Virtual Diffraction Techniques Applied to Study Dislocation-Grain Boundary Interactions (9.4 Synthesis and Processing of Materials)
Abstract
The technical objective of the proposed effort is to develop a model of slip transmissibility that is sensitive to dislocation- grain boundary interaction characteristics and is able to capture the complexity resulting from multiple dislocation collisions with grain boundaries. The proposed effort seeks to achieve the stated technical objective based on recent development of virtual diffraction techniques as a means to quantify elastic strain energy changes in the microstructure associated with dislocation- grain boundary interactions. Use of diffraction data from atomistic and dislocation dynamics simulations for slip transmission criteria validation has not been previously attempted. More specifically, the proposed effort is focused on three primary research tasks. First, the proposed effort will seek to use a recently developed computational method, capable of producing virtual X-ray 2-theta profiles and electron diffraction patterns on-the-fly during an atomistic simulation, to study the energetic and structural evolutions resulting from dislocations impinging on a grain boundary. Grain boundaries to be considered include symmetric < 100> and <110> tilt boundaries, as well as asymmetric "sigma3" grain boundaries. Second, the proposed research, will seek to perfonn a systematic investigation of existing discrete dislocation- grain boundary reaction criteria by means of discrete dislocation dynamics simulations. These simulations will seek to model bicrystals and generate virtual X-ray diffraction 2-theta profiles to be directly compared to both atomistic simulations in Task 1 and experiments in Task 3. Third, in-situ high-energy diffraction experiments will be perfonned to support the dislocation dynamics modeling. Bicrystals will be irradiated to promote dislocation channeling to enable a continuous flow of dislocations towards the grain boundary when plastically defonned. Collection of diffraction patterns will provide experimental data, representative of the energy change in the microstructure, which will be used to evaluate different reaction criteria.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 12, 2017
- Source ID
- W911NF1510623
Entities
People
- Douglas E Spearot
Organizations
- Army Contracting Command
- United States Army
- University of Florida