Fiber damage mechanisms in titanium metal matrix composites

The fatigue damage mechanisms of SiC fibers were examined to interpret the observed variations in composite strengths tested at different temperatures. A series of monotonic tension, residual fatigue strength and fatigue-life tests were conducted on SCS-6 fibers at 500 and 650 °C. The surface of the fatigued fibers were examined by scanning electron microscopy for damage features such as the distribution of cracks and the spalling of the carbon-rich coating. Both the static and fatigue strength of SiC SCS-6 fibers were unaffected by the test temperature of 650 °C and below. The mean strength of the fiber was found to be 3.05 GPa with one standard deviation of 0.6 GPa