Effects of interface chemistry on the fracture properties of titanium matrix 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 interface is studied using experimental characterization and computational modeling techniques. The objective of this study is to establish a link between the evolution of the interfacial chemistry and the resulting mechanical properties. SCS-6/Timetal21s composite is chosen as the candidate material system. The composite specimens are exposed to temperatures as high as 927°C for extended periods. The diffusion of elements across the interface is investigated through metallurgical techniques. Fiber push-out is used to characterize the mechanical properties 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 using this method.