Influence of dwell time on low cycle fatigue behavior of directionally solidified superalloy DZ125 at elevated temperature

摘要

Low cycle fatigue (LCF) tests of directionally solidified superalloy DZ125 were conducted with different dwell time at 850°C. The tensile dwell time of experiment was 1s, 60s, 120s and 240s. Contrastive analysis of different dwell time was carried out including stress-strain hysteresis loop, strain history and fatigue life. The results indicated that dwell time had significant effect to low cycle fatigue behavior, but the effect was not obvious when dwell time exceed a value. Finally, combined with SEM observation of fracture surface, the influence of fatigue damage and creep damage was analyzed. The results indicated that creep damage played more important role as dwell time increase.