A follow-spot-like model for dynamic dislocation Studies: Application to <111> screw dislocations in B2-NiAl

ZJ Wei and BL Lü and JH Wu and TX Li and XD Sun and ZZ Liu and JB Shang and C Zhao, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 941, 148609 (2025).

DOI: 10.1016/j.msea.2025.148609

A novel follow-spot-like model is proposed for studying dynamic dislocation behavior, which transforms motion into a quasi-static process. This model offers two key advantages: (i) dislocation motion can be analyzed using static research methods, ensuring precision; and (ii) it eliminates interference forces, providing a noise-free research environment. In this model, the initial dislocation line remains aligned with the cylindrical slab's central axis during movement, and only an axisymmetric constraint force is applied to maintain this alignment. The capabilities of this model are demonstrated by investigating the behavior of <111> screw dislocations in B2-NiAl. The dislocation energy surface is mapped, and the motion trajectory under a <121> glide force is determined, showing a winding path. Furthermore, the evolution of dislocation core configurations reveals three distinct states: compact, planar dissociation, and spatial dissociation. At many spatial locations, the core adopts a nonplanar dissociated configuration, likely explaining the difficulty in activating <111> screw dislocations in B2-NiAl. The proposed model provides a robust framework for studying dislocation dynamics and offers broad applicability to other material systems.

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