Influences of Cooling Rate and Dendrite Morphology Assumptions on the Cracking Susceptibility of Ternary Al-Cu-Si Alloys during Solidification

Abstract

The hot cracking susceptibility of ternary Al-Cu-Si alloys in Al rich corner were calculated using the author’s own program which was coupled with a CALPHAD software Thermo-Calc for phase diagram information. The influences of cooling rate and dendrite morphology assumptions on the hot cracking susceptibility of Al-Cu-Si alloys were mainly considered. It is found that the hot crack susceptibility of high cooling rate is more serious than that of low cooling rate and the alloys tending to form more eutectic phases have higher thermal cracking sensitivity. In addition, the predicted results show that the calculated susceptibility under the assumption of dendrite morphologies extraction in the middle or end stage of solidification, such as inward cylindrical, inward spherical and plate dendrite, are relatively higher than that of the initial stage of solidification, such as spherical and cylindrical dendrite.