|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Advanced Thermo-mechanical Characterization of Materials with Special Emphasis on In Situ Techniques
||Investigating Grain Rotations in Ultrafine-grained Aluminum Films Using In Situ TEM Straining with Automated Crystal Orientation Mapping
||Ehsan Izadi, Amith Darbal, Rohit Sarkar, Jagannathan Rajagopalan
|On-Site Speaker (Planned)
Automated crystal orientation mapping in TEM (ACOM-TEM) is highly suitable to obtain statistically meaningful information about microstructural changes in ultrafine-grained and nanocrystalline metals. We used a custom MEMS device to perform in situ ACOM-TEM tensile experiments on a non-textured, ultrafine-grained aluminum film and tracked orientation changes in hundreds of grains to correlate the macroscopic behavior of the film with its microstructural evolution. Our results show extensive orientation changes in a majority of grains during loading. The rotations are partially/fully reversible in a significant fraction of grains during unloading, leading to notable inelastic strain recovery. Surprisingly, a small fraction of grains continue to rotate in the same direction during unloading, even when the applied stress has been reduced significantly. The ACOM-TEM measurements also provide evidence of reversible/irreversible grain boundary migration. The microstructural observations point to a highly inhomogeneous and constantly evolving stress distribution in the film during both loading and unloading.
||Planned: Supplemental Proceedings volume