EFFECTS OF INTERFACE CHEMISTRY ON THE FRACTURE PROPERTIES OF TITANIUMMATRIX COMPOSITES

The fiber-matrix interface plays a critical role in the performance of titanium matrix composites (TMCs). In this work, the effect of fiber- matrix interfacial reactions on the fracture properties of the interfa ce is studied using experimental characterization and computational mo deling techniques. The objective of this study is to establish a link between the evolution of the interfacial chemistry and the resulting m echanical properties. SCS-6/Timetal21s composite is chosen as the cand idate material system. The composite specimens are exposed to temperat ures as high as 927 degrees C for extended periods. The diffusion of e lements across the interface is investigated through metallurgical tec hniques. Fiber push-out is used to characterize the mechanical propert ies of the interface. A novel computational method is used to simulate the propagation of interfacial cracks during the tests. The fracture toughness of the interface is evaluated from the experimental data usi ng this method. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.