2015 Volume 56 Issue 12 Pages 1930-1939
Nickel-base superalloys have become the key materials of hot-end components in the aeroengines over the past several decades. Nickel-base superalloys are easy to produce thermo-mechanical fatigue (TMF) behavior when withstanding the combined effects of high temperature, creep, oxidation, mechanical stress and thermal stress. The occurrence of TMF seriously affects the normal service for hot-end components. Thus, the investigation about TMF behavior is of great significance. The TMF test can be divided into in-phase (IP) tests and out-of-phase (OP) tests. The fatigue life was described and compared for IP-TMF and OP-TMF. The reasons for various lives were analyzed. The classical life prediction models were evaluated. Cyclic stress response behaviors and hysteresis loops were analyzed. Cyclic deformation mechanism was revealed in depth. Fatigue fractographs of crack initiation and propagation were characterized on the fracture surfaces of fracture specimens. Crack initiation mechanism and fatigue damage mechanism were revealed in depth for TMF.