Low‐Frequency Measurements on the Bordoni Internal Friction Peak in Copper

1961 ◽  
Vol 32 (5) ◽  
pp. 895-899 ◽  
Author(s):  
D. H. Niblett
Keyword(s):  
Internal Friction ◽  
Low Frequency ◽  
Internal Friction Peak ◽  
Frequency Measurements

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 of Li7La3Zr2O12 Based Lithium Ionic Conductors

2016 ◽  
Vol 61 (1) ◽  
pp. 21-24
Author(s):  
X.P. Wang ◽  
L. Song ◽  
J. Hu ◽  
Y.P. Xia ◽  
Y. Xia ◽  
...  
Keyword(s):  
Internal Friction ◽  
Tetragonal Phase ◽  
Diffusion Processes ◽  
Low Frequency ◽  
Peak Height ◽  
Cubic Phase ◽  
Ionic Conductors ◽  
Internal Friction Peak ◽  
Lithium Ions ◽  
Diffusion Mechanisms

The diffusion mechanisms of lithium ions in tetragonal phase as well as in Al and Nb stabilized cubic Li7La3Zr2O12 compounds were investigated by low-frequency internal friction technique. In the cubic Li7La3Zr2O12 phase, a remarkable relaxation-type internal friction peak PC with a peak height up to 0.12 was observed in the temperature range from 15°C to 60°C. In the tetragonal phase however, the height of the PT peak dropped to 0.01. The obvious difference of the relaxation strength between the cubic and tetragonal phases is due to the different distribution of lithium ions in lattice, ordered in the tetragonal phase and disordered in the cubic phase. Based on the crystalline structure of the cubic garnet-type Li7La3Zr2O12 compound, it is suggested that the high internal friction peak in the cubic phase may be attributed to two diffusion processes of lithium ions: 96h↔96h and 96h↔24d.

Low-Frequency Damping Behavior of Porous Magnesium

2011 ◽  
Vol 415-417 ◽  
pp. 2002-2007
Author(s):  
Gang Ling Hao ◽  
Qiao Ping Xu ◽  
Fu Sheng Han
Keyword(s):  
Internal Friction ◽  
Thermal Activation ◽  
Low Frequency ◽  
Damping Capacity ◽  
Activation Process ◽  
Internal Friction Peak ◽  
Damping Behavior ◽  
Thermal Activation Process ◽  
Porous Magnesium ◽  
Stress And Strain Distribution

The well-distributed porous magnesium was prepared through powder metallurgy route basing on space-holding method. The damping behavior of the porous magnesium was characterized by internal friction and measured by a multi-function internal friction apparatus. Experimental results revealed that the damping capacity of the porous magnesium was increased compared to that of the bulk magnesium, which can be understood by a dislocation damping mechanism associated with an inhomogeneous stress and strain distribution around the pores. In addition, an internal friction peak was observed in the spectra of internal friction against temperature. It was suggested that the dislocation sliding arising from a thermal activation process should be responsible for the peak appearance.

Study of Martensitic Transformation in Tini Intermetallic by the Methods of Low Frequency Internal Friction

2013 ◽  
Vol 738-739 ◽  
pp. 377-382 ◽  
Author(s):  
Galina Viktorovna Markova ◽  
Alexander V. Shuytcev ◽  
Anatoliy V. Kasimtcev
Keyword(s):  
Martensitic Transformation ◽  
Internal Friction ◽  
Heating Rate ◽  
Present Article ◽  
Strain Amplitude ◽  
Oscillation Frequency ◽  
Low Frequency ◽  
Equiatomic Composition ◽  
Thermoelastic Martensitic Transformation ◽  
Internal Friction Peak

The present article is dedicated to the study of thermoelastic martensitic transformation in the TiNi equiatomic composition by low-frequency internal friction. Considered the influence of oscillation frequency, strain amplitude and heating rate on the internal friction peak of the martensitic nature.

scholarly journals Low-Frequency Mechanical Spectroscopy of Lanthanum Cobaltite Based Mixed Conducting Oxides

2016 ◽  
Vol 61 (3) ◽  
pp. 1733-1738
Author(s):  
Xiu Sheng Wu ◽  
Ju Fang Cao ◽  
Zhi Jun Chen ◽  
Wei Liu
Keyword(s):  
Phase Transition ◽  
Internal Friction ◽  
Domain Walls ◽  
Low Frequency ◽  
Partial Substitution ◽  
Cubic Phase ◽  
Mechanical Spectroscopy ◽  
Internal Friction Peak ◽  
Lanthanum Cobaltite ◽  
Conducting Oxides

Abstract The low-frequency mechanical spectra of lanthanum cobaltite based mixed conducting oxides have been measured using a computer-controlled inverted torsion pendulum. The results indicate that the internal friction spectra and shear modulus depend on the Sr doping contents (x). For undoped samples, no internal friction peak is observed. However, for La0.8Sr0.2CoO3‒δ, three internal friction peaks (P2, P3 and P4) are observed. In addition to these peaks, two more peaks (P0 and P1) are observed in La0.6Sr0.4CoO3‒δ. The P0 and P1 peaks show characteristics of a phase transition, while the P2, P3 and P4 peaks are of relaxation-type. Our analysis suggests that the P0 peak is due to a phase separation and the P1 peak is related to the ferromagnetic–paramagnetic phase transition. The P2, P3 and P4 peaks are associated with the motion of domain walls. The formation of this kind of domain structure is a consequence of a transformation from the paraelastic cubic phase to the ferroelastic rhombohedral phase. With partial substitution of Fe for Co, only one peak is observed, which is discussed as a result of different microstructure.

Development of the Snoek Anelastic Relaxation Correlated with Oxygen in β-Ti Alloys

2019 ◽  
Vol 298 ◽  
pp. 59-63 ◽  
Author(s):  
Zheng Cun Zhou ◽  
J. Du ◽  
S.Y. Gu ◽  
Y.J. Yan
Keyword(s):  
Internal Friction ◽  
Physical And Mechanical Properties ◽  
Peak Height ◽  
Relaxation Peak ◽  
Interstitial Oxygen ◽  
Internal Friction Peak ◽  
Β Phase ◽  
Ti Alloys ◽  
Interstitial Atoms ◽  
The Stability

The β-Ti alloys exhibit excellent shape memory effect and superelastic properties. The interstitial atoms in the alloys have important effect on their physical and mechanical properties. For the interstitial atoms, the internal friction technique can be used to detect their distributions and status in the alloys. The anelastic relaxation in β-Ti alloys is discussed in this paper. β-Ti alloys possesses bcc (body center body) structure. The oxygen (O) atoms in in the alloys is difficult to be removed. The O atoms located at the octahedral sites in the alloys will produce relaxation under cycle stress. In addition, the interaction between the interstitial atoms and substitute atoms, e.g., Nb-O,Ti-O can also produce relaxation. Therefore, the observed relaxational internal friction peak during the measuring of internal friction is widened. The widened multiple relaxation peak can be revolved into Debye,s elemental peaks in Ti-based alloys. The relaxation peak is associated with oxygen movements in lattices under the application of cycle stress and the interactions of oxygen-substitute atoms in metastable β phase (βM) phase for the water-cooled specimens and in the stable β (βS) phase for the as-sintered specimens. The damping peak height is not only associated with the interstitial oxygen, but also the stability and number of βM in the alloys.

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