Microstructure and Properties of 40 mm-thick TC4 Titanium Alloy Welded Joint by Narrow-gap Laser Welding with Filler Wire
XU Kaixin1, LEI Zhen1, HUANG Ruisheng1, YIN Limeng2,3, FANG Naiwen1,4, ZOU Jipeng1, CAO Hao1
1 Harbin Welding Institute Limited Company, Harbin 150028, China 2 China-Ukraine E.O. Paton Institute of Welding, Guangdong Modern Welding Key Laboratory, Guangzhou 510651, China 3 School of Metallurgy and Materials Engineering, Chongqing University Science & Technology, Chongqing 401331, China 4 School of Material Science and Chemical Engineering, Harbin University of Science and Technology, Harbin 150006, China
Abstract: 40 mm-thick TC4 titanium alloy was welded by narrow-gap laser welding with filler wire. The microstructure and structure of each area of the welded joint were analyzed by OM, SEM, EDS, XRD, EBSD and other testing methods, and the mechanical properties were tested.The results show that the weld cross section is well formed without obvious lack of fusion and pore.The microstructure of the three areas of the joint is essentially the same: there are densely arranged needle α′ martensite and dispersed granular αg phase in the columnar crystal of the weld, in the same β grain, the α′ orientation is preferred and the ratio of grain boundary with large angle is higher and all the areas of the weld center have α′+β phase structure.The heat-affected zone presents as transition-state structure. The closer it is to the weld, the more similar its microstructure is to that of the weld. In the welding process, Al element diffuses into the heat-affected zone.The overall hardness of the weld area of the welded joint is higher than that of the base metal, and the cover layer is the highest, with an average value of about 380HV.The maximum tensile strength of the joint reaches 954 MPa. The tensile samples are all broken in the base metal with ductile fracture. The impact performance of the joints at room temperature is all lower than that of the base metal.
1 Chang H, Wang X D, Zhou L. Materials China, 2014(9),603(in Chinese). 常辉, 王向东, 周廉.中国材料进展, 2014(9), 603. 2 Zhang T G, Zhang Q, Zhuang H F, et al. Acta Optica Sinica, 2020, 40(11),1114001 (in Chinese). 张天刚, 张倩, 庄怀风, 等. 光学学报, 2020, 40(11),1114001. 3 Liao C H, Zhou J, Shen H. Chinese Journal of Lasers, 2020, 47(1), 0102003(in Chinese). 廖聪豪, 周静, 沈洪. 中国激光, 2020, 47(1), 0102003. 4 Yang T, Xu D Z, Chen W, et al. Materials Letters, 2019, 250(1),116. 5 Zhang G W, Xiao R S. Chinese Journal of Lasers, 2014, 41(8),0803007 (in Chinese). 张国伟, 肖荣诗. 中国激光, 2014, 41(8), 0803007. 6 Zhao Y, Wang Q Z, Huang J, et al. Chinese Journal of Lasers, 2015, 42(2),0203007 (in Chinese). 赵勇, 王清曌, 黄坚, 等. 中国激光, 2015, 42(2),0203007. 7 Wang H P, Yang X Y, Chen H, et al. Transactions of the China Welding Institution, 2019, 40(11),87 (in Chinese). 汪汉萍, 杨晓益, 陈辉, 等. 焊接学报, 2019, 40(11),87. 8 Cui B, Zhang H, Zhao C Y, et al. Materials Reports, 2018, 32(S2),333 (in Chinese). 崔冰, 张华, 赵常宇, 等. 材料导报, 2018, 32(S2),333. 9 Liu J, Zhan X, Gao Z, et al. International Journal of Advanced Manufacturing Technology, 2020, 108(3),1. 10 Wang J C, Guo C W, Li J J, et al. Acta Metallurgica Sinica, 2018, 54(5),48 (in Chinese). 王锦程, 郭春文, 李俊杰, 等. 金属学报, 2018, 54(5),48. 11 Xu P Q, Li L J, Zhang C B. Materials Characterization, 2014, 87,179. 12 Fang N W, Guo E J, Huang R S, et al. Materials Research Express, 2021(8), 016511. 13 Xu D Z. Investigation of microstructure evolution and property strengthening mechanisms of narrow-gap welded great thick TC4 titanium alloy joints. Master's Thesis, Southwest Jiaotong University, China, 2019 (in Chinese). 徐德志. 大厚板TC4钛合金窄间隙焊接接头组织演变规律及性能强化机制研究.硕士学位论文, 西南交通大学, 2019. 14 Anil Kumar V, Gupta R K, Manwatkar S K, et al. Journal of Materials Engineering and Performance, 2016, 25(6),2147. 15 Yu H, Li F, Yang J, et al. Materials Science and Engineering, 2018, 712(17),20. 16 Leary R K, Merson E, Birmingham K, et al. Materials Science and Engineering A, 2010, 527(29-30),7694. 17 Chen Y, Feng J, Li L, et al. Materials Science and Engineering A, 2013, 582(10),284. 18 Kumar C, Das M, Paul C P, et al. Optics & Laser Technology, 2018, 105,306. 19 Xu J, Wang W Y, Xie J P, et al. Rare Metals and Cemented Carbides, 2014(2),41 (in Chinese). 徐坚, 王文焱, 谢敬佩, 等. 稀有金属与硬质合金, 2014(2),41. 20 Kang S P, Li Z, Jiang X, et al. MW Metal Forming, 2014(Z2),193 (in Chinese). 康少酺, 李壮, 姜行, 等. 金属加工(热加工), 2014(Z2),193. 21 Cheng D H, Huang J H, Zhang H, et al. Rare Metal Materials and Engineering, 2009, 38(2),259 (in Chinese). 程东海, 黄继华, 张华, 等. 稀有金属材料与工程, 2009, 38(2),259. 22 Hu W M, Li G L, Liu X L, et al. The Chinese Journal of Nonferrous Metals, 2010, 20(S1),48 (in Chinese). 胡伟民, 李国林, 刘希林,等. 中国有色金属学报, 2010, 20(S1),48. 23 Abbasi K,Beidokhti B,Sajjadi S A. Materials Science and Engineering A, 2017, 702,272.