Effect of Fe and Si on the Phase Composition and Microstructure Evolution in Al-2 wt.% Cu-2 wt.% Mn Alloy During Solidification, Cold Rolling and Annealing

The effect of iron and silicon content on the phase composition, microstructure, hardness, and electrical conductivity of the Al-2% Mn-2% Cu (wt.%) base alloy in the as-cast state and after deformation and heat treatment has been studied. It has been shown that when Fe and Si are introduced together, they mainly bind to the eutectic Al15(Fe, Mn)2Si3 phase. At a cooling rate of ~ 20°C/s the formation of primary Al6(Fe, Mn, Cu) crystals is suppressed if the iron concentration is within 0.4%. Annealing at 400°C of the sheets from as-cast alloys with up to 0.4% Fe and Si leads to A slight softening due to the formation of about ~ 7 wt.% Al20Cu2Mn3 phase nano-dispersoids. The experimental results suggest the possibility of producing new cheap aluminum alloys with high heat resistance without the need for ingots homogenization.