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It was shown that, without computational fluid dynamics, intergranular liquid feeding in the mushy zone during welding of an alloy can still be calculated using an analytical model. The intergranular channel was approximated as a round pipe whose radius varies with the fraction of solid fS, which in turn varies with temperature T. The model was applied to 2014 Al (∼Al-4.4Cu) and 5086 Al (∼Al-4.0Mg) to compare their susceptibility to solidification cracking. Based on the extent of the liquid pressure drop caused by intergranular liquid flow, the contribution to the crack susceptibility by transverse tension was compared to that by solidification shrinkage. [ABSTRACT FROM AUTHOR] more...

It has been demonstrated that the susceptibility to solidification cracking can be calculated based on the index of |dT/d(fS)1/2| (T: temperature; fS: fraction solid) near the end of solidification. To distinguish the role of transverse tension verse that of solidification shrinkage in solidification cracking, however, computational fluid dynamics was used to calculate the flow of the intergranular liquid towards the roots of columnar dendritic grains using arc welding of Al–Cu alloys as an example. The calculated results show the solidification shrinkage dominates crack formation at the strain rate of 0.0001/s, but transverse tension dominates at the strain rate of 0.1/s. In between, both solidification shrinkage and transverse tension can play a significant role. [ABSTRACT FROM AUTHOR] more...

Solidification cracking can occur when neighbouring columnar grains are separated by tensile strain perpendicular to the grain boundary. In this study, a method to determine the tensile strain causing solidification cracking in welding was developed. A two-dimensional model was built to calculate the tensile strain perpendicular to the grain boundary during solidification, considering heat transfer, stress and strain evolution. The grain boundary direction was determined by calculating the temperature gradient and then the tensile strain causing solidification cracking was obtained by calculating the strain in the direction perpendicular to the grain boundary using strain transformation rule. This method to determine tensile strain causing solidification cracking can provide reference for future numerical and experimental studies on solidification cracking. [ABSTRACT FROM AUTHOR] more...