A rotor assembly is provided. The rotor assembly includes a rotor shaft and at least one blisk integrally formed with the rotor shaft. The at least one blisk includes an inner rim extending circumferentially about the rotor shaft, and a plurality of blades extending radially outward from the inner rim, wherein the rotor shaft and the at least one blisk are defined from a single billet of material.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH & DEVELOPMENT
 This invention was made with Government support under Contract No. DE-EE0005804 awarded by the Department of Energy. The Government has certain rights in this invention.