AMPLITUDE-DEPENDENT INTERNAL FRICTION IN HIGH PURITY MOLYBDENUM SINGLE CRYSTALS IN THE TEMPERATURE RANGE 5.9 - 300 K

1981 ◽  
Vol 42 (C5) ◽  
pp. C5-55-C5-60
Author(s):  
H. J. Kaufmann ◽  
P. P. Pal-Val ◽  
D. Schulze ◽  
V. I. Startsev
Keyword(s):  
Internal Friction ◽  
Single Crystals ◽  
High Purity ◽  
Temperature Range

Effect of Purity on Dislocation-Induced Relaxations in Molybdenum Single Crystals

2015 ◽  
Vol 363 ◽  
pp. 106-111
Author(s):  
Shigeru Suzuki ◽  
Alfred Seeger
Keyword(s):  
Internal Friction ◽  
Single Crystals ◽  
High Purity ◽  
Low Frequency ◽  
Activation Process ◽  
Dislocation Interaction ◽  
Dissolved Carbon ◽  
Dislocation Pinning ◽  
Friction Measurements ◽  
Substitutional Impurities

Dislocation-induced relaxations in different molybdenum single crystals were investigated by means of low-frequency internal friction measurements in the temperature range of 20–600 K. The results indicated that the appearance of the dislocation-induced relaxations strongly depends on the purity of the molybdenum, although the intrinsic dislocation relaxations appeared at about 100 K and 450 K in the high-purity molybdenum. The molybdenum containing a small amount of carbon did not exhibit the intrinsic dislocation relaxations but rather revealed a modulus increase due to the dislocation pinning caused by the dissolved carbon. When the molybdenum containing a small amount of carbon was annealed up to 700 K, a new relaxation peak appeared at about 450 K. The activation process for this relaxation indicated that it could be attributed to the relaxation due to a carbon-dislocation interaction. In addition, it was shown that the dislocation-induced relaxations in medium-purity molybdenum were small, which was attributed to the residual substitutional impurities in the molybdenum.

Internal Friction in Plastically Deformed High-Purity NiAl Single Crystals

1998 ◽  
Vol 552 ◽  
Author(s):  
M. Hirscher ◽  
D. Schaible
Keyword(s):  
Internal Friction ◽  
Single Crystals ◽  
High Purity ◽  
Formation Enthalpy ◽  
Dislocation Motion ◽  
Zone Melting ◽  
Interstitial Impurity ◽  
Impurity Atoms ◽  
Kink Pair ◽  
Friction Measurements

ABSTRACTHigh-purity stoichiometric NiAl single crystals have been prepared by crucible-free inductive zone melting and afterwards well annealed at temperatures below 1200 K. Internal friction measurements of torsionally deformed single crystals show two relaxation maxima at 500 and 800 K which anneal during the measurement. The first maximum can be assigned to the dislocation motion by kinkpair formation and the annealing to pinning of these dislocations by interstitial impurity atoms. The second maximum is attributed to the Snoek-Köster relaxation of dislocations in the presence of mobile interstitial impurity atoms and the annealing to the pinning of dislocations by vacancies. The kink-pair formation enthalpy in NiAl was estimated.

Anomalous Plasticity of High-purity LiF Single Crystals in the Temperature Range 0.55 to 4.2 K

1989 ◽  
pp. 379-384
Author(s):  
S.V. Lubenets ◽  
V.D. Natsik ◽  
V.V. Pustovalov ◽  
L.S. Fomenko ◽  
S.E. Shumilin ◽  
...  
Keyword(s):  
Single Crystals ◽  
High Purity ◽  
Temperature Range

scholarly journals Inelastic Behaviour of Ice Ih Single Crystals in the Low-Frequency Range Due to Dislocations

1978 ◽  
Vol 21 (85) ◽  
pp. 375-384 ◽  
Author(s):  
René Vassoille ◽  
Christian Maï ◽  
Joseph Perez
Keyword(s):  
High Temperature ◽  
Internal Friction ◽  
Single Crystals ◽  
Empirical Relation ◽  
Low Frequency ◽  
Frequency Range ◽  
High Temperature Range ◽  
Temperature Range ◽  
Inelastic Behaviour ◽  
Torsional Pendulum

Abstract The inelastic behaviour of ice Ih single crystals has been investigated by an inverted torsional pendulum in the low-frequency range. Three features are distinguished: (i) a relaxation peak previously observed by several authors in the higher-frequency range, (ii) an internal friction increasing with temperature in the high-temperature range (230–273 K), (iii) within this high-temperature range, internal friction becomes amplitude dependent, and this dependence becomes greater the greater the temperature. In this case, the internal friction has been interpreted in terms of movements of dislocations. Hence, the experimental results are interpreted with a model of internal friction based on an empirical relation for the velocity of dislocations. This model of internal friction is in fair agreement with experimental data . It is possible then to get an estimate of dislocation density. Hence it is shown that internal friction experiments can be useful in the study of the plastic behaviour of ice single crystals.

THE EFFECT OF HEAT TREATMENT ON LOW TEMPERATURE INTERNAL FRICTION MAXIMA

1958 ◽  
Vol 36 (1) ◽  
pp. 82-87 ◽  
Author(s):  
T. S. Hutchison ◽  
G. J. Hutton
Keyword(s):  
Heat Treatment ◽  
Plastic Deformation ◽  
Melting Point ◽  
Low Temperature ◽  
Internal Friction ◽  
High Purity ◽  
Temperature Relation ◽  
Temperature Range ◽  
High Purity Aluminum

Measurements of the attenuation of sound at a frequency of 5 megacycles have been made over the temperature range 100° to 200 ° K. on polycrystalline high purity aluminum subjected to various thermal and mechanical treatments. With samples annealed at 520 °C. a maximum in the attenuation versus temperature relation had been observed at 155 ° K. This maximum was greatly increased by small amounts of plastic deformation of the order of 1.0 to 1.5%.Aluminum initially annealed for extended periods at temperatures much closer to the melting point shows, however, either no increase in the attenuation maximum at 155 ° K. or, in extreme cases, no maximum in this region at all, after plastic deformation of the same order as before. It is believed that this indicates a dependence of the deformation-induced maximum on the distribution and possibly on the number of dislocations in the metal prior to deformation and on the arrangement of the dislocations after deformation.

Internal friction in high-purity aluminum single crystals

1984 ◽  
Vol 84 (1) ◽  
pp. 157-164 ◽  
Author(s):  
T. S. Kě ◽  
P. Cui ◽  
C. M. Su
Keyword(s):  
Internal Friction ◽  
Single Crystals ◽  
High Purity ◽  
High Purity Aluminum

On the dislocation internal friction in high-purity molybdenum single crystals

1987 ◽  
Vol 104 (1) ◽  
pp. K17-K20 ◽  
Author(s):  
B. K. Kardashev ◽  
H.-J. Kaufmann ◽  
A. B. Lebedev ◽  
P. P. Pal-Val
Keyword(s):  
Internal Friction ◽  
Single Crystals ◽  
High Purity
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