Performance Characterization of Ceramic Matrix Composites through Uniaxial Monotonic Tensile Testing

Ceramic matrix composite (CMC) samples were tested in order to characterize their mechanical performance and provide metrics for material process refinement and component design. Monotonic, uniaxial tensile testing of an uncoated carbon fiber reinforced silicon carbide ceramic at room temperature was performed following ASTM standard C1275 to measure ultimate tensile strength and elastic modulus. Equipment verification was carried out through alignment measurement with a gaged tensile specimen using ASTM E1012 to ensure the monotonic nature of the testing equipment. Tensile strength data was treated with Weibull statistical models to produce A and B-basis strength properties for design values. An alternative area measurement method separate from the C1275 procedure was employed to account for internal material voids. Using cross-sectional photography and image analysis, voids were measured and subtracted from area measurements for more accurate strength calculations. Successful tests of 11 CMC samples produced a mean tensile strength of 111.1 megapascals (MPa) and an elastic modulus of 912.8 MPa. The A-basis for strength was 77.54 MPa and the B-basis was 95.37 MPa