Effect of interatomic potential on modelling fracture behavior in hcp titanium: a molecular dynamics study

Molecular dynamics (MD) simulations have unique advantages in capturing the details of the crack tip deformation at the atomic scale. As the accuracy of simulation results is heavily dependent on the selected interatomic potential, a comprehensive study of the anisotropic crack tip behavior of hcp titanium under plane strain mode-I loading with the commonly utilized potentials is presented in this paper. The typical crystallographic planes in hcp materials including {0001}, {10 (1) over bar0}, {11 (2) over bar0}, {10 (1) over bar1} and {11 (2) over bar2} are considered as the pre-existing crack planes. The intrinsic brittleness and ductility of different crack systems are discussed from the perspective of linear elastic fracture criteria. Depending on the selected potential, the dominant crack tip deformation mechanism may be basal a slip, prismatic a, pyramidal c + a slip or twinning modes in different crack systems. Finally, in comparison with experimental results, the different potentials are evaluated in the light of their capability to reproduce the experimentally observed crack tip deformation. Overall, the recent developed Mendelev-II potential is recommended for MD simulation of fracture behavior under mode-I loading, as this potential gives a more realistic crack tip response than other studied potentials. (C) 2022 The Author(s). Published by Elsevier B.V.

Automated summary

Molecular dynamics simulations are uniquely advantageous in capturing atomic-scale crack tip deformation details. This study presents a comprehensive analysis of the anisotropic crack tip behavior of hcp titanium under plane strain mode-I loading with commonly used potentials, discussing different crack systems' intrinsic brittleness and ductility. Depending on the selected potential, the dominant crack tip deformation mechanism may vary, with the Mendelev-II potential recommended for its more realistic crack tip response.