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

摘要

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 (Al_(20)Cu_2Mn_3), the α-Fe (Al_(15) (FeMn)_3 (CuSi)_2) precipitated particles, and the decrease in AL_2Cu. 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.