Prediction of solidification cracking in pulsed laser welding of 2024 aluminum alloy

Laser welding of aluminum alloys can be associated with solidification cracking. The severity of cracking in these alloys depends on various factors, such as the initial temperature of the base metal and the temporal amplitude of the laser pulse. The purpose of this investigation is to understand this correlation, and thus to put forward a criterion for solidification cracking in laser welding of 2024 aluminum alloy. The criterion for cracking is devised based on a modification of the existing criteria, to account for non-steady conditions, and interpreted with respect to the loci of the relevant isotherms and the length of the vulnerable zone in the melt pool, during the solidification stage. Based on this criterion and the respective experimental observations, it is demonstrated that welding with suitable ramping down of the laser pulse can lead to the elimination of solidification cracking in the examined alloy.