scholarly journals Physical Property Changes in Plutonium Observed from Accelerated Aging using Pu-238 Enrichment

2006 ◽  
Vol 986 ◽  
Author(s):  
Brandon W. Chung ◽  
Bill Choi ◽  
Cheng Saw ◽  
Stephen Thompson ◽  
Conrad Woods ◽  
...  
Keyword(s):  
Ultimate Strength ◽  
Tensile Property ◽  
Aging Process ◽  
Accelerated Aging ◽  
Physical Property ◽  
Tensile Tests ◽  
Weight Percent ◽  
Volume Increase ◽  
Property Changes ◽  
Weapons Grade Plutonium

AbstractWe present changes in volume, immersion density, and tensile property observed from accelerated aged plutonium alloys. Accelerated alloys (or spiked alloys) are plutonium alloys enriched with approximately 7.5 weight percent of the faster-decaying 238Pu to accelerate the aging process by approximately 17 times the rate of unaged weapons-grade plutonium. After sixty equivalent years of aging on spiked alloys, the dilatometry shows the samples at 35°C have swelled in volume by 0.15 to 0.17 % and now exhibit a near linear volume increase due to helium in-growth. The immersion density of spiked alloys shows decrease in density, similar normalized volumetric changes (expansion) for spiked alloys. Tensile tests show increasing yield and engineering ultimate strength as spiked alloys are aged.

scholarly journals Physical Property Changes in Aging Plutonium Alloys

2008 ◽  
Vol 1104 ◽  
Author(s):  
Brandon W. Chung ◽  
Stephen R. Thompson ◽  
David S. Hiromoto
Keyword(s):  
Aging Process ◽  
Specific Activity ◽  
Physical Property ◽  
Alpha Decay ◽  
Mechanical Tests ◽  
Aging Effects ◽  
Extended Aging ◽  
Lattice Damage ◽  
Property Changes ◽  
Weapons Grade Plutonium

AbstractPlutonium, because of its self-irradiation by alpha decay, ages by means of lattice damage and helium in-growth. These integrated aging effects will result in microstructural and physical property changes. Because these effects would normally require decades to measure, studies are underway to asses the effects of extended aging on the physical properties of plutonium alloys by incorporating roughly 7.5 wt% of highly specific activity isotope 238Pu into the weapons-grade plutonium to accelerate the aging process. This paper presents updated results of self-irradiation effects on enriched and reference alloys measured from the immersion density, dilatometry, and mechanical tests. After nearly 90 equivalent years of aging, both the immersion density and dilatometry show that the enriched alloys at 35°C have decreased in density by ∼0.19 % and now exhibit a near linear density decrease, without void swelling. Both tensile and compression measurements show that the aging process continues to increase the strength of plutonium alloys.

scholarly journals Density Changes in Plutonium Observed from Accelerated Aging using Pu-238 Enrichment

2003 ◽  
Vol 802 ◽  
Author(s):  
B. W. Chung ◽  
S. R. Thompson ◽  
C. H. Woods ◽  
D. J. Hopkins ◽  
W. H. Gourdin ◽  
...  
Keyword(s):  
Accelerated Aging ◽  
Physical Property ◽  
Recoil Nucleus ◽  
Irradiation Damage ◽  
Volume Changes ◽  
Defect Clusters ◽  
Particle Decay ◽  
Lattice Damage ◽  
Property Changes ◽  
Inside Out

Plutonium, because of its radioactive nature, ages from the “inside out” by means of self-irradiation damage and thus produces Frankel-type defects (vacancies and self-interstitial atoms) and defect clusters. The self-irradiation damage in Plutonium-239 occurs mainly by α-particle decay, where most of the damage comes from the U-235 recoil nucleus. The defects resulting from the residual lattice damage and helium in-growth could result in microstructural and physical property changes. Because these self-irradiation effects would normally require decades to measure, with a fraction (7.5 wt%) of Pu-238 is added to the reference plutonium alloy thus accelerating the aging process by approximately 18 times the normal rate. By monitoring the properties of the Pu-238 spiked alloy over a period of about 3.5 years, the properties of plutonium in storage can be projected for periods up to about 60 years. This paper presents density and volume changes observed from the immersion density and dilatometry measurements equivalent to aging the reference plutonium alloys to nine years.

scholarly journals The Effect of Accelerated Aging on Polylactide Containing Plant Extracts

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 575 ◽  
Author(s):  
Krzysztof Moraczewski ◽  
Magdalena Stepczyńska ◽  
Rafał Malinowski ◽  
Tomasz Karasiewicz ◽  
Bartłomiej Jagodziński ◽  
...  
Keyword(s):  
Aging Process ◽  
Accelerated Aging ◽  
Tensile Tests ◽  
Butylated Hydroxytoluene ◽  
Plant Origin ◽  
Reference Compound ◽  
Scanning Calorimetry ◽  
Visual Evaluation ◽  
Melt Flow Rate ◽  
Natural Extracts

In this study, natural extracts of plant origin were used as anti-aging compounds of biodegradable polymers. Coffee (0.5–10 wt%), cocoa, or cinnamon extracts were added to the polylactide matrix. The obtained materials were subjected to an accelerated aging process (720, 1440, or 2160 h) at 45 °C and 70% relative humidity under continuous UV radiation. The effectiveness of the tested extracts was compared to a commercially available anti-aging compound, 2 wt% of butylated hydroxytoluene. Visual evaluation, scanning electron microscopy, melt flow rate, thermogravimetry, differential scanning calorimetry, tensile strength, and impact tensile tests were performed. We show that the use of smaller amounts of tested extracts is particularly advantageous, which do not adversely affect the properties of polylactide-based materials at low contents. At the same time, their effectiveness in stabilizing tested properties during the accelerated aging process is mostly comparable to or greater than the reference compound.

Effects of Accelerated Aging Period of Time at 150°C on Tensile Property of Plain Woven Fabric/Epoxy Resin Laminated Composites

2011 ◽  
Vol 282-283 ◽  
pp. 403-406 ◽  
Author(s):  
Lei Lei Song ◽  
Quan Rong Liu ◽  
Liang Sen Liu ◽  
Jia Lu Li
Keyword(s):  
Tensile Strength ◽  
Epoxy Resin ◽  
Tensile Property ◽  
Resin Composite ◽  
Accelerated Aging ◽  
Tensile Load ◽  
Tensile Tests ◽  
Woven Fabric ◽  
Obvious Effect ◽  
Composite Samples

The purpose of this paper is to investigate the tensile property of laminated epoxy resin composites reinforced by carbon fiber plain woven fabric after accelerated aging for different period of time at 150°C. For this purpose, the tensile tests of laminated resin composite samples without aging and aged 60 hours, 120 hours, 180 hours, at 150°C were carried out. The damage forms of composite samples tested were investigated. The experiment result indicates that the accelerated aging process has an obvious effect on the tensile strength of composite samples. The average tensile strengths of composite samples aged 60 hours, 120 hours, and 180 hours period of time at 150°C are 87.31%, 88.61%, 79.05% of average tensile strength of composite samples without aging, respectively. The observation of the damage form of samples tested shows that when accelerated aging, the resin in the composite samples is damaged and the adhesive force between fiber bundles and epoxy resin decline, which makes the ability of fiber and resin bearing the tensile load together decreases.

Regularities and properties of instrumented indentation diagrams obtained by ball-shaped indenter

2020 ◽  
Vol 86 (5) ◽  
pp. 43-51
Author(s):  
V. M. Matyunin ◽  
A. Yu. Marchenkov ◽  
N. Abusaif ◽  
P. V. Volkov ◽  
D. A. Zhgut
Keyword(s):  
Yield Strength ◽  
Ultimate Strength ◽  
Elastoplastic Deformation ◽  
Elastic Limit ◽  
Tensile Tests ◽  
Indentation Load ◽  
International Standards ◽  
Instrumented Indentation ◽  
Indentation Methods ◽  
Special Points

The history of appearance and the current state of instrumented indentation are briefly described. It is noted that the materials instrumented indentation methods using a pyramid and ball indenters are actively developing and are currently regulated by several Russian and international standards. These standards provide formulas for calculating the Young’s modulus and hardness at maximum indentation load. Instrumented indentation diagrams «load F – displacement α» of a ball indenter for metallic materials were investigated. The special points on the instrumented indentation diagrams «F – α» loading curves in the area of elastic into elastoplastic deformation transition, and in the area of stable elastoplastic deformation are revealed. A loading curve area with the load above which the dF/dα begins to decrease is analyzed. A technique is proposed for converting «F – α» diagrams to «unrestored Brinell hardness HBt – relative unrestored indent depth t/R» diagrams. The elastic and elastoplastic areas of «HBt – t/R» diagrams are described by equations obtained analytically and experimentally. The materials strain hardening parameters during ball indentation in the area of elastoplastic and plastic deformation are proposed. The similarity of «HBt – t/R» indentation diagram with the «stress σ – strain δ» tensile diagrams containing common zones and points is shown. Methods have been developed for determining hardness at the elastic limit, hardness at the yield strength, and hardness at the ultimate strength by instrumented indentation with the equations for their calculation. Experiments on structural materials with different mechanical properties were carried out by instrumented indentation. The values of hardness at the elastic limit, hardness at the yield strength and hardness at the ultimate strength are determined. It is concluded that the correlations between the elastic limit and hardness at the elastic limit, yield strength and hardness at the yield strength, ultimate tensile strength and hardness at the ultimate strength is more justified, since the listed mechanical characteristics are determined by the common special points of indentation diagrams and tensile tests diagrams.

scholarly journals Tensile property changes of metals irradiated to low doses with fission, fusion and spallation neutrons

1992 ◽  
Vol 191-194 ◽  
pp. 1177-1182 ◽  
Author(s):  
H.L. Heinisch ◽  
M.L. Hamilton ◽  
W.F. Sommer ◽  
P.D. Ferguson
Keyword(s):  
Tensile Property ◽  
Low Doses ◽  
Property Changes ◽  
Spallation Neutrons

scholarly journals Supersonic oscillation impact upon aging process of different metal alloys

2020 ◽  
Vol 2020 (2) ◽  
pp. 10-15
Author(s):  
Vladimir Alexandrov ◽  
Boris Kudryashov ◽  
Kirill Ivanov ◽  
Viktor Vdovin
Keyword(s):  
Aging Process ◽  
Metal Alloys ◽  
Stress Strain ◽  
Strain Property ◽  
Property Changes

A short literary review on the super-sound impact upon different alloy aging is shown. The super-sound impact upon aging processes martensite alloys is considered. A super-sonic plant allowing increasing a super-sound impact upon martensite steel aging is developed. There are shown the investigation results of frequency and intensity of sound oscillation upon stress-strain property changes in aging processes.

scholarly journals Study on Metakaolin Impact on Concrete Performance of Resisting Complex Ions Corrosion

2021 ◽  
Vol 8 ◽  
Author(s):  
Chen Xupeng ◽  
Sun Zhuowen ◽  
Pang Jianyong
Keyword(s):  
Physical Property ◽  
Similar Amount ◽  
Concrete Durability ◽  
Test Results ◽  
Micro Structure ◽  
Complex Ions ◽  
Cyclic Corrosion ◽  
Property Changes ◽  
Micro Morphology ◽  
Composition Changes

The main purpose of this study is to determine the metakaolin (MK) impacts on the concrete durability when the concrete is subjected to joint corrosion of SO42−,Mg2+ and, Cl−. Four groups of concrete test samples, which contained different MK contents, were designed and tested in order to see their physical property changes and macro-morphology differences during the cyclic corrosion process. And a series of approaches, including XRD, FTIR, SEM, and EDS, were applied to study the concrete phase composition changes and the micro-morphology features of all groups. According to the test results, when reaching 20 cycles, the concrete sample with 10% MK showed the best concrete physical properties; when reaching 120 cycles, the concrete with 5% MK content showed the best durability, produced similar amount of corrosion products to ordinary concrete, and presented relatively compacted micro-structure and small internal porosity. Mg2+ actually has a great impact on metakaolin. The corrosion product quantity increased significantly when MK admixture reached 15%. Due to the great number of produced M-S-H, the corrosive ions damaged the concrete for a second time, leading to serious aggregate peeling-off, powder surface of test samples, and porous micro-structure.

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