Numerical modelling of the annealing determined by short-term laser treatment using a physical simulation-based approach.

The local modification of the material properties, especially in the case of Aluminium alloys, is considered a promising solution to overcome the poor formability at room temperature. According to this approach, the Aluminium blank is preliminary subjected to a short-term local heat treatment (usually by laser heating) and then, once cooled down to room temperature, subjected to the forming operations. The present work proposes a numerical methodology to predict the effect of a laser heating, locally bringing a AA5754-H32 blank to the fully annealed state. The Gleeble 3180 physical simulator was used to reproduce the annealing laser treatment by heating AA5754-H32 striped samples under different conditions of time and temperature: specimens, once cooled down to room temperature, were then subjected to hardness measurement and the resulting data used to calibrate a sigmoid function describing the level of annealing according to the time and the maximum temperature reached during the heat treatment. The logistic function was then implemented in a python script able to post-process the results from a thermal transient simulation and, by extracting the temperature history from each node, predict the final distribution of properties. The methodology is then validated by comparing the predicted distribution of properties and the measured one on AA5754-H32 samples subjected to different laser heating strategies. [Display omitted] • The proposed methodology is based on data efficiently obtained by physical simulation tests. • Degree of Annealing (DoA) is related to time and temperature by a sigmoid function. • FE simulations implementing the DoA sigmoid function accurately predicts the laser annealing. • FE predictions are validated by Vickers hardness measurements. • The proposed methodology is versatile and can be applied to different alloys. [ABSTRACT FROM AUTHOR]