scholarly journals Nuclear Fuels for Very High Temperature Applications

1992 ◽  
Author(s):  
L. B. Lundberg ◽  
R. R. Hobbins
Keyword(s):  
High Temperature ◽  
Nuclear Fuels ◽  
Very High ◽  
Temperature Applications

scholarly journals Development of Austenitic ODS Strengthened Alloys for Very High Temperature Applications

2015 ◽  
Author(s):  
James Stubbins ◽  
Brent Heuser ◽  
Ian Robertson ◽  
Huseyin Sehitoglu ◽  
Petros Sofronis ◽  
...  
Keyword(s):  
High Temperature ◽  
Very High ◽  
Temperature Applications

Isochronous Stress/Strain Curves: Origins, Scope and Applications

2011 ◽  
Author(s):  
Douglas L. Marriott
Keyword(s):  
High Temperature ◽  
Constant Strain Rate ◽  
Strain Curve ◽  
Creep Damage ◽  
Tensile Tests ◽  
Variable Load ◽  
Stress Strain ◽  
Structural Problems ◽  
Very High ◽  
Temperature Applications

The isochronous stress/strain curve is a long established method of representing creep data in a manner which, under certain circumstances, provides a quick and often surprisingly accurate approximate solution to time dependent structural problems. Despite criticisms of the foundations of the method, it has survived over the years because it has either been the only method feasible at the time, or it is capable of providing solutions which are often good enough for practical purposes. This paper plans to trace the evolution of structural analysis based on isochronous curves, examining its boundaries of application and the circumstances under which it might be expected to yield plausible answers. Different types of isochronous curves will be described, together with procedures for constructing them from different forms of material data such as constant strain rate tensile tests. Special attention will be given to the representation of tertiary creep in the form of isochronous curves, and how such curves might be used in carrying out simplified analyses of propagating creep damage in complex components. Recent extensions to the original methodology to include variable load and thermal histories will be examined. Possible applications in the emerging field of very high temperature applications, as are expected to be experienced in Gen IV nuclear plant in the future, will be reviewed, with special attention given to the problem of rate dependent short term properties, which looks to become a serious question in development of design allowables for very high temperature applications.

New Developments in Soluble Thermoplastic High Glass Transition Temperature Polyimides

1992 ◽  
Vol 264 ◽  
Author(s):  
M. E. Rogers ◽  
T. M. Moy ◽  
Y. J. Kim ◽  
J. E. McGrath
Keyword(s):  
Glass Transition ◽  
High Temperature ◽  
Transition Temperatures ◽  
New Developments ◽  
Glass Transition Temperatures ◽  
Transparent Films ◽  
Very High ◽  
End Group ◽  
Temperature Applications

AbstractUtilizing solution imidization, molecular weight and end group control techniques, soluble, fully cyclized polyimides with very high glass transition temperatures have been developed to meet high temperature applications. Mechanistic aspects are investigated for solution imidization by both the polyamic acid route and by the ester-acid route. Polyimides based on pyromellitic dianhydride and a 3F diamine exhibit glass transition temperatures of 420 °C. These polyimides are soluble in polar aprotic solvents and form tough, transparent films which demonstrate mechanical integrity and thermooxidative stability at 700 °F. Various processing routes are explored to demonstrate the viability of these materials in high temperature applications. Details of the synthesis and characterization of these materials will be provided.

Use of LaB6 for a High Quality, Small Energy Spread Beam in an Electron Velocity Spectrometer

1976 ◽  
Vol 34 ◽  
pp. 534-535 ◽  
Author(s):  
P. E. Batson ◽  
C. H. Chen ◽  
J. Silcox
Keyword(s):  
High Temperature ◽  
Energy Resolution ◽  
Electron Velocity ◽  
Electronic Excitations ◽  
Small Energy ◽  
Small Intensity ◽  
Good Energy ◽  
Spectrometer System ◽  
Electron Energy Loss ◽  
Very High

Electron energy loss experiments combined with microscopy have proven to be a valuable tool for the exploration of the structure of electronic excitations in materials. These types of excitations, however, are difficult to measure because of their small intensity. In a usual situation, the filament of the microscope is run at a very high temperature in order to present as much intensity as possible at the specimen. This results in a degradation of the ultimate energy resolution of the instrument due to thermal broadening of the electron beam.We report here observations and measurements on a new LaB filament in a microscope-velocity spectrometer system. We have found that, in general, we may retain a good energy resolution with intensities comparable to or greater than those available with the very high temperature tungsten filament. We have also explored the energy distribution of this filament.

Microstructural characterization of a rapidly solidified Al-Fe-V-Si alloy for elevated temperature applications

1988 ◽  
Vol 46 ◽  
pp. 550-551
Author(s):  
R. E. Franck ◽  
J. A. Hawk ◽  
G. J. Shiflet
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Grain Growth ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Second Phase ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Temperature Applications

Rapid solidification processing (RSP) is one method of producing high strength aluminum alloys for elevated temperature applications. Allied-Signal, Inc. has produced an Al-12.4 Fe-1.2 V-2.3 Si (composition in wt pct) alloy which possesses good microstructural stability up to 425°C. This alloy contains a high volume fraction (37 v/o) of fine nearly spherical, α-Al12(Fe, V)3Si dispersoids. The improved elevated temperature strength and stability of this alloy is due to the slower dispersoid coarsening rate of the silicide particles. Additionally, the high v/o of second phase particles should inhibit recrystallization and grain growth, and thus reduce any loss in strength due to long term, high temperature annealing.The focus of this research is to investigate microstructural changes induced by long term, high temperature static annealing heat-treatments. Annealing treatments for up to 1000 hours were carried out on this alloy at 500°C, 550°C and 600°C. Particle coarsening and/or recrystallization and grain growth would be accelerated in these temperature regimes.

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