Thermo-mechanical fatigue (TMF) and high temperature isothermal low cycle fatigue (LCF) tests on unidirectionally SiC fiber reinforced SP700 Ti based metal matrix composite have been carried out It was found that, for the LCF conditions, the damage characteristics of this composite was similar to monolithic materials. On the other hand, for the TMF conditions the damage characteristics were different from that of monolithic materials, revealed b', the following examples. The specimens for LCF conditions had typical fatigue fracture surface like monolithic materials and fiber pullout length in that fracture surface vas short. But for the TMF conditions, the fracture surface had no evidence of fatigue crack propagation and fiber pullout length was quite long. To investigate thermal cycle damage behavior and the fiber/matrix interface shear strength, thermal cycle tests and fiber pushout tests have been carried out From the results of these tests. it was shown that the differences of damage characteristics may be concerned with the degradation of the fiber/matrix interface by the crack propagation and reaction layer due to thermal cycles. Based on these systematic investigations, the attentions should be paid to understand the mechanisms of thermo-mechanical fatigue failure, and to estimate thermo-mechanical fatigue life.
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