Grain boundary migration has been investigated for several decades. It is accepted that a grain boundary can move under the action of mechanical stresses and jumps in chemical potential [1, 2]. A jump in chemical potential occurs whenever there is gradient of any intensive thermodynamic variable for example grain boundary curvature. Experiments and simulations have substantiated differences in the motion of grain boundaries depending on the acting driving force [3-6]. Different activation enthalpies have been determined to be different for crystallographically similar grain boundaries depending on the type of the driving force. The migration enthalpy is a fingerprint of the migration mechanisms, which in turn depends on the grain boundary structure. In the present contribution, persistent homology (PH) was utilized to quantify the structure of the grain boundaries during their migration. To this aim, more than 1200 MD simulations of GB migration were performed. In these simulations, mechanical stresses and a jump in chemical potential were used to drive the motion of the boundaries. We show that PH can be used to quantify the GB structure and that by association it is possible to discriminate the type of migration of a boundary.

[1] S.L. Thomas, C. Wei, J. Han, Y. Xiang, D.J. Srolovitz, Disconnection description of triple-junction motion, Proc Natl Acad Sci U S A 116(18) (2019) 8756-8765.

[2] C. Wei, L. Zhang, J. Han, D.J. Srolovitz, Y. Xiang, Grain Boundary Triple Junction Dynamics: A Continuum Disconnection Model, SIAM Journal on Applied Mathematics 80(3) (2020) 1101-1122.

[3] J.-E. Brandenburg, L.A. Barrales-Mora, S. Tsurekawa, D.A. Molodov, Dynamic behavior of grain boundaries with misorientations in the vicinity of Σ3 coherent and incoherent twin boundaries in Al bicrystals, Acta Mater 259 (2023).

[4] L.A. Barrales-Mora, D.A. Molodov, Capillarity-driven shrinkage of grains with tilt and mixed boundaries studied by molecular dynamics, Acta Mater 120 (2016) 179-188.

[5] L.A. Barrales-Mora, J.-E. Brandenburg, D.A. Molodov, Impact of grain boundary character on grain rotation, Acta Mater 80 (2014) 141-148.

[6] J.E. Brandenburg, L.A. Barrales-Mora, D.A. Molodov, On migration and faceting of low-angle grain boundaries: Experimental and computational study, Acta Mater 77 (2014) 294-309.