Dilatometric and calorimetric studies on the phase transformations of the A380-type aluminum alloy during solidification and heat treatment

Abstract

In this paper, the sequence of solidification for A380-type alloys has been determined by employing techniques such as dilatometry, differential scanning calorimetry (DSC), and differential thermal analysis (DTA). Regions of balance of Cu- and Fe-rich phases present in the alloys were calculated using Thermo-Calc software, and the results indicate that the phenomena that occur during solidification are modified by differences in the purity of the alloys. The effect of heat treatment on the morphology and chemical composition of the Fe-, Mg-, Mn-, and Cu-rich intermetallic species were obtained. For a ratio of Fe–Mn < 1, it was observed that intermetallic Al6FeMn begins its formation in the liquid state, precipitating with a needle-like shape. The temperatures of formation of these intermetallic phases in the solid state were identified by DSC and DTA analysis. It was found that changes in the chemical composition (relative concentrations of Fe, Mn and Si) affect the formation of the α-AlFeMnSi phase during heat treatment.