| Abstract Scope |
The anisotropic local deformation behavior of lath martensite complicates the understanding of its underlying plasticity mechanisms. In this study, the dislocation dynamics responsible for local deformation in low-carbon steel lath martensite were investigated by combining in-situ tensile Electron Channeling Contrast Imaging (ECCI) with Molecular Dynamics (MD) simulations.
Sub-micron scale in-situ ECCI observations enabled direct tracking of intra-lath dislocation motion and boundary sliding behavior. In-lath-plane dislocations exhibited longer travel distances compared to out-of-lath-plane dislocations, contributing to the observed anisotropy in slip system activity. Lath boundary sliding was found to initiate only after a certain degree of plastic deformation had accumulated within the lath.
Complementary atomic-scale MD simulations provided insights into the evolution of dislocation networks at grain boundaries. The structural characteristics and critical resolved shear stresses (CRSS) of lath boundaries, sub-block boundaries, and block boundaries were quantitatively analyzed, highlighting the relationship between dislocation network evolution and boundary sliding behavior. |