The research objective of this Grant Opportunity for Academic Liaison with Industry (GOALI) award will combine two advanced electron microscopy techniques, electron tomography and in situ mechanical testing inside a transmission electron microscope (TEM), to experimentally study dislocation plasticity in Al-Mg alloys exhibiting serrated flow and Portevin-Le Chatelier (PLC) instability. The main aim of the project is to uncover the precise role of the 3D dislocation structure in dynamic strain ageing that limits the ductility of an important class of automotive grade AA5xxx materials. The experimental work will center on the imaging of the mesoscale defect configuration in three dimensions using electron tomography before and after quantitative in situ nanocompression and nanotension tests inside a transmission electron microscope (TEM). The experiments will measure the evolution of dislocation networks in Al-Mg alloys with and without the PLC instability. The data will provide for the first time insight into the aging characteristics and aging dynamics of dislocation networks in three dimensions to add insights into mesoscale modeling of the PLC effect in forming simulations.
This research, which combines state-of-the-art techniques in electron microscopy and nanomechanical experiments, will also provide an experimental basis for designing compositions and strain paths for Al-Mg alloys. As the research leads to new experimental techniques, they will underpin the creation of an advanced laboratory on electron tomography for a graduate TEM course and outreach activities related to increasing the role of women and minorities in science and engineering.
