Investigation of the heterogeneous nucleation in a peritectic AlNi alloy

Abstract

The goal of this research is a systematic investigation aiming at a quantitative understanding of the four different stages of peritectic solidification: 1) heterogeneous nucleation, 2) peritectic reaction, 3) peritectic transformation and 4) direct growth of the peritectic phase. Solidification experiments of the peritectic alloy Al-36wt.% Ni are carried out in differential scanning calorimetry (DSC), and the recently developed multi-phase-field techniques are employed to quantitatively model and simulate the peritectic phase transformation, by taking into account the precise thermodynamic description of the Al-Ni system. A previously developed phase-field model that had been successfully employed in the Al-Ni system is adapted here and calibrated by a novel method that simulates not only the final solidification microstructure but also DSC traces. The resulting kinetics of the phase-transformation processes are presented underlying the above four stages of phase transformation in detail.