Microstructure and Mechanical Properties of Laser Welded Al–Mg–Si Alloy Joints

Abstract

In this paper, AlMgSi alloy with the thickness of 2.5 mm was overlap welded by fiber laser. Optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, hardness tester, and electro-hydraulic servo testing machine were used for the microstructure observation and mechanical property examination. Specimens extracted from the welded plates were tested at room temperature for the determination of the tensile and fatigue properties of the welded joints. Results showed the columnar grains were formed in the fusion boundary, while equiaxed grains were formed in the fusion zone; the lowest hardness in the fusion zone is 72.0 HV, gradually increasing from the heataffected zone to the BM. Tensile shear strength of the welded joint is 96.0 Mpa, which is about 25% of the tensile strength of base metal. The fatigue limit at 1 © 10 6 conditional cycles is 22.5 MPa. The fractography showed intergranular and quasi-cleavage fracture. Bending deformation is related to the magnitude of the force. As the stress lower, the deformation become more severe.

Design of welding parameters for laser welding of thick-walled structures made of aluminum alloy

“…In modeling and numerical simulation, the influence of the laser beam on the material during the fusion welding process can be defined by means of different heat source models [7][8][9][10][11][12][13][14]. Understanding thermal phenomena and the heat transfer during the welding process is crucial for the analysis of microstructure, mechanical properties, and a quality of the weld joints [15][16][17][18]. Based on the results of numerical simulation, it is possible to predict the process of development of weld joints under different welding conditions and parameters.…”

Steel Sheets Laser Lap Joint Welding—Process Analysis

“…Rapid development of laser technology has determined LBW for use in advanced joint configuration. Currently, researchers are focusing on welding dissimilar materials, where low-carbon and austenitic steels are welded, and some works are related to joining advanced aluminum, nickel and titanium alloys [5][6][7][8][9]. Nonconventional joining methods, such as laser welding in butt, lap and T-joint configurations, are also being widely studied [10][11][12][13][14].…”