相和非平衡共晶相T-Mg32(Al, Zn)49组成。随着均匀化温度的升高和时间的延长，非平衡共晶相溶入基体，晶内有弥散Al3Zr粒子析出，该合金的最佳均匀化热处理工艺为470℃退火16h。
关键字: Al-Zn-Mg-Zr合金；铸锭；均匀化；显微组织；动力学
（1. School ofPhysics and Electronics, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Materials Science and Engineering, Ministry of Education,
School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The homogenization temperature and overburnt temperature of an Al-Zn-Mg-Zr alloy ingot were confirmed by differential scanning calorimetry, the microstructure evolution of the alloy during homogenization was investigated by optical microscopy(OM), scanning electron microscopy(SEM), energy dispersive X-ray spectrometry(EDX) and transmission electron microscopy(TEM). And the homogenization kinetics equation was derived by theFick’s law. The results show that the ingot of Al-Zn-Mg-Zr alloy contains a large mount of second solidifying phases, skeletal MgZn2 phase and T-Mg32(Al，Zn)49 phase, which distribute on the boundaries。The second phases are gradually dissolved into the matrix, and the grain boundaries become spare and thin during homogenization with the increase of the temperature and holding time. The results of homogenization kinetic equation and annealing experiments for the Al-Zn-Mg-Zr alloy both show that (470℃, 16h) is the optimal homogenizing treatment process.
Key words: Al-Zn-Mg-Zr alloy; ingot; homogenization; microstructure; kinetics
