Collinear-spin machine learned interatomic potential for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Fe</mml:mi><mml:mn>7</mml:mn></mml:msub><mml:msub><mml:mi>Cr</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:mi>Ni</mml:mi></mml:mrow></mml:math> alloy
Lakshmi Shenoy, Christopher D. Woodgate, J. B. Staunton, Albert P. Bartók, Charlotte Becquart, Christophe Domain, James R. Kermode
Abstract
We have developed a machine learned interatomic potential for the prototypical austenitic steel <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:msub><a:mi>Fe</a:mi><a:mn>7</a:mn></a:msub><a:msub><a:mi>Cr</a:mi><a:mn>2</a:mn></a:msub><a:mi>Ni</a:mi></a:mrow></a:math>, using the Gaussian approximation potential (GAP) framework. This GAP can model the alloy's properties with close to density functional theory (DFT) accuracy, while at the same time allowing us to access larger length and time scales than expensive first-principles methods. We also extended the GAP input descriptors to approximate the effects of collinear spins (spin GAP), and demonstrate how this extended model successfully predicts structural distortions due to antiferromagnetic and paramagnetic spin states. We demonstrate the application of the spin GAP model for bulk properties and vacancies and validate against DFT. These results are a step towards modeling the atomistic origins of ageing in austenitic steels with higher accuracy. Published by the American Physical Society 2024