Abstract
Joining dissimilar metals is very difficult due to the formation of brittle intermetallic phases which may be detrimental to mechanical properties. The present work aims to investigate the transport phenomenon in the weld bead and to understand the materials mixing during laser welding process of dissimilar Aluminum-Magnesium alloys. A three-dimensional transient model based on fluid flow, heat and mass transfer has been developed to predict the formation of the weld and to study numerically and experimentally the diffusion of alloying elements in the melted zone. SEM analysis of chemical composition has been realized to map elements distribution in the melted zone. The results of simulation show the formation of a heterogeneous mixture in the melt pool. The elements distribution map and the presence of brittle intermetallic phases in the fusion zone were analysed. The formation of intermetallic compounds, comprising Al3Mg2 and Al12Mg17 phases were predicted by studying the chemical elements distribution in the weld pool. A good tendency between experimental and numerical results is noticed for the weld.
Highlights
Laser welding is considered as one of the most effective process for joining different materials
They conducted that brittle intermetallic compounds (IMCs), such as γ-Al12Mg17 and β-Al3Mg2, were produced at the interfaces resulting in the formation of microcracks
-The thermo-physical properties vary with temperature and composition. -Fluid flow in the weld pool is incompressible and laminar. -The model is unsteady. -The free surface of the weld pool is flat. -The workpiece moves with a constant speed Uy
Summary
Laser welding is considered as one of the most effective process for joining different materials. Dehghani et al [2] performed welding of AA5186 aluminum alloy and low carbon steel by FSW They determined the effects of various parameters of the arc welding process, such as tool traverse speed and angle of inclination on the intermetallic volume fraction and the mechanical properties of the joint. Mohammed et al [4] studied the pulsed laser welding of stainless steel (304) and austenitic duplex (2205) They highlighted the effect of laser beam diameter and pulsed laser power, on the weld bead geometry. Liang et al [5] evaluated the weldability of aluminum and magnesium by stir friction They conducted that brittle intermetallic compounds (IMCs), such as γ-Al12Mg17 and β-Al3Mg2, were produced at the interfaces resulting in the formation of microcracks. The predicted elements distribution in the melting zone based on the model is validated by comparing the simulation results with experimental ones
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