铝锂合金电子束焊接数值模拟分析及工艺优化

采用组合热源模型对Al-Li合金电子束焊接温度场分布进行数值模拟分析,通过热-力耦合,模拟计算得到接头区域的残余应力分布.结果表明,Al-Li合金电子束焊接温度场沿焊接方向呈椭圆形分布,电子束热源中心的温度最高,其附近区域的等温线分布密集,随着与热源中心的距离增大,等温线分布逐渐稀疏,焊缝区存在较大的温度梯度,较好地模拟出了电子束焊缝的钉形分布特征.接头的残余应力分布模拟结果显示,残余应力主要集中于焊缝区,由于修饰焊的热作用,焊缝上部具有相对较大的应力值.利用模拟计算得到的结果进行焊接工艺及参数优化,焊接工艺试验表明,试验焊缝形貌与模拟熔池形貌相吻合,进一步验证了模拟计算结果的可靠性.

Numerical Simulation and Process Optimization on Electron Beam Welding of Al-Li Alloy

The combined heat source model is used to simulate the distribution of the electron beam welding(EBW) temperature field of Al-Li alloy, based on which, the residual stress distribution of weld zone was calculated through thermo-mechanical coupling. The results show that the temperature field of Al-Li alloy weldment presents an elliptical distribution along the welding direction. The temperature of heat source center is the highest, and the isothermal distribution is dense when adjacent to heat source and gradually becomes sparse with its increasing distance away from the heat source center. There exists a large temperature gradient in weld zone. The nail-shape characteristic of EBW joint is well simulated. The simulation results of residual stress show that the residual stress is mainly generated in the weld zone, and the stress value is higher in the upper part of joint due to the thermal effect by the modification welding. According to the results of numerical simulation, the welding parameters are optimized. The welding experiment demonstrates that the experimental weld morphology is consistent with the simulated molten pool, verifying the reliability of simulation results.