不同激光焊接工艺对6005A-T6系铝合金焊接接头高应变速率性能的影响

Effect of different laser welding processes on high strain rate performance of 6005A-T6 aluminum alloy welded joints

  • 摘要: 文中主要以3 mm厚6005A-T6铝合金对接接头为主要研究对象,采用激光填丝焊、激光-MIG复合焊、激光-CMT复合焊3种焊接工艺对其进行焊接,对焊后试样进行高应变速率下单向拉伸试验,得到高应变速率下的真应力-真应变曲线,对拉伸断口进行了SEM分析,对比3种焊接工艺下的高速拉伸性能,拟合3种焊接工艺塑性变形段Johnson-Cook本构方程曲线。研究结果表明,在200 s-1高应变速率下,激光填丝焊接头的抗拉强度最高,而激光-MIG复合焊、激光-CMT复合焊较激光填丝焊的抗拉强度略低;断裂方式均为韧性断裂;3种焊接工艺的Johnson-Cook本构方程曲线与试验曲线拟合较好,可以很好的描述3种焊接工艺在高应变速率下流变应力变化。创新点: (1)对6005A-T6铝合金焊接接头高应变速率动态力学性能进行了研究,通过拟合3种焊接方法塑性变形段Johnson-Cook本构方程曲线,发现在典型应变速率200 s-1高应变速率下,激光填丝焊接头的抗拉强度最高,激光-MIG复合焊、激光-CMT复合焊较激光填丝焊略低。(2)各焊接方法的Johnson-Cook本构方程曲线与试验曲线拟合较好,可以对不同焊接方法接头在高应变速率下的塑性变形进行预测,为实际生产中车身结构的轻量化设计及焊接方式等工艺的优化改进提供数据支撑。

     

    Abstract: In this paper,butt joint with 3 mm 6005A-T6 aluminum alloy was taken as the main object of study.The samples were welded by laser wire filling welding,laser-MIG welding and laser-CMT welding,and were tested with a high strain rate to obtain the true stress-true strain curve.Tensile fractures were analyzed by SEM to compare high-speed tensile properties of the three welding methods.Johnson-Cook constitutive equations’parameters of welding processes were calculated correspondingly by fitting to their plastic deformation parts of testing curves.The results showed that the tensile strength of the laser wire filling welded joints was the highest at the high strain rate of 200 s-1,while the joints’tensile strength of the other two welding processes was a little bit lower.The fracture mode was ductile.The curve of Johnson-Cook constitutive equation fit the testing curve well for each welding process,and it accurately described the variation of flow stress under high strain rate.Highlights:(1)The dynamic mechanical properties of 6005A-T6 aluminum alloy welded joints at high strain rates were studied.By fitting the Johnson-Cook constitutive equation curves of the plastic deformation section of three welding processes,it was found that the tensile strength of laser wire filled joints was the highest at the typical high strain rate of 200 s-1,while that of laser-MIG and laser-CMT hybrid welding was slightly lower.(2)The Johnson-Cook constitutive equation curve of each welding process fit well with the test curve,which could predict the plastic deformation of joints of different welding processes under high strain rate,and provide data support for the lightweight design of body structure and the optimization and improvement of welding method and other processes in actual production.

     

/

返回文章
返回