Visco-Elastic Energy Dissipation in a SiAlON Ceramic: Quantificationa nd Implications for Fatigue Resistance

The paper describes the stresws-strain response of a sialon material to cyclic loading at high temperatures. One batch is tested as sintered, while a second batch first underwent a heat treatment which crystallizes amorphous intergranular residues. Uniaxial tension-compression fatigue testing is performed between 150 and -150 MPa at decreasing frequencies between 1 and 0.001 Hz, at several temperatures from 750-1350:C. For both materials stress-strain hysteresis is observed in the lower frequency tests at the higher temperatures. For a given frequency, the higher viscosity of the intergranular phases in the heat treated sialon increases the temperature at which the hysteretic phenomenon occurs as compared to the as-sintered sialon.JRC.(IAM)-Institute For Advanced Material