Snoek Relaxation in bcc Metals and High Damping β-Ti Alloys

2009 ◽  
Vol 614 ◽  
pp. 175-180 ◽  
Author(s):  
Fu Xing Yin ◽  
Li Ming Yu ◽  
De Hai Ping ◽  
Satoshi Iwasaki
Keyword(s):  
Internal Friction ◽  
Temperature Stability ◽  
Relaxation Mechanism ◽  
Peak Height ◽  
Damping Capacity ◽  
Internal Friction Peak ◽  
Friction Mechanism ◽  
Bcc Metals ◽  
Temperature Position ◽  
Snoek Relaxation

The Snoek relaxation, a specific point-defect induced anelastic relaxation phenomenon, is characteristic of an internal friction peak in bcc metals with interstitial solutes. Such internal friction mechanism has not been applied in the development of high damping alloy while grain boundary and twin boundary featured anelastic relaxations are applied in some high damping alloys. In this paper, the fundamental principles and experimental results concerning the Snoek relaxation are reviewed, and the feasibility to apply the Snoek relaxation mechanism into high damping alloys is discussed. Due to the peak-shape behavior in the Snoek relaxation type damping, composition design of a high damping alloys should takes temperature position, broadness and also peak height into account. Ti-Nb-O and Ti-V-Cr-O alloys are designed and fabricated by CCLM casting in our laboratory. It is conformed that the damping behaviors of the alloys are of Snoek relaxation type showing obvious frequency and temperature dependence. While the broadened damping peak caused by the substitutional solutes is advantage to improve the temperature stability of damping capacity, a large concentration of interstitial solute and texture control are required to improve the reduced damping capacity.

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.

Internal Friction Influenced by Hydrogen in Super Duplex Stainless Steels

2005 ◽  
Vol 502 ◽  
pp. 345-350
Author(s):  
Toshio Kuroda ◽  
Katsuyuki Nakade ◽  
Kenji Ikeuchi
Keyword(s):  
Internal Friction ◽  
Stainless Steels ◽  
Sigma Phase ◽  
Peak Height ◽  
Phase Precipitation ◽  
Internal Friction Peak ◽  
Hydrogen Charging ◽  
Super Duplex Stainless Steels ◽  
Two Peaks ◽  
Friction Analysis

The influence of microstructure concerning sigma phase on hydrogen behavior was investigated by means of internal friction analysis. After hydrogen charging, a sharp significant internal friction peak by hydrogen in austenite of as-received specimen was observed at 245K for a frequency of 1.5Hz. However, the peak height in the specimen precipitated significant sigma phase was substantially lower than in as-received specimen since hydrogen in austenite have a concentration lower by sigma phase precipitation. In addition, the broadening and scattering of the internal friction peak was clearly identified by interaction between hydrogen and sigma phase. It means that the two peaks associated with hydrogen in the both sigma phase and austenite were considered to be overlapped. Consequently, it was clearly confirmed that hydrogen entered in the sigma phase lattice and hydrogen was also trapped at sigma/austenite interfaces.

Study on Damping Capacities of Nodular Cast Iron Dense Bar Produced by Horizontal Continuous Casting

2011 ◽  
Vol 399-401 ◽  
pp. 250-253
Author(s):  
Zhong Ming Zhang ◽  
Jin Cheng Wang ◽  
Chun Jie Xu ◽  
Wei Ming Li ◽  
Gang Wang
Keyword(s):  
Cast Iron ◽  
Internal Friction ◽  
Continuous Casting ◽  
Nodular Cast Iron ◽  
Damping Capacity ◽  
Temperature Dependent ◽  
Horizontal Continuous Casting ◽  
Increasing Temperature ◽  
Snoek Relaxation ◽  
Superposition Effect

Damping capacities of the annealed nodular cast iron dense bar produced by horizontal continuous casting were measured by Dynamic Mechanical Analyzer. The relation of damping capacities with vibration amplitude, frequency and temperature was analyzed to investigate the damping mechanism of the alloy. The results show that the damping capacities increase with increasing temperature and frequency. The internal friction spectra exhibits two internal friction peaks at about 40°C and 150°C and caused by Snoek relaxation and Snoek-Köster relaxation, respectively. The maximum damping capacity can be obtained at about 63Hz. The damping is positive amplitude-dependent, whereas critical amplitude exists where the damping increases dramatically. The temperature-dependent damping results from the superposition effect of point-defect damping, grain boundary damping and interface damping, while dislocation damping is predominant in the frequency dependent damping. The amplitude dependent damping can be interpreted by G-L theory.

Microstructure and Damping Capacity of AlNp/Mg-Al Composites with Different Particle Contents

2017 ◽  
Vol 898 ◽  
pp. 933-943 ◽  
Author(s):  
Yong Wang ◽  
Kai Ming Cheng ◽  
Ji Xue Zhou ◽  
Yuan Sheng Yang
Keyword(s):  
Internal Friction ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composites ◽  
Damping Capacity ◽  
Matrix Composites ◽  
Internal Friction Peak ◽  
Experimental Frequency ◽  
The Matrix ◽  
Temperature Ranges ◽  
Interface Sliding

The AlN particles reinforced magnesium-aluminum matrix composites were fabricated by powder metallurgy and the damping mechanism was discussed. The results showed that the best damping capacity of composite reached with the addition of 6wt% AlN reinforcement, while the AlN particles were uniformly dispersed in the matrix. The damping capacity of composites decreases with the increasing of the reinforcement content and the experimental frequency. The internal friction peak related to dislocation appearance in the temperature ranges of 100-150°C. In addition, another internal friction peak of composites between 200 and 250°C arose, which was related to interface sliding.

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.

Can Metallic Glass Damping Be Increased by Stress Training Treatment?

2006 ◽  
Vol 319 ◽  
pp. 145-150
Author(s):  
Tiburce A. M. Aboki
Keyword(s):  
Stress Concentration ◽  
Low Temperature ◽  
Internal Friction ◽  
Thermal Cycle ◽  
Atomic Clusters ◽  
Damping Capacity ◽  
Strength Increase ◽  
Internal Friction Peak ◽  
Glassy Alloys ◽  
Glassy Sample

We have subjected Zr59Cu20Al10Ni8Ti3 glassy sample to internal friction thermal cycle (IFTC) measurements under various conditions involving changes in heating/cooling rate, strain amplitude and frequency. Additional low temperature internal friction peaks (ALTIFP) were found to occur with the characteristic low temperature internal friction peak (CLTIFP) observed for some glassy alloys. The ALTIFP were enhanced on heating and reduced on cooling. Their strength increase following the number of IFTC can be related to a stress concentration in some zones of the glassy structure, which is abruptly relaxed by the viscous flow creating interfaces in the glassy structure. These interfaces are likely to be formed between atomic clusters. The growth of the ALTIFP increases significantly the whole IF level (IFL) from 10-4 to 10-2 enhancing the damping capacity of the glassy sample.

Internal Friction Study of Vacancy Hardening in B2 Fe Al Alloys

2012 ◽  
Vol 184 ◽  
pp. 81-86 ◽  
Author(s):  
Yoichi Nishino ◽  
Kazuya Ogawa ◽  
H. Tanaka
Keyword(s):  
Plastic Strain ◽  
Internal Friction ◽  
Strain Amplitude ◽  
Peak Height ◽  
Dislocation Motion ◽  
Al Alloys ◽  
Anomalous Increase ◽  
Internal Friction Peak ◽  
Quenching Temperature ◽  
Friction Study

nternal friction behaviour of B2 FeAl alloys has been examined to reveal the correlation of the microplasticity and thermal vacancies. The internal friction peak for Fe60Al40 appears at around 550 K, and the peak height increases with increasing quenching temperature. The curves of internal friction against the strain amplitude shift to larger strain amplitude as the quenching temperature increases. Analysis of the amplitude-dependent internal friction provides the plastic strain of the order of 10-9 as a function of effective stress on dislocation motion. It is found that the microflow stress at the plastic strain of 1×10-9 increases linearly with the square root of the net peak height. Remarkably, the microflow stress decreases with rising temperature but turns to increase above 500 K when measured after holding for 1 h at test temperatures. The anomalous increase in the microflow stress is caused by the creation of thermal vacancies at intermediate temperatures.

High Damping Performance of Hydrogenated Bulk Metallic Glasses

2006 ◽  
Vol 319 ◽  
pp. 133-138 ◽  
Author(s):  
H. Mizubayashi ◽  
K. Yamagishi ◽  
H. Tanimoto
Keyword(s):  
Internal Friction ◽  
Concentration Dependence ◽  
Metallic Glasses ◽  
Structural Relaxation ◽  
High Strength ◽  
Peak Height ◽  
Point Of View ◽  
The Other ◽  
Internal Friction Peak ◽  
Material Parameters

Hydrogenated Zr-Cu-base metallic glasses (MGs) are the potential high-damping and high-strength materials. On the other hand, the knowledge on the material parameters which govern the peak temperature, Tp, and the peak height, Q-1 p, of the hydrogen internal friction peak (HIFP) remains poor. In order to pursue this issue, the hydrogen concentration dependence of Tp and Q-1 p in the Zr-Cu-base MGs were investigated in the point of view of the hydrogen induced structural relaxation (HISR). It is found that the Tp vs. CH data and the Q-1 p vs. CH data are well fitted by the relationships of Tp = Tp exp(-CH/τH) +Tp,0 and Qp -1 ∝ ln(CH/τH), respectively, for various Zr-Cu-base MGs including bulk MGs, Zr55Cu30Al10Ni5 and Zr60Cu30Al10. That is, the observed relationship between Tp and CH is mainly governed by HISR. It is suggested that Tp,0 in Zr-Cu-base MGs is the highest among various MGs resulting in the highest Tp in Zr-Cu-base MGs. In other words, the control of Tp,0 is the key issue to find the high-Tp MGs.

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.

Internal Friction of Polymer Composites with Nanosilicas Fabricated by Ultraviolet Irradiation

2011 ◽  
Vol 24 (6) ◽  
pp. 767-776
Author(s):  
G.C. Xu ◽  
B.H. Yao ◽  
H.L. Xing ◽  
X.M. Zhang
Keyword(s):  
Activation Energy ◽  
Internal Friction ◽  
Polymer Composites ◽  
Vibration Frequency ◽  
Ultraviolet Irradiation ◽  
Peak Height ◽  
Polymer Chains ◽  
Internal Friction Peak ◽  
Friction Behavior ◽  
Nanocomposite Polymer

The internal friction behavior of the nanocomposite polymer was studied using a multifunction internal friction apparatus. It is shown that the internal friction peak in the polymer has relaxation feature and the peak height is almost independent of frequency for the polymer without nanosilica. Nevertheless, the peak height in the polymer with nanosilica increases not only with increasing vibration frequency, but also with increasing nanosilica content, which results from the stronger interaction between nanosilica with polymer chains. For the nanocomposite polymer with 3 wt.% nanosilica, the activation energy of polymer chain motion is higher than that of neat copolymers.

Sign in / Sign up

Export Citation Format

Share Document