scholarly journals Grain characteristics, electrical conductivity, and hardness of Zn-doped Cu–3Si alloys system

2021 ◽  
Vol 3 (11) ◽  
Author(s):  
K. C. Nnakwo ◽  
F. O. Osakwe ◽  
B. C. Ugwuanyi ◽  
P. A. Oghenekowho ◽  
I. U. Okeke ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Statistical Data ◽  
Alloy Composition ◽  
Gravity Casting ◽  
Casting Technique ◽  
Zinc Addition ◽  
Microstructure Examination ◽  
Parent Alloy ◽  
Automobile Components ◽  
Zn Alloys

AbstractThe grain characteristics, electrical conductivity, hardness, and bulk density of Cu–3Si–(0.1—1 wt%)Zn alloys system fabricated by gravity casting technique were investigated experimentally using optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The study established the optimal alloy composition and the significance of zinc addition on the tested properties using response surface optimal design (RSOD). The cooled alloy samples underwent normalizing heat treatment at 900 °C for 0.5 h. The average grains size and grains distribution were analyzed using the linear intercept method (ImageJ). The microstructure examination revealed a change in grain characteristics (morphology and size) of the parent alloy by addition of 0.1 wt% zinc. The average grains size of the parent alloy decreased from 12 µm to 7.0 µm after 0.1 wt% zinc addition. This change in grain characteristics led to an increase in the hardness of the parent alloy by 42.2%, after adding 0.1 wt% zinc. The electrical conductivity of the parent alloy decreased from 46.3%IACS to 45.3%IACS, while the density was increased by 8.4% after adding 0.1 wt% zinc. The statistical data confirmed the significance of the change in properties. The result of optimization revealed Cu–3Si–0.233Zn as the optimal alloy composition with optimal properties. The Cu–3Si–xZn alloy demonstrated excellent properties suitable for the fabrication of electrical and automobile components.

Hall-Petch Basis for Assessing Alloy Strengthening

1994 ◽  
Vol 362 ◽  
Author(s):  
Ronald W. Armstrong ◽  
R. Michael Douthwaite
Keyword(s):  
Grain Boundary ◽  
Alloy Composition ◽  
Friction Stress ◽  
Face Centered Cubic ◽  
Square Root ◽  
Petch Relation ◽  
Face Centered ◽  
Al Mg Alloys ◽  
Zn Alloys ◽  
Grain Boundary Strengthening

AbstractThe Hall-Petch relation σ = σo + kl−½, provides for the separate consideration of friction stress strengthening within the polycrystal grain volumes through σo and grain boundary strengthening through the product of the microstructural stress intensity k and the reciprocal square root of the grain diameter l Smaller grain diameters are normally obtained at higher alloy contents as illustrated for yield strength results reported for different face-centered-cubic Al-Mg alloys. Results on Al-Li alloy give an interesting example of substantial grain boundary strengthening that is associated with reduced ductility of the material. More complete results reported for the Cu-Al system, allow an evaluation of the strengthening component dependencies on alloy composition, in particular, connecting with a predicted square root of grain boundary obstacle stress in k. The much studied Cu-Zn alloys bring out subtle changes in σo and k

scholarly journals Preparation and Study of some Electrical Properties of PVA-Ni(NO3)2 Composites

2014 ◽  
Vol 40 ◽  
pp. 36-42 ◽  
Author(s):  
Sabah A. Salman ◽  
Nabeel A. Bakr ◽  
Mohammed H. Mahmood
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Electrical Properties ◽  
Filler Content ◽  
Experimental Results ◽  
Casting Technique ◽  
Different Temperatures

The aim of this paper is to prepare and study the (D.C.) electrical conductivity of (PVA-Ni (NO3)2) composites at different temperatures. For that purpose, PVA films with Ni (NO3)2 salt additive were prepared with different concentrations‎ 2, 4, 6, 8 and 10 wt. % and with thickness of 45μm by using casting technique. The experimental results for PVA-Ni (NO3)2) ‎films show that the (D.C.) electrical‏ ‏conductivity increased with increasing ‎the filler content and the‏ ‏temperature, and the activation energy was ‎decreased with increasing the filler content‎.

Enhancement of Thermoelectric Properties of P3HT by Addition of Carbon Nanotubes

2019 ◽  
pp. 59-77
Author(s):  
Arif ◽  
Muhammad Tahir ◽  
Hijaz Ahmad
Keyword(s):  
Thin Film ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Renewable Energy ◽  
Thermoelectric Properties ◽  
Material Characterization ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Casting Technique ◽  
Semiconducting Material

In this paper, the enhancement in the thermoelectric properties of the organic semiconducting material, poly(3-hexylthiophene) (P3HT) by addition of carbon nanotubes (CNTs), have been studied for applications in the renewable energy. For this purpose, the thin film of P3HT: CNTs blend has been deposited on the glass substrate by drop casting technique. The blend is prepared by the ratio of 10: 0.5 mg of P3HT: CNTs at room temperature in chloroform. The thickness of P3HT: CNTs nanocomposite found by ellipsometer was 2570 nm. The Seebeck coefficient of the film is measured to be 58.18 mV/K and the electrical conductivity of nanocomposite was 254 S/cm found by four probe method. The bandgap of P3HT: CNTs nanocomposite was 1.4 eV measured by UV-Vis spectrometer. In this blend, the CNTs are used for enhancement of the thermoelectric properties of the film. The films are also characterized by different material characterization techniques. These characterizations are correlated with the thermoelectric properties of the material. The optimized value of the figure of merit (ZT) for the thin film has been achieved ZT = 0.14 for the P3HT: CNTs nanocomposites.

ELECTRICAL CONDUCTIVITY AND DIELECTRIC RELAXATION STUDY OF POLYVINYL ACETATE/POLY METHYL METHACRYLATE BLENDS

2012 ◽  
Vol 26 (29) ◽  
pp. 1250159 ◽  
Author(s):  
R. M. AHMED
Keyword(s):  
Electrical Conductivity ◽  
Methyl Methacrylate ◽  
Conduction Mechanism ◽  
Polyvinyl Acetate ◽  
Qualitative Description ◽  
Scanning Calorimetry ◽  
Poly Methyl Methacrylate ◽  
Casting Technique ◽  
Transparent Films ◽  
Tan Δ

Transparent films of PMMA (poly methyl methacrylate), PVAc (polyvinyl acetate) and their blends, have been prepared by using a solution-casting technique. The dielectric properties and the electrical conductivity are reported. The frequency and temperature dependence of the dielectric constant, ε′ and tan δ, have been investigated for the studied samples in the frequency range from 1 kHz to 5 MHz and over a range of temperature from 303–413 K. In addition, AC conductivity values were calculated from the dielectric data and the conduction mechanism is discussed. The frequency-dependent conductivity behavior at different temperatures provides a qualitative description of the conduction mechanism. Also, differential scanning calorimetry (DSC) scans have been measured for the studied samples.

Microsture and Properties of a Cu-Cr-Zr-Fe-Ti Alloy

2015 ◽  
Vol 723 ◽  
pp. 556-560
Author(s):  
Fu Xiang Huang
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Transmission Electron Microscopy ◽  
Age Hardening ◽  
Peak Hardness ◽  
Ti Alloy ◽  
Hardening Behavior ◽  
Transmission Electron ◽  
Zn Alloys ◽  
Scanning Electron

The effect of 0.45 wt. % Fe and 0.2 wt. % Ti additions on the age hardening behavior of Cu-Cr-Zr-Zn alloys has been investigated with respect to hardness, electrical conductivity and microstructure. It was showed that the addition of Fe /Ti to Cu-Cr-Zr-Zn alloys enhance strength and hardness, but decrease the electrical conductivity, and increase the aging temperature and time for attaining peak hardness. The scanning electron microscope (SEM) and transmission electron microscopy (TEM) results showed that there are four types of phases in the alloy, Cu-matrix, Cr-rich, (Cu,Zr)-rich and (Fe,Ti)-rich phases.

scholarly journals Dielectrical and electrical properties of PVA-NaI composites

2019 ◽  
Vol 11 (22) ◽  
pp. 56-63
Author(s):  
Hussein Neama Najeeb
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Sodium Iodide ◽  
Electrical Field ◽  
Field Frequency ◽  
Casting Technique ◽  
Different Temperatures ◽  
Solution Casting Technique ◽  
Temperature Activation ◽  
Applied Electrical Field

                The electrical characteristics of polyvinyl alcohol PVA doped with different concentrations (0, 1, 2, 3 and 4wt%) of sodium  iodide NaI powder were studied. The films are prepared using solution casting technique, in order to investigate the effect of sodium iodide NaI additions on the electrical properties of PVA host. The D.C conductivity measured by measuring the D.C electrical resistance using the Keithly Electrometer type 616C, and for different temperatures ranging from 30 – 70oC.           The dielectric properties measured by measuring the capacitor and the loss angle tangent as a function of the alternating electric field frequency using the Agilent impedance analyzer 4294A, within the frequency range 50 – 6 ×106 Hz at room temperature.  The experimental results showed that the dielectric constant is decrease with increase frequency of applied electrical field and increase with increasing concentrations, dielectric loss is increase with increasing frequency of applied electrical field to be 1MHz after this it was decreasing, A.C electrical conductivity are increasing with increasing frequency of applied electrical field, also, the results showed that the D.C electrical conductivity are increasing with increase concentration of NaI and temperature, activation energy are decreasing with increase concentration of additive salt.     

scholarly journals Research on Mechanical Behavior of AMMC (Al-SiC) Composite in Disc Brake

2019 ◽  
Vol 8 (6S3) ◽  
pp. 1432-1437
Keyword(s):  
Silicon Carbide ◽  
Hybrid Composites ◽  
Stir Casting ◽  
Disc Brake ◽  
Mechanical And Thermal Properties ◽  
Pure Aluminium ◽  
Casting Technique ◽  
Automobile Components ◽  
And Performance ◽  
Industrial Needs

To meet the materials demand and performance of automobile components it is necessary of developing composite materials. Aluminium Metal Matrix Composite (AMMC) are utilized to meet the industrial needs. AMMC is the mixture of aluminium and silicon carbide with minimum quantity of other materials like magnesium, aluminium oxide, graphite which are mixed in precise quantity to increase the chemical, mechanical and thermal properties of material. This paper deals with the investigation of mechanical behaviour and properties of AMMC produced by stir casting technique where silicon carbide is reinforced with alloy 6061 for using in Disc Brake. The tensile, flexural, hardness and impact tests were performed and the results showed that the hybrid composites had better properties than pure aluminium and this kind of material may be subjected to use in Disc Brake. The microstructure of the hybrid composites were analyzed using Optical Microscopy.

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