Effects of single-phase and co-deposited interphases on mechanical properties of T700TM-C/SiC minicomposites: experiment and theory prediction

Experimental and theory investigations on the effects of single-phase (PyC) and co-deposited (PyC+SiC) interphases on the mechanical properties of T700^TM-C/SiC minicomposites were conducted. Monotonic tensile tests and fiber’s push-in tests were conducted to obtain the minicomposite’s macro tensile mechanical properties and micro interface properties. The tensile strength was analyzed via a two-parameter Weibull distribution. The failure mechanism was obtained by fiber’s push-in tests and characterized by fracture morphology, and a damage-based micromechanical constitutive model was adopted to predict the tensile stress-strain response and interface debonding ratio (η) of C/SiC minicomposites with different interphases. For C/SiC, the experimental tensile curves were linearly till final tensile fracture with the lowest tensile strength and failure strain, due to the low interface shear strength (i.e., τ _iss = 50.8 ± 15.3 MPa). For C/(PyC)_{300 nm}/SiC, the minicomposite with the moderate ISS (i.e., τ _iss = 62.2 ± 5.9 MPa) possessed the highest tensile strength and failure strain with the highest interface debonding ratio (i.e., η _max = 0.95). For C/(PyC+SiC)/SiC, the tensile strength and strain were both lower than those of C/(PyC)/SiC due to the lower η.