Zr添加及热处理对Al-Zn-Mg-Cu合金组织与性能的影响  

Effect of Zr addition and heat treatment on microstructure and mechanical properties of Al-Zn-Mg-Cu alloy

作　　者：刘守法[1] 王晋鹏[2] 李凡国[3] Liu Shoufa;Wang Jinpeng;Li Fanguo(School of Mechanical Engineering,Xijing University,Xi＇an Shaanxi 710123,China;School of Mechanical and Electrical Engineering,Northwestern Polytechnical University,Xi＇an Shaanxi 710072,China;College of Mechanical and Electronic Engineering,China University of Petroleum,Qingdao Shandong 266580,China)

机构地区：[1]西京学院机械工程学院,陕西西安710123 [2]西北工业大学机电学院,陕西西安710072 [3]中国石油大学华东机电工程学院,山东青岛266580

出　　处：《金属热处理》2018年第9期27-30,共4页Heat Treatment of Metals

基　　金：国家科技重大专项(2017ZX04011-010);陕西省教育厅专项科研计划项目(15JK2172)

摘　　要：分别制备了Al-4.9Zn-1.4Mg-0.08Cu和Al-4.9Zn-1.4Mg-0.08Cu-0.18Zr两种合金,并对两种合金分别实施了T6、T73和RRA热处理,利用拉伸机测试含Zr合金和无Zr合金热处理前后的屈服强度和抗拉强度,利用显微硬度仪测试含Zr合金和无Zr合金热处理前后的硬度,利用透射电镜（TEM）观察含Zr合金不同热处理状态析出相成分和分布情况,研究了Zr元素的添加对Al-4.9Zn-1.4Mg-0.08Cu合金热处理试样力学性能的影响。研究表明,Zr元素的添加使得Al-4.9Zn-1.4Mg-0.08Cu合金平均晶粒尺寸减小一半,同时促进了合金中溶质原子的固溶强化及析出强化作用,使含Zr合金的硬度和强度提高较大;经T6或RRA热处理的含Zr合金中的强化相主要为η＇相,且与基底保持整合的方向关系,析出强化效果较好;经T73热处理的含Zr合金中的η＇相转变为η相,造成基底晶格应变减少,析出强化效果较差;因细晶和析出强化共同作用促进了含Zr合金力学性能提高,使该合金的屈服强度超出Hall-Petch公式预测的增加量。Two kinds of Al alloys,Al-4. 9 Zn-1. 4 Mg-0. 08 Cu and Al-4. 9 Zn-1. 4 Mg-0. 08 Cu-0. 18 Zr,were fabricated and heat treated under T6,T73 and RRA heat treatment conditions respectively. The yield strength and tensile strength of the Zr-containing alloy and Zr-free alloy were measured by tensile machine,and the hardness of the Zr-containing alloy and Zr-free alloy were measured by microhardness tester. The composition and distribution of the precipitated phase of the Zr-containing alloy with different heat treatments were observed by transmission electron microscopy（ TEM）. Effect of the addition of Zr on the mechanical properties of Al-4. 9 Zn-1. 4 Mg-0. 08 Cu alloy with different heat treatments were investigated. The results show that the addition of Zr element reduces the average grain size of the Al-Zn-Mg-Cu alloy by half,and promotes the solid solution strengthening and precipitation strengthening of the solute atoms in the alloy,therefore,the hardness and strength of the Zr-containing alloy are improved. The strengthening phase in the Zr-containing alloy heat treated under T6 or RRA conditions is mainly η＇ phase,which keeps the direction of integration with the substrate. The η＇ phase in the Zr-containing alloy heat treated under T73 conditions is converted into η phase,resulting in reduced lattice strain and poor precipitation hardening effect. The combination of fine grain and precipitation could enhance the mechanical properties of the Zr-containing alloy,therefore,the yield strength of the Zr-containing alloy exceeds the value predicted by the Hall-Petch formula.

关 键 词：AL-ZN-MG-CU合金 Zr元素 热处理 力学性能 显微组织 强化相 

分 类 号：TG146.4[一般工业技术—材料科学与工程]