Assessment of the fiber/matrix interface bond strength in SiC/Ti-6Al-4V composites

The mechanical properties of composites are significantly influenced by the properties of the fiber/matrix interface. From a fundamental as well as an interface development standpoint it is necessary to determine the bond strength of interface. The calculated value of the interface bond strength is extremely sensitive to the value of the compressive radial residual stress at the interface since this residual stress has to be overcome before interface separation can occur. In this study, neutron diffraction was employed to measure radial residual stresses in SCS-6/Ti-6Al-4V composites. A combination of stress measurements, finite element analyses and transverse tension tests was employed to systematically evaluate the interface bond strength. The fiber/matrix interface bond strength for SCS-6/Ti-6Al-4V composites was determined to be about 140 MPa.