About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
|
| Symposium
|
High Entropy Materials: Concentrated Solid Solutions, Intermetallics, Ceramics, Functional Materials and Beyond V
|
| Presentation Title |
Coupling Self-Stabilization and Solute Grain Boundary Segregation Effects for Ultra-Stable Nanocrystalline High Entropy Alloy Design |
| Author(s) |
Moses Awenbiik Adaan-Nyiak, Ahmed A. Tiamiyu |
| On-Site Speaker (Planned) |
Moses Awenbiik Adaan-Nyiak |
| Abstract Scope |
Grain coarsening is common in nanocrystalline (NC) materials even at low temperatures; thereby limiting their widespread structural applications. In binary alloys, solute-element addition is used to effectively offset excess grain boundary (GB) energy that drives grain-growth. However, this thermodynamic approach is adjudged complex for multicomponent alloy systems. In this work, a novel alloy design strategy, the “pseudo-binary thermodynamic” approach, is proposed and developed for stabilizing NC-high entropy alloys (HEAs) as a model multicomponent alloy. Following empirical and GB segregation enthalpy considerations, Zr is identified as a solute-element that can segregate at the GBs of NC-AlCoCrFe-HEA to stabilize it against grain-growth. To experimentally-validate this approach, NC-AlCoCrFe-HEA is synthesized with minor addition of Zr, followed by heat treatment up to 1123 K. Using in-situ XRD, S/TEM, and APT, we report significant thermal stability resulting from the coupled effects of self-stabilization and solute-GB-segregation at high homologous-temperatures; the approach and coupled-effects will be discussed. |