ANALYSIS OF INTERFACIAL BEHAVIOR IN MMCS AND IMCS BY THE USE OF THIN-SLICE PUSH-OUT TESTS

A model is presented of the single-fiber push-out test with the objective of studying the interface failure process in metallic and intermetallic-matrix composites (MMCs and IMCs) and extracting the shear properties of fiber/matrix interface from the experimental data. The process of cooling from the composite consolidation temperature, specimen preparation for the push-out test, and the actual testing are simulated by using the finite element method. The mechanics of interface failure are analyzed and an attempt is made to capture the debonding sequence during a thin-slice push-out test. A stress-based criterion for debonding and a criterion for interfacial sliding based on frictional resistance are used to predict the interfacial behavior during the push-out test. The influence of processing-induced residual stresses on interface behavior during the push-out test is examined in detail. Load versus displacement behavior during the push-out test is numerically generated as a function of different interfacial strengths: these results are then used as a calibration curve to predict the interfacial shear strength for a given experimentally measured peak push-out load. The effect of the variation in the reported material data on processing-induced residual stress, and eventually on the push-out test results is studied. SiC/Ti-15-3 MMC is used as the model material for the prediction of interfacial shear strength.