|About this Abstract
||2020 TMS Annual Meeting & Exhibition
||High Entropy Alloys VIII
||J-76: Analysis of Strengthening due to Grain Boundaries and Annealing Twin Boundaries in the CrCoNi Medium-entropy Alloy
||Mike Schneider, Easo P George, Tomáš Záležák, Antonín Dlouhý, Gunther Eggeler, Guillaume Laplanche
|On-Site Speaker (Planned)
The CrCoNi medium-entropy-alloy has the best combination of strength and ductility among all single-phase FCC subsets of the Cr-Mn-Fe-Co-Ni Cantor system. In this study the yield strength of CrCoNi was determined in compression as a function of grain size (3µm-175µm) and temperature (77K-873K). Grain size and texture analyses were performed using backscattered electron imaging and diffraction, respectively. The Hall-Petch slope is roughly temperature independent between 77K and 673K while grain boundary sliding plays a role for T>673K. Transmission electron microscopy of deformed specimens revealed the formation of pile-ups at grain and annealing twin boundaries indicating that both contribute to strength, also shown by 1D DDD simulations. Assuming that both types of boundaries have the same strength, the boundary strength calculated using a pile-up model from our experimental data corresponds roughly to the stress required to constrict Shockley partials, suggesting that dissociated dislocations must recombine before crossing the grain/annealing twin boundaries.
||Planned: Supplemental Proceedings volume; Planned: Supplemental Proceedings volume