Understanding Deformation Twinning in Age-hardened Duplex Stainless Steel

Deformation twinning in age-hardened duplex stainless steel was investigated to understand its formation and characteristics within the ferrite phase. The material underwent age hardening to promote the development of twin bands specifically in ferritic grains. A region of interest was examined using electron backscatter diffraction (EBSD), and the resulting data were processed and visualized in MATLAB.

The EBSD maps reveal the presence of narrow twin bands within ferrite grains, characterized by a misorientation angle of approximately 60° relative to the parent crystal. Pole figure analysis of the {112} planes shows coinciding pole points between the twin and parent orientations, confirming the twin relationship.

Kernel Average Misorientation (KAM) analysis indicates elevated local misorientation values at grain boundaries, twin–grain boundary interfaces, and twin band intersections. These regions are associated with higher dislocation densities, suggesting they serve as sites of localized plastic strain accumulation.