Tension-Compression Fatigue Behavior of a Silicon Carbide Calcium-Aluminosilicate Ceramic Matrix Composite

The fatigue behavior of a silicon carbide fiber reinforced glass ceramic matrix composite, SiC/CAS subjected to tension-compression cycling was investigated. Two laminate lay-ups were studied—cross—ply, [0/90] _{2 s} and unidirectional, [0] ₁₆ . At first, the fatigue limit based on one million cycles was established for a tension-tension fatigue condition. Then, compression cycling was superimposed on this measured fatigue limit. The addition of this compression loading resulted in the development of longitudinal cracks parallel to the loading direction. This resulted in an increased amount of damage and ultimately led to total specimen failure. The larger the magnitude of the compression cycle, the earlier the development of longitudinal cracks occurred and, consequently, the earlier failure occurred. This behavior was due to the inherently poor interfacial bond be tween matrix and fiber of the tested ceramic matrix composites.