Methods of making squirrel cage rotors of aluminum based material end rings joined with high conductive and durable material (such as copper) conductor bars for use in electric motors. The methods include forming conductor bars by casting or other metal forming methods in the slots of laminate steel stack, or positioning the preformed or premade solid conductor bars in the longitudinal slots of the stacked laminated steel, with bar ends extending out of the laminated steel stack ends, optionally coating the extended part of the conductors (bars) with a latent exoergic coating containing Al and one or more conductor bar chemical elements, positioning the laminated steel stack having conductors (bars) in a casting mold that forms the cavity of both end rings of the rotor, filling the end ring cavities with aluminum melt, and allowing the end rings to solidify under pressure. Alternatively, the conductor bars and end rings can be made separately and mechanically joined together.