Influence of Annealing Time on ∑3 Boundary and ∑9 Boundary Evolutions in Hastelloy C-276 Alloy

Hastelloy C-276 was subjected to low strain deformation and then annealed at 1100 °C for different time. The ∑3 and ∑9 boundary percentages and grain boundary plane distributions were characterized by electron back-scatter diffraction (EBSD) and a five-parameter analysis method. The results show that the ∑3 boundary evolves towards a more exact coincident-site lattice (CSL) misorientation and the ∑3 boundary plane is closer to low surface energy plane {111} with the increasing of annealing time. This is consistent with fine tuning mechanism. While the population of incoherent ∑3 boundary is increasing, the proportion of ∑9 boundary with larger deviations increase, too. And the distributions of grain boundary density planes for ∑9 boundary are more intensive on the whole [110] zone.