Calculation update! New properties have been added to the website for dislocation monopole core structures, dynamic relaxes of both crystal and liquid phases, and melting temperatures! Currently, the results for these properties predominately focus on EAM-style potentials, but the results will be updated for other potentials as the associated calculations finish. Feel free to give us feedback on the new properties so we can improve their representations as needed.
Warning! Note that elemental potentials taken from alloy descriptions may not work well for the pure species. This is particularly true if the elements were fit for compounds instead of being optimized separately. As with all interatomic potentials, please check to make sure that the performance is adequate for your problem.
Citation: D.S. Oliveira, D.P. Kuritza, J.E. Padilha, and M.A. Cotta (2026), "An Atomistic Investigation of Cobalt’s Nanoindentation Response with An Angular Dependent Potential", ACS Omega11(4), 6324–6333. DOI: 10.1021/acsomega.5c11093.
Abstract: Cobalt and its alloys are essential in many advanced technologies and understanding their mechanical properties at the nanoscale is crucial for designing next-generation materials. In this work, an angular-dependent potential for cobalt was developed by fitting to a reference data set of atomic forces, energies, and stress tensors derived from first-principles density functional theory calculations. The potential's performance was systematically evaluated against experimental data and two established classical potentials-an embedded-atom method potential and a modified embedded-atom method potential-across a range of structural, mechanical, thermal, and defect properties for both HCP and FCC phases, as well as the liquid state. The ADP model demonstrates a favorable balance between accuracy and computational cost, exhibiting a mean absolute percentage error of 6.3% for mechanical and elastic properties. Large-scale molecular dynamics simulations of nanoindentation on the (0001) basal plane of HCP cobalt were performed to investigate the atomistic mechanisms of plastic deformation. The simulations reveal that plasticity initiates with the nucleation of <a>-type dislocations on basal planes, followed by the activation of pyramidal <c+a> slip and a localized, reversible HCP-to-FCC phase transformation under high pressure. The critical shear stress for dislocation nucleation was found to decrease with increasing indenter radius, converging to a value of (13.7 ± 0.6) GPa.
Notes: This ADP potential was generated using force-matching techniques based on DFT data and developed to balance accuracy and computational cost for Cobalt simulations. It has been systematically evaluated for structural, mechanical, thermal, and defect properties across HCP and FCC phases, as well as the liquid state. It performs particularly well for mechanical and elastic properties, with a mean absolute percentage error of 6.3%. The potential successfully captures the nucleation of dislocations and the localized, reversible HCP-to-FCC phase transformation under high pressure, as observed in nanoindentation simulations. It should not be used for simulations involving interatomic distances below 1.8 Å, as the fitting was optimized for larger distances. A cutoff radius of 5.8 Å was used in the parametrization.