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.

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.

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 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.

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.

Foamed Metal Materials Preparation Technology

2011 ◽  
Vol 197-198 ◽  
pp. 518-521
Author(s):  
Jian Ning Wei ◽  
Gao Ping Xu ◽  
Li Ling Zhou ◽  
Xue Yun Zhou ◽  
Wei Jun Xie
Keyword(s):  
Air Pressure ◽  
Preparation Technology ◽  
Infiltration Process ◽  
Pressure Infiltration ◽  
Metal Materials ◽  
Materials Preparation

The paper presents the technology of preparation about foamed metal materials, which were prepared by an air pressure infiltration process.

EFFECT OF PRE-DEFORMATION ON DAMPING CAPACITY OF TINI/NBTI COMPOSITE

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2392-2397 ◽  
Author(s):  
JIANG JIANG ◽  
LISHAN CUI ◽  
YANJUN ZHENG ◽  
TINGYONG XING ◽  
XINGQING ZHAO ◽  
...  
Keyword(s):  
Internal Friction ◽  
Elastic Strain ◽  
Strain Energy ◽  
Parent Phase ◽  
Elastic Strain Energy ◽  
Damping Capacity ◽  
Internal Friction Peak ◽  
Pinning Effect ◽  
Damping Behavior ◽  
Martensitic Variants

The present work aims to investigate the internal friction and effect of pre-deformation on damping capacity of Nb 60 Ti 25 Ni 15 alloy, which could be considered as TiNi / NbTi metal matrix composite. The internal friction results showed that this composite possesses excellent damping behavior, which is associated with the movement of a set of abundant interfaces, such as those between the TiNi and NbTi phases, those between martensitic variants and those between martensite and parent phase. Meanwhile, the peak temperature and the width of the internal peak increased with increasing of prestrain level. It appears to be due to the release of the stored elastic strain energy, or the pinning effect by the deformed structures. Furthermore, the height of internal friction peak decreased as the prestrain level increased.

Effect of Heat Treatments on the Damping Characteristics of TiNi-Based Shape Memory Alloys

2006 ◽  
Vol 319 ◽  
pp. 33-38 ◽  
Author(s):  
I. Yoshida ◽  
Kazuhiro Otsuka
Keyword(s):  
Internal Friction ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Low Frequency ◽  
Heat Treatments ◽  
Damping Capacity ◽  
Temperature Hysteresis ◽  
Temperature Spectrum ◽  
Two Peaks ◽  
Very High

Low frequency internal friction of Ti49Ni51 binary and Ti50Ni40Cu10 ternary shape memory alloys has been measured. The effect of solution and aging heat treatments on the damping property was examined. The temperature spectrum of internal friction for TiNi binary alloy consists, in general, of two peaks; one is a transition peak which is associated with the parent-martensite transformation and is rather unstable in a sense that it strongly depends on the frequency and decreases considerably when held at a constant temperature. The other one is a very high peak of the order of 10-2, which appears at around 200K. It appears both on cooling and on heating with no temperature hysteresis, and is very stable. The behavior of the peak is strongly influenced by the heat treatments. The trial of two-stage aging with a purpose of improving the damping capacity has been proved unsatisfactory. TiNiCu has a very high damping, the highest internal friction reaching 0.2, but by quenching from very high temperature, say 1373K, the damping is remarkably lowered. For the realization of high damping the quenching from a certain temperature range around 1173K seems the most preferable condition.

scholarly journals Synthesis and characterization of PIL/pNIPAAm hybrid hydrogels

2016 ◽  
Vol 2 (1) ◽  
pp. 1-4
Author(s):  
Sylvia Pfensig ◽  
Daniela Arbeiter ◽  
Klaus-Peter Schmitz ◽  
Niels Grabow ◽  
Thomas Eickner ◽  
...  
Keyword(s):  
Mechanical Characterization ◽  
Heating Temperature ◽  
Controlled Drug Release ◽  
Solution Temperature ◽  
Scanning Calorimetry ◽  
Critical Solution Temperature ◽  
Temperature Range ◽  
Hybrid Hydrogels ◽  
Higher Temperature

AbstractIn this study, varying amounts of NIPAAm and an ionic liquid (IL), namely 1-vinyl-3-isopropylimidazolium bromide ([ViPrIm]+[Br]−), have been used to synthesize hybrid hydrogels by radical emulsion polymerization. Amounts of 70/30%, 50/50%, 30/70%, 15/85% and 5/95% (wt/wt) of PIL/pNIPAAm were used to produce hybrid hydrogels as well as the parental hydrogels. The adhesive strength was investigated and evaluated for mechanical characterization. Thermal properties of resulting hydrogels have been investigated using differential scanning calorimetry (DSC) in a default heating temperature range (heating rate 10 K min−1). The presence of poly ionic liquids (PIL) in the polymer matrix leads to a moved LCST (lower critical solution temperature) to a higher temperature range for certain hybrid hydrogels PIL/pNIPAAm. While pNIPAAm exhibits an LCST at 33.9 ± 0.3°C, PIL/pNIPAAm 5/95% and PIL/pNIPAAm 15/85% were found to have LCSTs at 37.6 ± 0.9°C and 52 ± 2°C, respectively. This could be used for controlled drug release that goes along with increasing body temperature in response to an implantation caused infection.

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