LIFETIME, CYCLIC DEFORMATION AND DAMAGE BEHAVIOUR OF IN 706 AND IN 718 UNDER OUT-OF-PHASE TMF LOADINGS

摘要

OP-TMF tests were carried out on the wrought Ni-base superalloys IN 706 and IN 718. The minimum temperature of the TMF cycles generally was 150℃. Maximum temperatures between 650℃ and 800℃ and total mechanical strain amplitudes between 70% and 100% of the thermal strain amplitude were applied. The influence of the maximum temperature and the total mechanical strain amplitude on the lifetime-and cyclic deformation behaviour as well as on the damage mechanisms and the microstructure is discussed. The damage parameter of Ostergren accounts for the complex influence both of the total mechanical strain amplitude and the maximum temperature on the number of cycles to failure.