TC4钛合金激光-MIG复合焊接头组织性能  

Microstructure and Properties of Laser-MIG Hybrid Welded TC4 Titanium Alloy Joints

作　　者：马寅 韩晓辉 李刚卿 杨志斌 宋东哲 靳月强 MA Yin;HAN Xiaohui;LI Gangqing;YANG Zhibin;SONG Dongzhe;JIN Yueqiang(CRRC Qingdao Sifang Co.,Ltd.,Qingdao 266111,China;School of Material Science and Engineering,Dalian Jiaotong University,Dalian 116028,China)

机构地区：[1]中车青岛四方机车车辆股份有限公司,山东青岛266111 [2]大连交通大学材料科学与工程学院,辽宁大连116028

出　　处：《电焊机》2023年第8期93-97,114,共6页Electric Welding Machine

摘　　要：采用激光-MIG复合焊接方法实现了3 mm厚TC4钛合金的焊接,并研究了焊接接头的组织特征、硬度分布、拉伸性能和耐蚀性能。研究结果表明:激光-MIG复合焊接可以实现TC4钛合金的高质量焊接,焊缝成形良好,无明显缺陷;焊缝中心为粗大的β相柱状晶,晶内为细小的针状α′马氏体;热影响区主要为等轴状的α相+β相+α′马氏体,随着远离熔合线,晶粒越来越细且α′马氏体含量越少;焊缝区硬度最高、热影响区硬度次之,母材区硬度最低,且热影响区粗晶区硬度高于细晶区硬度;焊接接头平均抗拉强度为1069 MPa,平均断后伸长率为5.3%,试样均断裂在靠近热影响区的母材区域,断口呈现塑性断裂特征,同时焊接接头的耐蚀性能略高于母材。In this paper,3 mm thick titanium alloy was welded by laser-MIG hybrid welding technology.The microstructure,microhardness,tensile properties and corrosion resistance of the welded joints were studied.The results indicated that laser-MIG hybrid welding could realize high quality welding for TC4 titanium alloy with well weldrd formation and no obvious defects.The coarseβphase columnar crystals existed in the weld center,and the fine acicularα'martensite existed inside the crystals.The heat affected zone mainly consisted of equiaxedαphase+βphase+α'martensite,with finer grain and less martensiticα'martensite as the distance from the fusion line increased.The hardness of welded seam was the highest,followed by the heat-affected zone,and the base metal was the lowest,and the hardness of the coarse-grained zones was higher than that of the fine-grained zone in heat-affected zone.The average tensile strength of welded joints was 1069 MPa,and the average elongation was 5.3%.The specimens fractured in the base metal close to the heat affected zone,and the fracture characteristics were plastic fracture.The corrosion resistance of the welded joints were slightly higher than that of the base metal.

关 键 词：钛合金 激光-MIG复合焊 微观组织 力学性能 电化学腐蚀 

分 类 号：TG456.7[金属学及工艺—焊接]