Computational Analysis of Material Flow During Friction Stir Welding of AA5059 Aluminum Alloys
ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD SURVIVABILITY MATERIALS BRANCH
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Workpiece material flow and stirringmixing during the friction stir welding FSW process are investigated computationally. Within the numerical model of the FSW process, the FSW tool is treated as a Lagrangian component while the workpiece material is treated as an Eulerian component. The employed coupled EulerianLagrangian computational analysis of the welding process was of a two-way thermo-mechanical character i.e., frictional-slidingplastic-work dissipation is taken to act as a heat source in the thermal energy balance equation while temperature is allowed to affect mechanical aspects of the model through temperature-dependent material properties. The workpiece material AA5059, solid-solution strengthened and strain-hardened aluminum alloy is represented using a modified version of the classical Johnson-Cook model within which the strain-hardening term is augmented to take into account for the effect of dynamic recrystallization while the FSW tool material AISI H13 tool steel is modeled as an isotropic linear-elastic material. Within the analysis, the effects of some of the FSW key process parameters are investigated e.g., weld pitch, tool tilt-angle, and the tool pin-size. The results pertaining to the material flow during FSW are compared with their experimental counterparts. It is found that, for the most part, experimentally observed material-flow characteristics are reproduced within the current FSW-process model.
- Properties of Metals and Alloys