Revisiting high-energy X-ray diffraction and differential scanning calorimetry data of EN AW-6082 with mean field simulations

Abstract

The present work re-evaluates previously published in-situ high-energy x-ray diffraction (HEXRD) and differential scanning calorimetry (DSC) data on EN AW-6082, which were used to study the precipitation kinetics of stable β-Mg₂Si. Here, we address hitherto unattended information in the diffraction patterns. The revised analysis considers metastable precipitates and thermodynamically stable Fe-containing phases in addition to stable β-Mg₂Si investigated in the previous studies. Furthermore, we utilize mean-field simulations to convert the evolution of individual phases obtained from HEXRD data into an equivalent excess specific heat $c_p^{\text{ex}}$ signal. This methodology allows us to partly separate cooling and heating DSC data into the contributions of individual phases and make a quantitative comparison between results from HEXRD and DSC. This significantly improves our current understanding of DSC data and demonstrates, for instance, the difference in complexity between interpreting cooling and heating experiments in aluminum alloys.