Reduction in Interfacial Sliding Shear Resistance From Abrasive Wear in SiC Fiber-Reinforced Ceramics Composite
Lin-Sien H. Lum, Y Kagawa
Interface wear behavior and its effects on frictional sliding shear resistance in fiber-reinforced ceramics was studied using a SiC fiber (SCS-6) - Al203 matrix composite. Thin specimen pushout tests were performed and the wear behavior of the protruded fiber was observed. Abrasive wear tracks in the sliding direction were observed at the surface of the SCS coatinglayer; progressive abrasion was seen with increasing of relative interface siding. The abrasion was caused by a hard reaction products (mullite) that occurred at the debond interface between the coating layer and the matrix. Effects of abrasion wear on the sliding shear resistance are discussed. A model is proposed where hard asperities on a hard surface (matrix) sweep outsoft surface (coating layer). The pushout load-displacement curve is explained by the mode. According to the model, the contribution of the wear to be coefficient of friction Pl (u), is given as a function of fiber end displacement, u, after onset of fiber pushout from the back surface. The analysis suggests that the load strongly depends on the hard product shape, sizeand density at the sliding interface. The success of the agreement indicates that the interface wear plays an important role in degradation of interface load transfer potential.