Electrical Conductivity of Discontinuous Filament–reinforced Unidirectional Composites

2000 ◽  
Vol 15 (4) ◽  
pp. 940-943 ◽  
Author(s):  
Jyh-Ming Ting ◽  
Kuo-Wei Chen
Keyword(s):  
Electrical Conductivity ◽  
Filament Length ◽  
Unidirectional Composites ◽  
Interface Impedance ◽  
The Matrix ◽  
Discontinuous Reinforcement ◽  
Composite Conductivity

The electrical conductivity of discontinuous filament–reinforced unidirectional composites was investigated. The discontinuous reinforcement used was copper filament, and the matrix materials included solder and epoxy. It was found that the composite conductivity increases with filament length and eventually becomes a constant. Such behavior is described by introducing an interface impedance and the principle of rule of mixture. It was found both experimentally and theoretically that there exists a critical filament length that must be exceeded so the composites will exhibit conductivity as composites having continuous reinforcing filaments.

Investigation of Thermoelectric Materials: Substitution effect of Bi on the Ag1-xPb18MTe20 (M = Sb, Bi) (x = 0, 0.14, 0.3)

2007 ◽  
Vol 1044 ◽  
Author(s):  
Mi-kyung Han ◽  
Huijun Kong ◽  
Ctirad Uher ◽  
Mercouri G Kanatzidis
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Substitution Effect ◽  
Dimensionless Figure Of Merit ◽  
The Matrix ◽  
Mass Fluctuation

AbstractWe performed comparative investigations of the Ag1-xPb18MTe20 (M = Bi, Sb) (x = 0, 0.14, 0.3) system to better understand the roles of Sb and Bi on the thermoelectric properties. In both systems, the electrical conductivity nearly keeps the same values, while the Seebeck coefficient decreases dramatically in going from Sb to Bi. Compared to the lattice thermal conductivity of PbTe, that of AgPb18BiTe20 is substantially reduced. The lattice thermal conductivity of the Bi analog, however, is higher than that of AgPb18SbTe20 and this is attributed largely to the decrease in the degree of mass fluctuation between the nanostructures and the matrix (for the Bi analog). As a result the dimensionless figure of merit ZT of Ag1-xPb18MTe20 (M = Bi) is found to be smaller than that of Ag1-xPb18MTe20 (M = Sb).

Optimization of thermal conductivity in composites loaded with the solid-solid phase-change materials

2018 ◽  
Vol 25 (6) ◽  
pp. 1157-1165
Author(s):  
Taoufik Mnasri ◽  
Adel Abbessi ◽  
Rached Ben Younes ◽  
Atef Mazioud
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Phase Change Materials ◽  
Solid Phase ◽  
Spherical Inclusions ◽  
First Case ◽  
The Matrix ◽  
Composite Conductivity ◽  
First Time

AbstractThis work focuses on identifying the thermal conductivity of composites loaded with phase-change materials (PCMs). Three configurations are studied: (1) the PCMs are divided into identical spherical inclusions arranged in one plane, (2) the PCMs are inserted into the matrix as a plate on the level of the same plane of arrangement, and (3) the PCMs are divided into identical spherical inclusions arranged periodically in the whole matrix. The percentage PCM/matrix is fixed for all cases. A comparison among the various situations is made for the first time, thus providing a new idea on how to insert PCMs into composite matrices. The results show that the composite conductivity is the most important consideration in the first case, precisely when the arrangement plane is parallel with the flux and diagonal to the entry face. In the present work, we are interested in exploring the solid-solid PCMs. The PCM polyurethane and a wood matrix are particularly studied.

scholarly journals The influence of the matrix electrical conductivity on the dc poling behaviors and the loss of 0-3 ferroelectric composites

2008 ◽  
Vol 57 (6) ◽  
pp. 3840
Author(s):  
Yang Feng-Xia ◽  
Zhang Duan-Ming ◽  
Deng Zong-Wei ◽  
Jiang Sheng-Lin ◽  
Xu Jie ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
The Matrix

Micromechanical Analysis of Nonlinear Response of Unidirectional Composites: A Fundamental Approach

2001 ◽  
Author(s):  
Virendra R. Jadhav ◽  
Srinivasan Sridharan
Keyword(s):  
Mechanical Model ◽  
Nonlinear Response ◽  
Experimental Studies ◽  
Matrix Cracking ◽  
Type Model ◽  
Unidirectional Composites ◽  
The Matrix ◽  
Experimental Response ◽  
Square Cells ◽  
Experimental Comparisons

Abstract Micromechanical models with different representative volume elements have been developed to study their ability to predict nonlinear response of unidirectional composites. A simple, square cells type micro-mechanical model similar to those widely used by other researchers is compared with a more advanced 3-phase finite element based micro-mechanical model. The models utilize the “bulk” properties of the matrix without attempting to “tune” the model to fit with experimental response of laminae. This is a more fundamental approach and constitutes a departure from current practice. The models account for shear softening, matrix cracking and the presence of residual stresses. A smeared cracking approach was used to characterize the micro-cracking in matrix. Experimental studies were performed on laminae, laminates and cylinders made from carbon epoxy composites. Experimental comparisons show that the more accurate micro-mechanical model with proper partial cracking options provides good bounds on experimental response with consistent accuracy. A square cells type model however is not consistent in its predictions, thus raising questions about its applicability in any general micro-mechanics based analysis.

Effect of Solution Treatment on Second Phase Dissolution for an Al-9.2Zn-2.0Mg-1.9Cu Alloy

2020 ◽  
Vol 993 ◽  
pp. 321-326
Author(s):  
Hong Wei Liu ◽  
Kai Wen ◽  
Xi Wu Li ◽  
Zhi Hui Li ◽  
Li Zhen Yan ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Solution Treatment ◽  
Optical Microscope ◽  
Solution Temperature ◽  
Second Phase ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Phase Dissolution ◽  
Solution Treated ◽  
The Matrix

The second phase dissolution of Al-9.2Zn-2.0Mg-1.9Cu alloy conducted by various temperatures of 2h was researched with the help of optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), electrical conductivity and differential scanning calorimetry (DSC) analysis. The results gave rise to the second phase existence of Mg(Zn,Cu,Al)2 and Fe-containing phases in the as-extruded alloy. When the alloy solution treated with a temperature varied from 450°C to 470°C, a small quantity of Mg(Zn,Cu,Al)2 phase still existed in the alloy while its content exhibited a decrement trend with the solution temperature rose. For the alloy solution treated at a temperature of 475°C, Mg(Zn,Cu,Al)2 phase dissolved into the matrix completely while Fe-containing phase still remained. The electrical conductivity of quenched alloy decrease with the solution temperature increase and reached a minimum value at 470°C, and then rose slightly for the solution temperature of 475°C.

The Hall Carrier Mobility of AgBiTe2-Ag2Te Composite

2001 ◽  
Vol 691 ◽  
Author(s):  
T. Sakakibara ◽  
Y. Takigawa ◽  
K. Kurosawa
Keyword(s):  
Electrical Conductivity ◽  
Composite Material ◽  
Composite Materials ◽  
Hall Coefficient ◽  
Carrier Mobility ◽  
Matrix Phase ◽  
Second Phase ◽  
Temperature Range ◽  
The Matrix ◽  
Van Der Pauw

ABSTRACTWe prepared a series of (AgBiTe2)1−x(Ag2Te)x(0≤×≤1) composite materials by melt and cool down [1]. The Hall coefficient and the electrical conductivity were measured by the standard van der Pauw technique over the temperature range from 93K to 283K from which the Hall carrier mobility was calculated. Ag2Te had the highest mobility while the mobility of AgBiTe2was the lowest of all samples at 283K. However the mobility of the (AgBiTe2)0.125(Ag2Te)0.875composite material was higher than the motility of Ag2Te below 243K. It seems that a small second phase dispersed in the matrix phase is effective against the increased mobility.

Studies on Polyacrylate-Starch/Polyaniline Conducting Hydrogel

2019 ◽  
Vol 4 (1) ◽  
pp. 36-44 ◽  
Author(s):  
Reetu Prabhakar ◽  
Devendra Kumar
Keyword(s):  
Electrical Conductivity ◽  
Polymer Matrix ◽  
Polymer Network ◽  
Synthetic Polymer ◽  
Interpenetrating Polymer Network ◽  
Basic Medium ◽  
Aniline Monomer ◽  
The Matrix ◽  
Network Process ◽  
Starch Gel

Background: The superabsorbent polymers based conducting hydrogel such as polyaniline impregnated polyacrylate-starch hydrogel were synthesized via two -steps interpenetrating polymer network process. In the present work instead of using a synthetic polymer of acrylamide, a biodegradable polymer such as starch has been used with polyacrylate superabsorbent polymer. The main attempt of this work is to analyze the electrical conductivity of resulting hydrogel at varying concentrations of crosslinker, initiator, monomer, and a copolymer for improving the properties of synthesized hydrogel and elaborating the diversity of its utilization. Methods: The polymerization of aniline was performed through the absorption of aniline monomer into the polymer matrix followed by the addition of initiator/dopant solution. The morphological and structural analysis and thermal stability of the synthesized hydrogel were studied using Scanning Electron Microscopy (SEM), Fourier transform infrared spectroscopy and thermogravimetric analysis (TGA), respectively. The swelling behaviour of the synthesized hydrogel was performed in a different medium. Results: Electrical conductivity data of polyacrylate-starch/polyaniline (PAANa-starch/PANI) were compared from polyacrylate-co-polyacrylamide/polyaniline P(AANa-co-AM)/PANI hydrogel, which revealed that polyacrylate-starch/polyaniline shows higher conductivity than polyacrylate-co-polyacrylamide/ polyaniline conducting hydrogel. Maximum swelling of the synthesized hydrogel was reported in the basic medium. Conclusion: It is observed that the addition of starch into the matrix significantly improved the overall properties of hydrogel. The polymerization of aniline was done in-situ with the absorption of aniline monomer into the PAANa-starch polymer matrix followed by soaking in an initiator/dopant solution. The XRD pattern of PAANa-starch/PANI showed a broad peak at 22.8o while no peak was observed in the PAANa-starch gel, implying that PAANa-starch/PANI has a crystalline and more ordered structure. PAANa-starch/PANI has higher conductivity than the P(AANa-co-AM)/PANI hydrogel. This enhanced electrical conductivity in case of PAANa-starch/PANI hydrogel could be due to the more crosslink points of synthetic polymer polyacrylamide between PAANa-PANI hydrogel.

Design of High-Strength, High-Conductivity Alloys

MRS Bulletin ◽  
1996 ◽  
Vol 21 (6) ◽  
pp. 13-18 ◽  
Author(s):  
J. Miyake ◽  
G. Ghosh ◽  
M.E. Fine
Keyword(s):  
Electrical Conductivity ◽  
Computer Aided Design ◽  
Volume Fraction ◽  
High Strength ◽  
Pure Metal ◽  
Alloy Design ◽  
High Conductivity ◽  
Solid Solution Strengthening ◽  
Computer Aided ◽  
The Matrix

Computer-aided design of alloys is becoming increasingly useful, replacing the completely experimental approach. The computer-aided approach significantly reduces the cost of alloy design and more easily leads to optimum properties by reducing the amount of experimentation. Design of high-strength, high-conductivity alloys is a good example of the efficacy of using the computer to design experimental alloys.Alloys that have both high strength and high electrical conductivity are needed for many applications such as lead frames, connectors, conducting springs, and sliding contacts. Figure 1 shows the strength and conductivity of some commercially available copper-based alloys. Since dissolved solutes in an otherwise pure metal rapidly reduce the electrical conductivity (as well as the thermal conductivity), solid solution strengthening is not suitable for designing this class of alloys. Such alloys must be designed on the basis of precipitation or dispersion hardening. The theory of the yield stress of alloys with precipitates or dispersed phases has been well-formulated and may be used for alloy design. The solubility of the hardening phase in the matrix must be very small. Otherwise the conductivity will be degraded too much. Nordheim's rule relates conductivity to dissolved solute in alloys and is also available for alloy design. Decreasing the dissolved solute increases the conductivity and strength due to an increase in the volume fraction of the precipitate.

Effect of Milling Time on the Properties of Nanocrystalline CuCr50 Alloys

2011 ◽  
Vol 299-300 ◽  
pp. 824-827
Author(s):  
Kun Yu Shi ◽  
Tao Shen ◽  
Li Hong Xue ◽  
Chun Hao Chen ◽  
You Wei Yan
Keyword(s):  
Electrical Conductivity ◽  
Crystallite Size ◽  
Milling Time ◽  
Micro Hardness ◽  
Uniform Microstructure ◽  
High Relative Density ◽  
Plasma Sintering ◽  
The Matrix ◽  
Spark Plasma ◽  
Bulk Nanocrystalline

Nanocrystalline CuCr50 alloys were fabricated by means of mechanical alloying and spark plasma sintering. The influence of milling time on the as-milled powders and properties of sintered compacts were investigated. The results show that crystallite size of powders decreases gradually with increase of milling time, while the micro-strain increases firstly then decreases correspondingly. The crystallite size is 22 nm at milling 100h.The micro-hardness of the compacts improves greatly with the increase of milling time, reaching 363HV at 150h which is about 3 times as high as that of the industrial standard (120HV), while the electrical conductivity improves gradually decline. The bulk nanocrystalline CuCr50 alloys sintered at 900°C for 5min exhibit high relative density of 96% and uniform microstructure: nanoparticles Cr with size of about 120nm are uniformly dispersed in the matrix.

scholarly journals PHASE-TRANSFORMATION DYNAMICS AND CHARACTERIZATION OF PRECIPITATES IN THE Cu-3Ti-3Ni-0.5Si ALLOY

2021 ◽  
Vol 55 (4) ◽  
Author(s):  
Jia Liu ◽  
Jituo Liu ◽  
Xianhui Wang ◽  
Chong Fu ◽  
Yanlong Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Phase Transformation ◽  
Volume Fraction ◽  
Formation Enthalpy ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
The Matrix ◽  
Diffraction Patterns ◽  
Precipitated Phases

In this paper we investigated the phase-transformation dynamics of the Cu-3Ti-3Ni-0.5Si alloy by applying the Avrami method to phase-transformation dynamics and electrical conductivity based on the relationship between the electrical conductivity and the volume fraction of precipitates in the Cu-3Ti-3Ni-0.5Si alloy. The results corroborated well with the experimental data. The microstructure and precipitated phases were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The analysis of the selected-area electron-diffraction patterns indicated that the precipitates formed in the matrix of the Cu-3Ti-3Ni-0.5Si alloy during aging, correspond to the Ni3Ti, Ni3Si, and Ni2Si phases. According to the values of formation enthalpy and cohesive energy determined by first-principle calculations, the formation of the Ni2Si phase is more favorable compared to the Ni3Si and Ni3Ti phases, and the Ni3Ti exhibits improved structural stability compared to the Ni2Si and Ni3Si phases.

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