Accumulation of Time-Dependent Strain during Dwell-Fatigue Experiments of iBN-Sylramic Melt Infiltrated SiC/SiC Composites with and without Holes (Preprint)

摘要

Accumulation of time-dependent strain during dwell-fatigue experiments of iBN-Sylramic Melt Infiltrated SiC/SiC composites is investigated. A 2-hour load cycle is repeated for specimens without holes and specimens with a central hole under the following conditions: (i) a stress ratio of 0.05, (ii) various stress levels, (iii) 815 deg C and 1204 deg C, (iv) different times up to 600 hours, and (v) different hole diameters. An increase in the accumulation of time-dependent strain with the increase in time and stress level is observed for specimens with and without holes with the time- dependent strain at 1204 deg C, much higher than that observed at 815 deg C. All specimens recovered part of their time-dependent strain at the minimum stress level and the value of both time-dependent strain and recovery strain depreciated with time.