Ductile-brittle transition at edge cracks (001)[110] in BCC iron under different loading rates in mode I: a 3D atomistic study

0556328 - ÚT 2023 RIV GB eng J - Článek v odborném periodiku
Uhnáková, Alena - Machová, Anna - Červ, Jan - Hora, Petr - Joch, Jaroslav
Ductile-brittle transition at edge cracks (001)[110] in BCC iron under different loading rates in mode I: a 3D atomistic study.
Materials Research Express. Roč. 9, č. 3 (2022), č. článku 036508. E-ISSN 2053-1591
Grant CEP: GA ČR(CZ) GA19-03282S; GA MŠMT(CZ) EF15_003/0000493
Institucionální podpora: RVO:61388998
Klíčová slova: bcc iron * cracks * ductile-brittle transition * molecular dynamics * loading rate effect
Obor OECD: Materials engineering
Impakt faktor: 2.3, rok: 2022
Způsob publikování: Open access
https://iopscience.iop.org/article/10.1088/2053-1591/ac5708

3D atomistic simulations via molecular dynamics (MD) at temperature of 0 K and 295 K (22°C) with a high quasi-static loading rate dP/dt of 2.92 kN/s show that cleavage fracture is supported by surface emission of oblique dislocations and by their subsequent cross slip to {112} planes, which increases separation of the (001) cleavage planes inside the crystal. Under the slower loading rate by a factor 5, the crack growth is hindered by twin generation on oblique planes {112} and the fracture is ductile. The MD results explain the contribution of the crack itself to the ductile-brittle transition observed in our fracture experiments on Fe-3wt%Si single crystals of the same orientation and geometry, loaded at the same rates dP/dt as in MD. The loading rates are equivalent to the cross head speed of 5 mm/min and 1 mm/min used in the experiment. The MD results also agree with the stress analysis performed by the anisotropic LFM and comply with experimental observations.
Trvalý link: http://hdl.handle.net/11104/0331230