Reveal the stacking fault shearing mechanism by its annihilation process in Ni-based single crystal superalloys

Highlights: • The stacking fault shearing mechanism was revealed by a designed experiment. • The stacking fault would shrink and be transformed into a dislocation pair during high-temperature annealing. • Burgers vectors of the dislocation pair were characterized and identified using a series of two-beam conditions. Based on the reversibility of stacking fault formation, the annihilation process during annealing was characterized to reveal the stacking fault shearing mechanism in Ni-based single crystal superalloys. After the creep rupture test at 750 °C/750 MPa, lots of stacking faults would be created in γ' precipitates. Further annealing at 1000 °C for 4 h, these stacking faults would shrink and were transformed into dislocation pairs containing two a/2 110 dislocation with different Burgers vectors. Finally, the stacking fault shearing mechanism could be clarified as:$a/2\left(\overline{1}01\right)+a/2\left(0\overline{1}1\right)\to a/3\left(\overline{1}\overline{1}2\right)+\mathrm{SF}+a/6\left(\overline{1}\overline{1}2\right)$.