Effect of laser beam configuration on microstructure evolution and joint performance in laser joining AA 6111 panels

Publication date: 5 June 2017
Source:Materials & Design, Volume 123
Author(s): Guang Yang, Junjie Ma, Blair Carlson, Hui-Ping Wang, Radovan Kovacevic
Control of solidification through the selection of laser beams is an approach to improve the quality of visible coach-peel joints in automotive bodies. Laser joining of aluminum alloy 6111 panels with the addition of AA 4047 filler wire was investigated in this study using three types of laser beam, single-beam, in-line beam, and cross-beam. To compare the effect of laser beam arrangement on the weld qualities, the transient heat flow, cooling rate, and solidification rate were analyzed by three-dimensional finite element thermal models using ANSYS software. Microstructure evolution, surface roughness, and fracture mechanism of joints were investigated accordingly. Using the same processing parameters for the three joining processes, cross-beam laser generated the highest peak temperature and solidification rate, as well as the smallest molten pool size. Fusion-brazing joining achieved by the cross-beam laser resulted in the best weld surface quality with acceptable mechanical properties for application as non-load-bearing components. Therefore, cross-beam laser is recommended to join aluminum closure panels in the automotive body-in-white fabrication.

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