THERMOMECHANICAL FATIGUE BEHAVIOR OF A CROSS-PLY SCS-6 TI-15-3 METAL-MATRIX COMPOSITE/

The thermo-mechanical fatigue behavior of a cross-ply laminate of a si licon-carbide-fiber-reinforced titanium-matrix composite, SCS-6/Ti-15- 3, has been investigated. Two sets of tests involving in-phase and out -of-phase thermal-mechanical fatigue from 149 to 427-degrees-C at diff erent stress levels, which were below and above the static first ply f ailure strength of the laminate, were conducted. Fatigue damage origin ated at the fiber/matrix interface of 90-degrees-fibers, and progresse d as transverse cracking in the matrix. However, final damage modes we re dependent on stress level and test conditions. Furthermore, fatigue lives were also found to be dependent on test conditions at a given s tress level.