Determinación de la cinética de crecimiento de grano durante la solidificación de una aleación eutéctica Al-Cu

Abstract

In this work a methodology is applied to describe quantitatively grain growth during solidification of a near eutectic Al-Cu alloy using cooling curves, volume grain density and solid fraction evolution data. The methodology assumes free grain growth before impingement and an exponential dependence of the grain growth rate on undercooling. Information collected is processed numerically in order to find numerical values for the pre-exponential and exponential parameters that characterize the grain growth kinetics as a function of undercooling. The evolution of solid fraction in the sample during solidification is determined by applying the Fourier (FTA) and the Newton (NTA) thermal analysis methods in order to compare their performances. The volume grain density is obtained using metallographic methods. All the obtained parameters were feed into a mechanistic model, elaborated as a part of this work, to validate the methodology. It was found a relatively good agreement between the experimental and the predicted cooling curves, which suggest that this methodology could be used to generate useful information needed to simulate eutectic solidification. NTA method is less effective than FTA method to obtain the growth parameters but its simplicity justifies its use as a first approach.