自然时效对2024铝合金搅拌摩擦焊接头拉伸性能和显微硬度的影响  

Influence of Natural Aging on Tensile Properties and Microhardness of 2024 Aluminum Alloy Friction Stir Welded Joints

作　　者：霍仁杰 金玉花[2] 王宁 王广山[1] 周彦林 HUO Renjie;JIN Yuhua;WANG Ning;WANG Guangshan;ZHOU Yanlin(Department of Mechanical Engineering, Guidao Jiaotong Polytechnic Institute,Shenyang 110023, China;State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China;School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing 211167, China;Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology, Nanjing 211167, China;Dalian Nuclear Power and Petrochemical Company, China First Heavy Industry Group, Dalian 116033, China)

机构地区：[1]辽宁轨道交通职业学院机械工程系,辽宁沈阳110023 [2]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,甘肃兰州730050 [3]南京工程学院材料科学与工程学院,江苏南京211167 [4]江苏省先进结构材料与应用技术重点实验室,江苏南京211167 [5]中国一重集团大连核电石化公司,辽宁大连116033

出　　处：《热加工工艺》2019年第15期154-157,共4页Hot Working Technology

基　　金：甘肃省高等学校基本科研业务费资助项目(01-0071);辽宁省教育厅科学研究一般项目(L2014558)

摘　　要：对5 mm厚2024高强铝合金搅拌摩擦焊对接接头进行自然时效处理,时效时间为17520 h,研究焊接态和自然时效态接头的微观组织、显微硬度、力学性能和断口形貌。结果表明,自然时效态接头拉伸性能和显微硬度均较焊接态有所提高,当转速为1000 r/min,焊速为60 mm/min时,焊接接头组织经过自然时效析出大量细小且弥散分布的强化第二相,拉伸性能和显微硬度的改善最显著,抗拉强度达到了354.6 MPa,提高12.9 MPa,达到母材的84.4%,断裂发生在热影响区。焊核区硬度最高值为145.7 HV。自然时效态接头断口形貌呈现典型的韧-脆混合断裂特征。The natural aging was carried out for the friction stir butt welded joints of 5 mm thick 2024 high-strength aluminum alloy, and the aging time was 17520 h. The microstructure, microhardness, mechanical properties and fracture morphology of the welded and natural aged joints were studied. The results show that the tensile properties and microhardness are improved compared with that in welded state. When the rotating speed is 1000 r/min and the welding speed is 60 mm/min,the second strengthning phases precipitated in the welded joint are fine and diffusely distributed. Simultaneously, the tensile properties and microhardness are significantly improved. The tensile strength reaches 354.6 MPa, and increases by 12.9 MPa,which is 84.4% of the base metal. The fracture occurs in the heat affected zone. The highest hardness of the nugget zone is 145.7 HV. The fracture morphology of natural aged joints presents typical ductile-brittle mixed fracture characteristics.

关 键 词：自然时效 2024铝合金 搅拌摩擦焊 拉伸性能 显微硬度 

分 类 号：TG453.9[金属学及工艺—焊接]