Synergistic Effects of Simulating Engine Environments On Gas-Turbine Grade Sic/Sic Ceramic Matrix Composites

Abstract

This paper, as an extension of a previous work, presents in-depth results regarding how simulating synergistic engine environments would affect two different, gas-turbine grade, melt-infiltrated (MI) SiC/SiC CMCs in terms of durability. The simulating engine environments chosen were FOD (foreign object damage), erosion, CMAS (calcium magnesium aluminosilicate), and long-term high-temperature exposure at 1316 deg C for 500 h. A total of 18 elements of individual and combined environments were employed for each of the two MI SiC/SiC CMCs. Responses of the two CMCs to those environments were appraised quantitatively through residual-strength measurements. Irrespective of characteristic architectural differences of the two CMCs, FOD was found to be the most degrading environmental species of all, not only individually but synergistically. The residual strength was also observed to be in good correlation with respective elastic modulus (natural frequency), which could provide as a means of non-destructive structural assessments of CMCs for environmental damage at least in a first-order approximation.