Short fatigue crack growth under mixed mode loading in Ni3Al alloy single crystals

The nominal mode I and mixed mode I/II fatigue tests were carried out on Ni3Al alloy single crystals. The effects of crystal orientation and load mode on fatigue crack growth behavior were studied. It was found that the crack paths and short fatigue crack growth rate are dependent on both crystal orientation and applied loading mode. A short crack behavior similar to that in polycrystalline materials was observed in mixed mode crystallographic cracking. The results of short fatigue crack growth rates showed that the mode I short crack growth rate is higher than that of the mixed mode short crack.