| About this Abstract |
| Meeting |
MS&T23: Materials Science & Technology
|
| Symposium
|
High Entropy Materials: Concentrated Solid Solutions, Intermetallics, Ceramics, Functional Materials and Beyond IV
|
| Presentation Title |
A First-principles Study of Calculation Parameters Affecting Vacancy Formation Energy in CoCrNi and CoCrFeNiMn High-entropy Alloys, with Comparison to Creep Activation Energy |
| Author(s) |
Christopher Lafferty, Peter Liaw, Chelsey Z. Hargather |
| On-Site Speaker (Planned) |
Chelsey Z. Hargather |
| Abstract Scope |
High-entropy alloys (HEAs) are potential candidates for high-performance engineering material applications. Creep is permanent, time-dependent inelastic deformation under applied stress, and diffusion properties are an important contribution to secondary creep behavior. In the present work, first-principles calculations are employed to analyze activation energy for diffusion in the CoCrNi and CoCrFeNiMn HEAs. The effects of various calculation parameters, including the magnetic and non-magnetic states, and two versions of the generalized gradient approximation, are compared. Widom-type substitution techniques are used. Special quasi-random structures (SQS) are employed, and complications related to the structural complexity and magnetism when using first-principles techniques are discussed. The relationship between the creep-activation energy and diffusion-activation energy in well studied systems, such as CoCrNi, is explored. Results are compared to known literature where available, and the importance of the calculations for novel alloy design are discussed. |