Determination of the latent heat of fusion and solid fraction evolution of metals and alloys by an improved cooling curve analysis method

Abstract

In this work, a new computer-aided cooling curve analysis method (CA-CCA) called metal/mold energy balance method (MEB) is presented. Its originality relies on taking into account the thermal history, the mass, and the heat capacity of both the sample and the mold containing it, for the determination of the latent heat of fusion and the evolution of the solid fraction of metallic samples contained into metallic molds without using a baseline curve. The MEB method is based on the numerical processing of the cooling curves of the sample and the mold, which are obtained using two thermocouples, one located at the thermal center of the sample and the other placed into the mold wall. The mold containing the sample is thermally isolated at its top and bottom. The method was applied to explore its capability to determine values of latent heat of fusion and solid fraction evolution when compared to reported values in the literature of five metals of commercial purity (Cd, Zn, Sn, Pb, and Al) and two Al-based alloys (Al–7%Si and Al–14%Cu). The performance of the MEB method was compared with the results obtained by processing the cooling curves of the metal and alloys under study using the Newton baseline method, the dynamic baseline method, and the equation-based Newtonian method. The obtained results suggest that MEB method offers a simple and easy way to obtain accurate experimental values of latent heat of fusion with small errors respect to the reference reported values, while results on solidification paths are similar to those predicted by the other CA-CCA methods.