Abstract: An impeller includes first and second impeller portions that are secured to one another. An interior cavity is formed between the first and second portions. The first impeller portion supports multiple blades. The first and second impeller portions respectively include first and second surfaces that are secured to one another near a tip of the impeller. Inlet and outlet apertures are provided in the impeller and are in communication with the inner cavity to provide a cooling flow path there through. A circumferential gap is arranged between the first and second impeller portions opposite the tip to permit relative axial movement between the first and second impeller portions during centrifugal loading of the impeller.