Rapid solidification of hypoeutectic aluminum copper alloys using fast-scanning calorimetry

Abstract

The rapid solidification behaviour of binary aluminum copper alloys in the hypoeutectic range of compositions has been studied in this work. Solidification at cooling rates up to 40,000 °Cs−1 can be achieved using a chip-based calorimeter, but present challenges in sample preparation and temperature correction, which are addressed in this work. Data from calorimetry has been used to produce fraction of solid curves which are important input to metal manufacturing processing models. Undercoolings range from around 50 °C at 100 °Cs−1 to around 100 °C at 40,000 °Cs−1. From these, a kinetic phase diagram was constructed for the hypoeutectic region of the Al-Cu system, for cooling rates up to 40,000 °Cs−1. The undercoolings measured in this experiment are considerably higher than those predicted theoretically for growth-based rapid solidification, but not as high as those predicted under homogeneous nucleation.