• Applied Microscopy
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• v.46 no.3
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• pp.127-133
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• 2016

Atom probe tomography is a time-of-flight mass spectrometry-based microanalysis technique based on the field evaporation of surface atoms of a tip-shaped specimen under an extremely high surface electric field. It enables three-dimensional characterization for deeper understanding of chemical nature in conductive materials at nanometer/atomic level, because of its high depth and spatial resolutions and ppm-level sensitivity. Indeed, the technique has been widely used to investigate the elemental partitioning in the complex microstructures, the segregation of solute atoms to the boundaries, interfaces, and dislocations as well as following of the evolution of precipitation staring from the early stage of cluster formation to the final stage of the equilibrium precipitates. The current review article aims at giving a comment to first atom probe users regarding the limitation of the techniques, providing a brief perspective on how we correctly interprets atom probe data for targeted applications.

• Applied Microscopy
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• v.41 no.2
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• pp.89-98
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• 2011

Atom Probe Tomography (APT) can provide 3-dimensional information such as position and chemical composition with atomic resolution. Despite the ability of this technique, APT could not be applied for poor conductive materials such as semiconductor. Recently APT has dramatically developed by applying the laser pulsing and combining with Focused Ion Beam (FIB). The invention and combination of these techniques make possible site-specific sample preparation and permit the investigation of various materials including insulators. In this paper, we introduced the recently achieved state of the art applications of APT focusing on Si based FET devices, LED devices, low dimensional materials.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.5
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• pp.476-485
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• 2024

Understanding the structure-property relationship in functional materials is crucial as microstructural features such as nano-precipitates, phase boundary, grain boundary segregation, and grain boundary phases play a key role in their functional properties. Atom probe tomography (APT) is an advanced analytical technique that allows for the three-dimensional (3D) mapping of atomic distributions and the precise determination of local chemical compositions in materials. Moreover, it offers sub-nanometer spatial resolution and chemical sensitivity at the tens of parts per million (ppm) level. Owing to its unique capabilities, this technique has been employed to uncover the 3D elemental distributions in a wide range of materials, including alloys, semiconductors, nanomaterials, and even biomaterials. In this paper, various kinds of examples are introduced for elucidating structure-property relationships on functional materials by utilizing the atom probe tomography.

• Applied Microscopy
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• v.43 no.3
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• pp.122-126
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• 2013

The heterogeneous nucleation of the ${\Theta}^{\prime}$ phase on nanoscale precipitates has been investigated using a combination of three-dimensional atom probe tomography and high-resolution transmission electron microscopy. Two types of ${\Theta}^{\prime}$ phases were observed, namely small (~2 nm thick) cylindrical precipitates and larger (~100 nm) globular precipitates and both appear to be heterogeneously nucleated on the nanoscale precipitates. The composition and crystal structure of precipitates were directly analyzed by combination of two advanced characterization techniques.

• Applied Microscopy
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• v.41 no.2
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• pp.81-88
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• 2011

Even though importance of nano-scale structure and compositional analysis have been getting increased, existing analysis tools have been reached to their limitations. Recent development of Atom Probe Tomography (APT), providing 3-dimensional elemental distribution and compositional information with sub-nm scale special resolution and tens of ppm detection limit, is one of key technique which can overcome these limitations. However, due to the fact that APT is not well known yet in the domestic research area, it has been rarely utilized so far. Therefore, in this article, the theoretical background of APT was briefly introduced with sample preparation to help understanding APT analysis.

• Applied Microscopy
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• v.46 no.3
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• pp.117-126
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• 2016

Atom probe tomography (APT) has been fast rising in prominence over the past decade as a key tool for nanoscale analytical characterization of a range of materials systems. APT provides three-dimensional mapping of the atom distribution in a small volume of solid material. The technique has evolved, with the incorporation of laser pulsing capabilities, and, combined with progress in specimen preparation, APT is now able to analyse a very range of materials, beyond metals and alloys that used to be its core applications. The present article aims to provide an overview of the technique, providing a brief historical perspective, discussing recent progress leading to the state-of-the-art, some perspectives on its evolution, with targeted examples of applications.

• Nuclear Engineering and Technology
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• v.44 no.6
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• pp.673-682
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• 2012

Three dimensional atom probe tomography (3D APT) is applied to characterize the dissimilar metal joint which was welded between the Ni-based alloy, Alloy 690 and the low alloy steel, A533 Gr. B, with Alloy 152 filler metal. While there is some difficulty in preparing the specimen for the analysis, the 3D APT has a truly quantitative analytical capability to characterize nanometer scale particles in metallic materials, thus its application to the microstructural analysis in multi-component metallic materials provides critical information on the mechanism of nanoscale microstructural evolution. In this study, the procedure for 3D APT specimen preparation was established, and those for dissimilar metal weld interface were prepared near the fusion boundary by a focused ion beam. The result of the analysis in this study showed the precipitation of chromium carbides near the fusion boundary between A533 Gr. B and Alloy 152.

• Nuclear Engineering and Technology
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• v.44 no.5
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• pp.491-500
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• 2012

The dissimilar metal joints welded between Ni-based alloy, Alloy 690 and low alloy steel, A533 Gr. B with Alloy 152 filler metal were characterized by using optical microscope, scanning electron microscope, transmission electron microscope, secondary ion mass spectrometry and 3-dimensional atom probe tomography. It was found that in the weld root region, the weld was divided into several regions including unmixed zone in Ni-base alloy, fusion boundary, and heat-affected zone in the low alloy steel. The result of nanostructural and nanochemical analyses in this study showed the non-homogeneous distribution of elements with higher Fe but lower Mn, Ni and Cr in A533 Gr. B compared with Alloy 152, and the precipitation of carbides near the fusion boundary.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.273-276
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• 2008

In this study, microstructure and distribution of alloy elements were investigated in thermo-mechanically processed C-Mn-Si transformation induced plasticity (TRIP) steels. The microstructures of TRIP steels were investigated by using advanced analysis techniques, such as three dimensional atom probe tomography (3D-APT). At first, the microstructure was observed by using TEM. TEM results revealed that microstructure of C-Mn-Si TRIP steel was composed of ferrite, bainte, and retained austenite. 3D-APT was used to characterize atomic-scale partitioning of added elements at the phase interface. In the retained austenite phase, Ti and B were enriched with C. However, there was no fluctuation of Mn and Si concentration across the interface. Through these analysis techniques, the advanced characteristics of constituent microstructure in C-Mn-Si TRIP steels were identified.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.213-216
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• 2009

In this study, three cold-rolled TRIP steels containing different Al content (0.04wt%, 1.0 wt.% and 2.00wt%) were fabricated to understand the complex effects of Al in TRIP steel. The influences of Al on microstructural evolution of cold-rolled TRIP steels have been analyzed by using advanced analysis techniques, such as transmission electron microscope (TEM) and three dimensional atom probe tomography (3D-APT). TEM results revealed that second phases such as bainte and retained austenite decrease with increase of Al content. In addition, 3D-APT was used to characterize atomic-scale distribution of alloying elements at the constituent phases. Through these analysis techniques, the advanced characteristics of constituent microstructure in TRIP steels were identified depending on Al contents in TRIP steels.