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Almirall N, Wells PB, Ke H, Edmondson P, Morgan D, Yamamoto T, Odette GR. On the Elevated Temperature Thermal Stability of Nanoscale Mn-Ni-Si Precipitates Formed at Lower Temperature in Highly Irradiated Reactor Pressure Vessel Steels. Sci Rep 2019; 9:9587. [PMID: 31270423 PMCID: PMC6610118 DOI: 10.1038/s41598-019-45944-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 06/19/2019] [Indexed: 11/17/2022] Open
Abstract
Atom probe tomography (APT) and scanning transmission electron microscopy (STEM) techniques were used to probe the long-time thermal stability of nm-scale Mn-Ni-Si precipitates (MNSPs) formed in intermediate and high Ni reactor pressure vessel steels under high fluence neutron irradiation at ≈320 °C. Post irradiation annealing (PIA) at 425 °C for up to 57 weeks was used to determine if the MNSPs are: (a) non-equilibrium solute clusters formed and sustained by radiation induced segregation (RIS); or, (b) equilibrium G or Γ2 phases, that precipitate at accelerated rates due to radiation enhanced diffusion (RED). Note the latter is consistent with both thermodynamic models and x-ray diffraction (XRD) measurements. Both the experimental and an independently calibrated cluster dynamics (CD) model results show that the stability of the MNSPs is very sensitive to the alloy Ni and, to a lesser extent, Mn content. Thus, a small fraction of the largest MNSPs in the high Ni steel persist, and begin to coarsen at long times. These results suggest that the MNSPs remain a stable phase, even at 105 °C higher than they formed at, thus are most certainly equilibrium phases at much lower service relevant temperatures of ≈290 °C.
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Affiliation(s)
- N Almirall
- Materials Department, University of California, Santa Barbara, CA, 93106, USA
| | - P B Wells
- Materials Department, University of California, Santa Barbara, CA, 93106, USA.,Intel Corporation, Hillsboro, OR, 97124, USA
| | - H Ke
- Department of Materials Science and Engineering Department, University of Wisconsin, Madison, WI, 53706, USA.,Materials Science and Engineering Department, Ohio State University, Columbus, OH, 43210, USA
| | - P Edmondson
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - D Morgan
- Department of Materials Science and Engineering Department, University of Wisconsin, Madison, WI, 53706, USA
| | - T Yamamoto
- Materials Department, University of California, Santa Barbara, CA, 93106, USA
| | - G R Odette
- Materials Department, University of California, Santa Barbara, CA, 93106, USA.
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2
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Goto S, Hashimoto N. Effect of heat load on microstructural development in an irradiated low alloy steel. NUCLEAR MATERIALS AND ENERGY 2018. [DOI: 10.1016/j.nme.2018.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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3
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Martin TL, London AJ, Jenkins B, Hopkin SE, Douglas JO, Styman PD, Bagot PAJ, Moody MP. Comparing the Consistency of Atom Probe Tomography Measurements of Small-Scale Segregation and Clustering Between the LEAP 3000 and LEAP 5000 Instruments. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2017; 23:227-237. [PMID: 28441978 DOI: 10.1017/s1431927617000356] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The local electrode atom probe (LEAP) has become the primary instrument used for atom probe tomography measurements. Recent advances in detector and laser design, together with updated hit detection algorithms, have been incorporated into the latest LEAP 5000 instrument, but the implications of these changes on measurements, particularly the size and chemistry of small clusters and elemental segregations, have not been explored. In this study, we compare data sets from a variety of materials with small-scale chemical heterogeneity using both a LEAP 3000 instrument with 37% detector efficiency and a 532-nm green laser and a new LEAP 5000 instrument with a manufacturer estimated increase to 52% detector efficiency, and a 355-nm ultraviolet laser. In general, it was found that the number of atoms within small clusters or surface segregation increased in the LEAP 5000, as would be expected by the reported increase in detector efficiency from the LEAP 3000 architecture, but subtle differences in chemistry were observed which are attributed to changes in the way multiple hit detection is calculated using the LEAP 5000.
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Affiliation(s)
- Tomas L Martin
- 1Department of Materials,University of Oxford,Parks Road,Oxford,OX1 3PH,UK
| | - Andrew J London
- 1Department of Materials,University of Oxford,Parks Road,Oxford,OX1 3PH,UK
| | - Benjamin Jenkins
- 1Department of Materials,University of Oxford,Parks Road,Oxford,OX1 3PH,UK
| | - Sarah E Hopkin
- 1Department of Materials,University of Oxford,Parks Road,Oxford,OX1 3PH,UK
| | - James O Douglas
- 1Department of Materials,University of Oxford,Parks Road,Oxford,OX1 3PH,UK
| | - Paul D Styman
- 2National Nuclear Laboratory,Building D5,Culham Science Centre,Abingdon,Oxfordshire,OX14 3DB,UK
| | - Paul A J Bagot
- 1Department of Materials,University of Oxford,Parks Road,Oxford,OX1 3PH,UK
| | - Michael P Moody
- 1Department of Materials,University of Oxford,Parks Road,Oxford,OX1 3PH,UK
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4
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Zelenty J, Dahl A, Hyde J, Smith GDW, Moody MP. Detecting Clusters in Atom Probe Data with Gaussian Mixture Models. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2017; 23:269-278. [PMID: 28441977 DOI: 10.1017/s1431927617000320] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Accurately identifying and extracting clusters from atom probe tomography (APT) reconstructions is extremely challenging, yet critical to many applications. Currently, the most prevalent approach to detect clusters is the maximum separation method, a heuristic that relies heavily upon parameters manually chosen by the user. In this work, a new clustering algorithm, Gaussian mixture model Expectation Maximization Algorithm (GEMA), was developed. GEMA utilizes a Gaussian mixture model to probabilistically distinguish clusters from random fluctuations in the matrix. This machine learning approach maximizes the data likelihood via expectation maximization: given atomic positions, the algorithm learns the position, size, and width of each cluster. A key advantage of GEMA is that atoms are probabilistically assigned to clusters, thus reflecting scientifically meaningful uncertainty regarding atoms located near precipitate/matrix interfaces. GEMA outperforms the maximum separation method in cluster detection accuracy when applied to several realistically simulated data sets. Lastly, GEMA was successfully applied to real APT data.
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Affiliation(s)
| | - Andrew Dahl
- 2Department of Statistics,University of Oxford,Oxford OX1 3LB,UK
| | - Jonathan Hyde
- 3National Nuclear Laboratory,Culham Science Centre,Abingdon OX14 3DB,UK
| | | | - Michael P Moody
- 1Department of Materials,University of Oxford,Oxford OX1 3PH,UK
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5
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Liu L, Nishida K, Dohi K, Nomoto A, Soneda N, Murakami K, Li Z, Chen D, Sekimura N. Effects of solute elements on hardening and microstructural evolution in neutron-irradiated and thermally-aged reactor pressure vessel model alloys. J NUCL SCI TECHNOL 2016. [DOI: 10.1080/00223131.2015.1136902] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Li Liu
- Department of Nuclear Engineering and Management, The University of Tokyo, Tokyo, Japan
| | - Kenji Nishida
- Central Research Institute of Electric Power Industry, Tokyo, Japan
| | - Kenji Dohi
- Central Research Institute of Electric Power Industry, Tokyo, Japan
| | - Akiyoshi Nomoto
- Central Research Institute of Electric Power Industry, Tokyo, Japan
| | - Naoki Soneda
- Central Research Institute of Electric Power Industry, Tokyo, Japan
| | - Kenta Murakami
- Nuclear Professional School, The University of Tokyo, Ibaraki, Japan
| | - Zhengcao Li
- Advanced Materials Laboratory (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, China
| | - Dongyue Chen
- Department of Nuclear Engineering and Management, The University of Tokyo, Tokyo, Japan
| | - Naoto Sekimura
- Department of Nuclear Engineering and Management, The University of Tokyo, Tokyo, Japan
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Chen BL, Wang W, Xie H, Ge RR, Zhang ZY, Li ZW, Zhou XY, Zhou BX. Phase transformation of Cu-rich precipitates from 9R to 3R variant via ledges mechanism in ferritic steel containing copper. J Microsc 2015; 262:123-7. [PMID: 26599818 DOI: 10.1111/jmi.12352] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 10/28/2015] [Indexed: 11/29/2022]
Abstract
Precipitates and solute enrich in aged ferritic steel containing copper were examined using high-resolution electron microscopy, high-angle annular dark-field scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy. Two ledges with one-atom and two-atom layers height in the 9R/3R interface were observed. The enrichment of copper into two successive closed-packed planes with an interval of Fe-rich close-packed plane was detected. The passage of the Shockley partial, or the shearing, changes the stacking sequence of closed-packed planes. Finally, 9R Cu variant transformed into 3R Cu variant.
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Affiliation(s)
- B L Chen
- School of Materials Engineering, Shanghai University of Engineering Science, Shanghai, People's Republic of China
| | - W Wang
- School of Materials Engineering, Shanghai University of Engineering Science, Shanghai, People's Republic of China
| | - H Xie
- School of Materials Engineering, Shanghai University of Engineering Science, Shanghai, People's Republic of China
| | - R R Ge
- School of Materials Engineering, Shanghai University of Engineering Science, Shanghai, People's Republic of China
| | - Z Y Zhang
- School of Materials Engineering, Shanghai University of Engineering Science, Shanghai, People's Republic of China
| | - Z W Li
- School of Materials Engineering, Shanghai University of Engineering Science, Shanghai, People's Republic of China
| | - X Y Zhou
- School of Materials Engineering, Shanghai University of Engineering Science, Shanghai, People's Republic of China
| | - B X Zhou
- Institute of Materials, Shanghai University, Shanghai, People's Republic of China
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Cairney JM, Rajan K, Haley D, Gault B, Bagot PAJ, Choi PP, Felfer PJ, Ringer SP, Marceau RKW, Moody MP. Mining information from atom probe data. Ultramicroscopy 2015; 159 Pt 2:324-37. [PMID: 26095825 DOI: 10.1016/j.ultramic.2015.05.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 05/03/2015] [Accepted: 05/12/2015] [Indexed: 10/23/2022]
Abstract
Whilst atom probe tomography (APT) is a powerful technique with the capacity to gather information containing hundreds of millions of atoms from a single specimen, the ability to effectively use this information creates significant challenges. The main technological bottleneck lies in handling the extremely large amounts of data on spatial-chemical correlations, as well as developing new quantitative computational foundations for image reconstruction that target critical and transformative problems in materials science. The power to explore materials at the atomic scale with the extraordinary level of sensitivity of detection offered by atom probe tomography has not been not fully harnessed due to the challenges of dealing with missing, sparse and often noisy data. Hence there is a profound need to couple the analytical tools to deal with the data challenges with the experimental issues associated with this instrument. In this paper we provide a summary of some key issues associated with the challenges, and solutions to extract or "mine" fundamental materials science information from that data.
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Affiliation(s)
- Julie M Cairney
- School of Aerospace, Mechanical, Mechatronic Engineering, The University of Sydney, NSW 2006, Australia; Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006, Australia.
| | - Krishna Rajan
- Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011, USA
| | - Daniel Haley
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK; Max Planck Institut für Eisenforschung GmbH, Max-Planck Straße 1, 40237 Düsseldorf, Germany
| | - Baptiste Gault
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
| | - Paul A J Bagot
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
| | - Pyuck-Pa Choi
- Max Planck Institut für Eisenforschung GmbH, Max-Planck Straße 1, 40237 Düsseldorf, Germany
| | - Peter J Felfer
- School of Aerospace, Mechanical, Mechatronic Engineering, The University of Sydney, NSW 2006, Australia; Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006, Australia
| | - Simon P Ringer
- School of Aerospace, Mechanical, Mechatronic Engineering, The University of Sydney, NSW 2006, Australia; Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006, Australia
| | - Ross K W Marceau
- Institute for Frontier Materials, Deakin University, Geelong Technology Precinct, 75 Pigdons Road, Waurn Ponds, Victoria 3216, Australia
| | - Michael P Moody
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
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