Impact of directional walk on atom probe microanalysis

Gault, Baptiste; Danoix, F.; Hoummada, K.; Mangelinck, Dominique; Leitner, Harald

doi:10.1016/j.ultramic.2011.06.005

Cited by 140 publications

(90 citation statements)

References 70 publications

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“…Detector hit maps (DHMs, cumulative hit positions of ions on the detector) of alloys with low levels of solutes show a pattern that is characteristic of the crystallography and specic orientation of the APT sample [20]. Figure 2a illustrates such a map for the alloy Al0.33Si0.29Mg measured at 20 K, with a pulse fraction of 20% and a detection rate of 1%.…”

Section: Resultsmentioning

confidence: 99%

Atom Probe Tomography Investigations of Modified Early Stage Clustering in Si-Containing Aluminum Alloys

et al. 2015

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In this paper atom probe tomography is used to explore early stage clustering in aluminum alloys. Two novel concepts for a modication of clustering are discussed. Control of early stage clustering is welcome from an application point of view since clustering deteriorates strength evolution during the industrial heat treatment of the important class of AlMgSi precipitation-hardenable alloys. Nanoscale early stage clusters are very dicult to observe and atom probe tomography is the best technique to visualize and chemically measure Si or Mg-containing clusters in aluminum alloys. Restrictions remain in achieving the ultimate quantication of such small solute aggregates by atom probe tomography, such as detection eciency, local magnication eects, surface migration of solute atoms, and unresolved issues with the reconstruction procedure. Here we investigate one of these restricting eects, namely the migration of solute atoms during atom probe tomography measurements. In particular Si is found to be preferentially localized or absent at certain crystallographic poles in aluminum, which derogates the experimental results gained from atom probe tomography studies of clustering in Si-containing aluminum alloys. This artifact is investigated for dierent specimen temperatures, detection rates and pulse fractions during atom probe tomography measurements. Optimal strategies to analyze small-scale solute clusters in Si-containing aluminum alloys are presented.

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Section: Resultsmentioning

confidence: 99%

Atom Probe Tomography Investigations of Modified Early Stage Clustering in Si-Containing Aluminum Alloys

et al. 2015

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“…Surface migration is possible to occur for interstitial and substitutional elements. [114] A prominent example in Al alloys is Si, which is known to migrate to the (111)-pole. [115] The migration of solutes during the experiment results in false reconstructed location, and thus errors introduced in elemental distributions.…”

Section: Functionalitymentioning

confidence: 99%

Clustering in Age‐Hardenable Aluminum Alloys

et al. 2018

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This review gives an overview of the effects of clusters in various aluminum alloys. Characterization methods are discussed in general and results for the important AlMgSi alloys are presented in detail. Indirect characterization methods, such as hardness, tensile testing, electrical resistivity, differential scanning calorimetry, and positron annihilation spectroscopy are discussed, as well as atom probe tomography for the direct measurement of clusters. A particular focus is set on atom probe tomography, where possible artifacts influencing the cluster measurements as well as different cluster finding methods are summed up. A comprehensive summary of investigated alloys and cluster algorithm parameters is given. Moreover, the findings in AlMgSi alloys regarding clusters and changes upon different heat treatments are discussed, starting from early to the latest works. Drawn conclusions are discussed and compared to give a r esum e.

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“…Small carbides are more affected by included matrix in the surface voxels. Furthermore, carbon atoms might not be detected due to surface migration, 29) and the measured carbon concentration might be too low due to detector pile-up. 23) Figure 4 shows that the stable carbides of 34Cr4 steel at the industrial tempering temperature are cementite and M 7 C 3 .…”

Section: Characterization Of the Alloy Carbides 321 Thermocalc Studymentioning

confidence: 99%

A Comparison between Ultra-high-strength and Conventional High-strength Fastener Steels: Mechanical Properties at Elevated Temperature and Microstructural Mechanisms

et al. 2016

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A comparison is made between the mechanical properties of the ultra-high-strength steel KNDS4 of fastener grade 14.9 and of conventional, high-strength steels 34Cr4 of fastener grade 12.9 and 33B2 of grade 10.9. The results show that the ratio of the yield strength at elevated temperatures to the yield strength at room temperature is higher for the ultra-high-strength steel than for both conventional highstrength steels, especially at 500°C. Moreover, the results show a trend in which the nano-indentation creep rate is lower as the strength of the steels is higher. The improved mechanical properties of the KNDS4 steel compared to the conventional high-strength steels are related to the smaller size of the alloy carbides in the KNDS4 steel. Furthermore, the effect of an alternative (industrial) heat-treatment on the evolution of the microstructure and hardness of the KNDS4 steel was investigated. Changing the industrial heat treatment can increase the hardness of KNDS4 by about 8%, since more alloy carbides can nucleate and grow. However, the standard industrial heat treatment results in a refinement of the martensite microstructure (grain size), which might be more beneficial for the toughness of the steel. Independent of the heat treatment, the mechanical performance of KNDS4 fasteners at elevated temperature and the low nano-indentation creep rates are two strong indicators that fasteners made from KNDS4 steel might be used at higher service temperatures than traditional high strength fasteners.

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Impact of directional walk on atom probe microanalysis

Cited by 140 publications

References 70 publications

Atom Probe Tomography Investigations of Modified Early Stage Clustering in Si-Containing Aluminum Alloys

Atom Probe Tomography Investigations of Modified Early Stage Clustering in Si-Containing Aluminum Alloys

Clustering in Age‐Hardenable Aluminum Alloys

A Comparison between Ultra-high-strength and Conventional High-strength Fastener Steels: Mechanical Properties at Elevated Temperature and Microstructural Mechanisms

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