Molecular dynamics simulations of stress-induced phase transformations and grain nucleation at crack tips in Fe

Latapie, A.; Farkas, Diana

doi:10.1088/0965-0393/11/5/303

Cited by 81 publications

(42 citation statements)

References 40 publications

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“…This forced phase transformation results in a metastable displacive shear transition of bcc iron to closely packed fcc and hcp phases [46,47]. The orientation relationships between the transformed and untransformed regions were found to be similar to those observed for temperature-driven martensitic transformations in Fe and steels, and exactly the same as observed in the present study.…”

supporting

confidence: 86%

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Shear-induced α→γ transformation in nanoscale Fe–C composite

et al. 2006

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supporting

confidence: 86%

“…4 One can see that orientation relationship between the grains in Fig. 3b completely identical to the OR between the grains bcc 1 and bcc 2 in the MD simulations of reference [46], and thus we provide the first direct experimental evidence for the existence of the processes shown in the simulation study.…”

Section: Stability Of Austenite Nanograinssupporting

confidence: 67%

Shear-induced α→γ transformation in nanoscale Fe–C composite

et al. 2006

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“…Molecular dynamic simulation confirmed that the formation of nanocrystalline structure and dissolved carbides increased Gibbs free energy, providing driving force from bcc to fcc. Laptaoie [28] stated that the transformation from bcc to fcc was controlled by the stress. The fcc structure is not stable because it has a high energy make the transformation from bcc to fcc is reversible.…”

Section: Phase Transformation and Amorphization In The Weamentioning

confidence: 99%

Phase transformation in white etching area in rolling contact fatigue

et al. 2018

MATEC Web Conf.

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Abstract. Rolling contact fatigue (RCF) involves microstructural change in the subsurface of contact. The changed microstructure is generally termed as white etching area (WEA) as it appears white under optical microscope when etching in nital solution. WEA has been acknowledged as one of the primary failure modes in RCF since it causes severe local inhomogeneity of microstructure. It was reported that WEA consists of nano ferrites as martensite grains and carbides are significantly refined in the WEA. Some carbides are dissolved. In some cases, an amorphous-like structure was occasionally observed in the WEA, indicating that phase transformation may possibly occur. The WEAs were studied by using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Electron back scattered diffraction (EBSD). The result showed that WEA is dominated with an amorphous phase with martensite, austenite and carbides embedded interior. A distinct interface between the matrix and the WEA was present. In addition to grain refinement down to nanometers, phase transformation including amorphization and austenitization happened in WEAs. The content of austenite was increased from 2% in the matrix to 20% in the WEA. The analysis showed that phase transformation is controlled by plastic deformation mechanism.

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“…They also discussed whether the grain size and impurities would improve the ductility of nanocrystalline metals. Furthermore, in the literatures [14,15] both intragranular and intergranular fracture were observed. Other people found that a material should not be simply classified as intrinsically brittle or ductile [16] because under some specific conditions of mechanical load, the nanocrystalline materials may be shown to exhibit either brittle or ductile fracture behaviour.…”

Section: Introductionmentioning

confidence: 99%

A Molecular Dynamics Simulation of Fracture in Nanocrystalline Copper

Pei

Lü

Zhu

et al. 2013

JNanoR

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A large-scale molecular dynamics simulation was used to investigate the propagation of cracks in three dimensional samples of nanocrystalline copper, with average grain sizes ranging from 5.34 to 14.8 nm and temperatures ranging from 1K to 500 K. It was shown that intragranular fracture can proceed inside the grain at low temperature, and plastic deformation around the tip of the crack is accommodated by dislocation nucleation/emission; indeed, both fully extended dislocation and deformation twinning were visible around the tip of the crack during fracture. In addition, due to a higher concentration of stress in front of the crack at a relative lower temperature, it was found that twinning deformation is easier to nucleate from the tip of the crack. These results also showed that the decreasing grain size below a critical value exhibits a reverse HallPetch relationship due to the enhancing grain boundary mediation, and high temperature is better for propagating ductile cracks. © (2013) Trans Tech Publications, Switzerland. Abstract.A large-scale molecular dynamics simulation was used to investigate the propagation of cracks in three dimensional samples of nanocrystalline copper, with average grain sizes ranging from 5.34 to 14.8 nm and temperatures ranging from 1K to 500 K. It was shown that intragranular fracture can proceed inside the grain at low temperature, and plastic deformation around the tip of the crack is accommodated by dislocation nucleation/emission; indeed, both fully extended dislocation and deformation twinning were visible around the tip of the crack during fracture. In addition, due to a higher concentration of stress in front of the crack at a relative lower temperature, it was found that twinning deformation is easier to nucleate from the tip of the crack. These results also showed that the decreasing grain size below a critical value exhibits a reverse Hall-Petch relationship due to the enhancing grain boundary mediation, and high temperature is better for propagating ductile cracks.

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Molecular dynamics simulations of stress-induced phase transformations and grain nucleation at crack tips in Fe

Cited by 81 publications

References 40 publications

Shear-induced α→γ transformation in nanoscale Fe–C composite

Shear-induced α→γ transformation in nanoscale Fe–C composite

Phase transformation in white etching area in rolling contact fatigue

A Molecular Dynamics Simulation of Fracture in Nanocrystalline Copper

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