Influence of Anneal Time on Σ3 Boundary Segregation in Commercially Pure Nickel

Abstract

Commercially pure nickel (Ni200) samples were thermo-mechanically processed to drive segregation into Σ3, special grain boundaries. The special grain boundaries were characterized using electron backscatter diffraction, and their segregation behavior at the atomic level was studied using atom probe tomography. Local electrode atom probe analyses showed a lack of segregation at the Σ3 special grain boundary for a specimen annealed at 1000 °C for 30 h except for a slight increase in Si. This specimen was utilized in a previous study by the authors to compare the effects of segregation of type-specific grain boundaries. Local electrode atom probe results showed no segregation at the special grain boundary for a specimen annealed at 1000 °C for 100 h providing preliminary evidence that there is a correlation between increased anneal time and the effectiveness of Σ3 special grain boundaries to inhibit grain boundary segregation.