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.

Low frequency internal friction in zinc single crystals

1962 ◽  
Vol 10 (4) ◽  
pp. 430-441 ◽  
Author(s):  
J.M Roberts ◽  
N Brown
Keyword(s):  
Internal Friction ◽  
Single Crystals ◽  
Low Frequency

A low frequency internal friction study of high purity chromium

1983 ◽  
Vol 17 (6) ◽  
pp. 759-763 ◽  
Author(s):  
O. Yoshinari ◽  
M. Koiwa ◽  
M. Isshiki ◽  
K. Igaki
Keyword(s):  
Internal Friction ◽  
High Purity ◽  
Low Frequency ◽  
Friction Study

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

Twofold Resonance in the Internal Friction Measurements of Tin Single Crystals

1973 ◽  
Vol 12 (9) ◽  
pp. 1466-1467
Author(s):  
Toshio Yokoyama ◽  
Gen-ichi Kamoshita ◽  
Hironobu Nishikawa
Keyword(s):  
Internal Friction ◽  
Single Crystals ◽  
Friction Measurements

Study of Fe3Al-Based Alloys by Internal Friction and 59Fe Radiotracer Diffusion Measurements

2005 ◽  
Vol 237-240 ◽  
pp. 1258-1263
Author(s):  
Tatiana S. Pavlova ◽  
S.B. Golovina ◽  
Sergiy V. Divinski ◽  
Igor S. Golovin
Keyword(s):  
Internal Friction ◽  
Vacancy Concentration ◽  
Vacancy Diffusion ◽  
Diffusion Study ◽  
Snoek Peak ◽  
Dissolved Carbon ◽  
Friction Measurements ◽  
Nb Alloying

Anelastic effects caused by carbon and vacancy diffusion in Fe3Al based alloys with and without strong carbide forming elements (Ti and Nb) are investigated by internal friction measurements. The decrease of the Snoek peak in Fe–26Al–2Ti and Fe–26Al–0.3Nb alloys with respect to the Fe–26Al alloy is related to a decrease in the amount of interstitially dissolved carbon (C). The so-called X peak, which is observed in the Fe–26Al alloy, also almost disappears after alloying. In order to elucidate the vacancy contribution to the origin of the X peak radiotracer measurements of 59Fe diffusion were performed. The results indicate that the change in the interstitially dissolved C concentration is the main reason of the observed changes in the X peak, although a certain influence of Ti and Nb alloying on the total vacancy concentration may be deduced from the diffusion study.

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