Investigation of metal mixing in laser keyhole welding of dissimilar metals
Investigation of metal mixing in laser keyhole welding of dissimilar metals
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DOI：
10.1016/j.matdes.2020.109056
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发表时间：
2020-10-01
影响因子：
8.4
通讯作者：
Tan, Wenda
中科院分区：
文献类型：
--
作者：
Huang, Wenkang;Wang, Hongliang;Tan, Wenda
异种金属激光小孔焊接在各个工业领域有着广泛的应用。然而，熔池中的异种金属混合通常会导致有害的金属间化合物的形成，从而损害异种金属接头的性能。在这项研究中，结合实验和建模方法研究了异种金属激光小孔焊接中的金属混合过程。参数实验研究旨在揭示激光功率、焊接速度和热输入对熔化区金属混合的影响。采用异位能量色散X射线光谱元素映射来表征熔融区金属混合状态。为了研究焊接过程的基础物理原理，开发了一个数值模型来模拟熔池中的传热、流体流动和金属混合。研究发现，反冲压力有助于向上流动，推动铜从熔池底部迁移到顶部。同时，马兰戈尼力产生一股回流和两侧涡流，有利于金属混合。激光功率的增加会增加反冲压力和马兰戈尼应力，从而驱动更多的铜向上迁移并与铝混合。焊接速度的增加会缩短熔池寿命，从而减少流体流动引起的金属混合。异种金属再分布的研究提供了有关接头中金属间化合物形成的见解，这对于不同行业的焊接工艺的设计和优化具有重要价值。 (c) 2020 通用汽车。由 Elsevier Ltd 出版。这是一篇遵循 CC BY-NC-ND 许可证 (http://creativecommons.org/licenses/by-nc-nd/4.0/) 的开放获取文章。
Laser keyhole welding of dissimilar metals has broad applications in various industrial fields. However, dissimilar metal mixing in the molten pool often causes the formation of detrimental intermetallic compounds that can undermine the performances of the dissimilar metal joints. In this study, the metal mixing process in laser keyhole welding of dissimilar metals is investigated with a combination of experimental and modeling approaches. The parametric experimental study is conducted to reveal the effects of laser power, welding speed, and heat input on the metal mixing in the fusion zone. Ex-situ energy-dispersive X-ray spectroscopy element mapping is used to characterize the metal mixing status in the fusion zone. To investigate the underlying physics of the welding process, a numerical model is developed to simulate the heat transfer, fluid flow, and metal mixing in the molten pool. It is found that the recoil pressure contributes to an upward flow that pushes copper to migrate from the bottom of the molten pool to the top. Meanwhile, the Marangoni force generates one backward flow and two side vortices that facilitate the metal mixing. An increase of laser power increases both the recoil pressure and the Marangoni stress, which drives more copper to migrate upward and mix with aluminum. An increase of welding speed reduces the molten pool lifetime, which reduces the metal mixing by the fluid flow. The investigation of dissimilar metal redistribution provides insights regarding the formation of intermetallic compounds in the joints, which is valuable for the design and optimization of the welding process in different industries. (c) 2020 General Motors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).