Contribution of the Fe-rich phase particles to the high temperature mechanical behaviour of an Al-Cu-Fe alloy

Abstract

The high temperature strengthening mechanisms in Al-Cu-Fe aluminium alloy was analysed basis on a comprehensive microstructural study of the as-cast alloy and mechanical testing results. An approach which extracts the specific contribution of solid solution atoms, precipitates, and Fe-rich particles to the creep strengthening was utilized. Additionally, the Shear Lag model, was employed to account for the contribution to strengthening of the Fe-rich intermetallic particles through a load transfer mechanism. For this study, an as-cast Al-Cu alloy, which does not contain Fe impurities, has been also used for comparative purposes. The findings suggest that the large and 3D interconnected Fe-rich phase particles (Al6(MnFe) and α-Fe) generate the main strengthening effect at high temperature through a load transfer mechanism, whereas the contribution of the nanometric Al2CuMg precipitates were very limited.