Fabrication and Damping Properties of Porous Cu

2012 ◽  
Vol 560-561 ◽  
pp. 1078-1083
Author(s):  
Jin Xiang Wang ◽  
Xiao Bo Peng
Keyword(s):  
Low Temperature ◽  
Internal Friction ◽  
Grain Boundaries ◽  
Mechanical Model ◽  
Damping Capacity ◽  
Temperature Peak ◽  
Damping Properties ◽  
Infiltration Process ◽  
Bulk Metal ◽  
Damping Behavior

The porous Cu specimens were prepared using infiltration process. Its damping behavior was investigated using multifunction internal friction apparatus over the temperature range from 40°C to 500°C.The size of macroscopic pore is in the order of a millimeter (1.0mm) and in large proportions, typically up to 60vol%. The measured IF (internal friction) shows that the damping capacity of porous Cu is higher than that of its bulk metal. It’s found that two IF peaks present at the internal friction against temperature curves at around 280°C and 400°C.The high-temperature arises from the relaxation of grain boundaries. The low-temperature peak may origin from the interaction of dislocation and grain boundaries. TEM observations showed the dislocation substructures exist in the porous Cu. Based on the observed experimental phenomena, a four-parameter mechanical model was used for describing the operative damping mechanism of the low-temperature peak in the porous Cu specimen.

Effects of Macroscopic Pores on the Damping Behaviors of Metal Materials

2011 ◽  
Vol 66-68 ◽  
pp. 1155-1162
Author(s):  
Jian Ning Wei ◽  
Gen Mei Li ◽  
Li Ling Zhou ◽  
Xue Yun Zhou ◽  
Jian Min Yu ◽  
...  
Keyword(s):  
Internal Friction ◽  
Pure Aluminum ◽  
Air Pressure ◽  
Damping Capacity ◽  
Infiltration Process ◽  
Pressure Infiltration ◽  
Temperature Range ◽  
Commercially Pure ◽  
Damping Behavior ◽  
Metal Materials

A large number of macroscopic pores were introduced into commercially pure aluminum (Al) and Zn-Al eutectoid alloy by air pressure infiltration process to comparatively study the influence of macroscopic pores on the damping behaviors of the materials. Macroscopic pores size are on the order of a millimetre (0.5~1.4mm) and in large proportions, typically high 76vol.%. The damping behavior of the materials is characterized by internal friction (IF). The IF was measured on a multifunction internal friction apparatus (MFIFA) at frequencies of 0.5, 1.0 and 3.0 Hz over the temperature range of 25 to 400 °C, while continuously changing temperature. The damping capacity of the metal materials is shown to increase with introducing macroscopic pores. Finally, the operative damping mechanisms in the metal materials with macroscopic pores were discussed in light of IF measurements.

Effects of Macroscopic Pores on the Damping Behavior of Zn-Al Eutectoid Alloy

2012 ◽  
Vol 182-183 ◽  
pp. 213-216
Author(s):  
J.N. Wei ◽  
X.B. Chao ◽  
T.C. Huang ◽  
L.S. Yu ◽  
J.S. Zou ◽  
...  
Keyword(s):  
Internal Friction ◽  
Heating Temperature ◽  
Air Pressure ◽  
Damping Capacity ◽  
Alloy Specimen ◽  
Infiltration Process ◽  
Pressure Infiltration ◽  
Temperature Range ◽  
Damping Behavior ◽  
Eutectoid Alloy

The objective of present work is to investigate the effect of macroscopic pores on the damping behavior of Zn-Al eutectoid alloy. The damping behavior of the foamed Zn-Al (FZA) eutectoid alloy prepared by air pressure infiltration process with macroscopic pores is characterized by internal friction (IF). Macroscopic pores size are on the order of a millimetre (0.51.0mm). The IF was measured on a multifunction internal friction apparatus (MFIFA) at frequencies of 0.5, 1.0 and 3.0 Hz over the temperature range of 25 to 400°C, while continuously heating temperature. The damping capacity of the FZA eutectoid alloy, with two different porosity and sizes of macroscopic pores, were compared with that of bulk Zn-Al eutectoid alloy specimen. The damping capacity of the materials is shown to increase with introducing macroscopic pores. Finally, the operative damping mechanisms in the FZA eutectoid alloy were discussed in light of IF measurements.

Search for High Damping Metallic Glasses

2006 ◽  
Vol 319 ◽  
pp. 151-156 ◽  
Author(s):  
Y. Hiki ◽  
M. Tanahashi ◽  
Shin Takeuchi
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Internal Friction ◽  
Metallic Glass ◽  
Room Temperature ◽  
Temperature Stability ◽  
Temperature Peak ◽  
High Temperature Side ◽  
Side Slope ◽  
Temperature Side

In a hydrogen-doped metallic glass, there appear low-temperature and high-temperature internal friction peaks respectively associated with a point-defect relaxation and the crystallization. The high-temperature-side slope of low-temperature peak and also the low-temperature-side slope of high-temperature peak enhance the background internal friction near the room temperature. A hydrogen-doped Mg-base metallic glass was proposed as a high-damping material to be used near and somewhat above the room temperature. Stability of the high damping was also checked.

Effect of plastic deformation on the shape and parameters of the low-temperature peak of internal friction in niobium

1999 ◽  
Vol 25 (7) ◽  
pp. 558-565 ◽  
Author(s):  
V. D. Natsik ◽  
P. P. Pal-Val ◽  
L. N. Pal-Val ◽  
Yu. A. Semerenko
Keyword(s):  
Plastic Deformation ◽  
Low Temperature ◽  
Internal Friction ◽  
Temperature Peak

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.

Second Low-Temperature Peak in the Internal Friction of Aluminum

1959 ◽  
Vol 114 (5) ◽  
pp. 1273-1273 ◽  
Author(s):  
Edward Lax ◽  
Daniel H. Filson
Keyword(s):  
Low Temperature ◽  
Internal Friction ◽  
Temperature Peak

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.

Damping Properties of EVA Modified Cement Pastes

2013 ◽  
Vol 687 ◽  
pp. 161-165
Author(s):  
Zhen Lei Zhang ◽  
Pei Ming Wang ◽  
Jian Guo Wu
Keyword(s):  
Cement Paste ◽  
Morphological Difference ◽  
Ethylene Vinyl Acetate ◽  
Ocean Waves ◽  
Damping Capacity ◽  
Damping Properties ◽  
Sem Images ◽  
Cement Pastes ◽  
Damping Behavior ◽  
Noise Vibration

Earthquakes, wind buffeting, ocean waves， noise vibration and explosion are all harmful to people’s life. For controlling the vibrations, one way is by improving the material damping capacity. Effects of improving the damping properties of cement based material by adding polymer, fiber and interfacial modification have been admitted. Whereas the relationship of the influence of the dosage of polymer to the damping functions and the changes of damping behaviors at different frequency, temperature environment have received much less attention. Furthermore, ethylene-vinyl acetate (EVA) which used as one of the mainly modified has been widely applied in various aspects such as improving ductility, impermeability and mechanical properties. However, the ability of EVA modification in cement on improving the damping capacity has received less attention. The main objective of this paper is to research the damping behavior of EVA modified cement pastes at different frequencies, temperatures and polymer contents by dynamic mechanical analyzer. Experimental results showed that damping property of EVA modification in cement was dramatically increased. For a certain EVA modified cement paste, tanδ slightly increases with the frequency increases and a sharp peak was found at the glass transition temperature. The SEM images indicated that there was a morphological difference in the plain cement paste and EVA modified cement paste.

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.

Damping Capacity of Fe-Ga Alloys

2011 ◽  
Vol 228-229 ◽  
pp. 937-941 ◽  
Author(s):  
Fang Mei Ling ◽  
Jie Zhu ◽  
Li Ji Heng ◽  
Gao Xue Xu
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Wide Temperature Range ◽  
Room Temperature ◽  
Damping Capacity ◽  
Torsion Pendulum ◽  
Temperature Peak ◽  
Temperature Range ◽  
Computer Controlled ◽  
Increasing Temperature

The damping capacity of Fe-Ga rods and sheets has been studied using a computer-controlled automatic inverted torsion pendulum instruments in a wide temperature range in a series of frequency. The frequency and temperature has different influence on the damping capacity of solidified Fe83Ga17 rods and (Fe83Ga17)97.25Cr2B0.75 sheets. The damping capacity of all specimens increased with frequencies. The solidified Fe-Ga rods showed an obvious low-temperature peak and a potential high-temperature peak with increasing temperature. However, the damping capacity of Fe-Ga sheets kept steady in a wide temperature range and then rapidly increased on further heating above 400°C. Damping capacity of about 0.02 was obtained in both Fe-Ga rods and sheets at temperatures from room temperature to 500°C. Thus, The Fe-Ga alloys are considered to be a class of promising high damping alloys.

Sign in / Sign up

Export Citation Format

Share Document