First successful experimental observation of the dislocation nucleation process, which has been predicted only by theory
Prof. OH, SANG HO
PhD. LEE, SU BIN
The microelectronics revolution is one of the most influential drivers of current industrial developments. To probe the mechanical properties of ever shrinking materials and components, nanoindentation has come to be an omnipresent and indispensable method. In a recent combined experimental and computational approach, Prof. Sang Ho Oh was able to resolve the dynamic atomistic processes taking place at the elastic-plastic transition during nanoindentation for the first time. Further, Prof. Oh could determine the rate limiting processes governing the so-called pop-in event, as well as the origins for the observed transitions in dislocation mechanisms succeeding this event based on the dynamics of so-called prismatic dislocation loops. In the future, these fundamental insights will enable modifications of established nanoindentation models in order to better describe the most common small scale mechanical characterization technique.
The research result was published on May 12 in Nature Communications (IF 11.880), an international science journal.
Full details can be found in this open access article: In-situ observation of the initiation of plasticity by nucleation of prismatic dislocation loops
S. Lee et al, Nature Communications, published 05/12/2020
[Fig. 1] Formation of shear loops during plastic deformation. From the real-time transmission electron microscopy nanoindentation transformation experiment of gold nanowires, the experimental results and atomic simulation results of observing the formation process of dislocation loops during the initial plastic deformation process