42 research outputs found
New Equipment for Correlative FIB/TEM/Atom Probe and Site-Specific Preparation Using STEM Live Imaging
No full textExtended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.</jats:p
Data for: Advanced concentration analysis of atom probe tomography data: Local proximity histograms and Pseudo-2D concentration maps.
No full textSoftware programs to load/save atom probe data into Matlab and calculate local proxigrams and concentration maps
Shaping the lens of the atom probe: Fabrication of site specific, oriented specimens and application to grain boundary analysis
No full textAtom Probe Tomography of Interfaces at the Near-Lattice Level
No full textExtended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.</jats:p
Atom probe tomography data collection from DIN 1.4970 (15-15Ti) austenitic stainless steel irradiated with Fe ions
No full textThis dataset comprises a large collection of atom probe tomography datasets collected from DIN 1.4970 alloy that was irradiated with Fe ions at different conditions. The DIN 1.4970 alloy is an austenitic stainless steel with 15 wt% Cr, 15 wt% Ni, a small addition of Ti. The full composition and characterization of our material can be found published elsewhere [1,2].
Some of our material was subjected to ageing heat treatments at different temperatures for different times. Small samples of our original material and aged material was irradiated at the Michigan Ion Beam Laboratory in 2017 with 4.5 MeV Fe ions up to 40 dpa at an average dose rate of dpa/s. This was done at three different temperatures: 300, 450, and 600 ºC. Atom probe samples were made of the irradiated layers (approximately 1.5 micron deep) with focused ion beam and mounted on Microtip coupons. APT measurements took place on three CAMECA LEAP-HR systems located at CAES in Idaho Falls, USA (files beginning with R33), at Montanuniversität Leoben in Leoben, Austria (R21) and at Friedrich–Alexander University in Erlangen, Germany (R56).
The contents of this archive are:
A folder containing the raw RHIT files
A folder containing all the reconstructions and miscelaneous analysis files made by the author
An excel file which indicates which measurement number stands for what material
A suggested range file
The RHIT files can only be used if one has access to the full IVAS 3.x version in order to make new reconstructions.
The reconstructions and analysis folder can be useful to anyone. The folder buildup structure is similar to a project folder created by IVAS and should be directly importable into IVAS. Most folders are simply named after the RHIT file they were constructed from, though some have slightly modified names to include date of creation, extra information,... Inside all these folders you will find the recons folder and inside multiple reconstructions. At the deepest level you will find .pos files which can be read into free software such as python or 3depict. The range file that will give decent results on all these measurements is given at the top level; slight modifications may need to be applied for each measurement. Inside all folders you will also find numerous files (csv, png, jpg, ...) that were created by analyzing the data in IVAS. Sometimes the file names are very descriptive, sometimes less so. Sometimes these files were not saved to the default analysis folder but elsewhere on my drive. To be complete, I have moved all of these files into the top level folder. Therefore, besides the imagoAnalysis and recons folders, you will sometimes find additional folders and files in the folder. By different merging procedures, there may be multiple copies of the same files present as well. Unfortunately, the reconstructions and analysis folder is rather chaotic, as is the nature of file creation by IVAS.
It is most instructive to start with the excel file at the top level of the archive. The first sheet contains some information, mostly the same as mentioned here. The second sheet pertains to the ion irradiations that were performed. The table colunms are self explanatory. Each irradiated sample was given a particular alias (first column), which relates it to the slot in the storage box in which it is stored. 5 different materials appear in the irradiations:
T24 = tube, 24% cold worked. This represents the material as it was received from the manufacturer.
T24-800C2h = the as-received material with an ageing heat treatment of 2 hours for 800 ºC applied.
T24-600C4h = the as-received material with an ageing heat treatment of 4 hours for 600 ºC applied.
T24-600C2868h = the as-received material with an ageing heat treatment of 2868 hours for 600 ºC applied.
T46 = tube 46% cold worked. This represents another material received from the manufacturer
AIM1 = another related material with a higher P and Si content obtained from another research institute
All these materials were irradiated under different conditions as given in the subsequent columns. The irradiation parameters were drawn directly from reports produced by the lab, but we suspect some typos slipped into the reports. We do know for certain that the samples were irradiated up to a surface dose of 40 dpa, at least according to a SRIM calculation with the K-P model. Atom probe results only pertain to T24 and T24-800C2h. A few measurements were conducted on T24-600C4h material but this material was not irradiated.
The last sheet gives an overview of all the APT measurements included in this archive. The first column pertains to the sample alias in sheet 2: the irradiated disc from which the samples were made. The sample detail column details the history of the sample for convenience: T24 - - . When in doubt, one can look up the sample alias in sheet 2. The filename pertains to the APT measurement RHIT file. For the 3 measurements performed in Leoben, RHIT files are not included in this archive. Finally a few details such as approximate ion count and some comments are included for some measurements.
Funding: This work was supported by ENGIE [contract number 2015-AC-007 e BSUEZ6900]; the U.S. Department of Energy, Office of Nuclear Energy under DOE Idaho Operations Office Contract DE-AC07- 051D14517 as part of a Nuclear Science User Facilities experiment; and by the MYRRHA program in development at SCK-CEN, Belgium. Funding of the Austrian BMVIT (846933) in the framework of the program "Production of the future" and the "BMVIT Professorship for Industry" is gratefully acknowledged.
[1] N. Cautaerts, R. Delville, E. Stergar, D. Schryvers, M. Verwerft, Tailoring the Ti-C Nanoprecipitate Population and Microstructure of Titanium Stabilized Austenitic Steels, J. Nucl. Mater. 507 (2018) 177–187. doi:10.1016/j.jnucmat.2018.04.041.
[2] N. Cautaerts, R. Delville, E. Stergar, D. Schryvers, M. Verwerft, Characterization of (Ti,Mo,Cr)C Nanoprecipitates in an Austenitic Stainless Steel on the Atomic Scale, Acta Mater. 164 (2018) 90–98. doi:10.1016/J.ACTAMAT.2018.10.018
Atom probe microscopy characterization of as quenched Zr-0.8 wt% Fe and Zr-0.15 wt% Cr binary alloys
No full textTwo binary Zr-alloys with a β-quenched structure were analysed by atom probe tomography to provide a better understanding of how Fe and Cr perform in industrial Zr alloys. In a Zr-0.8 Fe (wt%) alloy, we observed a dispersion of precipitates with a composition close to Zr3Fe, and Fe segregated to a grain boundary. In a Zr-0.15 Cr (wt%) alloy, Cr was observed in solid solution in the Zr-matrix and segregated to grain boundary where it formed small spherical particles or elongated atmospheres.</p
Oxide scale microstructure and failure mechanism of alloy 601 under varying metal dusting conditions
No full textChemical plants which process highly carbonaceous gases at elevated temperatures are prone to catastrophic corrosion by metal dusting. Typically, commercial alloys with high amounts of protective oxide scale formers (Cr, Al, and Si) are used in these environments. However, scale failure is still frequently observed after an incubation time initiating pits. In this study, the microstructure and subsequent metal dusting-induced failure of the oxide scale on the commercial Ni-based alloy 601 was analyzed. Samples were exposed in different aggressive metal dusting gases and characterized using metallographic cross sections, electron beam microanalysis (EPMA), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and transmission electron microscopy (TEM). A thin and protective chromia scale formed in some regions with a continuous silica layer below. Across most of the alloy 601 surfaces, internal oxidation of Al could be linked to metallic particles in the outer scale. Additionally, MnCr2O4 was observed in the outer scale. Together with pores in the chromia, the spinel and metallic particles in the outer scale combined to provide pathways for carbon ingress. After exposure in a gas with a higher driving force for carbon deposition, a higher amount of carbon was incorporated in the growing oxide scale, resulting in earlier scale failure and metal dusting pit initiation.Graphical AbstractOpen Access funding enabled and organized by Projekt DEAL.H2020 Leadership in Enabling and Industrial Technologieshttp://dx.doi.org/10.13039/100010668H2020 European Research Councilhttp://dx.doi.org/10.13039/100010663Bundesministerium für Wirtschaft und Klimaschutzhttp://dx.doi.org/10.13039/100021130DECHEMA-Forschungsinstitut (4351
Nanostructuring of Nb-Si-Cr Alloys by Electron Beam Melting to Improve the Mechanical Properties and the Oxidation Behavior
No full textMaterials processed by additive manufacturing often exhibit a very fine-scaled microstructures due to high cooling rates in the process. In this study, single-layer surface electron beam melting is used to create very high cooling rates similar to additive manufacturing processes to investigate the resulting microstructure. In the case of Nb-Si-Cr in-situ composites, a nano-scaled eutectic microstructure is beneficial for improving the mechanical and oxidational properties. Fast solidification results in the formation of supersaturated phases of Nbss and Cr2Nb with phase diameters down to 10 nm as well as in the stabilization of the metastable Nb9(Cr,Si)5 phase at room temperature. After processing with different solidification rates, the decomposition of the Nb9(Cr,Si)5 phase has been studied in detail with atom probe microscopy. The stabilization of mixed silicide phases by electron beam melting shows a new pathway for improving hardness and enhancing oxidation resistance of nanostructured eutectic in-situ composites, by which the inherent weaknesses of Nb-Si-Cr can be overcome without further alloying elements
Analysing the pore formation in ternary and quaternary diborides during high-temperature oxidation
No full textTo improve the high-temperature (T > 1000 °C) oxidation resistance of transition metal diborides TMB2, alloying approaches with Si, as a strong oxide-forming element, have proven to be successful [1-3]. Both ternary (TM-Si-B) and quaternary (e.g., TM-Mo-Si-B by alloying TMB₂ with MoSi₂) systems have shown pore formation due to phase changes and diffusion processes during annealing above 1100 °C. Regarding long-term (t > 1000 h) applications, pores significantly weaken the protective function of the coatings and pose a problem. This study investigates PVD-synthesized ternary and quaternary TM diborides regarding the effect of different TM/B stoichiometries as well as alloying elements influencing pore formation. Phase transformations, as well as diffusion processes and the pore formation itself, were examined in detail using high-resolution techniques such as transmission electron microscopy (TEM), elastic recoil detection analysis (ERDA), atom probe tomography (APT), and Rutherford backscattering spectrometry (RBS).
References
[1] T. Glechner, H.G. Oemer, T. Wojcik, M. Weiss, A. Limbeck, J. Ramm, P. Polcik, H. Riedl, Influence of Si on the oxidation behavior of TM-Si-B2±z coatings (TM = Ti, Cr, Hf, Ta, W), Surf. Coat. Technol. 434 (2022) 128178.
[2] L. Zauner, A. Steiner, T. Glechner, A. Bahr, B. Ott, R. Hahn, T. Wojcik, O. Hunold, J. Ramm, S. Kolozsvári, P. Polcik, P. Felfer, and H. Riedl, Role of Si segregation in the structural, mechanical, and compositional evolution of high-temperature oxidation resistant Cr-Si-B2±z thin films, 10.2139/ssrn.4251252.
[3] A. Bahr, S. Richter, R. Hahn, T. Wojcik, M. Podsednik, A. Limbeck, J. Ramm, O. Hunold, S. Kolozsvári, H. Riedl, Oxidation behaviour and mechanical properties of sputter-deposited TMSi2 coatings (TM = Mo, Ta, Nb), Journal of Alloys and Compounds 931 (2023) 167532
