Atomistic study on the deformation behavior of CSL low angle tilt grain boundaries in BCC iron

J Veerababu and A Nagesha and V Shankar, MATERIALS TODAY COMMUNICATIONS, 40, 110111 (2024).

DOI: 10.1016/j.mtcomm.2024.110111

Many deformation features of symmetric tilt grain boundaries (STGBs) in BCC (Body-Centered Cubic)-Fe must be addressed. The present atomistic study focused on the tensile and compressive deformation characteristics of various low-angle STGBs in BCC-Fe. A competition between slip and twinning with changes in the Rotaion-axis, misorientation angle (theta degrees), and loading mode was noticed. Two major deformation mechanisms were observed: namely, dislocation dissociation nucleation and heterogeneous dislocation nucleation. The (001)-STGBs deformed through slip followed by twinning in tension and a slip in compression. The (110)-STGBs, on the other hand, are deformed by twinning under tension and compression. However, they shifted to a slip mode under compression for theta > 15 degrees. The < 111 > and < 112 >-STGBs deformed through the slip in both tension and compression. Each of these STGBs dissociated into two new low-angle STGBs for theta < 15 degrees C structural units were identified as the precursors for the slip. A positive linear correlation was obtained between grain boundary energy and effective free volume per unit area.

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