Local magnification effects in the atom probe

Miller, M.K.; Hetherington, M.G.

doi:10.1016/0039-6028(91)90449-3

Cited by 239 publications

(62 citation statements)

References 4 publications

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“…This situation is a common occurrence in alloy systems involving precipitation of a second phase and in multilayer materials. Variations in evaporation field of phases intersecting the curved specimen surface lead to a non-uniform radius of curvature and in turn produce local magnification effects, which can produce apparent variations in atomic density and distortions of the reconstructed microstructure [3]. In addition to this, simulations of ion trajectories in a two-phase tip specimen undergoing field evaporation have shown that trajectory overlaps can occur and affect the measured composition of features [4,5].…”

Section: Introductionmentioning

confidence: 97%

Determining the composition of small features in atom probe: bcc Cu-rich precipitates in an Fe-rich matrix

et al. 2009

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Section: Introductionmentioning

confidence: 97%

Determining the composition of small features in atom probe: bcc Cu-rich precipitates in an Fe-rich matrix

et al. 2009

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“…The lateral Co concentration distribution through the filaments is challenging to determine accurately, due to experimental artifacts. There is a known artifact during APT field evaporation that arises from two linked sources: the change in dielectric constants in regions of high doping, and the evolution of a locally different radius of curvature due to differing evaporation fields, both causing lateral deviation of electric field lines from the surface-normals assumed during data reconstruction [10][11][12][13] . This causes areas of differing composition to be "magnified" in the reconstructed data.…”

Section: Structural Characterizationmentioning

confidence: 99%

Single‐Phase Filamentary Cellular Breakdown Via Laser‐Induced Solute Segregation

Akey

Recht

Williams

et al. 2015

Adv Funct Materials

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Nanosecond melting and quenching of materials offers a pathway to novel structures with unusual properties. Impurity-rich silicon processed using nanosecond-pulsed-laser-melting is known to produce nanoscale features in a process referred to as "cellular breakdown" due to destabilization of the planar liquid/solid interface. Here, we apply atom probe tomography combined with electron microscopy to show that the morphology of cellular breakdown in these materials is significantly more complex than previously documented. We observe breakdown into a complex, branching filamentary structure topped by a few nm of a cell-like layer. Singlephase diamond cubic silicon highly supersaturated with at least 10% atomic Co and no detectable silicides is reported within these filaments. In addition, the unprecedented spatio-chemical accuracy of the atom probe allows us to investigate nanosecond formation dynamics of this 2 complex material. Previously-reported properties of these materials can now be reconsidered in light of their true composition, and this class of inhomogeneous metastable alloys in silicon can be explored with confidence.

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“…In such a case, a defocussing of ions trajectories emitted from dipersoids is expected. 6,7 This should result in a lower apparent atomic density in dispersoids displayed in the 3D reconstruction. 7 Sc and Zr positions in a 3D reconstructed volume of an ECOTAP analysis are shown in Fig.…”

Section: Methodsmentioning

confidence: 96%

“…Overlaps of ion trajectories due to local magnification effect 6,7 might be the main cause for this overestimate. On the other hand, local magnification cannot explain why the Al concentration in hardening precipitates of Al-Mg-Si alloys would be overestimated.…”

Section: Introductionmentioning

confidence: 94%

3DAP measurements of Al content in different types of precipitates in aluminium alloys

Lefebvre

Danoix

Costa

et al. 2007

Surface & Interface Analysis

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Three-dimensional atom probe and field ion microscopy have been used to determine the composition of precipitates formed in several types of aluminium-based alloys. Special attention has been paid to local magnification artefacts, which are often suspected to strongly disrupt the precipitates' apparent composition. The charge state of Al ions has been used to identify the nature of precipitates (lower or higher evaporation field than the matrix) and also to determine the origin of Al ions observed in 3D reconstructions. The use of a cluster identification method, which allows erosion concentration profiles to be drawn, has revealed the importance of trajectory overlaps in the measurement of the precipitates' composition. By applying this method to low-evaporation-field precipitates in a 7XXX alloy, good agreement was found between atom probe measurements and observations in transmission electron microscopy and small angles X-ray scattering.

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Local magnification effects in the atom probe

Cited by 239 publications

References 4 publications

Determining the composition of small features in atom probe: bcc Cu-rich precipitates in an Fe-rich matrix

Determining the composition of small features in atom probe: bcc Cu-rich precipitates in an Fe-rich matrix

Single‐Phase Filamentary Cellular Breakdown Via Laser‐Induced Solute Segregation

3DAP measurements of Al content in different types of precipitates in aluminium alloys

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