Creep activation energy of flow process in Bi2Te2·8Se0·2 single crystals

1999 ◽  
Vol 22 (1) ◽  
pp. 21-23 ◽  
Author(s):  
C F Desai ◽  
P H Soni ◽  
S R Bhavsar
Keyword(s):  
Activation Energy ◽  
Single Crystals ◽  
Flow Process ◽  
Creep Activation Energy

CREEP ACTIVATION ENERGY OF FLOW PROCESS IN Sn0.2Bi1.8Te3 SINGLE CRYSTALS

2004 ◽  
Vol 11 (04n05) ◽  
pp. 443-446
Author(s):  
P. H. SONI ◽  
C. F. DESAI ◽  
S. R. BHAVSAR
Keyword(s):  
Activation Energy ◽  
Time Dependence ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Vickers Microhardness ◽  
Indentation Creep ◽  
Flow Process ◽  
Creep Activation Energy ◽  
Temperature Range ◽  
Different Temperatures

Temperature dependence of the Vickers microhardness of Sn 0.2 Bi 1.8 Te 3 single crystals has been studied. Loading time dependence of microhardness at different temperatures has been used for creep study in the temperature range 303 K–373 K. The activation energy for indentation creep of the crystals has been evaluated.

Magnetic properties of undoped and Co-doped n-type β–FeSi2.5 single crystals

2002 ◽  
Vol 17 (11) ◽  
pp. 2960-2965 ◽  
Author(s):  
E. Arushanov ◽  
L. Ivanenko ◽  
D. Eckert ◽  
G. Behr ◽  
U. K. Rößler ◽  
...  
Keyword(s):  
Activation Energy ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
External Field ◽  
Single Crystals ◽  
Spin Glasses ◽  
Paramagnetic Centers ◽  
Temperature Dependent ◽  
Paramagnetic Curie Temperature ◽  
Co Doped

Results of magnetization and magnetic susceptibility measurements on undoped and Co-doped FeSi2.5 single crystals are presented. The temperature dependence of the magnetic susceptibility of the Co-doped sample in the range of 5–300 K can be explained by temperature-dependent contributions due to paramagnetic centers and the carriers excited thermally in the extrinsic conductivity region. The values of the paramagnetic Curie temperature and activation energy of the donor levels were estimated. It is also shown that the magnetic susceptibility of Co-doped samples cooled in zero external field and in a field are different. This resembles the properties of spin-glasses and indicates the presence of coupling between magnetic centers.

scholarly journals Глубокие центры радиационных дефектов в монокристаллах CdZnTe, созданные потоком быстрых нейтронов

2018 ◽  
Vol 52 (3) ◽  
pp. 322 ◽  
Author(s):  
С.В. Пляцко ◽  
Л.В. Рашковецкий
Keyword(s):  
Activation Energy ◽  
Neutron Flux ◽  
Fast Neutron ◽  
Single Crystals ◽  
Isothermal Annealing ◽  
Fast Neutron Flux ◽  
Photoluminescence Properties ◽  
Radiation Induced ◽  
Induced Defects

AbstractThe effect of a fast neutron flux (Φ = 10^14–10^15 cm^–2) on the electrical and photoluminescence properties of p -CdZnTe single crystals is studied. Isothermal annealing is performed ( T = 400–500 K), and the activation energy of the dissociation of radiation-induced defects is determined at E _D ≈ 0.75 eV.

PHOTOELECTRIC PROPERTIES OF MnIn2S4 SINGLE CRYSTALS

2021 ◽  
Vol 88 (6) ◽  
pp. 967-969
Author(s):  
N. N. Niftiyev
Keyword(s):  
Activation Energy ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Spectral Distribution ◽  
Photoconductivity Spectrum ◽  
Intracenter Transition ◽  
Photoelectric Properties ◽  
Impurity Photoconductivity ◽  
Donor Defect

The spectral distribution of the photoconductivity and the temperature dependence of the photocurrent of MnIn2S4 single crystals are investigated. The intrinsic, impurity photoconductivity and a maximum at an energy of 2.69 eV, which is associated with the intracenter transition of Mn2+ ions (6A1→4A1), are revealed in the photoconductivity spectrum. The region of the wavelengths of 600–1000 nm appears with an excess of manganese in the crystals and is caused by a donor defect. At temperatures of 80—145 K, the increase in the photocurrent is associated with the thermal depletion of the adhesion levels. The activation energy of the adhesion levels is determined.

scholarly journals PLASTIC DEFORMATION OF THICK-WALLED SNOW-ICE CYLINDERS UNDER HYDROSTATIC PRESSURE

1962 ◽  
Vol 40 (10) ◽  
pp. 1310-1318 ◽  
Author(s):  
H. H. G. Jellinek
Keyword(s):  
Activation Energy ◽  
Plastic Deformation ◽  
Hydrostatic Pressure ◽  
Strain Rate ◽  
Plastic Flow ◽  
Constant Pressure ◽  
Circumferential Stress ◽  
Sine Function ◽  
Kcal Mole ◽  
Flow Process

The results of experiments on the plastic deformation of hollow snow-ice cylinders, closed at one end, as a function of circumferential stress and temperature are discussed. Data are graphed on deformation as a function of time for a snow-ice cylinder under 7.03 and 14.06 kg/cm2 hydrostatic pressure at −4.5 °C, deformation as a function of hydrostatic pressure from 2.11 to 7.03 kg/cm2, and deformation as a function of temperature at a constant pressure of 10.55 kg/cm2. The natural strain rate of closure at constant circumferential stress and temperature was a constant, which varied with circumferential stress as a sine function and was "exponentially dependent on temperature, with an activation energy of 14.1 kcal/mole at an average circumferential stress of 3.1 kg/cm2. The experiments agree well with an earlier interpretation of the plastic flow process representing flow between grain boundaries.

The Compression Creep Behavior of Ni3Al-X Single Crystals

1990 ◽  
Vol 213 ◽  
Author(s):  
Seiji Miura ◽  
Tohru Hayashi ◽  
Mitsuhiro Takekawa ◽  
Yoshinao Mishima ◽  
Tomoo Suzuki
Keyword(s):  
Activation Energy ◽  
Single Crystals ◽  
Power Law ◽  
Creep Behavior ◽  
Creep Resistance ◽  
Constant Strain Rate ◽  
State Equation ◽  
Ternary Alloys ◽  
Plastic Behavior ◽  
Compression Tests

ABSTRACTCompressive creep behavior is investigated in ternary Ni3Al single crystals containing Ti, Si, Hf and Cr with stress axes parallel to the crystallographic orientation near [001]. Then a comparison is made with the results of high temperature compression tests under a constant strain rate for the same orientation where plastic behavior is characterized by a distinct yield drop followed by steadystate deformation. It is found that the deformation mechanism for the two cases is identical, namely octahedral viscous flow being expressed by the state equation of the power-law type with a stress exponent of about 3 to 4. The effect of offstoichiometry on the creep resistance is then examined in Ni3(Al,5 at%Ti) alloys with different Ni concentrations. The results support the observation in the polycrystalline compound where the creep resistance increases with Ni concentration on both sides of stoichiometry exhibiting a discontinuity at stoichiometry. Finally, the apparent activation energy in the power-law type state equation for the steady state creep deformation is estimated for all the ternary alloys examined. They are in general in good agreement with that for diffusion of ternary elements in Ni3Al. However, the relative magnitude of the value can not simply be compared since the activation energy depends on deviations from stoichiometry.

scholarly journals The Creep Activation Energies of Ice

1978 ◽  
Vol 21 (85) ◽  
pp. 429-444 ◽  
Author(s):  
D. R. Homer ◽  
J. W. Glen
Keyword(s):  
Activation Energy ◽  
Grain Boundary ◽  
Creep Deformation ◽  
Tensile Axis ◽  
Strain Rates ◽  
Boundary Slip ◽  
Creep Tests ◽  
Creep Activation Energy ◽  
Single Grain ◽  
Image Position

AbstractMonocrystals and bicrystals of ice have been creep tested at temperatures between 4 and — 30°C. The bicrystals had a single grain boundary running parallel to the tensile axis; this configuration inhibited grain-boundary slip between the two grains. The creep tests, which were carried out at constant stress σ and temperature T, yielded data of strain ϵ for time elapsed since the start of the test. These data showed accelerating creep for both monocrystals and bicrystals at all strain levels. Strain-rates were derived at strains of 0.01, 0.05. and 0.10, and these rates were fitted to the expressionk is Boltzmann’s constant and E is the creep activation energy. Derived values of n were 1.9 for monocrystals and 2.9 for bicrystals. The creep activation energy was found to be 78 kJ/mol for monocrystals and 75 kJ/mol for bicrystals. The processes of creep deformation in mono-, bi- and polycrystals are discussed.

The Creep Behavior of Cr Modified Ni3 Al Single Crystals

1988 ◽  
Vol 133 ◽  
Author(s):  
S. E. Hsu ◽  
C. H. Tong ◽  
T. S. Lee ◽  
T. S. Liu
Keyword(s):  
Activation Energy ◽  
Steady State ◽  
Single Crystals ◽  
Creep Behavior ◽  
Aluminum Content ◽  
Dislocation Core ◽  
Transient Creep ◽  
Cr Addition ◽  
Dislocation Core Structure ◽  
Different Levels

ABSTRACTNi-Al-Cr single crystals with 4 at% Cr and different levels of aluminum content are grown in a directional solidification facility. The crystals are creep tested at temperatures from 760°C to 860°C. Steady state, as well as transient, creep rates are measured. The results show that Cr modified Ni3 A1, when tested along the <100> direction, exhibit remarkably high values of activation energy for creep. Along with evidence from dislocation structures, it is likely that there is a change in the dislocation core structure upon Cr addition.

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