Cyclic plasticity of nickel single crystals at elevated temperatures

Bretschneider, J.; Holste, C.; Tippelt, B.

doi:10.1016/s1359-6454(97)00030-x

Cited by 80 publications

(27 citation statements)

References 23 publications

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“…The "ladder-like" arrangement of dislocation walls is then turned into a pronounced cell structure. Imaging of PSBs by ECCI is mainly useful for the determination of parameters like dislocation wall thickness and channel width [102] or the dependence of the PSB formation on the crystallographic orientation and/or grain size [103] due to the good statistics, which can be achieved by this method. Another aspect for which the ECC imaging can be used is the investigation of the activation of cyclic slip within the PSBs [62].…”

Section: Ecci and The Slip Activity Of Psbsmentioning

confidence: 99%

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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Section: Ecci and The Slip Activity Of Psbsmentioning

confidence: 99%

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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“…Besides Cu single crystals, such periodically ordered structure also appeares in the fatigued Ni, Ag and Au single crystals [13][14][15][16][17]. Then, the question is whether all the FCC pure metals can form the classical dislocation patterns by cyclic deformation.…”

mentioning

confidence: 99%

Basic criterion for the formation of self-organized dislocation patterns in fatigued FCC pure metals

Zhongguang

Zhang

2015

Sci. China Mater.

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tively proposed based on stacking fault energy (SFE).As shown in Fig. 1, PSB ladders or walls are a three-dimensional structure. PSB ladders from t he (12 − 1) plane or PSB walls from the (111) plane occupy about 10% of the PSBs by volume. The walls are 0.03-0.25 μm in thickness with a spacing of about 1.3 μm (see Fig. 2) and they consist of numerous dipoles, especially faulted dipole. The socalled faulted dipole consists of four Shockley partial dislocations and three stacking faults. Th e stair-rods lie at the ends of the stacking fault in the secondary slip plane and their relative position are thus fixed. The dipole as a whole can assume an S-or Z-shaped configuration depending on the position of the Shockley partials. In 1976, Antonopoulos et al. [11,12] pointed out that the matrix vein contained both primary edge dipole and faulted dipole, however, the PSBs were almost full of faulted dipoles, which reflected the microstructure evolution of dislocation patterns. On Based on a large number of experimental results available, it is found that not all the fatigued face-centered-cubic (FCC) pure metals can form the classical persistent slip band (PSB)-ladder structure. The formation of the regular dislocation patterns, especially the PSB ladders, follows one unified principle on the dislocation aggregation and evolution. According to the principle, a simple criterion based on stacking fault energy is proposed to judge whether or not the regular PSB ladders in different FCC pure metals can form.

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“…Especially, it is extremely suitable for studying the dislocation arrangements over a large specimen area and at some special sites, for example, the vicinity of GBs [21 -24], deformation bands [28] and cracks. Obviously, the dependence of intergranular fatigue cracking on the interactions of PSBs with GBs can be clearly revealed with the help of the SEM-ECC technique.…”

Section: Discussionmentioning

confidence: 99%

“…After cyclic deformation, the slip morphology and fatigue cracks on the bicrystal surface were observed by optical microscopy (OM) and scanning electron microscopy (SEM), respectively. To reveal the interaction of PSBs or dislocations with GBs, the dislocation patterns of the bicrystal were observed by the SEM-ECC technique as reported in our recent work [21][22][23][24] and the associated literature [25][26][27][28][29].…”

Section: Methodsmentioning

confidence: 99%

“…They found that low-angle GB and symmetrical S3 GB are particularly strong, and all high-angle GBs, independent of their S, are weak. In this paper, based on the observations about the interactions of PSBs with the two types of GBs in a copper bicrystal with embedded grains, the difference in intergranular fatigue cracking possibility along large-and low-angle GBs will be compared and revealed with the help of the electron channelling contrast (ECC) technique in SEM [21][22][23][24][25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

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Comparison of fatigue cracking possibility along large- and low-angle grain boundaries

Zhang

Wang

2000

Materials Science and Engineering: A

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Cyclic plasticity of nickel single crystals at elevated temperatures

Cited by 80 publications

References 23 publications

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

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

Basic criterion for the formation of self-organized dislocation patterns in fatigued FCC pure metals

Comparison of fatigue cracking possibility along large- and low-angle grain boundaries

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