20 mm厚Ti-6Al-4V钛合金窄间隙激光填丝焊接头组织性能研究  

Microstructure and Mechanical Properties of 20 mm Thick Ti-6Al-4V Titanium Alloy Narrow-gap Laser Wire-fill Welded Joints

作　　者：赵代娣 刘沁源 ZHAO Daidi;LIU Qinyuan(School of Marine Engineering,Guangxi Transport Vocational and Technical College,Nanning 530012,China;China Waterborne Transport Research Institute,Beijing 100088,China)

机构地区：[1]广西交通职业技术学院航海工程学院,南宁530012 [2]交通运输部水运科学研究院,北京100088

出　　处：《精密成形工程》2024年第12期180-188,共9页Journal of Netshape Forming Engineering

基　　金：广西科技重大专项(AA23062037)。

摘　　要：目的探究20 mm厚Ti-6Al-4V钛合金窄间隙激光填丝焊接头显微组织与力学性能的分布规律,分析焊接接头沿壁厚区域的断裂特征。方法应用窄间隙激光填丝焊接技术对20 mm厚Ti-6Al-4V钛合金板进行连接,采用光学显微镜和扫描电镜对焊接接头的显微组织分布进行观察,使用拉伸性能试验机和冲击性能试验机对焊接接头进行维氏硬度测试、拉伸性能测试与断裂韧性测试,同时对试样断口形貌进行观察分析。结果焊接接头沿壁厚方向的微观组织分布及形貌特征相似,焊缝区由长针状α'马氏体交叉分布,相互交织分布的α'马氏体之间还存在次生α'马氏体,熔合区主要由针状α'马氏体、少量初始αp相及魏氏组织构成,热影响区主要由α'马氏体、粗大的β相、少量次生α_(s)相和晶界αgb相组成,但组织尺寸明显较焊缝区细化许多;细晶区则由粗大的β相、短粗次生α_(s)相、晶界αgb相及长条状α'马氏体构成。焊接接头上、中、下3部分的抗拉强度平均值为955 MPa、规定非比例延伸强度平均值为783 MPa、断后伸长率平均值为19.5%;上、中、下焊接接头三部分的室温平均冲击韧性测试结果为31 J。结论窄间隙激光填丝焊接技术适用于厚壁钛合金的焊接,可以获得组织性能优异的焊接接头,可以有效保障厚壁钛合金焊接结构的安全服役。The work aims to investigate the distribution of microstructure and mechanical properties of 20 mm thick Ti-6Al-4V titanium alloy narrow gap laser wire filler welding joints,and analyze the fracture characteristics of the welded joint along the wall thickness region.The narrow gap laser wire filling welding technology was applied to the connection of 20 mm thick Ti-6Al-4V titanium alloy plates.The microstructure distribution of the welded joint was observed by optical microscope and scanning electron microscope.The welded joint was tested by tensile testing machine and impact testing machine for microhardness,tensile property and fracture toughness.At the same time,the fracture morphology of the sample was observed and analyzed.The microstructure distribution and morphology of welded joints along the wall thickness direction were similar.The welded seam was composed of long acicularα'martensite cross-distribution,and there were secondaryα'martensite between the interwovenα'martensite.The fusion zone was mainly composed of acicularα'martensite,a small amount of initialαp phase and Widmanstatten.The HAZ was mainly composed ofα'martensite,coarseβphase,a small amount of secondaryα_(s) phase and grain boundaryαgb phase,but the structure size was much finer than that of the welded seam.The fine crystal region was composed of coarseβphase,short coarse secondaryα_(s) phase,grain boundaryαgb phase and long stripα'martensite.The average tensile strength of the upper,middle and lower parts of the welded joint was 955 MPa,the average non-proportional extension strength was 783 MPa,and the average elongation after fracture was 19.5%.The average impact toughness test results of the 3 parts of the upper,middle and lower welded joints at room temperature were 31 J.The narrow gap laser wire filling welding technology is suitable for the welding of thick wall titanium alloy,and can obtain the welded joint with excellent microstructure and properties,and can effectively ensure the safety of the welded structure of thic

关 键 词：钛合金 窄间隙 激光填丝焊 微观组织 力学性能 

分 类 号：TG456.7[金属学及工艺—焊接]