Elastic interaction-induced anisotropic growth of dislocation loop arrays

• Published in: Journal of materials research Vol. 36; no. 17; pp. 3426 - 3435
• Main Authors: Chakraborty, Pranay, Ma, Tengfei, Cui, Yinan, Hunter, Abigail, Cao, Lei
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 14-09-2021; Springer Nature B.V; Materials Research Society
• Subjects: Applied and Technical Physics; Arrays; Biomaterials; Chemistry and Materials Science; Dislocation loops; Edge dislocations; Elastic anisotropy; Fatigue failure; Granulation; Inorganic Chemistry; Invited Paper; Materials Engineering; Materials research; MATERIALS SCIENCE; Nanotechnology; Segments; Strain hardening; Strain rate; Stress distribution; Substructures (crystalline)
• ISSN: 0884-2914; 2044-5326
• DOI: 10.1557/s43578-021-00305-3

The elastic interactions and reactions of dislocations lead to the formation of complex dislocation substructures, which is critical to the strain hardening and fatigue failure. Phase field dislocation dynamics simulations are conducted as a first step to understand the elastic interactions between dislocation loops. When the interloop spacing is small, the elastic interactions with neighboring loops become strong, rendering the edge segments strongly pinned, while allowing for the screw segments to propagate more easily. The interactions are found to result in an anisotropic stress distribution around the dislocation loops, leading to the formation of arrays of long, straight edge dislocations that could act as barriers to subsequent slip. Furthermore, the effect of initial loop size and applied strain rate on the elastic interaction-induced anisotropic pinning effect is investigated and discussed. The results are important for coarse-graining dislocation substructures formation into continuum level models of deformation in crystalline solids.
Graphic abstract