Study on microstructure and mechanical properties of 6005A joint in laser-MIG hybrid welding
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School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China;
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State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China
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Corresponding author:
WANG Chunming, cmwang@hust.edu.cn
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Received Date:
2014-01-21
Accepted Date:
2014-02-24
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Abstract
In order to study the welding of high-strength aluminum alloy, understand the interaction mechanism between laser and metal inert gas (MIG) and optimize the welding process parameters further, experimental investigation on 6005A aluminum alloy with 3mm thickness in laser-MIG hybrid welding was performed using fiber laser and MIG welding machine. The influence of process parameters on weld quality was analyzed after combining weld morphology with mechanical properties of joints. The results show that a joint with good deformation for 6005A aluminum alloy under appropriate process parameters can be achieved in laser-MIG hybrid welding. Phases in the weld are mainly composed of -Al solid solution and the second phase Mg2Si dispersed in the matrix. It also is found that the hardness in the weld zone is significantly lower than that of the heat affected zone and the base metal. The fracture of welded joint occurs in the weld zone on account of microstructure coarsening and porosity defect induced by welding thermal cycle. It ruptures in the form of ductile fracture, where a lot of dimples appear. The tensile strength of the joint is 251.52MPa, 89.19% of the parent material. The weld quality meets the project requirements.
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