Solid-state welded multi-piece radial turbine with air cooled blades for gas turbine engines

A radial turbine rotor, the rotor comprising:

• a hub arranged around a central axis that defines a radially-innermost surface of the rotor,
• a plurality of turbine blades located circumferentially outward of the hub, each of the plurality of turbine blades shaped to include a root portion and an airfoil portion radially outward of the root portion, and
• a flowpath ring coupled with each of the plurality of turbine blades and the hub to locate the flowpath ring radially between the hub and each of the plurality of turbine blades, the flowpath ring formed to include a plurality of apertures extending radially through the flowpath ring, wherein each of the plurality of turbine blades is located in a corresponding one of the plurality of apertures of the flowpath ring such that the root portion of each of the plurality of turbine blades is within the corresponding one of the plurality of apertures,
• wherein the hub is fixed to the flowpath ring by a friction weld joint formed between a radially-outwardly facing surface of the hub and a radially-inwardly facing surface of the flowpath ring,
• wherein each of the plurality of turbine blades is fixed circumferentially around the flowpath ring by a blade joint formed between the root portion of each of the plurality of turbine blades and surfaces of the corresponding one of the plurality of apertures of the flowpath ring.