On The Fatigue Short Crack Behaviors of Directionally Solidified Superalloy DZ4 by In Situ SEM Observations

摘要

Small fatigue crack behaviors in a nickel-based directionally solidified superalloy DZ4 were studied by in situ scanning electron microscopy. The crack initiation and propagation manners were identified under different temperatures, i.e. 25℃, 350℃, 700℃. Crack growth showed to be associated with the configuration and relative direction of carbide. The anomalous short crack growth was pronounced at 25℃, 350℃ and not evident at 700℃, which was analyzed by in situ examining the effect of microstructure.