Researchers use CEMAS to study stacking fault energy in concentrated alloys

Posted: July 30, 2021

a An example image showing both Shockley partial dislocations of a dissociated dislocation obtained by Weak beam dark field scanning transmission electron microscopy (WB DF STEM); and (b) experimentally measured dissociation distances in equiatomic CrCoNi medium entropy alloy at room temperature (RT) condition and cryogenic temperature (CT) condition.

Ohio State researchers leveraged the Center for Electron Microscopy and Analysis (CEMAS) to advance their work interpreting stacking fault energy (SFE) in alloys and explaining the discrepancy between experiments and computations. Their work, a collaboration between researchers representing Ohio State’s Department of Materials Science and Engineering, was published in Nature Communications.

“Without the capabilities CEMAS provided, our work would be incomplete,” Mulaine Shih, co-author of the study and a graduate research associate in materials science and engineering at Ohio State. “The experiential images clearly captured the defect configurations, specifically dislocations, in CrCoNi alloy.

“Motivated by the experimental observations, our work examined the important factors resulting in the captured dislocation configurations,” Shih continued. ”We performed atomistic simulations on a model fcc alloy to enclose all possibilities. Ultimately, we revisited the conditions for the equilibrium dissociation of a lattice dislocation and showed that considering the interaction of dislocations with local solute environments is critical in concentrated alloys such as CrCoNi alloy.”

Other co-authors on the study were Jiashi Miao, research associate in materials science and engineering at Ohio State; Michael Mills, chair of Ohio State’s Department of Materials Science and Engineering; and Maryam Ghazisaeidi, associate professor in materials science and engineering at Ohio State.

“I had a great experience working at CEMAS,” Miao said. “It has one of the best electron microscopy facilities in the world, providing us with a great research environment. The collaboration between users and the world’s leading microscopy experts working at CEMAS also contribute to our work, as do the state-of-the-art training facilities, including the Digital Theater.”

To access their published work titled “Stacking fault energy in concentrated alloys,” please visit https://rdcu.be/craet.

Category: Research