焊后在线热处理对7075铝合金焊接接头组织与性能的影响

doi:10.13251/j.issn.0254-6051.2025.11.028

摘要/Abstract

摘要： 采用7075铝合金焊丝对3 mm厚7075-T6铝合金板材进行MIG对接焊并随焊水冷,之后进行人工时效(120 ℃×24 h)处理。通过光学显微镜、X射线衍射仪、扫描电镜与能谱仪结合显微硬度与室温拉伸试验,研究焊后在线热处理工艺对焊接接头显微组织和力学性能的影响,并与焊后空冷接头进行对比。结果表明,焊后空冷接头的焊缝区主要为枝晶结构,析出相主要有η(MgZn₂)、AlCuMg、AlCu₃与Al₁₃Fe₄相,且分布在晶界处。与焊后空冷相比,随焊水冷+人工时效处理后,焊缝晶粒尺寸并无明显变化,且整体析出相尺寸有所减小,分布更加均匀。焊后在线热处理后焊接接头力学性能得到提升,90 A电流下,焊缝抗拉强度由331 MPa(焊后空冷)提高至389 MPa(随焊水冷+人工时效);100 A电流下,焊缝区平均硬度由105.2 HV0.2提升至128.4 HV0.2。

关键词: 7075铝合金, 随焊水冷, MIG焊, 组织, 力学性能

Abstract: 3 mm-thick 7075-T6 aluminum alloy plates were butt-welded by using MIG welding with 7075 aluminum alloy welding wire, followed by water-cooling during welding. Subsequent to this, an artificial aging treatment (120 ℃ × 24 h) was conducted. The effect of post-weld on-line heat treatment process on the microstructure and mechanical properties of welded joints was studied by using optical microscope (OM), X-ray diffraction (XRD), scanning electron microscope (SEM) combined with energy dispersive spectroscopy (EDS), as well as microhardness and room-temperature tensile tests. These results were compared with those of the welded joints air-cooled after welding. The results show that the weld zone of the joint air-cooled is mainly composed of dendritic structure, and the precipitated phases mainly include η(MgZn₂), AlCuMg, AlCu₃ and Al₁₃Fe₄ phases, which are distributed along grain boundaries. Compared with air-cooling after welding, after post-weld water-cooling and artificial aging, there is no significant change in the grain size of the weld zone, and the overall precipitated phases become smaller in size and more uniformly distributed. After post-weld on-line heat treatment, the mechanical properties of the welded joints are improved. At a current of 90 A, the tensile strength of the weld zone increases from 331 MPa (air-cooled) to 389 MPa (water-cooled+artificial aged); at a current of 100 A, the average hardness of the weld zone rises from 105.2 HV0.2 to 128.4 HV0.2.

Key words: 7075 aluminum alloy, water-cooling during welding, MIG welding, microstructure, mechanical properties

中图分类号:

TG457.14

周春锴, 李小平, 刘骁, 张衡昌. 焊后在线热处理对7075铝合金焊接接头组织与性能的影响[J]. 金属热处理, 2025, 50(11): 200-208.

Zhou Chunkai, Li Xiaoping, Liu Xiao, Zhang Hengchang. Effect of post-weld on-line heat treatment on microstructure and properties of 7075 aluminum alloy welded joints[J]. Heat Treatment of Metals, 2025, 50(11): 200-208.

参考文献

[1] Wang Zhongxing, Ma Chunyin, Li Mengyu, et al. Mechanical properties of 7A04-T6 high strength structural aluminium alloy at elevated temperatures and after cooling down[J]. Thin-Wall Structures, 2022, 180: 109930.
[2] Zhou Bo, Liu Bo, Zhang Shengen. The advancement of 7××× series aluminum alloys for aircraft structures: A review[J]. Metals, 2021, 11(5): 718.
[3] 文超, 朱正锋, 王群, 等. 7×××系超高强铝合金在我国轨道交通车辆的研究应用现状与展望[J]. 金属热处理, 2024, 49(3): 302-312.
Wen Chao, Zhu Zhengfeng, Wang Qun, et al. Research application status and prospect of 7××× series ultra-high strength aluminum alloy in rail transit vehicles in China[J]. Heat Treatment of Metals, 2024, 49(3): 302-312.
[4] Zheng Ye, Zhu Hongyi, Wang Shifei, et al. Fabricate high-strength 7075 aluminum alloy joint through double pulse MIG welding process[J]. Journal of Manufacturing Processes, 2024, 125: 512-522.
[5] 陈轩, 李萌蘖, 卜恒勇, 等. 7系铝合金焊接技术的研究现状及展望[J]. 材料导报, 2023, 37(13): 200-208.
Chen Xuan, Li Mengnie, Bu Hengyong, et al. Research status and progress on the welding technologies of 7××× aluminum alloy series[J]. Materials Reports, 2023, 37(13): 200-208.
[6] 倪维源, 杨尚磊, 贾进, 等. 高速列车用高强A7N01铝合金焊接接头的组织与性能[J]. 热加工工艺, 2014, 43(19): 22-25.
Ni Weiyuan, Yang Shanglei, Jia Jin, et al. Microstructure and performance of A7N01 Al alloy welding joint used in automotive high-strength[J]. Hot Working Technology, 2014, 43(19): 22-25.
[7] 李晶琨, 李欣荻, 刘永跃. 7075铝合金时效过程组织和力学性能演变规律[J]. 热处理技术与装备, 2024, 45(3): 1-6.
Li Jingkun, Li Xindi, Liu Yongyue. Evolution of microstructure and mechanical properties during aging process of 7075 aluminum alloy[J]. Heat Treatment Technology and Equipment, 2024, 45(3): 1-6.
[8] Li Xiaoping, Liu Xiao, Li Runzhou, et al. Microstructure and property research on welded joints of 7××× aluminum alloy welding wire TIG for 7075 aluminum alloy[J]. China Welding, 2021, 30(4): 58-64.
[9] Oropeza D, Hofmann D C, Williams K, et al. Welding and additive manufacturing with nanoparticle-enhanced aluminum 7075 wire[J]. Journal of Alloys and Compounds, 2020, 834: 154987.
[10] 张琨, 刘政军. 固溶处理对7075铝合金同质TIG焊接头显微组织及力学性能的影响研究[J]. 热加工工艺, 2019, 48(3): 83-88.
Zhang Kun, Liu Zhengjun. Effect of solution treatment on the microstructure and mechanical properties homogeneous TIG welded joint of 7075 aluminum alloy[J]. Hot Working Technology, 2019, 48(3): 83-88.
[11] 郝先芃, 邹超. 在线热处理技术在铝挤压中的运用探讨[J]. 世界有色金属, 2021(7): 180-181.
Hao Xianpeng, Zou Chao. Application of on line heat treatment technology in aluminum extrusion[J]. World Nonferrous Metals, 2021(7): 180-181.
[12] 何宗政, 吴名冬, 袁硕, 等. Zn/Mg比对7075铝合金显微组织、力学性能和耐蚀性能的影响[J]. 金属热处理, 2024, 49(5): 1-9.
He Zongzheng, Wu Mingdong, Yuan Shuo, et al. Effect of Zn/Mg ratio on microstructure, mechanical properties and corrosion resistance of 7075 aluminum alloy[J]. Heat Treatment of Metals, 2024, 49(5): 1-9.
[13] 李彩文, 潘学著, 刘露露, 等. 在线淬火对6061、6005铝合金型材组织与性能的影响[J]. 金属热处理, 2010, 35(6): 59-62.
Li Caiwen, Pan Xuezhu, Liu Lulu, et al. Effect of on-line quenching on microstructure and properties of 6061 and 6005 alloy profile[J]. Heat Treatment of Metals, 2010, 35(6): 59-62.
[14] 岳小明, 刘文辉, 宋宇峰, 等. 在线淬火对7A62铝合金的显微组织与力学性能的影响[J]. 中国有色金属学报, 2023, 33(11): 3595-3605.
Yue Xiaoming, Liu Wenhui, Song Yufeng, et al. Effect of online quenching on microstructure and mechanical properties of 7A62 aluminum alloy[J]. Chinese Journal of Nonferrous Metals, 2023, 33(11): 3595-3605.
[15] 王利华. 杂质元素含量对7075铝合金组织和性能的影响[J]. 铸造技术, 2014, 35(5): 1029-1031.
Wang Lihua. Effect of impurity element content on structure and properties of 7075 Al alloy[J]. Foundry Technology, 2014, 35(5): 1029-1031.
[16] 郭立祥, 李小平, 刘骁, 等. 7075铝合金TIG焊焊缝的组织和性能与耐腐蚀性[J]. 焊接学报, 2022, 43(5): 104-112.
Guo Lixiang, Li Xiaoping, Liu Xiao, et al. Microstructure and corrosion resistance of 7075 aluminum alloy welded by TIG[J]. Transactions of the China Welding Institution, 2022, 43(5): 104-112.
[17] 王文安. 铝合金焊接头的软化及改善措施分析[J]. 中国设备工程, 2021(12): 73-74.
[18] 刘成豪, 陈芙蓉. 超声冲击强化7A52铝合金VPPA-MIG焊接接头的疲劳性能[J]. 材料导报, 2022, 36(15): 137-141.
Liu Chenghao, Chen Furong. Fatigue properties of the VPPA-MIG welded joint of the 7A52 aluminum alloy strengthened by ultrasonic impact[J]. Materials Reports, 2022, 36(15): 137-141.
[19] 刘文辉, 岳小明, 曹平, 等. T9I6热处理对2519A铝合金厚板厚向组织与性能的影响[J]. 中国有色金属学报, 2022, 32(12): 3589-3598.
Liu Wenhui, Yue Xiaoming, Cao Ping, et al. Effect of T9I6 heat treatment on microstructure and properties of 2519A aluminum alloy thick plate[J]. The Chinese Journal of Nonferrous Metals, 2022, 32(12): 3589-3598.
[20] Geng Yingxin, Zhang Di, Zhang Jishan, et al. Early stage clustering and precipitation behavior in the age hardened Al-Mg-Zn-Cu alloys[J]. Materials Science and Engineering A, 2022, 856: 144015.
[21] 王晨阳, 李小平, 刘骁, 等. 7075与ER5356铝合金焊丝用于7075铝合金MIG焊接头性能对比研究[J]. 世界有色金属, 2023, 30(13): 145-147.
Wang Chenyang, Li Xiaoping, Liu Xiao, et al. 7075 and ER5356 aluminum alloy wire for MIG welding of 7075 aluminum alloy comparative study of joint performance[J]. World Nonferrous Metals, 2023, 30(13): 145-147.
[22] 唐鹏, 黄嘉良, 刘倩男, 等. 时效时间对7075-T6铝合金组织与性能的影响[J]. 金属热处理, 2023, 48(7): 131-137.
Tang Peng, Huang Jialiang, Liu Qiannan, et al. Effect of aging time on microstructure and properties of 7075-T6 aluminum alloy[J]. Heat Treatment of Metals, 2023, 48(7): 131-137.