AN ANOMALOUS INTERNAL FRICTION PEAK IN Au3Cu

1981 ◽  
Vol 42 (C5) ◽  
pp. C5-951-C5-956
Author(s):  
K. Iwasaki
Keyword(s):  
Internal Friction ◽  
Internal Friction Peak

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.

scholarly journals On Glass Forming Ability of Bulk Metallic Glasses by Relating the Internal Friction Peak Value

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 767
Author(s):  
Xianfeng Zhang ◽  
Xiao Cui ◽  
Zhuotong Du ◽  
Fangqiu Zu ◽  
Jinjing Li ◽  
...  
Keyword(s):  
Internal Friction ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Glass Forming Ability ◽  
Liquid Region ◽  
Internal Friction Peak ◽  
Glass Forming ◽  
Constituent Elements ◽  
Valid Criterion ◽  
Peak Value

The internal friction (IF) behaviors of a series of LaCe-, Zr-, and La-based bulk metallic glasses (BMGs) were studied by a computer-controlled, conventional inverted torsion pendulum. The results indicate that with an increasing temperature, the IF also increases gradually in the supercooled liquid region, followed by a decrease caused by crystallization. BMGs with a good glass forming ability (GFA) usually possess a high IF peak value for an alloy system with the same constituent elements. Furthermore, the magnitude of the IF value (Qi−1) of the inflection point is an efficient criterion of GFA. The Qi−1 value is a valid criterion under the conditions of identical constituent elements and different element contents. However, Qi−1 and GFA have no relationship among different alloy systems.

High-Temperature Mechanical Relaxation due to Dislocation Motion inside Dislocation Networks

2008 ◽  
Vol 137 ◽  
pp. 21-28 ◽  
Author(s):  
Andre Rivière ◽  
Michel Gerland ◽  
Veronique Pelosin
Keyword(s):  
Internal Friction ◽  
Relaxation Effect ◽  
Dislocation Motion ◽  
Relaxation Peak ◽  
Mechanical Relaxation ◽  
In Situ Tem ◽  
Mechanical Spectroscopy ◽  
Internal Friction Peak ◽  
First Case ◽  
Dislocation Walls

Internal friction peaks observed in single or polycrystals are clearly due to a dislocation relaxation mechanism. Because a sample observed by transmission electron microscopy (TEM) often exhibits in the same time various dislocation microstructures (isolated dislocations, dislocation walls, etc.) it is very difficult to connect the observed relaxation peak with a particular dislocation microstructure. Using isothermal mechanical spectroscopy (IMS), it is easier to compare, for instance, the evolution of a relaxation peak with measurement temperature to the microstructural evolution observed by in-situ TEM at the same temperatures. IMS was used to study a relaxation peak in a 5N aluminium single crystal firstly 1% cold worked and then annealed at various temperatures. TEM experiments performed in the same material at various temperatures equal to the temperatures used for the damping experiments made possible to link this internal friction peak with a relaxation effect occurring inside dislocation walls. In two other experiments in a 4N aluminium polycrystal and in a metal matrix composite with SiC whiskers, it is shown that the observed relaxation peaks are connected to the motion of dislocations inside polygonization boundaries in the first case and in dislocation pile-ups around each whisker in the second one. Theoretical models proposed to explain such relaxation peaks due to a dislocation motion inside a dislocation wall or network are discussed.

Reaction Mechanisms of Li5La3Ta2O12 Powder with Ambient Air: H+/Li+ Exchange with Water

2012 ◽  
Vol 463-464 ◽  
pp. 123-127 ◽  
Author(s):  
Wei Guo Wang ◽  
Qian Feng Fang ◽  
Gang Ling Hao
Keyword(s):  
Internal Friction ◽  
Lithium Ion ◽  
Ambient Air ◽  
Exchange Property ◽  
Measured Temperature ◽  
Internal Friction Peak ◽  
Lower Temperature ◽  
Lithium Ion Conductors ◽  
Grain Surface ◽  
Water Gas

The proton/lithium exchange property of the garnet-related lithium-ion conductors Li5La3Ta2O12 is shown to occur at room temperature under ambient air. The internal friction, TGA analysis, and IR spectroscopy techniques are used to investigate the reaction mechanism. XRPD analysis demonstrates the topotactic character of the exchange reaction. The water gas in ambient air is adsorbed on the grain surface and then to exchange proton for lithium ion into the garnet structure,(Li5-xHx)La3Ta2O12. The H+/Li+ exchanging processes are reversible. When the measured temperature is higher over 573K, the internal friction peak gradually shifts toward lower temperature and the like garnet-like phase is recovered.

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.

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