研究了一种电子束焊接规范对轧制+增材TC4钛合金焊接接头组织影响，分析了焊后钛合金力学性能.结果表明，轧制侧热影响区合金组织变化较大，离焊缝中心距离越近，β转变组织含量增加，晶粒逐渐转变为等轴晶组织，等轴晶内有集束状马氏体α'相析出，越靠近焊缝等轴晶尺寸越大；增材侧热影响区组织形态变化较小，β晶粒形态保持柱状晶形态，无等轴晶区产生，晶内组织转变为马氏体α'相.焊缝两侧热影响区显微硬度变化趋势相同，均为越靠近焊缝中心，显微硬度越高，焊接重熔区硬度最高，达400 HV左右.焊接接头力学性能与TC4钛合金锻件相当，且断裂位置均位于激光沉积母材区域.
This paper studied the influence of a specification of electron beam welding on the structure of ‘rolled+ laser deposited’ TC4 welded joints, and analyzed the mechanical properties of the joints. Results show that on the rolled side, the microstructure of heat affected zone changes obviously, the shorter the distance away from welding center, the more amount of transformed β generates, and the columnar grain gradually transforms into equiaxed grain, with the appearance of clustered martensite α'. However, on the laser-deposited side, few changes are observed in the heat affected zone, β grain stays columnar, in which martensite α' generates, no equiaxed grain generates. The change trend of microhardness on both sides is similar, the closer the distance from the center, the higher the microhardness gets, the maximum hardness is around 400 HV found in the fusion zone. The mechanical properties of welded joints are similar to forged TC4, all the fractures locate in the laser-deposited base metal region.
[1] Li G C, Li J, Tian X J, et al. Microstructure and properties of a novel titanium alloy Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si manufactured by laser additive manufacturing[J]. Materials Science&Engineering A, 2007, 684:233-238.
[2] 牛超楠,宋晓国,胡胜鹏,等.钎焊温度对TC4/Ti60接头组织及性能的影响[J].焊接学报, 2018, 39(6):77-80 Niu Chaonan, Song Xiaoguo, Hu Shengpeng, et al. Effect of brazing temperature on the interfacial microstructure and mechanical properties of TC4/Ti60 brazed joints[J]. Transactions of the China Welding Institution, 2018, 39(6):77-80
[3] 赵志业.金属塑性变形与轧制理论(第2版)[M].北京:冶金工业出版社, 1996.
[4] 王华明,张述泉,王向明.大型钛合金结构件激光直接制造的进展与挑战(邀请论文)[J].中国激光, 2009, 36(12):3204-3209 Wang Huaming, Zhang Shuquan, Wang Xiangming. Progress and challenges of laser direct manufacturing of large titanium structural components (Invited Paper)[J]. China Laser, 2009, 36(12):3204-3209
[5] Dirk H, Vanessa S, Eric W, et al. Additive manufacturing of metals[J]. Acta Materialia, 2016, 117:371-392.
[6] Zhu Y Y, Tang H B, Li Z, et al. Solidification behavior and grain morphology of laser additive manufacturing titanium alloys[J]. Journal of Alloys and Compounds, 2019, 777:712-716.
[7] 许鸿吉,尹丽香,李晋炜,等. TC4钛合金电子束焊接接头组织和性能[J].焊接学报, 2005, 26(11):43-46 Xu Hongji, Yin Lixiang, Li Jinwei, et al. Microstructure and properties of electron beam welded joints in TC4 titanium alloy[J]. Transactions of the China Welding Institution, 2005, 26(11):43-46
[8] 何伟,杜小平,马红征,等. TC4钛合金相变温度的测定与分析[J].理化检验(物理分册), 2014, 50(7):461-464 He Wei, Du Xiaoping, Ma Hongzheng, et al. Determination and analysis of phase transition temperature of TC4 titanium alloy[J]. Physical Testing and Chemical Analysis (Part A:Physical Testing), 2014, 50(7):461-464
[9] 杨晶晶,喻寒琛,韩婕,等.激光选区熔化成形TC4合金的β转变温度[J].材料热处理学报, 2016, 37(9):80-85 Yang Jingjing, Yu Hanchen, Han Jie, et al. Transition temperature of TC4 alloy by laser selective melting forming[J]. Journal of Material Heat Treatment, 2016, 37(9):80-85
[10] Zhou X, Huang Y, Chen Y, et al. Laser joining of Mo and Ta sheets with Ti6Al4V or Ni filler[J]. Optics and Laser Technology, 2018, 106:487-494.
[11] Li Z, Cheng X, Li J, et al. Thermal expansion properties of laser melting deposited Ti-6. 5Al-2Zr-1Mo-1V alloy during α+β zone annealing[J]. Materials Characterization, 2017, 128:115-122.
[12] Li Z, Li J, Zhu Y Y, et al. Variant selection in laser melting deposited α+β titanium alloy[J]. Journal of Alloys and Compounds, 2016, 661:126-135.
[13] He J, Li D, Jiang W, et al. The martensitic transformation and mechanical properties of Ti6Al4V prepared via selective laser melting[J]. Materials, 2019, 12(2):1-14.
[14] 吴新强,王少刚,李燕.线能量对TC4钛合金激光焊接残余应力和变形的影响[J].电焊机, 2011, 41(6):6-12 Wu Xinqiang, Wang Shaogang, Li Yan. Effects of linear energy on residual stress and deformation in laser welding of TC4 titanium alloy[J]. Welding Machine, 2011, 41(6):6-12
[15] Palanivel R, Dinaharan I, Laubscher R F. Microstructure evolution and mechanical characterization of Nd:YAG laser beam welded titanium tubes[J]. Materials Characterization, 2017, 134:225-235.
[16] 国防科学工业技术委员会.航空用钛及钛合金锻件规范国家标准:GJB 2744A-2007[S].北京:国防科学工业技术委员会, 2007.
