摘要铝合金作为一种轻质材料，具有其密度低，强度高，热电导率高，耐腐蚀能力高 等性能，从而焊接结构件在航空航天、汽车、机械制造、船舶等领域广泛应用。然而 铝合金热膨胀系数大，焊接工程中容易产生残余应力与变形，特别是对于铝合金中厚 板该问题更为严重。而作为一种先进焊接技术激光+GMAW 复合焊综合了两者的优点， 弥补了各自的缺点，具有实现铝合金高效焊接的优质工艺，有助于全面了解铝合金复 合焊的成行机理，促进该新型工艺在铝合金中的推广及应用。因此，研究铝合金中厚 板激光+GMAW 复合焊热源应力场分布特征,具有很重要的理论意义和工程实用价值83345

本文对 12mm 厚 6061 铝合金进行光纤激光+GMAW 复合焊接;基于热弹塑性理论建 立了铝合金复合焊对接接头残余应力的三维数值分析模型，利用 ANSYS 软件对温度场 和应力场进行模拟数值计算。结果表明：对于铝合金进行激光+GMAW 复合焊时，残余 应力在焊缝区及近缝区域较高。激光复合焊的纵向残余应力峰值为 225MP，小于母材 的屈服强度，横向残余应力峰值为 98MP，等效应力峰值为 185MP；与复合焊相比 MIG 焊的纵向残余应力峰值为 198MP，同样小于母材的屈服强度，横向应力为峰值 110MP， 等效应力峰值为 175MP。两种焊接方法在不同方向的残余应力均小于母材的强度。

毕业论文关键词：铝合金；复合焊；残余应力；数值分析

Abstract Aluminum alloy is a kind of lightweight metal material。 It has the characteristics of small density, high strength, high thermal conductivity and high corrosion resistance。 So it is widely used in industrial welding structure。The coefficient of thermal expansion of medium and heavy plate aluminum alloy is large, which is the main factor leading to the residual stress of aluminum alloy。 In addition, the high melting point of aluminum alloy in the production and preparation process will inevitably lead to drastic changes in temperature and deformation of the workpiece, the aluminum alloy will produce residual stress。 Therefore, it is very valuable to study the heat source in thick plate laser +GMAW hybrid welding of Aluminum alloy and analysis the distribution of temperature field and stress field 。 At present, the research on the residual stress of laser clad aluminum alloy is still relatively small。 Most people focus their research on the process and microstructure of aluminum alloy。

In this paper, the 12mm thick 6061 aluminum alloy was welded by laser +GMAW。 Based on thermal elastic plastic theory, a numerical analysis model of temperature field and stress field numerical analysis model was established and the temperature field and stress field results were analyzed。 The experimental results show that in the laser +GMAW hybrid welding of 6061 aluminum alloy, the residual stress exists in the weld area is higher。 The longitudinal residual stress is 225MP, the transverse residual stress is 100MP, and the equivalent stress in the thickness direction is 185MP。 Compared to the longitudinal stress and the equivalent stress in the thickness direction, the transverse residual stress is small。

Keywords: aluminum alloy, stress field, temperature field, numerical analysis

目 录

第一章 绪论 1

1。1  选题意义 1

1。2  铝合金的焊接性及焊接方法 1

1。2。1  铝合金的焊接性 1

1。2。2  铝合金焊接方法 2

1。3  激光+GMAW 复合焊 3

1。3。1  激光+GMAW 复合焊特点