Microstructural characterization of accident tolerant fuel cladding with Cr–Al alloy coating layer after oxidation at 1200 °C in a steam environment

Small and medium reactors using lead alloys as coolants are one of the promising reactor concepts with improved safety because of their thermal-physical and chemical properties. This paper focuses on the development of Al-alloy coating for nuclear systems using liquid lead-bismuth eutectic (LBE). Since corrosion attack becomes severe against structural steels at high temperatures in liquid LBE, it is necessary to improve the corrosion resistance of steels. An Al-alloy coating method using Al, Ti, and Fe powders, and laser beam heating has been developed. The main defects formed in the Al-powder-alloy coating process are surface defects and cracks. The conditions required to avoid these defects are the employment of the laser beam scanning rate of 20 mm/min and the adjustment of the Al concentration in the coating layer. According to the results of the corrosion tests at 550ÃÂ °C in liquid LBE, the Al-alloy coating layers on 316SS prevent severe corrosion attack such as grain boundary corrosion and LBE penetration observed in the 316SS without coating. The good corrosion resistance of the Al-alloy coating is based on the thin Al-oxide film, which can be regenerated in liquid LBE. From the viewpoint of the soundness of the produced Al-powder-alloy coating layers and the preservation of their corrosion resistance, it is estimated that the range of adequate Al concentration in the coating layer is from 4 to 12 wt. %.

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Coextrusion and Mechanical Characterization of Aluminum Coated Mg-Profiles

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.554-557.767 ◽

2013 ◽

Vol 554-557 ◽

pp. 767-775 ◽

Cited By ~ 3

Author(s):

Maik Negendank ◽

Constanze Weber ◽

Soeren Mueller ◽

Walter Reimers

Keyword(s):

Material Flow ◽

Noble Metals ◽

Alloy Coating ◽

Equilibrium Potential ◽

Al Alloy ◽

Forming Process ◽

Diffusion Layers ◽

Single Production ◽

Push Out

Due to their low density and high specific strengths Mg-alloys provide an excellent potential to be used for light weight constructions. However, their equilibrium potential is very low resulting in relatively low corrosion resistance, especially in contact with other, more noble metals. In order to separate Mg from a corrosive environment hybrid billets with Al-alloy coating and AZ31-core were coextruded. Thus, the extrusion and coating of Mg-profiles can be done in a single production step, resulting in aluminum coated Mg-profiles. The influence of the extrusion ratio as well as of different die angles on the formation of diffusion layers at the interface was investigated. Furthermore the phases formed in the diffusion zones were analyzed using EDS and synchrotron XRD. Additionally, FEM-simulations were conducted in order to reveal the material flow of core and shell material during the forming process and to identify differences in using different die angles. The FEM-results were verified by comparison with the real extrusion experiments. Finally, the shear strengths of the produced compounds were evaluated in push-out tests.

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Development of Aluminum Alloy Coating for Advanced Nuclear Systems Using Lead Alloys

ASME 2011 Small Modular Reactors Symposium ◽

10.1115/smr2011-6545 ◽

2011 ◽

Cited By ~ 1

Author(s):

Yuji Kurata ◽

Hitoshi Yokota ◽

Tetsuya Suzuki

Keyword(s):

Corrosion Resistance ◽

Laser Beam ◽

Coating Layer ◽

Alloy Coating ◽

Al Alloy ◽

Corrosion Attack ◽

Lead Alloys ◽

Nuclear Systems ◽

Coating Layers ◽

Al Powder

Small and medium reactors using lead alloys as coolant are one of the promising reactor concepts with improved safety because of their thermal-physical and chemical properties. This paper focuses on development of Al-alloy coating for nuclear systems using liquid lead-bismuth eutectic (LBE). Since corrosion attack becomes severe against structural steels at high temperatures in liquid LBE, it is necessary to improve corrosion resistance of steels. An Al-alloy coating method using Al, Ti and Fe powders, and laser beam heating has been developed. Main defects formed in an Al-powder-alloy coating process are surface defects and cracks. Conditions required to avoid these defects are employment of the laser beam scanning rate of 20 mm/min and adjustment of the Al concentration in the coating layer. According to results of the corrosion tests at 550°C in liquid LBE, the Al-alloy coating layers on 316SS protect severe corrosion attack such as grain boundary corrosion and LBE penetration observed in 316SS without coating. The good corrosion resistance of the Al-alloy coating is based on the thin Al-oxide film which can be regenerated in liquid LBE. From the viewpoints of the soundness of produced Al-powder-alloy coating layers and preservation of their corrosion resistance, it is estimated that the range of the adequate Al concentration in the coating layer is from 4 to 12 wt%.

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Microstructural Characterization of 5083 Al Alloy Joints Friction Stir Welded

Materials Science Forum ◽

10.4028/www.scientific.net/msf.514-516.510 ◽

2006 ◽

Vol 514-516 ◽

pp. 510-515

Author(s):

Mónica Reis ◽

Rui Louro ◽

Paulo J. Morais ◽

Leonel Santos ◽

Helena Gouveia

Keyword(s):

Microstructural Characterization ◽

Auger Spectroscopy ◽

Al Alloy ◽

Second Phase ◽

Friction Stir ◽

Second Phase Particles ◽

Joint Properties ◽

Structural Applications ◽

Onion Ring

The Friction Stir Welding (FSW) process is a quite recent joining method whose particular characteristics yield to materials modifications not yet fully understood. This paper aims to present the research results of a study focused on the modifications induced in an aluminium alloy AA5083 – H111, when processed by FSW to build components for structural applications. The welded samples were firstly analysed by optical microscopy in order to define the different joined zones and to identify defects. Further tests included the measurement of the Vickers microhardness, grain and particle distribution and chemical analysis of the constituents, particularly of the intermetallic second phase particles, by Auger spectroscopy. Special attention has been given to the characterisation of several microstructural “non-homogeneities” like a laminated structure called onion ring and an identified anomaly (in the form of a line), whose presence was evaluated in order to determine its effects on the final joint properties. The results have shown important new details about the relationship between the microstructure and the final joint structural properties, contributing to improve the knowledge about the materials behaviour increasing the potential of utilization of the FSW process.

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Microstructural characterization of an ultra-precision-machined surface of a Zn–Al alloy

Journal of Micromechanics and Microengineering ◽

10.1088/0960-1317/19/5/054005 ◽

2009 ◽

Vol 19 (5) ◽

pp. 054005 ◽

Cited By ~ 5

Author(s):

S To ◽

C Y Chan ◽

S J Zhang ◽

C F Cheung ◽

Y H Zhu ◽

...

Keyword(s):

Microstructural Characterization ◽

Al Alloy ◽

Machined Surface ◽

Ultra Precision

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Microstructural characterization of CoPtCr/Cr thin film disks by cross-section TEM and elongated probe micro-diffraction

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100088129 ◽

1991 ◽

Vol 49 ◽

pp. 762-763

Author(s):

M.A. Parker ◽

K.E. Johnson ◽

C. Hwang ◽

A. Bermea

Keyword(s):

Magnetic Recording ◽

Electron Probe ◽

Microstructural Characterization ◽

Crystallographic Structure ◽

Recording Media ◽

Layer By Layer ◽

Cross Sectional ◽

New Techniques ◽

Polished Side

We have reported the dependence of the magnetic and recording properties of CoPtCr recording media on the thickness of the Cr underlayer. It was inferred from XRD data that grain-to-grain epitaxy of the Cr with the CoPtCr was responsible for the interaction observed between these layers. However, no cross-sectional TEM (XTEM) work was performed to confirm this inference. In this paper, we report the application of new techniques for preparing XTEM specimens from actual magnetic recording disks, and for layer-by-layer micro-diffraction with an electron probe elongated parallel to the surface of the deposited structure which elucidate the effect of the crystallographic structure of the Cr on that of the CoPtCr.XTEM specimens were prepared from magnetic recording disks by modifying a technique used to prepare semiconductor specimens. After 3mm disks were prepared per the standard XTEM procedure, these disks were then lapped using a tripod polishing device. A grid with a single 1mmx2mm hole was then glued with M-bond 610 to the polished side of the disk.

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Microstructural Characterization of Au-Ge-Ni based ohmic contacts to GaAs/AlGaAs modfet device

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126433 ◽

1987 ◽

Vol 45 ◽

pp. 326-327

Author(s):

A.K. Rai ◽

A.K. Petford-Long ◽

A. Ezis ◽

D.W. Langer

Keyword(s):

Contact Resistance ◽

Ohmic Contact ◽

Ohmic Contacts ◽

Microstructural Characterization ◽

Almost Everywhere ◽

Spacer Layer ◽

Good Contact ◽

The Relationship ◽

Lower Contact

Considerable amount of work has been done in studying the relationship between the contact resistance and the microstructure of the Au-Ge-Ni based ohmic contacts to n-GaAs. It has been found that the lower contact resistivity is due to the presence of Ge rich and Au free regions (good contact area) in contact with GaAs. Thus in order to obtain an ohmic contact with lower contact resistance one should obtain a uniformly alloyed region of good contact areas almost everywhere. This can possibly be accomplished by utilizing various alloying schemes. In this work microstructural characterization, employing TEM techniques, of the sequentially deposited Au-Ge-Ni based ohmic contact to the MODFET device is presented.The substrate used in the present work consists of 1 μm thick buffer layer of GaAs grown on a semi-insulating GaAs substrate followed by a 25 Å spacer layer of undoped AlGaAs.

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