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高强铝合金可变转速回填式搅拌摩擦点焊温度场及接头组织性能调控

赵运强, 赵宇佳, 刘喆, 林志成, 董春林, 邓军

赵运强, 赵宇佳, 刘喆, 林志成, 董春林, 邓军. 高强铝合金可变转速回填式搅拌摩擦点焊温度场及接头组织性能调控[J]. 焊接学报, 2022, 43(6): 50-55. DOI: 10.12073/j.hjxb.20220102001
引用本文: 赵运强, 赵宇佳, 刘喆, 林志成, 董春林, 邓军. 高强铝合金可变转速回填式搅拌摩擦点焊温度场及接头组织性能调控[J]. 焊接学报, 2022, 43(6): 50-55. DOI: 10.12073/j.hjxb.20220102001
ZHAO Yunqiang, ZHAO Yujia, LIU Zhe, LIN Zhicheng, DONG Chunlin, DENG Jun. Control of temperature field, microstructure and mechanical properties of variable rotation speed refill friction stir spot welded high strength aluminum alloys[J]. TRANSACTIONS OF THE CHINA WELDING INSTITUTION, 2022, 43(6): 50-55. DOI: 10.12073/j.hjxb.20220102001
Citation: ZHAO Yunqiang, ZHAO Yujia, LIU Zhe, LIN Zhicheng, DONG Chunlin, DENG Jun. Control of temperature field, microstructure and mechanical properties of variable rotation speed refill friction stir spot welded high strength aluminum alloys[J]. TRANSACTIONS OF THE CHINA WELDING INSTITUTION, 2022, 43(6): 50-55. DOI: 10.12073/j.hjxb.20220102001

高强铝合金可变转速回填式搅拌摩擦点焊温度场及接头组织性能调控

基金项目: 国家自然科学基金资助项目(51905112);广东省科协科技人计划项目(SKXRC202221);广州市对外科技合作计划项目(201807010068); 东莞市重点领域研发项目(20201200300122).
详细信息
    作者简介:

    赵运强,博士,高级工程师; 主要从事智能化搅拌摩擦焊接技术、工艺及机理的研究; Email: yunqiangzhao@163.com

    通讯作者:

    邓军,工程师;Email: 858116178@qq.com.

  • 中图分类号: TG 453.9

Control of temperature field, microstructure and mechanical properties of variable rotation speed refill friction stir spot welded high strength aluminum alloys

  • 摘要: 针对7B04-T74铝合金,采用可变转速回填式搅拌摩擦点焊(variable rotation speed-refill friction stir spot welding, V-RFSSW)新方法开展了数值仿真及试验研究. 结果表明,V-RFSSW温度场围绕搅拌头轴线呈圆形对称分布,焊点高温区域集中在搅拌套空腔内部. 与扎入阶段转速相同的常规回填式搅拌摩擦点焊(refill friction stir spot welding, RFSSW)相比,V-RFSSW新方法既可在扎入阶段使材料充分塑化,以保证焊点成形,同时,通过降低回填阶段搅拌头转速降低焊接峰值温度及高温停留时间,抑制组分液化的发生,避免了共晶相的生成. V-RFSSW与常规RFSSW接头显微硬度均呈“W”形分布,且扎入阶段转速相同的情况下V-RFSSW接头搅拌区平均硬度更高. 在拉剪载荷下两种接头均以“纽扣”形式发生断裂,其中V-RFSSW接头拉剪失效载荷为8835 N,高于RFSSW接头的8162 N.
    Abstract: For 7B04-T74 aluminum alloy, a new method of variable rotation speed refill friction stir spot welding (V-RFSSW) was used. Numerical simulation and experiments were conducted. The results showed that the V-RFSSW temperature field was symmetrically distributed around the axis of the welding tool, and the high temperature area was concentrated in the cavity of the sleeve. Compared with the conventional refill friction stir spot welding (RFSSW) with the same rotation speed during the plunging stage, the new V-RFSSW method can fully plasticize the materials during the plunging stage to ensure the weld formation. At the same time, by reducing the rotation speed of the welding tool during the refilling stage, the welding peak temperature and high temperature dwelling time can be reduced, the occurrence of component liquefaction can be restrained and the formation of eutectic phase can be avoided. The microhardness distribution of the V-RFSSW joint and conventional RFSSW joint was "W" shape The average hardness of V-RFSSW joint was higher at the condition of the rotation speed iduring the plunging stage was the same. Under the tensile shear load, the two kinds of joints fractured in the form of "button", in which the tensile shear failure load of V-RFSSW joint was 8 835 N, which was higher than that of RFSSW joint (8 162 N).
  • 图  1   V-RFSSW几何模型

    Figure  1.   Geometric model of V-RFSSW

    图  2   焊接热循环仿真与试验结果对比

    Figure  2.   Comparison of welding thermal cycle simulation and measurement results

    图  3   不同时刻V-RFSSW接头上表面及横截面的温度分布

    Figure  3.   Temperature distributions of the top surface and cross-section of the joints at different time for V-RFSSW. (a) t = 1 s (the top surface); (b) t = 2.5 s (the top surface); (c) t = 4 s (the top surface); (d) t=1 s (cross-section); (e) t = 2.5 s (cross-section); (f) t = 4 s (cross-section)

    图  4   RFSSW与V-RFSSW搅拌区热循环曲线

    Figure  4.   Thermal recycles of RFSSW and V-RFSSW

    图  5   RFSSW和V-RFSSW焊点横截面

    Figure  5.   Cross sections of RFSSW and V-RFSSW joints. (a) ω1 = ω2 = 1 500 r/min; (b) ω1 = 1 500 r/min, ω2 = 1 000 r/min; (c) ω1 = ω2 = 1 250 r/min

    图  6   RFSSW和V-RFSSW接头搅拌区微观组织

    Figure  6.   Microstructures in stir zones of RFSSW and V-RFSSW joints. (a) ω1 = ω2 = 1500 r/min; (b) ω1 = 1500 r/min, ω2 = 1000 r/min; (c) SEM magnification of black strip microstructure in Fig. 6a; (d) EDS results of eutectic phase

    图  7   RFSSW和V-RFSSW接头的横截面显微硬度分布

    Figure  7.   Hardness distributions in the cross-sections of RFSSW and V-RFSSW joints

    图  8   RFSSW和V-RFSSW接头的拉剪性能

    Figure  8.   Tensile shear property of RFSSW and V-RFSSW joints

    表  1   7B04-T74铝合金的化学成分和力学性能

    Table  1   Chemical compositions and mechanical properties of 7B04-T74 aluminum alloy

    化学成分(质量分数,%) 力学性能
    Zn Mg Cu Mn Fe Cr Si Ni Ti Al 抗拉强度Rm/MPa 屈服强度ReL/MPa 断后伸长率A(%)
    5.86 2.51 1.62 0.34 0.18 0.15 0.07 0.05 0.03 余量 550 492 10.0
    下载: 导出CSV

    表  2   工艺参数

    Table  2   Welding parameters

    序号方法扎入阶段转速
    ω1 /(r·min−1)
    回填阶段转速
    ω2 /(r·min−1)
    下扎深度
    p /mm
    焊接时间
    tw /s
    峰值温度
    Tmax /℃
    高温停留时间
    th /s
    1RFSSW125012502.554750
    2RFSSW150015002.555221.6
    3V-RFSSW150010002.554930.4
    下载: 导出CSV
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出版历程
  • 收稿日期:  2022-01-01
  • 网络出版日期:  2022-05-27
  • 刊出日期:  2022-07-07

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