Correlative Atom probe tomography

Correlative use of atom probe tomography (LEAP) in conjunction with electron microscopy for revealing both the structure and the chemical composition of a nanolaminate Cu Zr multilayer material (W. Guo, E. A. Jägle, P.-P. Choi, J. Yao, A. Kostka, J. M. Sc Correlative use of atom probe tomography (LEAP) in conjunction with electron microscopy for revealing both the structure and the chemical composition of a nanolaminate Cu Zr multilayer material (W. Guo, E. A. Jägle, P.-P. Choi, J. Yao, A. Kostka, J. M. Sc
Shear-Induced Mixing Governs Codeformation of Crystalline-Amorphous Nanolaminates
PRL 113, 035501 (2014) PHYSICAL REVIEW LETTERS
Guo Raabe PHYSICAL REVIEW LETTERS vol 11[...]
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Intrinsic and extrinsic size effects in the deformation of amorphous CuZr/nanocrystalline Cu nanolaminates
Acta Materialia 80 (2014) 94–106
Acta Materialia 80 (2014) 94 Nanolaminat[...]
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What is correlative electron microscopy and atom probe tomography ?

The correlative use of electron microscopy and atom probe tomography describe an experimental probing methodology which aims at revealing both, all relevant structural features and the chemical composition at exactly the same material position in three dimensions at full atomic scale at ppm chemcial precision. This method is also sometimes referred to as correlative atom probe tomography. 
Typically the method works by preparing needle shaped tips with a tip apex radius of around 50 nm that are suited for atom probe tomography, yet, before doing so these tips are first exposed to electron microscopical observations. 
Then the two data sets from electron microscopy and atom probe tomography or jointly analysed. 

Currently this combination of methods applied to exactly the same material portion represents the highest resolving joint crystallographic and chemical analysis method that can be applied to materials in 3D.

Coupled investigation of nanoparticles in a steel matrix conducted by using correlated electron microscopy and atom probe tomography, S. Jiang, H. Wang, Y. Wu, X. Liu, H. Chen, M. Yao, B. Gault, D. Ponge, D. Raabe, A. Hirata, M. Chen, Y. Wang, Z. Lu, Ultr Coupled investigation of nanoparticles in a steel matrix conducted by using correlated electron microscopy and atom probe tomography, S. Jiang, H. Wang, Y. Wu, X. Liu, H. Chen, M. Yao, B. Gault, D. Ponge, D. Raabe, A. Hirata, M. Chen, Y. Wang, Z. Lu, Ultr
Ultrastrong steel via minimal lattice misfit and high-density nanoprecipitation
460 | NATURE | VOL 544 | 27 April 2017
Ultrastrong steel via minimal lattice mi[...]
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Why is correlative electron microscopy and atom probe tomography important ?

Using correlative electron microscopy and atom probe tomography  enables us to reveal complex structural phenomena in materials and their interplay with chemical features. Most structural effects in complex modern materials, be at the formation of certain phases or the vast hierarchy of different types of lattice defects such as point defects, dislocations, grain boundaries or hetero-phase interfaces are characterized by specific chemical features. Therefore a more holistic understanding of nanostructured materials requires to reveal both, the local chemical composition together with the local structure of phases and defects to highest possible resolution in three dimensions.

 

Atomic-Scale Quantification of Grain Boundary Segregation in Nanocrystalline Material; PRL 112, 126103 (2014) PHYSICAL REVIEW LETTERS 28 MARCH 2014 Atomic-Scale Quantification of Grain Boundary Segregation in Nanocrystalline Material; PRL 112, 126103 (2014) PHYSICAL REVIEW LETTERS 28 MARCH 2014
Atomic-Scale Quantification of Grain Boundary Segregation in Nanocrystalline Material
PRL 112, 126103 (2014) PHYSICAL REVIEW LETTERS 28 MARCH 2014
Phys Rev Lett. 2014 grain boundary segre[...]
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Combining structural and chemical information at the nanometer scale by correlative transmission electron microscopy and atom probe tomography
Ultramicroscopy vol 153 (2015) pages 32–39
APT Herbig Ultramicroscopy correlative m[...]
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TEM analysis performed on APT tip. (a) BF-STEM micrograph of a martensitic Fe–9Mn alloy containing Mn-enriched precipitates. (b) STEM-EDX analysis of the Mn distribution (c) BF-TEM magnification (d) HRTEM image of austenite / martensite TEM analysis performed on APT tip. (a) BF-STEM micrograph of a martensitic Fe–9Mn alloy containing Mn-enriched precipitates. (b) STEM-EDX analysis of the Mn distribution (c) BF-TEM magnification (d) HRTEM image of austenite / martensite
Grain boundary segregation engineering in metallic alloys: A pathway to the design of interfaces
Current Opinion in Solid State and Materials Science 18 (2014) 253–261
Current Opinion in Solid State Materials[...]
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Combining structural and chemical information at the nanometer scale by correlative transmission electron microscopy and atom probe tomography on nanocrystalline iron. Combining structural and chemical information at the nanometer scale by correlative transmission electron microscopy and atom probe tomography on nanocrystalline iron.
Mechanisms of subgrain coarsening and its effect on the mechanical properties of carbon-supersaturated nanocrystalline hypereutectoid steel
Acta Materialia 84 (2015) 110–123
Acta Materialia 84 (2015) 110-123 atom p[...]
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Atomic-scale mechanisms of deformation-induced cementite decomposition in pearlite
Acta Materialia 59 (2011) 3965–3977
Acta Materialia 59 (2011) 3965 pearlite [...]
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What is the advantage of correlative electron microscopy and atom probe tomography compared to crystallographic atom probe tomography ?

Crystallographic atom probe refers to a method where some of the lattice planes can be resolved without the use of electron microscopy only through the adequate analysis of field desorption poles of crystallographic nature from atom probe tomography directly. 
However, different from electron microscopy in many atom probe tomographic experiments only some of the lattice planes can be resolved so that typically a full local crystallographic analysis is not always possible. 
Therefore a combined application of electron microscopy and atom probe tomography to the same sample region gives a more complete structural analysis then using crystallographic atom probe tomography alone. 

In some cases crystallographic lattice planes can be directly resolved from atom probe tomography alone without the aid of electron microscopical methods. In some cases crystallographic lattice planes can be directly resolved from atom probe tomography alone without the aid of electron microscopical methods.

 

 

Can we coupled also high resolution electron microscopy with atom probe tomography ?

Atom probe tomography can also be directly coupled with high resolution electron microscopy to resolve discrete atomic columns. The reason for this is that the needle shaped tips that are produced by using focused ion beam method for instance are so thin so that scanning transmission electron microscopy can resolve the atomic columns in such atom probe specimens prior to evaporation. Therefore atom probe tomography can be at the same region of interest directly combined with atomically resolving scanning transmission electron microscopy for resolving structural features in concert with chemical features at atomic scale. 

 

Combining high resolution scanning transmission electron microscopy with atom probe tomography, Acta Materialia 140 (2017) 258-273. Combining high resolution scanning transmission electron microscopy with atom probe tomography, Acta Materialia 140 (2017) 258-273.

 

Acta Mat. 2011, 59, p. 364