Abstract: The fatigue-creep behaviour of three microstructures in TC11 alloy discs is studied, the results show that when cycle stressσmax is ranged from 560~660 MPa, the bimodel is associated with the best fatigue-creep behaviour, the basket-weaver, the better and the equiaxed the worst. In other stress range, the life of the basket-weaner is far longer than that of the equiaxed and longer than that of the bimodel also. By SEM observation it is found that cleavage fracture is obvious on the source of fracture and at the beginning of propagation; furthermore, the forming of these facets is related to plastic strain accumulation at crack-tip and oxidation at high temperature; with cracking, cleavage facets decrease gradully, while fatigue striations and creep holes rapidly increase hence fatigue-creep interaction enhance obviously.

Key words: Fatigue-creep interaction, Cleavage fracture, Dislocation pile-ups, Creep hole, Fa- tigue striation