Influence of cerium and yttrium addition on strength and electrical conductivity of pure aluminum alloys

Abstract

To develop pure aluminum alloys with high conductivity and strength, Al-0.2Ce and Al-0.2Ce-0.1Y alloys were prepared by rolling and annealing processes in this study. The effects of trace rare earth elements on the strength and electrical conductivity of the pure aluminum alloys were investigated. It is revealed that the addition of Ce and Y to pure aluminum can effectively enhance the strength and electrical conductivity of the alloys. In Al-0.2Ce, the addition of Ce can effectively refine the grain size of α-Al, with an average grain size of 90.68 μm in the as-cast state. The grain size of the alloy is further reduced to 87.55 μm by the simultaneous addition of Y. The synergistic addition of Ce and Y changes the properties of the alloy. The addition of Ce and Y also produces the Al11Ce3 and Al3Y second phases, which have coherent relationship with α-Al. The two-dimensional mismatch degree was calculated to be only 4.43% and 0.85%, respectively, which can provide a certain amount of nucleation substrate for α-Al in the incubation stage. The interfacial match between the L12 structure of Al3Y and α-Al was calculated using first-principles simulations. The results indicate that Al3Y has a strong bonding effect with α-Al. Nanoscale second phases at grain boundaries can be effective in reducing resistivity due to dislocation motion. Nanoscale second phases with better matching interfaces to the substrate have no positive effect on the scattering motion of electrons.