Study on the Structural Evolution During Non Isothermal Aging of an Al–Cu–Mg–Si Alloy by Means of Thermal Analysis

Abstract

In the present paper, the precipitation sequences that take place in an Al–Cu–Mg–Si alloy have been identified by means of dilatometry and differential scanning calorimetry (DSC). While the dilatometric curves shows nine dilatometric anomalies, the DSC scans present seven effects. By comparing these two methods, the dilatometric anomalies have been linked to the precipitation and dissolution of GP and GPB zones, β″, θ′ and Q′ precipitates. The effect of the different precipitation reactions on the dilatometric behavior of the studied alloy has been explained by the depletion of the Al matrix from alloying elements, and the differences between specific volumes of the developed precipitates and the matrix. The occurrence of these precipitation reactions has been confirmed by measuring the corresponding activation energies and X-ray diffraction analysis. The results obtained using the aforementioned techniques in this research are in good agreement with several previous works found in literature.