Virtual Diffraction Techniques used to Study Dislocation Loop-Grain Boundary Interactions and Assess Slip Transfer Criteria
Abstract
Major Goals: The overarching objective of this project is to develop a multiscale simulation approach to investigate dislocation - grain boundary interactions and to employ this approach to advance criteria for slip transfer across grain boundaries to include the grain boundary damage state. Existing atomistic simulation approaches to study dislocation grain boundary interactions, where an atomistic model of an infinitely long (periodic) edge or screw dislocation is forced to interact with a grain boundary at high driving stress, are not sufficient to resolve the multiscale nature of dislocation core absorption, decomposition and slip transfer. Furthermore, existing discrete dislocation dynamics (DDD) simulations do not consider the stress state of a grain boundary (GB) and its effect on slip transfer. This work introduces a different atomistic approach based on the use nanoscale dislocation loops and proposes a disclination based approach to incorporate residual dislocation content into DDD simulations. Over the project period, the following technical goals were defined: (1) Compute important properties related to dislocation core structure, Peierls barriers and dislocation mobility as a function of dislocation character angle and local stress state using atomistic simulations. Importantly, the role of local stress state must be considered because as a dislocation approaches another dislocation or a grain boundary, the interaction stresses are significant and these can affect core structure. (2) Incorporate dislocation related data from atomistic simulations into DDD simulations and perform validation simulations to confirm that DDD is capable of reproducing dislocation behaviors observed in atomistic simulations. This includes character angle dependent and stress state dependent dislocation mobilities.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 03, 2021
- Accession Number
- AD1204478
Entities
People
- Douglas E Spearot
Organizations
- University of Florida