Characterization of Mechanical Reliability of Silicon Nitride Microturbine Rotors

Abstract

This paper summarizes the recent results on component characterization efforts carried out to verify the mechanical reliability of SN237 and SN281 silicon nitride microturbine rotors manufactured by Kyocera. Mechanical properties of biaxial discs machined from airfoils of microturbine rotors were evaluated by a ball-on-ring test technique. Results showed that the mechanical properties of samples from airfoils with as–processed surfaces exhibited lower characteristic strength than those machined from the hub region with as-machined surfaces. The differences in mechanical performance and reliability between asprocessed components and simple-shaped test coupons appear to arise mainly from differences in strength limiting flaw type and population.