Abstract: A hybrid gas turbine rotor having a silicon carbide ceramic turbine wheel portion and a nickel alloy steel shaft portion further includes a hollow silicon carbide ceramic stub shaft integral with the turbine wheel portion having a frustoconical outer surface tapering away from the wheel portion and a tubular end on the shaft portion having an inner frustoconical surface tapering toward the shaft portion at an angle corresponding to the outer surface taper angle. The shaft portion is connected to the wheel portion by shrink fitting the tubular end over the stub shaft so that the shrink fit is the sole medium whereby the wheel portion is supported on the shaft portion and torque is transferred therebetween.

Abstract: A unitary ceramic gas turbine wheel for use in gas turbine engines having turbine inlet temperatures in excess of 2000.degree. F. includes an outer rim of reduced axial length that is merged with scallops in the upstream face of the turbine wheel to reduce leading edge stresses in integral turbine wheel blades of airfoil configuration and wherein the fairing of the airfoil into the rim is configured to produce a reduction in the polar moment of inertia of the turbine wheel to improve engine acceleration characteristics.