深冷处理对AZ91镁合金组织与性能的影响  

Effect of deep cryogenic treatment on microstructure and mechanical properties of AZ91 magnesium alloy

作　　者：饶楚楚[1] 周明安[1] 兰叶深[1] 徐文俊[1,2] RAO Chu-chu;ZHU Ming-an;LAN Ye-shen;XU Wen-jun(School of Mechanical Engineering,Quzhou College of Technology,Quzhou 324000,China;School of Mechanical Engineering,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]衢州职业技术学院机电工程学院,浙江衢州324000 [2]武汉理工大学机械工程学院,湖北武汉430070

出　　处：《轻合金加工技术》2021年第5期66-71,共6页Light Alloy Fabrication Technology

基　　金：浙江省自然科学基金(LZY21F050001);衢州市科技攻关项目(2019kl9);浙江省高校国内访问工程师校企合作项目(FG2019164、FG2020221)。

摘　　要：对AZ91镁合金进行了固溶+不同深冷处理时间+时效的复合工艺处理,采用光学显微镜、X射线衍射仪、硬度仪、万能试验机以及摩擦磨损试验机等仪器设备研究了不同深冷处理时间对A291镁合金显微组织、力学性能及耐磨性能的影响规律。结果表明:AZ91镁合金经410℃8 h固溶+(-196)℃12 h深冷处理+180℃8 h时效复合工艺处理后,其硬度、抗拉强度及伸长率较未深冷处理的分别提高了19.2%、25%和37.4%,其平均摩擦因数与磨损率分别为0.22和0.382 mg/(m·N),较未深冷处理的降低了50%和32.7%。深冷处理工艺有效细化了AZ91镁合金组织的晶粒尺寸,促使β-Mg_(17) Al_(12)相成颗粒状且弥散均匀分布的析出,显著提高了其力学性能和耐磨性能。但随着深冷处理时间的增加,β-Mg_(17) Al_(12)相会逐渐偏聚与粗化,导致合金的力学性能有所下降。AZ91 magnesium alloy was treated by the composite process of solution+differ-ent cryogenic treatment time+aging.The effects of cryogenic treatment time on microstruc-ture,mechanical properties and wear resistance of AZ91 magnesium alloy were studied by optical microscope,X-ray diffractometer,hardness tester,universal tester and friction and wear tester.The results show that after solution treatment at 410 C for8 h+cryogenic treat-ment at-196 ℃ for 12 h+aging treatment at 180 ℃ for8 h,the hardness,tensile strength and elongation of AZ91 magnesium alloy are increased by 19.2%,25%and 37.4%respec-tively and the average friction coefficient and wear rate are 0.22 and 0.382 mg/(m·N),respectively,which are reduced by 50%and 32.7%compared with those without cryogenic treatment.Cryogenic treatment can effectively refine the grain size of AZ91 magnesium alloy,promote the precipitation ofβ-Mg_(17) Al_(12) phase in granular form and uniform distribu-tion,and significantly improve its mechanical properties and wear resistance.However,with the increase of cryogenic treatment time,β-Mg_(17) Al_(12) phase will gradually segregate and coarsen,resulting in the degradation of properties.

关 键 词：深冷处理 AZ91镁合金 β-Mg_(17)Al_(12)相 力学性能 耐磨性 

分 类 号：TG156.91[金属学及工艺—热处理] TG166.4[金属学及工艺—金属学]