About this Abstract |
Meeting |
2nd World Congress on High Entropy Alloys (HEA 2021)
|
Symposium
|
2nd World Congress on High Entropy Alloys (HEA 2021)
|
Presentation Title |
Spontaneous Grain Boundary Roughening in HEAs and Implications for Mobility |
Author(s) |
Carolina Baruffi, William Curtin |
On-Site Speaker (Planned) |
Carolina Baruffi |
Abstract Scope |
High Entropy Alloys (HEAs) possess intriguing combinations of properties including enhanced thermal stability against grain growth that is not understood. Here, we argue that natural compositional fluctuations in HEAs can enable a flat grain boundary to spontaneously roughen at zero temperature to a lower energy state. GB motion from this lower energy state is then naturally inhibited, providing an explanation for the resistance to grain coarsening observed in HEAs. This phenomenon is totally different from solute-drag/solute-segregation pinning and arises solely from the intrinsic randomness of HEAs. We present a parameter-free theoretical framework for this mechanism which predicts that, depending on GB structure and alloy composition, a GB will roughen to the smallest possible scales (structural unit scale) when solute/GB interactions are strong enough. The theory is applied to two high-angle GBs in fcc and validated by Molecular Statics simulations. |
Proceedings Inclusion? |
Undecided |