Seok-Woo receives UConn Research Excellence Program Award. The proposal title is “Giant Pseudo-elasticity of High Temperature Superconductor CaFe2As2”
Jake, Andrew, Leo and Jack will work on Ni-based and Cu-based metal-intermetallic nanostructured composite for this summer in my laboratory. Welcome all!
Roman Kositski, Oleg Kovalenko, Seok-Woo Lee, Julia R. Greer, Eugen Rabkin, Dan Mordehai, “Cross-split of dislocations: an athermal and rapid plasticity mechanism,”Nature Scientific Report 2 25966 (2016) – [link].
[Abstract]: The pathways by which dislocations, line defects within the lattice structure, overcome microstructural obstacles represent a key aspect in understanding the main mechanisms that control mechanical properties of ductile crystalline materials. While edge dislocations were believed to change their glide plane only by a slow, non-conservative, thermally activated motion, we suggest the existence of a rapid conservative athermal mechanism, by which the arrested edge dislocations split into two other edge dislocations that glide on two different crystallographic planes. This discovered mechanism, for which we coined a term “cross-split of edge dislocations”, is a unique and collective phenomenon, which is triggered by an interaction with another same-sign pre-existing edge dislocation. This mechanism is demonstrated for faceted α-Fe nanoparticles under compression, in which we propose that cross-split of arrested edge dislocations is resulting in a strain burst. The cross-split mechanism provides an efficient pathway for edge dislocations to overcome planar obstacles.
Lee’s Capstone Senior Design Team (Michael McGeever, Jeremy Higgins and Amy Hernadez) won the second place ($1,000) in the MSE final Capstone presentation! I am very proud of their achievement over the year! The title of the project was “Reliable rapid repair using additive manufacturing (sponsored by Sikorsky).”
(From left to right: Jeremy, Mike, and Amy)