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The Role of Oxides in Nanostructured Ferritic Alloys and Bilayers : = Interfaces, Helium Partitioning and Bubble Formation.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	The Role of Oxides in Nanostructured Ferritic Alloys and Bilayers :/
Reminder of title:	Interfaces, Helium Partitioning and Bubble Formation.
Author:	Stan, Tiberiu.
Description:	1 online resource (212 pages)
Notes:	Source: Dissertation Abstracts International, Volume: 78-12(E), Section: B.
Subject:	Materials science. -
Online resource:	click for full text (PQDT)
ISBN:	9780355270648

The Role of Oxides in Nanostructured Ferritic Alloys and Bilayers : = Interfaces, Helium Partitioning and Bubble Formation.
Stan, Tiberiu.

The Role of Oxides in Nanostructured Ferritic Alloys and Bilayers :Interfaces, Helium Partitioning and Bubble Formation. - 1 online resource (212 pages)

Source: Dissertation Abstracts International, Volume: 78-12(E), Section: B.

Thesis (Ph.D.)--University of California, Santa Barbara, 2017.

Includes bibliographical references

Despite the successful development of Tokamak nuclear fusion plasma physics devices, commercial power production remains elusive partly due to the severe environments produced during the deuterium-tritium fusion reaction. Nanostructured Ferritic Alloys (NFAs) are candidate structural materials for first-wall/blanket applications. The stainless steels are thermally stable up to 900 °C and remarkably irradiation tolerant. NFAs typically contain a high number density (5x1023/m2) of Y-Ti-O nano-oxides (NOs) with average diameters ≈ 2.5 nm. Most of the smallest NOs are Y 2Ti2O7 (YTO) fcc pyrochlore. The NOs impede dislocation climb and glide, stabilize dislocation and grain structures, and trap He in fine-scale bubbles at matrix-NO interfaces. Detailed characterization and analysis of the NO-matrix interfaces is needed to develop first principles and atomic-scale models that are part of multi-scale efforts to predict the behavior of NFAs during processing and in irradiation service environments. YTO-matrix orientation relationships (ORs) are of particular interest because they impact selection of compositions and processing paths, service stability, mechanical properties and irradiation tolerance of NFAs.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9780355270648Subjects--Topical Terms:

557839
Materials science.
Index Terms--Genre/Form:

554714
Electronic books.

The Role of Oxides in Nanostructured Ferritic Alloys and Bilayers : = Interfaces, Helium Partitioning and Bubble Formation.
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245 1 4 $a The Role of Oxides in Nanostructured Ferritic Alloys and Bilayers : $b Interfaces, Helium Partitioning and Bubble Formation.
264 0 $c 2017
300 $a 1 online resource (212 pages)
336 $a text $b txt $2 rdacontent
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500 $a Source: Dissertation Abstracts International, Volume: 78-12(E), Section: B.
500 $a Adviser: George R. Odette.
502 $a Thesis (Ph.D.)--University of California, Santa Barbara, 2017.
504 $a Includes bibliographical references
520 $a Despite the successful development of Tokamak nuclear fusion plasma physics devices, commercial power production remains elusive partly due to the severe environments produced during the deuterium-tritium fusion reaction. Nanostructured Ferritic Alloys (NFAs) are candidate structural materials for first-wall/blanket applications. The stainless steels are thermally stable up to 900 °C and remarkably irradiation tolerant. NFAs typically contain a high number density (5x1023/m2) of Y-Ti-O nano-oxides (NOs) with average diameters ≈ 2.5 nm. Most of the smallest NOs are Y 2Ti2O7 (YTO) fcc pyrochlore. The NOs impede dislocation climb and glide, stabilize dislocation and grain structures, and trap He in fine-scale bubbles at matrix-NO interfaces. Detailed characterization and analysis of the NO-matrix interfaces is needed to develop first principles and atomic-scale models that are part of multi-scale efforts to predict the behavior of NFAs during processing and in irradiation service environments. YTO-matrix orientation relationships (ORs) are of particular interest because they impact selection of compositions and processing paths, service stability, mechanical properties and irradiation tolerance of NFAs.
520 $a X-ray absorption spectroscopy (XAS) measurements on embedded NOs are most consistent with Y2Ti2O7, while the slightly larger extracted oxides are primarily consistent with Y2TiO 5. A bulk extraction and selective filtration technique was developed to dissolve the ferritic matrix, trap the larger Y2TiO5 oxides, and yield samples well suited for XAS measurements. Further, a 14YWT alloy was annealed to coarsen the NOs, and He implanted to produce bubbles. High resolution transmission electron microscopy shows two dominant ORs (cube-on-edge and cube-on-cube). The smaller NOs are associated with smaller bubbles, while some of the largest NOs (>6 nm) often have two bubbles. Most bubbles nucleate near dislocation cores at {111} NO facets.
520 $a The second research approach is to study a model bilayer system. For the first time, the dominant deposited Fe-YTO interface ORs are reported. Most Fe grains deposited on {111}YTO have the Nishiyama-Wasserman OR: {110}Fe//{111}YTO and Fe//YTO. The dominant OR for depositions on {100}YTO is: {110}Fe\\{100}YTO and Fe\\YTO. Finally, most Fe grains deposited on {110}YTO show axiotaxial texturing with off-normal {110}Fe planes parallel to off-normal {100}YTO planes. Room temperature He implantation of a Fe-{110}YTO bilayer shows a range of bubble sizes in the Fe film, and larger &sim;2 nm bubbles at the Fe-YTO interface. In this experiment, He did not diffuse into the YTO. In a second, high temperature implantation, 99.3% of the He remained in the Fe film and interfacial pores, but 0.7% was found in the YTO substrate. The studies performed in this dissertation provide crucial experimental inputs for the development of computational models that accurately predict NFA in-service behavior. The results provide an important step into turning the promise of fusion energy into a reality.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Materials science. $3 557839
655 7 $a Electronic books. $2 local $3 554714
690 $a 0794
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a University of California, Santa Barbara. $b Materials. $3 1187227
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10264441 $z click for full text (PQDT)