Atomistic Study of Helium Bubbles in Fe: Equilibrium State

ABSTRACTIn the fusion irradiation environment, helium created by transmutation will play an important role in the response of structural materials to neutron radiation damage. Recently we have developed a new 3-body potential to describe the Fe–He interaction in an Fe matrix. We have used this potential to investigate the equilibrium state of He bubbles embedded into the bcc Fe matrix. We have investigated bubble size, He content and temperature effects. It was found that the equilibrium He content is rather low and at a room temperature it is ~0.38 to 0.5 He per vacancy for bubble diameters from 1 to 6 nm. At constant bubble size, the equilibrium He/vacancy ratio decreases with temperature increase. For bubbles of 6 nm diameter it goes down as low as ~0.25 at 900K. The results are compared with the capillarity model often used for estimating the equilibrium pressure of He bubbles.

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Studies on Water in the Hydration Chamber of a Modified Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069715 ◽

1970 ◽

Vol 28 ◽

pp. 544-545

Author(s):

R. C. Moretz ◽

G. G. Hausner ◽

D. F. Parsons

Keyword(s):

Thin Film ◽

Thin Films ◽

Electron Microscope ◽

Steady State ◽

Room Temperature ◽

Small Mass ◽

Equilibrium Pressure ◽

Biological Objects ◽

Mechanical Pump ◽

Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

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Changes in the upper critical fields and critical currents of Nb3Sn and V3Ga owing to neutron radiation damage

Applied Physics Letters ◽

10.1063/1.89277 ◽

1977 ◽

Vol 30 (12) ◽

pp. 662-664 ◽

Cited By ~ 12

Author(s):

C. L. Snead

Keyword(s):

Radiation Damage ◽

Neutron Radiation ◽

Critical Currents ◽

Critical Fields ◽

Upper Critical Fields ◽

Neutron Radiation Damage

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Effects of neutron radiation on the electrical resistivity of copper at room temperature

Nuclear Instruments and Methods ◽

10.1016/0029-554x(76)90384-0 ◽

1976 ◽

Vol 136 (3) ◽

pp. 575-578 ◽

Cited By ~ 2

Author(s):

B. McGrath ◽

H. Schönbacher ◽

M. Van de Voorde

Keyword(s):

Electrical Resistivity ◽

Room Temperature ◽

Neutron Radiation

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Simulating Neutron Radiation Damage of Graphite by In-situ Electron Irradiation

Journal of Physics Conference Series ◽

10.1088/1742-6596/522/1/012051 ◽

2014 ◽

Vol 522 ◽

pp. 012051

Author(s):

Brindusa E Mironov ◽

H M Freeman ◽

R M D Brydson ◽

A V K Westwood ◽

A J Scott

Keyword(s):

Radiation Damage ◽

Electron Irradiation ◽

Neutron Radiation ◽

Neutron Radiation Damage

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Temperature Effects on Optical Trapping Stability

Micromachines ◽

10.3390/mi12080954 ◽

2021 ◽

Vol 12 (8) ◽

pp. 954

Author(s):

Dasheng Lu ◽

Francisco Gámez ◽

Patricia Haro-González

Keyword(s):

Brownian Motion ◽

Environmental Conditions ◽

Temperature Effects ◽

Room Temperature ◽

Optical Trapping ◽

State Of The Art ◽

Thermal Sensing ◽

The Stability ◽

Object Of Study ◽

Optically Trapped

In recent years, optically trapped luminescent particles have emerged as a reliable probe for contactless thermal sensing because of the dependence of their luminescence on environmental conditions. Although the temperature effect in the optical trapping stability has not always been the object of study, the optical trapping of micro/nanoparticles above room temperature is hindered by disturbances caused by temperature increments of even a few degrees in the Brownian motion that may lead to the release of the particle from the trap. In this report, we summarize recent experimental results on thermal sensing experiments in which micro/nanoparticles are used as probes with the aim of providing the contemporary state of the art about temperature effects in the stability of potential trapping processes.

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Helium Bubbles Effect on the Mechanical Properties of CLAM Alloys by Milte-Scale Simulations

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.577.81 ◽

2014 ◽

Vol 577 ◽

pp. 81-85

Author(s):

Jing Wei Zhang ◽

Jun Cai ◽

Shuang Jiang ◽

Xin Guo ◽

Qiao Zhi Sun ◽

...

Keyword(s):

Mechanical Properties ◽

Yield Strength ◽

Bubble Size ◽

Simulation Method ◽

Experimental Results ◽

Helium Bubble ◽

Yield Strain ◽

Helium Bubbles

The effect of the different sizes and densities of He bubble on the mechanical properties of CLAM alloy was studied by milt-scale simulation method. It is found that with the increasing of helium bubble size and density, the yield strength and yield strain of CLAM alloys reduced, and the yield strength and yield elongation are predicted to be consistent with the experimental results.

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Room temperature effects on ofﬁce work

Creating the Productive Workplace ◽

10.4324/9780203696880-24 ◽

2006 ◽

pp. 209-220

Keyword(s):

Temperature Effects ◽

Room Temperature ◽

Office Work

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An Atomistic Study of Ti Segregation to Lamellar Interfaces in Ti-RICH TiAl

MRS Proceedings ◽

10.1557/proc-492-255 ◽

1997 ◽

Vol 492 ◽

Author(s):

K. Ito ◽

V. Vitek

Keyword(s):

The Other ◽

Many Body ◽

Monte Carlo Calculations ◽

Narrow Region ◽

Specific Distribution ◽

Thin Region ◽

Body Potential ◽

Atomistic Study ◽

Lamellar Interfaces ◽

The Ideal

ABSTRACTIn this paper we analyze the effect of the surplus of titanium in the bulk on γ/γ interfaces. Monte Carlo calculations using a central force many-body potential suggest that in Ti rich alloys titanium segregates to the 120° rotational fault and the pseudotwin. This leads to the formation of a thin region of the DO19 Ti3Al at these interfaces. While titanium does not segregate to the ordered twin, it does to the ordered twin with the APB. But in this case the interface dissociates into the 120° rotational fault and the pseudotwin. The calculations further show that there are two types of atomic sites at the interfaces. One is the same as in the ideal L10 the other, to which the segregation takes place, is specific for interfaces parallel to {111} planes. The specific distribution of the sites favored for segregation is the reason why segregation leads to the formation of a narrow region of the DO19 Ti3Al in the 120° rotational fault and the pseudotwin.

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