新型Al-Mg-Mn-Er合金TIG焊接头的微观组织及力学性能  

Microstructure and mechanical properties of joints of a new Al-Mg-Mn-Er alloy by TIG welding

作　　者：王虎[1,2] 靳立坤 彭云 WANG Hu;JIN Likun;PENG Yun(North China Institute of Aerospace Engineering,Langfang,065000,China;State Key Laboratory of Advanced Steel Processes and Products,Central Iron&Steel Research Institute,Beijing,100081,China;Beijing Hainachuan Automotive Parts Co.,Ltd.,Beijing,100083,China)

机构地区：[1]北华航天工业学院,廊坊065000 [2]钢铁研究总院,先进钢铁流程及材料国家重点实验室,北京100081 [3]北京海纳川汽车部件股份有限公司,北京100083

出　　处：《焊接学报》2020年第3期74-79,I0005,共7页Transactions of The China Welding Institution

基　　金：河北省重点研发计划项目(18211041);河北省高等学校科学技术研究项目(QN2020256);北华航天工业学院青年基金项目(KY201822);北华航天工业学院教学建设与教学改革研究项目(JY2019022);河北省大学生创新创业训练计划项目(CX2020205).

摘　　要：对一种Al-Mg-Mn-Er合金薄板进行TIG填丝焊接,并研究接头的微观组织以及力学性能.结果表明,焊缝中心为等轴树枝晶,熔合线附近未出现典型的联生结晶形貌,而是存在着一个宽度约为100μm的细晶带,热影响区出现再结晶组织.焊缝中的析出相主要以初生Al3Er的形式存在,与母材相比,焊缝中初生Al3Er的尺寸更加细小,分布更加均匀,焊缝中次生Al3Er的数量相对较少,而且这些次生Al3Er是焊接时母材中未熔化而保留下来的.焊接区和热影响区的硬度均低于母材,其中焊缝区的硬度最低.随着焊接热输入的增加,接头的抗拉强度先增加后减小,当焊接热输入为218 J/mm时,接头的抗拉强度最高,达到母材的71.4%,试样的断裂位置均位于焊缝区,断口形貌呈现韧性断裂特征.New Al-Mg-Mn-Er alloy sheets were welded by TIG welding with filler wires.The microstructure and mechanical properties of the joints were studied.The results show that the center of the weld seam is mainly composed of equiaxed crystals.There is no typical epitaxial solidification appeared,but a fine-grained zone with width of 100μm is formed near the fusion line.The recrystallized structure is appeared in the heat affected zone.The precipitates in the weld zone mainly exist in the form of primary Al3Er.Compared with the base metal,the size of primary Al3Er in the weld seam is smaller and its distribution is more uniform.The number of secondary Al3Er in the weld seam is relatively small and the secondary Al3Er is from the base metal.The microhardness of the weld zone and the heat affected zone are lower than that of base metal,and the microhardness of the weld zone is the lowest.With the increase of the welding heat input,the tensile strength of the joints increases first and then decreases.When the welding heat input is 218 J/mm,the tensile strength of the joint is the highest which is 71.4%of that of the base metal.The fracture of all tensile samples is located at the weld zone,and the fracture morphology shows the typical ductile fracture characteristics.

关 键 词：Al-Mg-Mn-Er合金 TIG焊 微观组织 力学性能 

分 类 号：TG407[金属学及工艺—焊接]