Crack growth in Fe-Si (2 wt%) single crystals on macroscopic and atomistic level

0506915 - ÚT 2020 RIV NL eng J - Journal Article
Ševčík, Martin - Zídek, Jan - Nejezchlebová, Jitka - Štefan, Jan - Machová, Anna - Seiner, Hanuš - Uhnáková, Alena - Čapek, Jaroslav - Lejček, Pavel
Crack growth in Fe-Si (2 wt%) single crystals on macroscopic and atomistic level.
Results in Physics. Roč. 14, September (2019), č. článku 102450. ISSN 2211-3797. E-ISSN 2211-3797
R&D Projects: GA ČR(CZ) GA17-12925S; GA MŠMT(CZ) EF15_003/0000493; GA ČR GBP108/12/G043; GA MŠMT(CZ) EF16_019/0000760; GA ČR(CZ) GA17-12925S
Grant - others:OP VVV - SOLID21(XE) CZ.02.1.01/0.0/0.0/16_019/0000760
Institutional support: RVO:61388998 ; RVO:68378271
Keywords : Fe-Si single crystals * experiments * fracture * T-stress * molecular dynamics * bcc iron
OECD category: Materials engineering; Condensed matter physics (including formerly solid state physics, supercond.) (FZU-D)
Impact factor: 4.019, year: 2019
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/pii/S2211379719305492?via%3Dihub

This paper is dedicated to experimental and atomistic study of the influence of so called T-stress (acting along the crack plane) on fracture processes in bcc iron. We analyze experimental results from fracture tests performed at room temperature on bcc iron-silicon single crystals with a long edge crack (1¯10)[1 1 0] (crack plane/crack front). The specimens were loaded in tension mode I under different border conditions inducing different sign of the T-stress. The brittle-ductile behavior at the crack front was monitored on-line via optical microscopy together with external force and prolongation of the specimens. Topology of the specimens has been investigated before and after the fracture tests via the white light interferometer. The microscopic processes produced by the crack itself were studied at 300 K via 3D molecular dynamic (MD) simulations in bcc iron under equivalent boundary conditions and the T-stress was examined by means of stress calculations on the atomistic level. The experimental and atomistic results show that the sign of the T-stress affects the fracture behavior. MD simulations reveal that positive T-stress makes the emission of blunting dislocations 〈1 1 1〉{1 1 2} from the crack front more difficult. As a consequence, higher external loading is needed for crack blunting in the experimental specimens with T > 0 in comparison with the specimen having T < 0.
Permanent Link: http://hdl.handle.net/11104/0298245