When comparing the laser welding of near to pure aluminum (AA1050) and different aluminum alloys (AA5182 and AA7075), significant differences can be found in the process behavior, and the operating conditions at which a weld can be made. In particular, the weld pool dimensions show considerable differences under similar process conditions. Among the causes of the observed differences are the different thermal coefficients of each of the different alloys, the different melt temperatures and differences in the evaporation process due to the presence of volatile alloy components.
In this study, the importance of these different causes is evaluated and discussed, based on results obtained from numerical simulations. In particular, the influence of volatile alloy components is studied. A theoretical model is proposed to describe the evaporation process of binary alloys. A thermal simulation model is used to quantify the effects of the volatile component on the laser welding process.
The simulation results are compared with experimental observations during the laser welding process of the three different alloys, and it is demonstrated that the evaporative effects are the most significant cause of differences in the weld pool dimensions for the different alloys.