Mechanisms for Ce-induced remarkable improvement of conductivity in Al alloys

Effect of Ce addition on electric conductivity of Al alloys is investigated in this paper. Addition of proper amount of Ce leads to a remarkable improvement of electric conductivity. Adding Ce enhances the formation of binary, ternary, or quaternary compounds of Ce, Si, Fe, and Al and reduces the solution content of Fe and Si in the Al solution accordingly, well consistent with the Al lattice constant calculations and the Bragg models. Density of state adjacent to Fermi level of Al–Ce solution is obviously different from other solute atoms involving in La, Fe, and Si etc. and fairly similar with that of pure Al. Two possible contributions of Ce lead to the remarkable improvement of conductivity. First, Ce addition alleviates the lattice static distortion of Al solution and hence expands the average electrical free path. Second, Ce-induced alteration of electron energy band structure may intensify the effective electron number that participates conduction.