Effect of Isothermal Ageing on Damping Capacity of Cu-20.4Al-8.7Mn

2012 ◽  
Vol 268-270 ◽  
pp. 312-315
Author(s):  
Gang Ling Hao ◽  
Qiao Ping Xu ◽  
Wei Guo Wang
Keyword(s):  
Internal Friction ◽  
Room Temperature ◽  
Ageing Temperature ◽  
Damping Capacity ◽  
Temperature Ageing ◽  
Changing Trend ◽  
Higher Temperature ◽  
Friction Measurements ◽  
Isothermal Ageing ◽  
Lower Temperature

The effect of ageing temperature on damping capacity of the Cu-20.4Al-8.7Mn alloy at room temperature was investigated by internal friction measurements. The results indicated that damping capacity of the alloy exhibits a non-monotonous changing trend with ageing temperature. Ageing at lower temperature of less than 150oC, damping capacity rapidly increses even up to maximum of 0.01 with the increasing ageing temperature, the reason of which should relate with the increased amount of twin boundaries and phase interfaces between martensites due to the thinning and splitting of martensitic plates, whereas when the ageing temperature exceeds 150oC, the damping capacity trends to steeply decrease as the ageing temperature increases until close to a constant in last corresponding to the ageing at higher temperature due to the occurrence and complete finish of transformation of martensites to austenites.

Effect of H-Doping on Damping Capacity of Various NiTi-Based Alloys at kHz Frequencies

2006 ◽  
Vol 128 (3) ◽  
pp. 254-259 ◽  
Author(s):  
B. Coluzzi ◽  
A. Biscarini ◽  
G. Mazzolai ◽  
F. M. Mazzolai ◽  
A. Tuissi
Keyword(s):  
Internal Friction ◽  
Twin Boundary ◽  
Room Temperature ◽  
Mechanical Energy ◽  
Noise Pollution ◽  
Metal Alloy ◽  
Maximum Efficiency ◽  
Damping Capacity ◽  
Good Opportunity ◽  
Hydrogen Doping

The internal friction Q−1 and the Young’s modulus E of NiTi based alloys have been measured as a function of temperature after various thermomechanical and hydrogen-doping treatments given to the materials. Hydrogen is found to play a major role introducing tall damping peaks associated with Snoek-type and H-twin boundary relaxations. Levels of Q−1 as high as 0.08 have been detected, which are among the highest to date measured in metal alloy systems. For appropriate alloy compositions, these peaks occur at around room temperature (for acoustical frequencies), thus providing a good opportunity to reduce machinery vibrations and noise pollution. In the paper, the conditions are highlighted under which maximum efficiency can be reached in the conversion of mechanical energy into heat.

Effect of Aging Treatment on Damping Capacity in Mncunife Alloy

2012 ◽  
Vol 246-247 ◽  
pp. 1158-1162
Author(s):  
Xu Fu ◽  
Ning Li ◽  
Yu Hua Wen ◽  
Jing Teng ◽  
Ying Zhang
Keyword(s):  
Electron Microscope ◽  
Aging Treatment ◽  
Damping Capacity ◽  
Torsion Pendulum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Higher Temperature ◽  
Lower Temperature ◽  
The Relationship

M2052 alloys with various aging treatments are obtained in order to investigate the relationship between aging treatment and damping capacity by the torsion pendulum, X-Ray Diffraction (XRD) and Transmission Electron Microscope (TEM) methods. The results show that M2052 can obtain high damping capacity (δ>0.2) when aged at a range from 400°C to 450°C, and the damping capacity after aged at a lower temperature is higher than that aged at a higher temperature for the maximum values. TEM and XRD results show that fcc-fct transformation occurs after aging treatment. The volumes of fct structures are one of reason to affect the damping capacity in M2052 alloy. The better understanding aging treatment could promote the applications of M2052 alloy.

Effects of Interphase Thickness on Damping Behavior of 2D C/SiC Composites

2007 ◽  
Vol 546-549 ◽  
pp. 1531-1534 ◽  
Author(s):  
Qing Zhang ◽  
Lai Fei Cheng ◽  
Wei Wang ◽  
Xi Wei ◽  
Li Tong Zhang ◽  
...  
Keyword(s):  
Internal Friction ◽  
Chemical Vapor ◽  
Mechanical Analysis ◽  
Chemical Vapor Infiltration ◽  
Damping Capacity ◽  
Air Atmosphere ◽  
Damping Behavior ◽  
Sic Composites ◽  
Lower Temperature ◽  
Damping Peak

Internal friction of 2D C/SiC composites fabricated by chemical vapor infiltration (CVI) method was measured by dynamical mechanical analysis (DMA) at different frequencies from room temperature (RT) to 400°C in air atmosphere. Internal friction of 2D C/SiC composites increased gradually with increasing temperature and then decreased after damping peak appeared in the temperature range of 250°C to 300°C. Damping capacity and peak value decreased gradually with increasing frequency, accompanied with a shift of damping peak towards lower temperatures. Moreover, the effect of interphase thickness on damping behavior of 2D C/SiC composites was investigated. The results showed that damping peak of the composites increased gradually and the temperature of the peak shifted to the lower temperature with increasing PyC interphase thickness, when the interphase thickness is in the range of 90~296nm. The influence of interphase thickness on interfacial bonding strength, sliding resistance and the microstructure of SiC matrix was discussed, which was considered to be responsible for the results.

scholarly journals PHOTODYNAMIC HEMOLYSIS AT LOW TEMPERATURES

1954 ◽  
Vol 37 (3) ◽  
pp. 301-311 ◽  
Author(s):  
Harold F. Blum ◽  
Elizabeth Flagler Kauzmann
Keyword(s):  
Solid State ◽  
Low Temperatures ◽  
Room Temperature ◽  
Photosensitized Oxidation ◽  
Higher Temperature ◽  
Semi Solid ◽  
Lower Temperature ◽  
Dye Molecule

It is shown that photodynamic hemolysis may occur at –79°C. if the erythrocytes are suspended in a solution containing 70 per cent glycerol which prevents hemolysis by freezing; but that there is no hemolysis under the same conditions at –210°C. At the higher temperature the viscosity of the solution is still low enough to permit appreciable movement of molecules, whereas at the lower temperature the molecules must be virtually immobile. The findings are compatible with the idea that the dye molecule acts in a cycle, bringing about successive oxidations by O2 molecules, as has been shown for photodynamic hemolysis at room temperature. The assumption of a combination between dye, O2, and substrate does not explain photosensitized hemolysis in the semi-solid state. The mechanism of photosensitized oxidation by O2 is discussed.

Antiferromagnetic Transition and Martensite Transformation in γ-Mn-Fe Alloys

2010 ◽  
Vol 146-147 ◽  
pp. 916-919
Author(s):  
Su Yi Gu ◽  
Ji Hua Zhang
Keyword(s):  
Internal Friction ◽  
Dynamic Modulus ◽  
Martensite Transformation ◽  
Magnetic Domain ◽  
Antiferromagnetic Transition ◽  
Friction Temperature ◽  
Induced Motion ◽  
Higher Temperature ◽  
Fe Alloys ◽  
Lower Temperature

The detailed investigation of internal friction and relative dynamic modulus has been carried out for the γ-MnFe alloys with 61.4at%~86.4at%Mn in the temperature range from -50 to 250 using LMR by means of force vibration method. The internal friction was found to exhibit in turn three peaks from higher temperature to the lower temperature on the internal friction-temperature curves. They are PA,PM and PT progressively. It can be concluded that PA may be connected with the stress-induced motion of magnetic domain. The PM was suggested to be originated from the stress-induced movement of interfaces between the fcc and fct phases. The PT is due to a relaxation process associated with the movement of the {101}-twin boundaries in the fct phase or fcc antiferromagnetic phase.

Wet forming, sintering behavior, and dielectric properties of BaTi0.8Zr0.2O3

1996 ◽  
Vol 11 (12) ◽  
pp. 3071-3076 ◽  
Author(s):  
Yoshihiro Hirata ◽  
Takahiro Kawazoe
Keyword(s):  
Dielectric Properties ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Lattice Parameter ◽  
Sintering Behavior ◽  
Ferroelectric State ◽  
Uniform Microstructure ◽  
Higher Temperature ◽  
Lower Temperature ◽  
Diffuse Phase

Density, grain size, lattice parameter, and dielectric properties were measured on BaTi0.8Zr0.2O3 sintered at 1100–1600 °C. The hydrothermally prepared BaTi0.8Zr0.2O3 particles of 128 nm diameter were consolidated by filtration of 2-methoxyethanol suspensions and subsequently compressed by isostatic pressing under a pressure of 294 MPa to form a uniform microstructure of high density (52% of the theoretical density). These green compacts were sintered to a relative density of above 99% in the temperature range from 1350 to 1600 °C where rapid grain growth to above 30 μm occurred. Increase of sintering temperature was accompanied by the increase of lattice parameter and dielectric constant of BaTi0.8Zr0.2O3 at room temperature. The sintered BaTi0.8Zr0.2O3 showed a diffuse phase transition from paraelectric (higher temperature) to ferroelectric state (lower temperature) at 32 °C.

Influences of Annealing and Deformation on the High Temperature Internal Friction Spectra of Al-0.013%Wt Ce Alloy

2011 ◽  
Vol 197-198 ◽  
pp. 1573-1576
Author(s):  
Xiao Hui Cao ◽  
Shou Jing Wang
Keyword(s):  
High Temperature ◽  
Internal Friction ◽  
Grain Boundary ◽  
Low Frequency ◽  
Grain Boundary Sliding ◽  
Boundary Sliding ◽  
Higher Temperature ◽  
Lower Temperature ◽  
Two Peaks ◽  
Internal Friction Spectra

By using a low frequency inverted torsion pendulum, the high temperature internal friction spectra of Al-0.013wt%Ce alloy subjected to deformation at different tensile rates was measured, and three peaks, the conventional grain boundary peak (P1), the bamboo peak (P2) and the soild solution peak (P3) were found. Increases of annealing temperature and deformation rate make P1 and P2 lower with P1 shifting to higher temperature and P2 to lower temperature. P3 was only found in the as-received samples. The dependence of P1 and P2 on grain size indicates that the two peaks are originated from the grain boundary sliding, and P3 may be associated with the diffusion of Ce atoms or other impurities at grain boundaries.

scholarly journals Tailoring Multi-Level Structural and Practical Features of Gelatin Films by Varying Konjac Glucomannan Content and Drying Temperature

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 385
Author(s):  
Dongling Qiao ◽  
Zhong Wang ◽  
Chi Cai ◽  
Song Yin ◽  
Hong Qian ◽  
...  
Keyword(s):  
Structural Changes ◽  
Structural Features ◽  
Konjac Glucomannan ◽  
Multi Scale ◽  
Gelatin Films ◽  
Film Forming ◽  
Changing Trend ◽  
Higher Temperature ◽  
Multi Level ◽  
Lower Temperature

Here, we tailored the multi-level structural and practical (mechanical/hydrophilic) features of gelatin films by varying the konjac glucomannan (KGM) content and the film-forming temperatures (25 and 40 °C). The addition of KGM apparently improved the mechanical properties and properly increased the hydrophilicity. With the lower temperature (25 °C), the increase in KGM reduced the gelatin crystallites of films, with detectable KGM–gelatin interactions, nanostructures, and micron-scale cracks. These structural features, with increased KGM and negligibly-occurred derivatizations, caused initially an insignificant decrease and then an increase in the strength, with a generally-increased elongation. The higher temperature (40 °C) could reduce the strength and slightly increase the elongation, related to the reduced crystallites of especially gelatin. With this higher temperature, the increase in KGM concurrently increased the strength and the elongation, mainly associated with the increased KGM and crystallites. Additionally, the increase in KGM made the film more hydrophilic; the multi-scale structural changes of films did not dominantly affect the changing trend of hydrophilicity.

Training Effects on Damping Capacity in Mn-22.5mass%Cu-5mass%Ni-2mass%Fe Alloy

2012 ◽  
Vol 706-709 ◽  
pp. 2026-2031 ◽  
Author(s):  
Yoshimi Watanabe ◽  
Yuusuke Suga ◽  
Eri Miura-Fujiwara ◽  
Hisashi Sato ◽  
Yoichi Nishino
Keyword(s):  
Thermal Cycling ◽  
Shape Memory ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Damping Capacity ◽  
Training Effects ◽  
Solution Treated ◽  
Free Decay ◽  
Lower Temperature ◽  
Thermal Training

The training treatments in the shape memory alloy are known as useful method to improve the shape memory effect. In our previous study, it was shown that the training treatments can also improve both the damping capacity and the hardness of the Fe–Mn alloy. In this study, training effects on damping capacity in solution treated Mn-22.5mass%Cu-5.08mass%Ni-1.96mass%Fe alloy have been investigated. As training treatments, the thermal training (only thermal cycling) and the thermo-mechanical training (thermal cycling with deformation) are carried out. Internal friction was measured at room temperature (R. T.) using a free-decay method. Although training effect cannot be found for the samples trained at higher annealing temperature (600 °C and 700 °C), damping capacity of the alloy is improved by thermal training annealed at 400 °C and 500 °C. The trade-off between the damping capacity and mechanical properties can be overcome by the training at lower temperature.

STUDY OF THE Cu-Zn-Al MARTENSITE AGING BY INTERNAL FRICTION MEASUREMENTS

1987 ◽  
Vol 48 (C8) ◽  
pp. C8-567-C8-572
Author(s):  
M. MORIN ◽  
M. HAOURIKI ◽  
G. GUENIN
Keyword(s):  
Internal Friction ◽  
Friction Measurements
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