Studies of dislocations by field ion microscopy and atom probe tomography

Smith, G.D.W.; Hudson, D. R.; Styman, Paul; Williams, Ceri A.

doi:10.1080/14786435.2013.818257

Cited by 46 publications

(20 citation statements)

References 82 publications

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“…We also detect fluctuations of the matrix elements and impurities at confined two-dimensional and line-shaped features, which are most likely stacking faults (SF) and dislocations [31,32], respectively (see Supplemental Material [48] for how to distinguish GBs from SFs). Figures 4(a) and 4(b) shows an APT dataset of the Cu-poor precursor.…”

Section: Chemical Fluctuations At Stacking Faults and Dislocationsmentioning

confidence: 99%

Variable chemical decoration of extended defects in Cu-poor Cu2ZnSnSe4 thin films

Schwarz

Redinger

Siebentritt

et al. 2019

Phys. Rev. Materials

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We report on atom probe tomography studies of variable chemical decorations at extended defects in Cu-poor and Zn-rich Cu 2 ZnSnSe 4 thin films. For a precursor film, which was co-evaporated at 320 • C, grain boundaries and dislocations are found enriched with Cu. Furthermore, Na out-diffusion from the soda-lime glass substrate occurs even at such a low temperature, resulting in Na segregation at defects. In contrast, stacking faults in the precursor film show clear Zn enrichment as well as Cu and Sn depletion. After an annealing step at 500 • C, we detect changes in the chemical composition of grain boundaries as compared to the precursor. Moreover, we measure an increase in the grain boundary excess of Na by one order of magnitude. We show that grain boundaries and dislocations in the annealed Cu 2 ZnSnSe 4 film exhibit no or only slight variations in composition of the matrix elements. Thus, the effect of annealing is a homogenization of the chemical composition.

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Section: Chemical Fluctuations At Stacking Faults and Dislocationsmentioning

confidence: 99%

Variable chemical decoration of extended defects in Cu-poor Cu2ZnSnSe4 thin films

Schwarz

Redinger

Siebentritt

et al. 2019

Phys. Rev. Materials

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“…It has been suggested in low-carbon steels that Cottrell atmospheres form at the lath boundaries for as-quenched conditions [14,15]; further carbon redistribution occurs during tempering forming precipitates at the boundaries [13]. Chang et al [16] observed in two steels containing 0.45 and 0.85 at.% carbon that the matrix was almost depleted in carbon, whilst carbon-rich regions extending for radial distances of at least 3 nm could be seen from the dislocation lines [17]. Wilde et al [14] extended this work to quantify the carbon atom distribution and concentration within the atmospheres; they found the carbon saturation in the atmosphere to be at about 7-8 at.%.…”

Section: Introductionmentioning

confidence: 98%

A model for the microstructure behaviour and strength evolution in lath martensite

Galindo-Nava

Rivera-Dı́az-del-Castillo

2015

Acta Materialia

295

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a b s t r a c tA new model describing the microstructure and strength of lath martensite is introduced. The packet and block size were found to linearly depend on the prior-austenite grain size when introducing relevant crystallographic and geometric relationships of their hierarchical arrangements. A mechanism for the lath boundary arrangement within a block is postulated to ensure complete carbon redistribution to the lath boundaries. Accordingly, the dislocation density is obtained by considering the lattice distortion energy within a lath being equal to the strain energy of the dislocation density at the lath boundaries. Tempering effects are introduced by estimating the extent of carbon diffusing away from the lath boundaries; this mechanism relaxes the Cottrell atmospheres of lath dislocations and coarsens the boundaries. The yield stress as well as the microstructure evolution during tempering are successfully predicted by combining these results. The model is further extended to describe the yield stress in dual-phase steel microstructures by employing the iso-work principle. The model predictions are validated against experimental data in seven martensitic and five dual-phase steels, where the prior-austenite grain size, carbon content, tempering conditions and martensite volume fraction are employed as input. These results cover wide composition, initial microstructure and tempering conditions.

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“…FIM has brought valuable insights into the structure of crystalline defects, e.g. dislocations and grain boundaries [8,9], in pure metals. The nature of the contrast in FIM has been under debate [10,11], in particular when atoms from different species are involved.…”

Section: Introductionmentioning

confidence: 99%

Imaging individual solute atoms at crystalline imperfections in metals

et al. 2019

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Directly imaging all atoms constituting a material and, maybe more importantly, crystalline defects that dictate materials' properties, remains a formidable challenge. Here, we propose a new approach to chemistry-sensitive field-ion microscopy (FIM) combining FIM with time-of-flight mass-spectrometry (tof-ms). Elemental identification and correlation to FIM images enabled by data mining of combined tof-ms delivers a truly analytical-FIM (A-FIM). Contrast variations due to different chemistries is also interpreted from density-functional theory (DFT). A-FIM has true atomic resolution and we demonstrate how the technique can reveal the presence of individual solute atoms at specific positions in the microstructure. The performance of this new technique is showcased in revealing individual Re atoms at crystalline defects formed in Ni-Re binary alloy during creep deformation. The atomistic details offered by A-FIM allowed us to directly compare our results with simulations, and to tackle a long-standing question of how Re extends lifetime of Ni-based superalloys in service at high-temperature.

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Studies of dislocations by field ion microscopy and atom probe tomography

Cited by 46 publications

References 82 publications

Variable chemical decoration of extended defects in Cu-poor Cu2ZnSnSe4 thin films

Variable chemical decoration of extended defects in Cu-poor Cu2ZnSnSe4 thin films

A model for the microstructure behaviour and strength evolution in lath martensite

Imaging individual solute atoms at crystalline imperfections in metals

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