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The metal inert gas (MIG) welding and the crucial parameters influenced on the
thermal and mechanical behaviours, and microstructure of AA 6063 aluminum were
investigated through the experiment and the FE simulation. A thermo-mechanical model was
extended using the finite element software of ABAQUS. In this manner, the thermal distribution
and time-temperature histories made during MIG welding were derived. To achieve more
accuracy, a subroutine was developed by FORTRAN. The real-time temperature measurements
and the effective parameters of the thermal distribution, including the welding speed and the
arc voltage were studied by conducting MIG bead-on-plate welds and the residual stresses
derived from the simulation were compared with the empirical observations. The results
depicted that the simulation would estimate rigorously the temperature gradients and the fields
of welding-induced stress. The microstructural and microhardness examinations were also
conducted which allowed - alongside the TTT curve - the phases precipitated and the heat sink
effects were studied and foreseen. Indeed, the microstructure images demonstrated that the
overaged, agglomerated β-Mg2Si phases, in the HAZ, and the modified β-AlFeSi pseudo-platelike
precipitates alongside the smaller and coarsened β-Mg2Si phases, in the fusion zone, were
precipitated.
Keywords: FE simulation, in-situ measurement, 6063 aluminum, welding residual stress, thermo-mechanical properties, TTT curve, microstructural examination. |
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