动态冲击载荷对7A52铝合金焊接接头组织和力学性能的影响  

Effect of dynamic impact load on microstructure and mechanical properties of 7A52 aluminum alloy welded joint

作　　者：杨兵 罗忠宇 黄浩 刘文辉[2,3] 刘子聪 肖明月 YANG Bing;LUO Zhong-yu;HUANG Hao;LIU Wen-hui;LIU Zi-cong;XIAO Ming-yue(Jiang Lu Electromechanical Group Co.,Ltd.,Xiangtan 411100,China;School of Mechanical and Electrical Engineering,Hunan University of Science and Technology,Xiangtan 411201,China;Evaluation of Forming Technology and Damage Resistance of High Efficiency Light Alloy Components,Hunan Engineering Research Center,Hunan University of Science and Technology,Xiangtan 411201,China)

机构地区：[1]江麓机电集团有限公司,湖南湘潭411100 [2]湖南科技大学机电工程学院,湖南湘潭411201 [3]湖南科技大学高功效轻合金构件成形技术及耐损伤性能评价湖南省工程研究中心,湖南湘潭411201

出　　处：《塑性工程学报》2022年第11期200-208,共9页Journal of Plasticity Engineering

基　　金：国家自然科学基金重点资助项目(U21A20130);国家自然科学基金面上资助项目(51875197);湖南省自然科学基金资助项目(2020JJ6027)。

摘　　要：利用霍普金森压杆对7A52铝合金焊接接头进行了不同温度(-80~300℃)和应变速率(2600~4600 s^(-1))下的冲击实验,研究了动态冲击载荷下的7A52铝合金焊接接头的组织和力学性能。结果表明,在常温下,焊接接头不同区域发生了不均匀塑性变形,铸态组织的焊缝区在动态冲击过程中发生了均匀的塑性变形。母材区塑性较差,当应变速率为4600 s^(-1)时,发生断裂失效。过渡区(熔合区附近焊缝与母材结合处)组织差异大,容易产生绝热剪切带。随着冲击温度的升高,焊接接头不同区域的非均匀变形减小,当温度为300℃时,母材区组织以形变带为主,焊缝与母材均发生了动态回复和动态再结晶。而随着冲击温度的降低,焊接接头强度增加,塑性变差,在-80℃、4600 s^(-1)的冲击条件下,过渡区产生裂纹。The impact experiments of 7A52 aluminum alloy welded joints at different temperatures(-80-300℃)and strain rates(2600-4600 s^(-1))were carried out with Hopkinson pressure bar.The microstructure and mechanical properties of 7A52 aluminum alloy welded joints under dynamic impact load were studied.The results show that at room temperature,uneven plastic deformation occurs in different zones of the welded joint,and uniform plastic deformation occurs in the welded zone of as-cast microstructure during dynamic impact.The plasticity in the base metal zone is poor,and when the strain rate is 4600 s^(-1),fracture failure occurs.The microstructure difference of transition zone(junction zone between weld and base metal near fusion zone)is big,and it is easy to produce adiabatic shear band(ASB).With the increase of impact temperature,the uneven deformation in different zones of welded joint decreases.When the temperature is 300℃,the microstructure in the base metal zone is mainly deformation band.Dynamic recovery and dynamic recrystallization occur in both weld and base metal.With the decrease of impact temperature,the strength of welded joint increases and the plasticity becomes worse.Under the impact condition of-80℃and 4600 s^(-1),cracks appear in transition zone.

关 键 词：7A52铝合金 焊接接头 力学性能 微观组织 绝热剪切带 

分 类 号：TG407[金属学及工艺—焊接]