An investigation was made on the strain-controlled low cycle fatigue of a cast Ni-base superalloy M963 over a wide total strain range of 0.15 to 0.6% at 700 to 950C in air. Correlations between dislocation structure and the testing temperature and applied strain amplitude were enabled through transmission electron microscopic observation. At a low temperature region (700 and 800C), dislocation shearing γ' precipitates by dislocation pairs and stacking faults at medium and high strain amplitudes, and a well-defined dislocation network at low total strain amplitudes were evident. At 900 and 950C, dislocation by-passing γ' precipitates was the main deformation mode.

Effect of Temperature and Strain Amplitude on Dislocation Structure of M963 Superalloy during High-Temperature Low Cycle Fatigue. L.He, Q.Zheng, X.Sun, H.Guan, Z.Hu, K.Tieu, C.Lu, H.Zhu: Materials Transactions, 2006, 47[1], 67-71