Fine-grained AA5083, an aluminum-magnesium alloy, can be formed into complex closure components with a suitable gas pressure profile at high temperatures (450°C) over short cycle times. Material models that account for independent creep mechanisms at 450°C are required for accurate prediction of thinning in the formed component and for inferring the locations of potential failure sites during forming. Using a commercial finite element solver, high-temperature gas-pressure forming simulations for a vehicle closure component were conducted using a material model that accounts for grain boundary sliding and dislocation creep. The model was compiled into the finite element code at run time in a user subroutine. Strain rates at specific positions in the material during forming were investigated to determine the active creep mechanism. Predicted thinning profiles were compared against data measured from closure components formed into the same die geometry and under the same forming conditions used for the simulations. The theoretical/experimental comparisons generally showed good agreement, thereby confirming the importance of using accurate material models in finite element simulations of high temperature sheet forming.
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