NSUF 18-1566: In-situ TEM deformation of neutron irradiated FeCrAl alloys

The objectives of this in-situ TEM study on neutron irradiated FeCrAl-based alloys are to dynamically observe the influence of precipitate density on collective dislocation behavior, and to understand the effects of possible dislocation relaxation process and microstructures, i.e., grain boundary characteristics and disorientation, on deformed dislocation configurations and consequently on mechanical properties. We propose to perform in-situ tensile deformation on thin film FeCrAl samples, with tensile axis along [010] direction, while being observed at [100] zone axis. In this way, the two primary slip planes (110) and (011) will be at edge-on view, so that both individual dislocation nucleation/slip event and collective dislocation band/cell nucleation will be captured. In addition, it is noted that post-mortem characterization can shed little light on the dislocation “relaxation” model since dislocation structure is bound to change upon unloading according to this model. However, taking advantage of the in-situ capability, deformation process will be interrupted at various strain levels, so that possible dislocation “relaxation” process can be captured, which will be compared against classic theories. Last but not least, since the samples are made with the assistance of EBSD, some samples will contain a low angle or high angle grain boundary, which will reveal the role of grain boundaries on collective dislocation and deformation behavior. This fundamental study will then feed into the macroscale deformation mechanisms in FeCrAl alloys as well as inform crystal plasticity models currently under development within the Department of Energy – Nuclear Energy Advanced Modeling and Simulation (NEAMS) program. This project is predicted to take no more than 5 months to complete. Fabrication of TEM samples in house using EBSD and FIB techniques is estimated to take no more than 2 months. In-situ TEM deformation on all samples is expected to take about one week. Data analysis and reporting will take approximately 2 months from the date of initial data collection.

Допълнителна информация

Поле	Стойност
Awarded Institution	Oak Ridge National Laboratory
Embargo End Date	2026-02-27
Facility Tech Lead	Alina Montrose, Mukesh Bachhav
NSUF Call	FY 2018 RTE 3rd Call
PI	Dalong Zhang
Project Member	Dr. Kevin Field, Associate Professor - University of Michigan (https://orcid.org/0000-0002-3105-076X)
Project Member	Dalong Zhang, Postdoctoral Associate - Oak Ridge National Laboratory (https://orcid.org/0000-0002-3840-396X)
Project Notes	Awarded on 09/17/2018
Project Type	RTE
Publication	Method for fabricating depth-specific TEM in situ tensile bars Janelle Wharry, George Warren, Yaqiao Wu JOM 72 2020-05-01 https://doi.org/10.1007/s11837-020-04105-8
RTE Number	1566