Microstructure evolution and homogenization parameters optimization of Al-3Cu-1Li-xMg alloys

Abstract

Abstract An ideal homogenization parameter is essential to achieve outstanding final performances from Al-Cu-Li alloys. In this current study, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and differential scanning calorimetry (DSC) techniques were used to examine the evolution of the microstructure of Al-3Cu-1Li-xMg alloys at the homogenization process, where x=0.86 wt.% (Alloy 1#) and x=0.42 wt.% (Alloy 2#). The outcome demonstrates that Ag-containing AlCuMg phases dominated Alloy 1# in its as-cast state. In contrast, Alloy 2# contained more block-like Al2Cu phases. Moreover, the area of the major endotherm peak of the DSC graph increased by 40% in Alloy 1# compared to Alloy 2# due to the addition of Mg concentration. This increases the difficulty of dissolving the soluble in subsequent stages. 495°C/16h+515°C/8h was the optimal homogenization treatment for Alloy 1#, while 495°C/16h was optimal for Alloy 2#. This finding is a benchmark for research on the impact of Mg concentrations on the formation and dissolution of eutectic phases in Al-3Cu-1Li alloys.