Effect of chemical composition on hot cracking susceptibility (HCS) using various hot cracking criteria

The paper aims to evaluate the effect of chemical composition on the Hot Cracking Susceptibility (HCS) using mechanical and non-mechanical hot cracking criteria during solidification. The criteria were SKK as a mechanical criterion. Feurer, Clyne Davis, and Katgerman as non-mechanical criteria. The criteria were implemented at various parameters to evaluate their abilities in the hot cracking susceptibility (HCS) prediction at varied chemical composition. In this study, The Mg content was varied in Al9Zn (1, 1.5, 2, 2.5 %wt.) Mg2Cu alloys and Cu content in Al9Zn2Mg (1, 1.5, 2, 2.5 %wt.) Cu alloys. The validation of the result is also conducted by comparing with the experimental data. Based on Feurer criterion, The hot cracking initiates at lower temperature and at higher critical rate of feeding and shrinkage with Cu content, and the hot cracking initiates at higher temperature with Mg content, and it initiates at higher critical rate of feeding and shrinkage from 1 up to 1.5 of Mg, and the critical rate of feeding and shrinkage remains constant from 1.5 up to 2.5 of Mg. Based on Clyne & Davies, the HCS decreases with Cu content from 1 up to 2 of Cu, and it increases from 2 up to 2.5 of Cu. The HCS decreases with Mg content from 1 up to 2 of Mg, and it remains constant from 2 up to 2.5 of Mg. Based on Katgerman criterion, the HCS decreases with Cu content from 1 up to 1.5 of Cu, it increases from 1.5 up to 2 of Cu, and it decreases from 2 up to 2.5 of Cu. The HCS decreases sequentially with Mg content. Based on SKK criterion, the HCS curves shift to the right with Cu content which means that the hot cracking initiates at lower temperature, and the HCS curves shift to the left with Mg content which means that the hot cracking initiates at higher temperature with Mg content. The Feurer, Clyne & Davies, and some specific range for SKK criteria are in agreement for the effect of Cu content on HCS of alloys, and Katgerman and some specific range for Clyne&Davies criteria are in agreement for the effect of Mg content on HCS of alloys.