热处理工艺对Mg-6Zn-3Al镁合金显微组织和力学性能的影响  

Effects of heat treatment technology on microstructure and mechanical properties of Mg-6Zn-3Al magnesium alloy

作　　者：张玉[1] 黄晓锋[1,2] 郭峰[1] 李元东[1,2] 毕广利[1,2] 马颖[1,2] 郝远[1,2] ZHANG Yu;HUANG Xiao-feng;GUO Feng;LI Yuan-dong;BI Guang-li;MA Ying;HAO Yuan(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China;Key Laboratory of Non-ferrous Metal Alloys and Processing,Ministry of Education,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,兰州730050 [2]兰州理工大学有色金属合金及加工教育部重点实验室,兰州730050

出　　处：《中国有色金属学报》2018年第6期1092-1100,共9页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(51464032);国家重点基础研究发展计划项目(2010CB635106)~~

摘　　要：通过金属型铸造制备新型Mg-6Zn-3Al(ZA63,质量分数,%)镁合金,并利用光镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)和力学性能测试研究ZA63合金在铸态、固溶和时效处理后显微组织和力学性能的变化规律。结果表明:合金铸态组织主要由基体α-Mg、晶界处呈连续或半连续分布的(α-Mg+Mg_2Zn_3+Mg_7Zn_3+Mg_(32)(Al,Zn)_(49))共晶和晶内孤立的颗粒相组成。合金在350℃固溶12～36 h时,随着时间延长,固溶效果逐渐增强,且在28 h时获得了较好的组织和241 MPa的抗拉强度及11.12%的伸长率。随后在180℃时效6～72 h后,合金的抗拉强度进一步提高,力学性能随保温时间延长呈先增加后减小的趋势,其中时效24 h时同时出现抗拉强度、伸长率和硬度的峰值298 MPa、9.78%和96.3 HV,比铸态的214 MPa、8.54%、62.2 HV分别提高39.25%、14.52%和54.82%。180℃时效24 h后,析出相的主要形态有板条状和短棒状。A new type Mg-6Zn-3Al （noted ZA63, mass fraction, %） magnesium alloy was prepared by permanent mould casting, and the microstructure and mechanical properties of the alloy under the conditions of as-cast, solution and aging treatment were systematically investigated by OM, SEM, TEM, XRD and mechanical tests, respectively. The results indicate that the as-cast alloy is mainly comprised of matrix α-Mg, eutectic phases （α-Mg＋Mg2Zn3＋Mg7Zn3＋ Mg32（Al,Zn）49） with continuous or semi-continuous precipitated along grain boundaries and a few divorced granules within grains. When the alloy is treated at 350 ℃ for 12？36 h, the solution effects are gradually enhanced with increasing solution time. At 350 ℃ for 28 h, the alloy reveals relatively homogeneous microstructure, and the ultimate tensile strength （UTS） and elongation （EL） of 241 MPa and 11.12% are achieved, respectively. Subsequently, when the alloy is aged at 180 ℃ for 6？72 h, the mechanical test demonstrates that, the UTS further increases, the mechanical properties increase firstly and then decrease, the peak values of UTS, EL and micro-hardness of the alloy aged at 180 ℃ for 24 h are simultaneously obtained, which are 298 MPa, 9.78% and 96.3 HV and increase by 39.25%, 14.52% and 54.82% compared with those of the as-cast alloy （214 MPa, 8.54% and 62.2 HV）, respectively. There are mainly two types of precipitates of the alloy after aging at 180 ℃ for 24 h, namely, the first precipitate is lath-like, the secondary one is a short-rod.

关 键 词：Mg-6Zn-3Al镁合金 固溶处理 时效处理 显微组织 力学性能 析出相形态 

分 类 号：TG146.2[一般工业技术—材料科学与工程]