Quantitative Investigation of Hot Tearing of Al-Cu Alloy (206) Cast in a Constrained Bar Permanent Mold

The mechanisms of hot tearing are generally understood; inadequate feeding initiates the tear and further thermal deformation propagates the tear. However, a reliable experimental methodology/apparatus to quantitatively measure and characterize hot tearing is not available for the casting industry. In this study, a hot tearing apparatus with a load cell and LVDT developed at CANMET-MTL was used to measure the load and contraction in the mushy zone of an Al-Cu alloy. The onset of hot tearing can be determined from the load curve, its first derivative and cooling curve. The linear solidification contraction of the bar is measured. Alloy 206, which is an alloy that is quite prone to hot tearing was evaluated by the apparatus; results are given and discussed.