铝合金搅拌摩擦焊过程热力演变的三维数值模拟  

3D numerical simulation of temperature and stress evolution in friction stir welding of aluminum alloy

作　　者：董平[1] 窦作勇[1] 张鹏程[1] 

机构地区：[1]中国工程物理研究院材料研究所,绵阳621900

出　　处：《焊接学报》2015年第4期71-74,116-117,共6页Transactions of The China Welding Institution

基　　金：国家重大科学仪器开发资助项目(2012YQ130234)

摘　　要：对搅拌摩擦焊过程中搅拌头速度变化进行分析,建立了考虑搅拌摩擦焊过程中焊缝产热的热源模型.对2024铝合金搅拌摩擦焊温度场和应力场进行了三维有限元模拟,表明焊缝两侧温度和应力分布的不对称现象不明显,主要由于焊接速度远小于搅拌头转速所致,但随着焊接速度加快,这种不对称现象逐渐加强.焊接过程中焊缝中心温度低于搅拌头边缘温度,焊接前方和两侧均为压应力,后方为拉应力;焊接结束后与搅拌头接触区的横向和纵向残余应力为较大拉应力,远离焊缝残余应力较小;沿厚度方向上,横向和纵向残余应力均逐渐降低.有限元计算结果与短波长X射线应力测试结果进行对比,结果表明,二者趋势基本吻合.The instantaneous velocity of stirring tool during friction stir welding( FSW) process was analyzed to build a heat source model of FSW,which took into account the heat difference near the weld line. The temperature and stress fields of 2024 aluminum alloy during friction stir welding were numerically simulated by using 3D finite element method. The results show that the asymmetry of temperature and stress fields was not obvious because the moving velocity was much smaller than the rotating velocity of stirring tool,but this asymmetry would be enhanced with increasing the moving velocity. The temperature at the weld center was lower than that at the tool edge during welding. The stresses were compressive at the weld front and on two sides,but tensile at the weld rear. After welding,the transverse and longitudinal residual stresses were large tensile stress within the stirring tool, which gradually became smaller along the depth. Far from the weld line,the transverse and longitudinal residual stresses were very small. The residual stresses by finite element simulation were compared to those by short wavelength X-ray stress measurement; two results were basically identical in trend.

关 键 词：铝合金 搅拌摩擦焊接 温度场 应力场 有限元分析 

分 类 号：TG453.9[金属学及工艺—焊接]