Interfacial properties of SiC monofilament reinforced β′-SiAlON composites

Interfacial mechanical properties of SiC monofilament-reinforced β′-SiAlON composites were characterized by a single fiber push-out technique. Interfacial parameters were studied as a function of embedded filament lengths, including comparisons of linear, nonlinear shear-lag, and progressive debonding analysis models. The interfacial debonding peak load (Pp) and maximum frictional sliding load (Pmax) were both measured from the apparent load-displacement curves. Linear and shear-lag analyses were fitted to the data as a function of embedded filament lengths, respectively. In comparison, the progressive debonding analysis was conducted by fitting the effective load-displacement curves obtained by subtraction of machine compliance from the apparent load-displacement curves. The nonlinear shear-lag model gave better regression fits to the data than did the linear model, while the progressive debonding model provided much more interfacial information than did the shear-lag model. In addition to the coefficient of friction (μ) and radial residual stress (σN), axial residual load (Pr), critical load for interfacial crack initiation or propagation (Pd), interfacial fracture toughness (Gi), as well as the interfacial roughness amplitude (A) and its contribution to the interfacial normal stress (σr) were extracted from the progressive debonding model, using a three-parameter, non-linear least squares fitting method on the effective load-displacement curves.