Heat Treatment, Microstructure and Mechanical Properties of the Squeezing Cast Al-7.8Zn-2.0Mg-1.6Cu-0.15Zr-0.18Sc Alloy

作     者：Tu Qiang, Yang Fubao, Xu Jun, Zhang Zhifeng, Li Daquan Nonferrous Metals Processing Division , General Research Institute for Non-ferrous Metals, Beijing 100088, China 

作者机构：Gen Res Inst Nonferrous Met Nonferrous Met Proc Div Beijing 100088 Peoples R China 

出 版 物：《稀有金属材料与工程》 (Rare Metal Materials and Engineering)

年 卷 期：2011年第40卷第S3期

页      面：82-85页

核心收录：

学科分类：0806[工学-冶金工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

主　　题：squeezing casting homogenization treatment multi-stage solution mechanical properties 

摘      要：The microstructure of squeezing cast Al-7.8Zn-2.0Mg-1.6Cu-0.15Zr-0.18Sc alloy and those after industrial homogenization treatment and multi-stage solution treatments, were studied by differential scanning calorimetry (DSC), optical microscopy (OM), transmission electron microscope (TEM), scanning electron microscopy with energy dispersive X-ray spectroscopy (TEM-EDX). The results shows that, by complex adding the micro-alloying elements Mn, Sc, Zr, etc ,the microstructure of squeezing casting ingot are fine, uniform, equiaxed, and with the average sizes of 40 μm. The melting point of the non-equilibrium eutectic is 468 ℃ for the casting ingot. After industrial homogenization treatment at 450 ℃ for 24 h, the tensile strength of as-cast alloy is 340-350 MPa and the elongation is 3.5%-4.5%. The multi-stage solution treatment at 465 ℃, 48 h +475 ℃, 8 h +485 ℃, 2 h results in the disappearance of the non-equilibrium eutectics at grain boundary, though some phases containing Fe and Cu can not dissolve completely. After 120 ℃, 24 h aging treatment, the tensile strength is nearly 600 MPa, and the elongation improve to more than 10%.