A multiscale approach for modeling metal laser welding

The growing application of laser welding in the industry motivates the development of computational models to help improve and understand the details of the laser welding process. Classical molecular dynamic (MD) or finite element (FE) methods are insufficient to model the process due to several limitations. The coupling of both methods provides a unique approach for modeling the laser welding process. A laser welding model that accounts for free-electron conduction and three-dimensional laser beam growth was developed on the basis of this coupling. The model was tested on a Cu sample, and the results showed that the amount of energy required to weld the interface was much lower than the energy used in previous studies of MD laser processes. The temperatures in the weld pool and the heat-affected zones were similar to those in previous FE studies. The crystal structure near the weld pool matched the observations of the previous MD studies. Moreover, the scanning speeds associated with this model were relatively higher than those of previous MD models due to the effects of fast electron conduction.