A rotor shaft for a high speed motor that has a coating that is secured to a shaft body. The coating and the shaft body are formed from dissimilar materials. More specifically, the coating may be an alloy material, such as, for example, a copper alloy, while the shaft body may be a steel material. According to certain embodiments, the alloy material of the coating may be secured to at least a portion of a rotor body blank in a solution treated condition via a low temperature welding procedure. Additionally, the coating may be hardened, such as for example, through the use of an age hardening process. The coating and the rotor body blank may be machined together to form the rotor shaft. According to certain embodiments, such machining may configure the rotor shaft for use with a turbo-compressor that is configured for air compression.