Effects of cold working path on strain concentration, grain boundary microstructure and stress corrosion cracking in Alloy 600

Grain boundary microstructure, strain distribution and stress corrosion cracking (SCC) in one dimensional (1D), two dimensional (2D) and three dimensional (3D) cold worked Alloy 600 were investigated. The cold working decreased the annealing twins and increased low angle boundaries. 2D cold working caused lower strain concentration at grain boundaries than 1D and 3D cold working. The intergranular SCC (IGSCC) susceptibility was the highest in 1D cold worked alloy while lowest in 2D cold worked alloy. The IGSCC susceptibility displayed a strong correlation with the grain boundary strain concentration and the grain boundary microstructure.

► Cold working lowered the annealing twin but increased the low angle boundary.
► 1D cold working caused highest strain concentration at grain boundaries.
► The IGSCC resistance of 1D, 2D and 3D cold worked Alloy 600 is 2D > 3D > 1D.
► 2D cold working displayed least damage to the microstructure and SCC resistance.
► IGSCC correlates with cold work path by microstructure and strain distribution.