(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 烟台南山学院 工学院，烟台 265713)
摘 要: 采用光学显微镜(OM)、扫描电镜(SEM)、电子探针(EPMA)、波谱分析(WDS)、X射线衍射(XRD)以及差示扫描量热仪(DSC)等技术对Al-Zn-Mg-Cu-Zr-0.12Ce合金铸态组织及均匀化退火过程中的组织演变进行研究。结果表明：该合金铸态组织存在严重的枝晶偏析，主要由α(Al)基体、α(Al)+Mg(Zn, Al, Cu)2 非平衡共晶组织以及少量的θ(Al2Cu)相、Al8Cu4Ce相、Al7Cu2Fe相构成；均匀化退火过程中，大量层片状共晶组织溶入基体，同时转变生成Al2CuMg相；合金的过烧温度为474.87 ℃；合金的最佳单级均匀化退火工艺为465 ℃、40 h，这与均匀化动力学方程测算结果接近；合金经(435 ℃，8 h)+(470 ℃，32 h)双级均匀化退火处理后，回溶效果更好，主要残留相为难溶的Al2CuMg相，少量含Fe杂质相以及Al8Cu4Ce相。
关键字: Al-Zn-Mg-Cu-Zr-0.12Ce合金；均匀化；组织演变；均匀化动力学
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. School of Engineering, Yantai Nanshan University, Yantai 265713, China）
Abstract:The microstructure of the as-cast Al-Zn-Mg-Cu-Zr-0.12Ce aluminum alloy and microstructure evolution during homogenization were investigated by means of optical microscopy (OM), scanning electron microscopy (SEM), electron probe micro-analyzer (EPMA), wavelength dispersive spectroscopy (WDS), X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). The results indicate that the severe dendritic segregation exists in Al-Zn-Mg-Cu-Zr-0.12Ce alloy ingot. The as-cast microstructure mainly involves α(Al), non-equilibrium eutectics (α(Al)+Mg(Zn, Al, Cu)2), and small amounts of θ(Al2Cu), Al8Cu4Ce and Al7Cu2Fe phases. During homogenization, the lamellar eutectic structures in the as-cast alloy is dissolved into the matrix, meanwhile, a transformation from Mg(Zn, Al, Cu)2 to Al2CuMg phase also occurs. The overburnt temperature of the alloy is 474.87 ℃. The optimum parameters of single homogenization are (465 ℃, 40 h), which is consistent with the result of homogenization kinetic analysis. The eutectic phases are eliminated more sufficiently with two-step homogenization treatment at 435 ℃ for 12 h and then at 470 ℃ for 32 h. The residual second particles after homogenization are some small Al2CuMg, Fe-rich and Al8Cu4Ce phases.
Key words: Al-Zn-Mg-Cu-Zr-0.12Ce alloy; homogenization; microstructure evolution; homogenization kinetics
