Enhanced mechanical properties of Al–Si–Cu–Mn–Fe alloys at elevated temperatures through grain refinement and dispersoid strengthening

Abstract

The effect of Ti content on the microstructure and mechanical properties of heat-treated Al–Si–Cu–Mn–Fe alloys was investigated. It was found that the mechanical properties increased with the increase of Ti content. This was attributed to the refinement of grain size, the increased amount of T (Al20Cu2Mn3), the α-Fe (Al15(FeMn)3(CuSi)2) precipitated particles, and the decrease in Al2Cu. At an elevated temperature of 300°C, the heat-treated Al–Si–Cu–Mn–Fe alloy with 0.5% Ti demonstrated the best mechanical properties, which are superior to those of commercial aluminium alloys. The yield strength contribution at 300°C was quantitatively evaluated based on the dispersoid, solid solution, and matrix contributions. It was confirmed that the main strengthening mechanism in the experimental alloys was the dispersoid strengthening.