HIGH TEMPERATURE FATIGUE OF THE UNIDIRECTONALLY REINFORCED MMC Ti64/SiC

摘要

The fatigue fracture process of a Ti6Al4V matrix composite, unidirectionally reinforced with 8 plies of SiC fibres, is studied at the operation temperatures planned for these materials (550°C and 600°C). Tests at different load levels were performed (R = 0.1, f = 1 Hz) in the reinforcement direction up to a maximum number of 200000 cycles. The fractographic analysis and microstructural observations of the tested samples at both temperatures are used to determine the mechanisms of nucleation and propagation of damage until fracture and to estimate the toughness of the material (K{sub}I ≈ 60 MPa√m).