High-temperature internal friction peak and oxygen diffusion in Li2O�2SiO2 glass

1995 ◽  
Vol 14 (16) ◽  
pp. 1126-1128 ◽  
Author(s):  
T. Sakai ◽  
K. Takizawa ◽  
T. Eguchi ◽  
J. Horie
Keyword(s):  
High Temperature ◽  
Internal Friction ◽  
Oxygen Diffusion ◽  
Internal Friction Peak

A Study on Influence of Annealing and Aging on High Temperature Internal Friction in Al-Zr Alloy

2012 ◽  
Vol 535-537 ◽  
pp. 1027-1030
Author(s):  
Xiao Hui Cao ◽  
Yu Wang
Keyword(s):  
High Temperature ◽  
Internal Friction ◽  
Grain Boundary ◽  
Low Frequency ◽  
Grain Boundary Sliding ◽  
High Temperature Side ◽  
Internal Friction Peak ◽  
Average Grain Size ◽  
Lower Temperature ◽  
Zr Alloy

By using a low frequency inverted torsion pendulum, the high temperature internal friction spectra of Al-0.02wt%Zr and Al-0.1wt%Zr alloys were investigated respectively. In Al-0.02wt%Zr alloy, the conventional grain boundary internal friction peak (Pg) is observed with some small unstable peaks. In Al-0.1wt%Zr alloy, the bamboo peak is observed to appear at the high temperature side of the conventional grain boundary internal friction peak. The conventional grain boundary internal friction peak decreased and moved to higher temperature. The bamboo peak owns an activation energy of 1.75eV. When average grain size exceeded the diameter of samples, Pb strength was reduced and its position was shifted to a lower temperature. Based on the grain boundary sliding model, Pg and Pb peaks were explained. Their dependence on annealing temperature and time was determined by considering the effects of contained Ce atoms and other impurities on the relaxation across grain boundary.

scholarly journals Internal Friction and Dynamic Modulus in Ultra-High Temperature Ru-Nb Functional Intermetallics / Tarcie Wewnętrzne I Moduł Dynamiczny W Bardzo Wysoko Temperaturowych Funkcjonalnych Związkach Międzymetalicznych Z Układu Ru-Nb

2015 ◽  
Vol 60 (4) ◽  
pp. 3069-3072
Author(s):  
M.L. Nó ◽  
L. Dirand ◽  
A. Denquin ◽  
J. San Juan
Keyword(s):  
High Temperature ◽  
Internal Friction ◽  
Martensitic Transformations ◽  
Time Dependent ◽  
Structural Defects ◽  
Complete Analysis ◽  
Internal Friction Peak ◽  
Thermally Activated ◽  
Temperature Ranges ◽  
Lower Temperature

In the present work we have studied the high-temperature shape memory alloys based on the Ru-Nb system by using two mechanical spectrometers working in temperature ranges from 200 to 1450ºC and -150 to 900ºC. We have studied internal friction peaks linked to the martensitic transformations in the range from 300 to 1200ºC. In addition, we have evidenced another internal friction peak at lower temperature than the transformations peaks, which apparently exhibits the behaviour of a thermally activated relaxation peak, but in fact is a strongly time-dependent peak. We have carefully studied this peak and discussed its microscopic origin, concluding that it is related to the interaction of some structural defects with martensite interfaces. Finally, we perform a complete analysis of the whole internal friction spectrum, taking into account the possible relationship between the time-dependent peak and the martensitic transformation behaviour.

Hydrogen-Induced Mechanical Losses in Oxygen-Free Copper

2012 ◽  
Vol 184 ◽  
pp. 122-127 ◽  
Author(s):  
Mykola Ivanchenko ◽  
Yuriy Yagodzinskyy ◽  
H. Hänninen
Keyword(s):  
High Temperature ◽  
Internal Friction ◽  
Oxygen Content ◽  
Hydrogen Atoms ◽  
Internal Friction Peak ◽  
Exponential Factor ◽  
Hydrogen Charging ◽  
High Temperature Component ◽  
Temperature Component ◽  
High Temperature Components

Two oxygen-free copper grades with purity of 99.99 % were studied by means of free decay inverted torsion pendulum at the temperature range of 90 – 300 K and frequencies of 0.5 – 2 Hz. One copper grade was oxygen free electrolytically refined copper with oxygen content of 1.2 wt. ppm. The other one was oxygen-free phosphorous-alloyed grade with oxygen content less than 5 wt. ppm and phosphorous content of 30 – 70 wt. ppm. Electrochemical hydrogen charging induces a complex internal friction peak in the studied copper grades. The observed internal friction peak has a relaxation origin with apparent activation enthalpy and pre-exponential factor for the oxygen-free grade of 0.276 ± 0.002 eV and 10-11.59 ± 0.08 s, respectively. The internal friction peak can be fitted by three broadened Debye peaks (P1, P2 and P3) with activation enthalpies and pre-exponential factors of 0.248 ± 0.003 eV and 10-11.4 ± 0.4 s; 0.297 ± 0.004 eV and 10-11.8 ± 0.2 s; 0.36 ± 0.04 eV and 10-12.7 ± 1.4 s, respectively. Phosphorous doping markedly reduces the height of the observed peak. It was also shown that prior deformation by tension suppresses high-temperature components of the complex internal friction peak. Mechanism of relaxation is presumably caused by interaction of H – H pairs (low-temperature component, peak P1), interaction of hydrogen atoms with dislocations (P2) and interaction of hydrogen with impurities (high-temperature component, peak P3). Absorption of hydrogen in the studied copper grades during electrochemical hydrogen charging was confirmed by the thermal desorption method.

High-Temperature Internal Friction Peak in Al–0.008 wt% Sn Single Crystals

1990 ◽  
Vol 121 (2) ◽  
pp. 475-481 ◽  
Author(s):  
G. Y. Tian ◽  
J. Z. Lu ◽  
S. P. Wu ◽  
L. D. Zhang
Keyword(s):  
High Temperature ◽  
Internal Friction ◽  
Single Crystals ◽  
Internal Friction Peak

High Temperature Internal Friction Relaxations in Cold-Rolled Titanium

2018 ◽  
Vol 279 ◽  
pp. 30-34
Author(s):  
Zheng Cun Zhou ◽  
J. Du ◽  
S.Y. Gu ◽  
Y.J. Yan
Keyword(s):  
Grain Size ◽  
Phase Transformation ◽  
High Temperature ◽  
Internal Friction ◽  
Room Temperature ◽  
Forced Oscillations ◽  
Internal Friction Peak ◽  
Temperature Relaxation ◽  
Cold Rolled ◽  
Cp Ti

The high temperature relaxation in cold-rolled Ti (CR-Ti) and commercial pure Ti (CP-Ti) has been investigated using internal friction apparatus operating in forced oscillations from room temperature to 650°C. It is shown that there is an internal friction peak at around 510°C for the CR-Ti and there is no 510°C internal friction peak in the CP-Ti. The internal friction peak shows typical features of phase transformation in the CR-Ti. It is tentatively suggested that this peak is due to the ordering of disordered lattices resulted from cold-rolling. The high temperature background damping (HTBD) in the CP-Ti is much lower than that in the CR-Ti. It is concluded that the HTBD is related to the microstructure observed inside the grains and does not dependent on grain size.

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