Plasticization effect and the excitation of the electronic subsystem in an LiF single crystal by an ultraweak thermalized-neutron flux in the stress-relaxation regime

JETP Letters ◽  
1999 ◽  
Vol 70 (2) ◽  
pp. 123-128 ◽  
Author(s):  
A. G. Lipson ◽  
D. M. Sakov ◽  
V. I. Savenko ◽  
E. I. Saunin
Keyword(s):  
Stress Relaxation ◽  
Neutron Flux ◽  
Single Crystal ◽  
Electronic Subsystem ◽  
Plasticization Effect ◽  
Thermalized Neutron ◽  
Thermalized Neutron Flux

Determination of k0-values for the reactions 94Zr (n, γ) 95Zr and 96Zr (n, γ) 97Zr–97mNb by irradiation in highly thermalized neutron flux

2009 ◽  
Vol 67 (12) ◽  
pp. 2092-2096 ◽  
Author(s):  
X. Lin ◽  
H. Gerstenberg ◽  
Ch. Lierse von Gostomski ◽  
R. Henkelmann ◽  
A. Türler ◽  
...  
Keyword(s):  
Neutron Flux ◽  
Thermalized Neutron ◽  
Thermalized Neutron Flux

scholarly journals Creep and Stress Relaxation Anisotropy of a Single-Crystal Superalloy

2014 ◽  
Vol 45 (5) ◽  
pp. 2532-2544 ◽  
Author(s):  
Mikael Segersäll ◽  
Johan J. Moverare ◽  
Daniel Leidermark ◽  
Kjell Simonsson
Keyword(s):  
Stress Relaxation ◽  
Single Crystal ◽  
Single Crystal Superalloy ◽  
Creep And Stress Relaxation

scholarly journals Experimental confirmation of a new method for selective neutron separation

2020 ◽  
Vol 6 (4) ◽  
pp. 235-241
Author(s):  
Yuri V. Drobyshevsky ◽  
Ilya M. Anfimov ◽  
Valery A. Varlachev ◽  
Svetlana P. Kobeleva ◽  
Sergey A. Nekrasov ◽  
...  
Keyword(s):  
Neutron Flux ◽  
Single Crystal ◽  
Thermal Neutron ◽  
Single Crystal Silicon ◽  
Hydrogen Uptake ◽  
Experimental Confirmation ◽  
Crystal Silicon ◽  
Neutron Reflection ◽  
Neutron Beams ◽  
Integral Neutron

The article presents an experimental confirmation of the operability of neutron concentrators in devices that form and use directed high-intensity thermal neutron beams with elliptical channels made as blocks of profiled graphite and aluminum plates. The effect of neutron reflection from the surface of materials is the basis of a device capable of selecting neutrons by their directions in space. The study experimentally confirmed the efficiency of a moderating-focusing structure (MFS) based on a pack of elliptical neutron mirrors, which makes it possible to form oriented thermal neutron beams from the outgoing neutron flux. To record the effects of selective thermal neutron separation, silicon single-crystal wafers were used, due to which it was possible to obtain portraits of integral neutron fluxes in the reactor. The experiments were carried out in a horizontal experimental channel (HEC-4) at the IRT-T reactor of the National Research Tomsk Polytechnic University. The integral neutron flux was (2.3–3.02)·1017 cm–2. The neutron flux was detected by the change in the specific electrical resistivity of the single-crystal silicon wafers. The effect of concentration of thermal neutrons was recorded both on the block of graphite neutron mirrors and on the block of aluminum thin-walled elliptical mirrors. In the near future, on this basis, it will be possible to solve such problems as extending the reactor life by reducing the hydrogen uptake in the inner walls. In addition, the experiments have proved the possibility of creating anisotropic structures that lie outside the formalism of Liouville’s theorem, in which the surfaces of thermal neutron sinks are formed with subsequent concentration in the areas separated by aluminum or graphite plates.

Synthetic single crystal diamond as a fission reactor neutron flux monitor

2007 ◽  
Vol 90 (18) ◽  
pp. 183509 ◽  
Author(s):  
Marco Marinelli ◽  
E. Milani ◽  
G. Prestopino ◽  
A. Tucciarone ◽  
C. Verona ◽  
...  
Keyword(s):  
Neutron Flux ◽  
Single Crystal ◽  
Reactor Neutron ◽  
Flux Monitor ◽  
Fission Reactor ◽  
Neutron Flux Monitor ◽  
Single Crystal Diamond

PORTEVIN–LE CHÂTELIER INSTABILITY IN L10-TiAl SINGLE CRYSTAL

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4189-4194 ◽  
Author(s):  
Y. L. CHIU ◽  
P. PENHOUD ◽  
P. VEYSSIÈRE
Keyword(s):  
Stress Relaxation ◽  
Slip System ◽  
Single Crystal ◽  
Plastic Flow ◽  
Temperature Regime ◽  
Deformation Behaviour ◽  
Experimental Results ◽  
Screw Dislocations ◽  
Strain Ageing ◽  
First Time

We studied the deformation behaviour of γ Ti -54.5% Al single crystal at temperatures ranging from 200°C to 700°C along [153] orientation, where the major operative slip system is [Formula: see text]. During this temperature regime, deformation microstructure consists of long heavily pinned screw dislocations. Serrated plastic flow has been observed at 500°C, the serration amplitude decreases with strain. The combination of the strain ageing and stress relaxation experimental results demonstrate for the first time the Portevin–Le Châtelier type instability in TiAl single crystal.

scholarly journals Modelling of TMF Crack Initiation in Smooth Single-Crystal Superalloy Specimens

2014 ◽  
Vol 891-892 ◽  
pp. 1283-1288 ◽  
Author(s):  
Daniel Leidermark ◽  
Mikael Segersäll ◽  
Johan Moverare ◽  
Kjell Simonsson
Keyword(s):  
Stress Relaxation ◽  
Crack Initiation ◽  
Single Crystal ◽  
Fatigue Behaviour ◽  
Creep Model ◽  
Critical Plane ◽  
Critical Plane Approach ◽  
Nickel Base ◽  
As Stress ◽  
Tension Compression Asymmetry

In this paper the TMF crack initiation behaviour of the single-crystal nickel-base superalloyMD2 is investigated and modelled. TMF tests were performed in both IP and OP for varying mechanicalstrain ranges in the [001] crystallographic direction until TMF crack initiation was obtained. Acrystal plasticity-creep model was used in conjunction with a critical-plane approach, to evaluate thenumber of cycles to TMF crack initiation. The critical-plane model was evaluated and calibrated ata stable TMF cycle, where the effect of the stress relaxation had attenuated. This calibrated criticalplanemodel is able to describe the TMF crack initiation, taking tension/compression asymmetry aswell as stress relaxation anisotropy into account, with good correlation to the real fatigue behaviour.

Simulation on Stress Relaxation of DD3 Nickel-Based Single Crystal Superalloy Based on Micro-Cell Model

2013 ◽  
Vol 834-836 ◽  
pp. 1557-1562
Author(s):  
Zhi Ping Ding ◽  
Jun Zeng ◽  
Xiao Peng Bai ◽  
Jian Hui Fang
Keyword(s):  
Stress Relaxation ◽  
Single Crystal ◽  
Cell Model ◽  
Low Cycle Fatigue ◽  
Thin Wall ◽  
Simulation Studies ◽  
Two Phase ◽  
Single Cell Model ◽  
The Matrix ◽  
Accumulation Phenomenon

Tension-torsion experiments at 680°C and 850°C on thin-wall tube specimens of DD3 nickel-based single crystal superalloys were successfully completed. It shows that specimens have stress relaxation obviously and inelastic deformation accumulation phenomenon with different crystal orientation under asymmetric cyclic loadings. Based on the microstructure characteristics of nickel-based single crystal superalloys, a two-phase multi-cell microscopic mechanical model was established by finite element method to simulate the test with displacement. Numerical simulation studies showed that the matrix phase appeared plastic deformation accumulation at first and resulted in low cycle fatigue damage, but stress distortion occurred on the boundary with a single cell model under tension-torsion displacement loading, which is not consistent with experimental results. While using multi-cell model can avoid this phenomenon, it could be better to simulate stress relaxation behavior under asymmetric cyclic loading at elevated temperature and to study on stress weaken damage for single crystal superalloys.

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