About this Abstract |
Meeting |
2020 TMS Annual Meeting & Exhibition
|
Symposium
|
High Entropy Alloys VIII
|
Presentation Title |
Theory for Yield Strength of BCC HEAs |
Author(s) |
William A. Curtin, Francesco Maresca |
On-Site Speaker (Planned) |
William A. Curtin |
Abstract Scope |
The collective fluctuations in solute/dislocation interaction energies in dilute and HEA BCC alloys lead to the spontaneous energy-lowering formation of a kinked/wavy structure over characteristic lengths ζc,screw(edge). Dislocation motion is determined by the energetics at scale ζc. New general theories for both screw and edge motion in BCC alloys starting from this basic phenomenon are presented. The screw theory accurately predicts strength in Nb-Mo binary, and suggests some existing HEAs are pseudo-binaries. The edge theory shows that edges can control strengthening, especially at high temperatures. The edge theory explains (i) the exceptional retention of strength measured in MoNbTaW and MoNbTaVW at temperatures up to 1900K, (ii) why the V-containing alloy is stronger, and (iii) trends in other recent data. A simplified analytic form enables efficient computationally-guided design of new alloy compositions across the entire family of Cr-Mo-Nb-Ta-V-W-Hf-Ti-Zr BCC HEAs. Several new compositions are proposed and discussed. |
Proceedings Inclusion? |
Planned: Supplemental Proceedings volume; Planned: Supplemental Proceedings volume |