Thermal fatigue damage mechanisms in a unidirectional SCS-6/Ti-24Al-11Nb metal matrix composite
Okazaki Masakazu; Hayashi Keijiroh; Nakatani Hiroshi
Abstract:Thermal fatigue tests of a unidirectional SiC fiber reinforced Ti-24Al-11Nb matrix composite were carried out without external load in air, where the fiber was a b SiC fiber of 140mm in diameter with a carbon rich graded silicon carbide coating on the surface: SCS-6. By employing the composite specimens to which the thermal cycle had been previously given, both the change of elastic properties of the composite and that of the resistance to stable crack growth were evaluated, compared with those of the specimens subjected to long term isothermal exposure at high temperatures in air. Summarizing the experimental results obtained and the findings of the previous work, discussions were made on the mechanics and mechanisms of thermal fatigue damage. Key Words:Ti-24Al-11Nb matrix composite, SiC fiber, thermal fatigue, stable crack growth resistance, change of elastic moduli, interface, mechanics and mechanisms of damage