INTERFACIAL PROPERTIES OF SIC MONOFILAMENT REINFORCED BETA'-SIALON COMPOSITES

Interfacial mechanical properties of SiC monofilament-reinforced beta' -SiAlON composites were characterized by a single fiber push-out techn ique. Interfacial paramenters were studied as a function of embedded f ilament lengths, including comparisons of linear, nonlinear shear-lag, and progressive debonding analysis models. The interfacial debonding peak load (P-p) and maximum frictional sliding load (P-max) were both measured from the apparent load-displacement curves. Linear and shear- lag analyses were fitted to the data as a function of embedded filamen t lengths, respectively. In comparison, the progressive debonding anal ysis was conducted by fitting the effective load-displacement curves o btained by subtraction of machine compliance from the apparent load-di splacement curves. The nonlinear shear-lag model gave better regressio n fits to the data than did the linear model, while the progressive de bonding model provided much more interfacial information than did the shear-lag model. In addition to the coefficient of friction (mu) and r adial residual stress (sigma(N)), axial residual load (P-r), critical load for interfacial crack initiation or propagation (P-d), interfacia l fracture toughness (G(i)), as well as the interfacial roughness ampl itude (A) and its contribution to the interfacial normal stress (sigma (r)) were extracted from the progressive debonding model, using a thre e-parameter, non-linear least squares fitting method on the effective load-displacement curves.