In situ X-ray diffraction study of stacking fault formation in the near-surface region of transformation induced plasticity steels

Rafaja, David; Krbetschek, Christina; Borisova, Daria; Schreiber, Gerhard; Klemm, Volker

doi:10.1016/j.tsf.2012.07.067

Cited by 29 publications

(31 citation statements)

References 32 publications

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“…5,6 In face-centered cubic crystals, the (004) diffraction peak shifts to the higher angle side with an increase in the density of the stacking-fault defects along the (111) plane. 28,29,30 We observe many stacking-fault defects especially in the locally high-Fe-concentration regions. 5 We think that the higher the T S is, the larger the non-uniformity of the Fe concentration becomes, which results in the increase in the density of the stacking-fault defects.…”

Section: Discussionmentioning

confidence: 88%

Important role of the non-uniform Fe distribution for the ferromagnetism in group-IV-based ferromagnetic semiconductor GeFe

Wakabayashi

Ohya

Ban

et al. 2014

Journal of Applied Physics

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We investigate the growth-temperature dependence of the properties of the group-IV-based ferromagnetic semiconductor Ge1−xFex films (x = 6.5% and 10.5%), and reveal the correlation of the magnetic properties with the lattice constant, Curie temperature (TC), non-uniformity of Fe atoms, stacking-fault defects, and Fe-atom locations. While TC strongly depends on the growth temperature, we find a universal relationship between TC and the lattice constant, which does not depend on the Fe content x. By using the spatially resolved transmission-electron diffractions combined with the energy-dispersive X-ray spectroscopy, we find that the density of the stacking-fault defects and the non-uniformity of the Fe concentration are correlated with TC. Meanwhile, by using the channeling Rutherford backscattering and particle-induced X-ray emission measurements, we clarify that about 15% of the Fe atoms exist on the tetrahedral interstitial sites in the Ge0.935Fe0.065 lattice and that the substitutional Fe concentration is not correlated with TC. Considering these results, we conclude that the non-uniformity of the Fe concentration plays an important role in determining the ferromagnetic properties of GeFe.

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Section: Discussionmentioning

confidence: 88%

Important role of the non-uniform Fe distribution for the ferromagnetism in group-IV-based ferromagnetic semiconductor GeFe

Wakabayashi

Ohya

Ban

et al. 2014

Journal of Applied Physics

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“…Feaugas [44] detected planar dislocation structures comprising pile-ups and stacking faults in a 316L austenitic stainless steel at tensile strains <1.5%. Stacking faults were also observed in the austenite grains of transformation induced plasticity steel at a tensile strain of 0.5% [45]. Prior to the observation of deformation twinning, stacking faults in the form of widely separated partial dislocations or as long and narrow straight features have been detected in a Fe-18Mn-0.6C-1.5Al TWIP steel at 4% tensile strain [46].…”

Section: The Observation Of In-grain Striationsmentioning

confidence: 92%

Microstructure and texture evolution in a twinning-induced-plasticity steel during uniaxial tension

2013

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. (2013). Microstructure and texture evolution in a twinning-induced-plasticity steel during uniaxial tension. Acta Materialia, 61 (7), 2671-2691.Microstructure and texture evolution in a twinning-induced-plasticity steel during uniaxial tension AbstractA combination of electron back-scattering diffraction and X-ray diffraction was used to track the evolution of the microstructure and texture of a fully recrystallized Fe-24 Mn-3 Al-2 Si-1 Ni-0.06 C twinning-inducedplasticity steel during interrupted uniaxial tensile testing. Texture measurements returned the characteristic double fibre texture for face-centred cubic materials, with a relatively stronger 〈1 1 1〉 and a weaker 〈1 0 0〉 partial fibre parallel to the tensile axis. The interaction with the stable 〈1 1 1〉 oriented grains results in preferential plastic flow in the unstable 〈1 1 0〉 oriented grains. Consequently, the grains oriented along the 〈1 1 0〉 and 〈1 0 0〉 fibres record the highest and lowest values of intragranular local misorientation, respectively. The viscoplastic self-consistent model was used to simulate the macroscopic stress-strain response as well as track the evolution of bulk crystallographic texture by detailing the contributions of perfect and/or partial slip, twinning and latent hardening. The simulations revealed the dominant role of perfect slip and the limited volume effect of twinning on the texture development. The effects of initial orientation and grain interaction on the overall orientation stability during uniaxial tension showed that while the 〈1 0 0〉 fibre remains stable and does not affect the unstable orientations along the 〈1 1 0〉 fibre, the orientations along the stable 〈1 1 1〉 fibre strongly affect the unstable 〈1 1 0〉 orientations. on the overall orientation stability during uniaxial tension showed that while the 100  fibre remains stable and does not affect the unstable orientations along the 110  fibre, the orientations along the stable 111  fibre strongly affect the unstable 110  orientations.

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“…Figure 3 shows two examples of HR-ECCI micrographs visualizing individual SFs in metastable high-alloy austenitic cast steel after uniaxial tensile (a) and cyclic (b) deformation, respectively. The investigated steel exhibits a quite low SFE of about 17 kJ/mol [72,73] and, therefore, a high tendency to form SFs. In both micrographs, deformation bands on different activated slip systems as well as individual SFs are clearly visible.…”

Section: Observation Of Sfs By Hr-eccimentioning

confidence: 97%

Case studies on the application of high-resolution electron channelling contrast imaging – investigation of defects and defect arrangements in metallic materials

Weidner

Biermann

2015

Philosophical Magazine

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In 1967, Coates discovered the electron channelling contrast of backscattered electrons (BSEs) in scanning electron microscopy, and by this the possibility to investigate arrangements of lattice defects in deformed microstructures of materials. Since that time, a straightforward development of the scanning electron microscopes as well as of the electron channelling contrast technique took place. Nowadays, the performance of scanning electron microscopes is high enough that the resolution of electron channelling contrast imaging (ECCI) micrographs is comparable with conventional bright field transmission electron microscopy (TEM) micrographs. In the first part of the present paper, a historical review on the development of the ECCI technique starting from its discovery more than 45 years ago up to the combination with other advanced methods of scanning electron microscopy like electron backscatter diffraction or high-resolution selected area channelling patterning in the last few years is given. Major important investigations using this technique for the visualization of individual lattice defects like stacking faults (SFs) and dislocations or dislocation arrangements are chronologically summarized. The second part demonstrates that nowadays, ECCI micrographs taken in high-resolution scanning electron microscopes can be called high-resolution ECCI (HR-ECCI). It is shown that the resolution of individual SFs and dislocations in the HR-ECCI micrographs is comparable to that of conventional TEM (about 15 nm defect image width). Furthermore, the paper is demonstrating that HR-ECCI micrographs can be obtained for various types of materials after different mechanical loadings and different grain sizes ranging from large grain size of 500 μm (cast steel) down to less than 2 μm (γ-TiAl).

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In situ X-ray diffraction study of stacking fault formation in the near-surface region of transformation induced plasticity steels

Cited by 29 publications

References 32 publications

Important role of the non-uniform Fe distribution for the ferromagnetism in group-IV-based ferromagnetic semiconductor GeFe

Important role of the non-uniform Fe distribution for the ferromagnetism in group-IV-based ferromagnetic semiconductor GeFe

Microstructure and texture evolution in a twinning-induced-plasticity steel during uniaxial tension

Case studies on the application of high-resolution electron channelling contrast imaging – investigation of defects and defect arrangements in metallic materials

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