Characteristics of microstructural and mechanical evolution in 6111Al alloy containing Al3(Er,Zr) nanoprecipitates

Abstract The evolution of microstructure and mechanical performances in 6111Al matrix alloy affected by trace amount of Er and Zr elements was thoroughly explored in this research work. Nanosized Al3(Er,Zr) particles with core-shell or hybrid structure owned perfect coherent relation with matrix Al, which acted as effective sites for the heterogeneous nucleation of α-Al. The average grain size was significantly refined from 147 ± 5 μm to 53 ± 2 μm in 6111Al-0.3wt%Er-0.1wt%Zr alloy. Besides, the precipitation behavior of the initial Mg2Si strengthening phase was also enhanced by these Al3(Er,Zr) dispersoids. Assisted by the cooperation of Grain refinement strengthening and Orowan strengthening etc., the yield strength, ultimate tensile strength and elongation of the alloy were high up to 289 MPa, 320 MPa and 12.9% respectively. A traditional hot rolling process has been conducted here to study the promotion and inhibition effect induced by Al3(Er,Zr) phases on recrystallization during deformation. The interaction among dislocations, grain boundaries and dispersoids was systematically and comprehensively revealed in this paper.