Synthesis of Cu/Cr and Cu/Cr/W Materials by Powder Metallurgy Techniques

2018 ◽  
Vol 880 ◽  
pp. 241-247
Author(s):  
Claudiu Nicolicescu ◽  
Victor Horia Nicoară ◽  
Costel Silviu Bălulescu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Powder Metallurgy ◽  
Chemical Composition ◽  
Electrical Properties ◽  
Mechanical Alloying ◽  
Ball Mill ◽  
Weight Percent ◽  
Scanning Electron

Alloys based on Cu/Cr and Cu/Cr/W attract the attention due to their presence in different applications that require higher electrical properties which are combined with good mechanical properties. In order to synthesis the material based on Cu/Cr and Cu/Cr/W, mechanical alloying technique was used. Four mixtures, X1 (99%CuCr), X2 (97%CuCr), X3 (94%Cu1%CrW), X4 (92%Cu3%CrW – weight percent), were prepared using a vario planetary ball mill Pulverisette 4 made by Fritsch. The mixtures obtained after 10 hours were analyzed by scanning electron microscopy (SEM). It was found that the presence of chromium and tungsten influence the morphology and the particles tend to be flat. Sinter ability and microhardness are influenced by the chemical composition of the samples.

Vacuum Breakdown Behavior of CuWCr Composites

2008 ◽  
Vol 569 ◽  
pp. 125-128
Author(s):  
Peng Xiao ◽  
Zhi Kang Fan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Powder Metallurgy ◽  
Electrical Properties ◽  
Mechanical Alloying ◽  
Arc Erosion ◽  
Before And After ◽  
Chopping Current ◽  
Uniform Composition ◽  
Scanning Electron

The Cu20W70Cr10 composites were fabricated by two methods which are the conventional powder metallurgy, and mechanical alloying to prepare WCr compound powders, followed by sintering and infiltration. The erosion behavior of CuWCr composites under breakdown was investigated. The surfaces of the composites before and after erosion and the mechanism of arc erosion were studied by scanning electron microscopy. The results show that the CuWCr composites prepared by mechanical alloying have superfine microstructure, uniform composition and high density, thus result in good characteristics of diffusing arcs and arc eroding endurance. Arc erosion zones are dispersive and uniform on the surfaces with some flat eroding pits. The Cu20W70Cr10 composites have excellent electrical properties such as high breakdown voltage, low chopping current and long arc life.

Studies on Solid Solution of Fe50-Cu50 Compounds by Mechanical Alloying

2013 ◽  
Vol 788 ◽  
pp. 31-33
Author(s):  
Zhan Wen He
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Mechanical Alloying ◽  
Ball Mill ◽  
Composite Powder ◽  
Powder Particle Size ◽  
Distribution Analysis ◽  
Solution Condition ◽  
Scanning Electron

This paper discusses Fe50Cu50 composite powder mechanical alloying of morphology and solution condition, through to the mechanical alloying Fe50Cu50 after composite powder on scanning electron microscopy and distribution analysis has determined its morphology and Fe -Cu the solution conditions. The experimental results show that the ball mill 50 h, Fe50Cu50 composite powder particle size basically stable, size in a few microns or so, and Fe and Cu has fully fuses in together to form the uniform solid solution.

Enhanced Electrical Properties of Fly Ash Geopolymer Composites with Carbon Nanotubes

2019 ◽  
Vol 296 ◽  
pp. 137-142 ◽  
Author(s):  
Cecílie Mizerová ◽  
Ivo Kusák ◽  
Pavel Rovnaník ◽  
Patrik Bayer
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Fly Ash ◽  
Electrical Properties ◽  
Mercury Intrusion Porosimetry ◽  
Mercury Intrusion ◽  
Geopolymer Composites ◽  
Scanning Electron

Carbon nanotubes (CNTs) are used for the application in concrete especially due to their excellent physical properties. In this study, CNTs were used as a conductive admixture to prepare composites with enhanced electrical properties that might be potentially used in smart concretes or structures. We assessed the changes in selected electrical properties of fly ash geopolymer mortars (conductivity, resistance, capacitance) depending on the concentration of CNTs that ranged from 0.05 to 0.20%. The most convenient CNTs concentration was discussed considering both the electrical and mechanical properties (compressive and flexural strength). Mercury intrusion porosimetry and scanning electron microscopy were used to observe the distribution of CNTs and porosity of the mortars.

scholarly journals Effect of Different Raw Material Property for the Fabrication on Al/CNT Nanocomposite Using a Ball Mill with a Discrete Element Method (DEM) Simulation

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3291 ◽  
Author(s):  
Battsetseg Jargalsaikhan ◽  
Amgalan Bor ◽  
Jehyun Lee ◽  
Heekyu Choi
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Discrete Element Method ◽  
Ball Mill ◽  
Raw Material ◽  
Experimental Conditions ◽  
Dem Simulation ◽  
Scanning Electron

Carbon nanotubes (CNTs) have received interest as an attractive reinforcing agent metal matrix composites regarded as an increase to mechanical properties of the final product. Aluminum/carbon nanotubes (Al/CNTs) nanocomposites were observed with different raw material at the optimized experimental condition. In this study, Al-based CNTs composites were three different samples, including un-milled Al, un-milled Al with CNTs, and milled Al with CNTs nanocomposites in the presence of additional CNTs with various experimental conditions while using a traditional ball mill (TBM). The particle morphology and CNT dispersions of milled composites were respectively analysed by scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM), and the mechanical properties of the fabricated composites were tested. In each sample, CNTs were well dispersed on the surface of Al powder at different experimental conditions for milling in a TBM. The Al/CNTs nanocomposites were processed by compacting, sintering and rolling process. The Vickers hardness was used to characterize the mechanical properties. The hardness of Al/CNTs nanocomposites that were fabricated with milled Al with CNT was higher than the reached to in the nanocomposites prepared with the use of un-milled Al with CNT nanocomposites. Therefore, the discrete element method (DEM) simulation was used to complete quantitative analysis. The flow pattern, impact force, and energy at various experimental conditions are considered. The results of the simulations are compared with experimental data.

Mechanical Properties of AlMgB14-xTiB2 Prepared by Field Activated and Pressure Assisted Synthesis

2013 ◽  
Vol 745-746 ◽  
pp. 652-656
Author(s):  
Yang Miao ◽  
Wen Liu ◽  
Lei Zhuang ◽  
Hui Ling Cheng ◽  
Qing Sen Meng
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Scanning Electron Microscopy ◽  
Mechanical Alloying ◽  
Composite Ceramic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wear Tests ◽  
Scanning Electron

In this paper, Mechanical alloying (MA) and field activated and pressure assisted synthesis (FAPAS) were used for preparing the ultra-hard, super-abrasive AlMgB14-xTiB2 composite ceramic. The samples were fabricated at 1500 under a pressure of 60 MPa. The microstructures and compositions of samples were observed and determined by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD). It was indicated that addition of TiB2 was effective for increasing both quantities. A maximum Vichers hardness of 38.5GPa and a fracture toughness of 3.85MPam½ of AlMgB14 reinforced with 70 wt.% of TiB2 were achieved. Abrasion wear tests showed that adding TiB2 would improve the wearability obviously.

scholarly journals Influence of mechanical activation on structural and electrical properties of sintered MgTiO3 ceramics

2009 ◽  
Vol 41 (2) ◽  
pp. 117-123 ◽  
Author(s):  
S. Filipovic ◽  
N. Obradovic ◽  
V. Pavlovic ◽  
V. Petrovic ◽  
M. Mitric
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electrical Properties ◽  
Mechanical Activation ◽  
Ball Mill ◽  
Sintering Process ◽  
Electrical Measurements ◽  
Structural And Electrical Properties ◽  
Microstructure Parameters ◽  
Scanning Electron

The aim of this work was to analyze the influence of mechanical activation on the MgCO3-TiO2 system. Mixtures of MgCO3-TiO2 were mechanically activated for 15, 30, 60 and 120 minutes in a planetary ball mill and after that sintered at 1100?C for 1h. XRD analyses were performed in order to give information about the phase composition and to determine a variety of microstructure parameters using Scherrer's method. Also, the effect of tribophysical activation and sintering process on microstructure was investigated by scanning electron microscopy. Electrical measurements were performed in order to determine electrical properties of sintered samples. Our conclusions are that the sample activated for 120 min showed the best electrical properties ( ? r=23.86, Q=233, ?=0.38) and exhibited the best sinterability.

Densification Study of Titanium Powder Compacts

2005 ◽  
Vol 498-499 ◽  
pp. 211-216 ◽  
Author(s):  
Márcia Christina Carneiro Ueta ◽  
Carlos Augusto Fracote ◽  
Vinicius André Rodrigues Henriques ◽  
Mario Lima de Alencastro Graça ◽  
Carlos Alberto Alves Cairo
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Ball Mill ◽  
Titanium Powder ◽  
Titanium Sponge ◽  
Kroll Process ◽  
Titanium Powders ◽  
Powder Compacts ◽  
Scanning Electron

Powder compaction characteristics is a very important parameter to control in order to obtain products with best mechanical properties made by P/M techniques. This work presents a study on the densification of titanium powders trying to optimize the particle size distribution for the best packing and the maximum densification by pressure compaction. The powders used were made from titanium sponge obtained by the Kroll process. The powders were embrittled by mean of the Hydride-Dehydride process (HDH) and milled in a rotative ball-mill under vacuum. Powders with different particles sizes distributions were mixed in several proportions according to Alfred's and Andreasen’s Theory. The samples were compacted by uniaxial and isostatic pressing and sintered under vacuum. The evaluation of the densification was made following the Standard method of test for density of glass by Buoyancy (ASTM – C693-74) and by scanning electron microscopy (SEM). The samples made with powder milled during 36 hours and 12 hours presented better densification than the ones milled during shorter time and the ones with distributions combinations.

Investigation on the Microstructure and Mechanical Properties of New Al-Si Piston Alloys

2012 ◽  
Vol 445 ◽  
pp. 289-294 ◽  
Author(s):  
S.G. Shabestari ◽  
R. Gholizadeh
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Chemical Composition ◽  
Optical Microscopy ◽  
The Other ◽  
X Ray ◽  
Scanning Electron

Dense precipitation of various intermetallic compounds is a common feature in the microstructure of Al-Si piston alloys. In this investigation, microstructure of LM13 alloy and three high Cu-containing Al-Si piston alloys with different amounts of Ni, Fe, and Mn were studied by means of optical microscopy (OM) and scanning electron microscopy (SEM). Chemical composition of the phases was determined by using energy dispersive X-ray analysis (EDX). The precipitation of the phases was studied through thermal analysis of the solidifying samples. Also, tensile properties and hardness of the samples were measured. The results showed that the various intermetallics such as Al12(FeMn)3Si2, Al3Ni, Al9FeNi, and Al3CuNi precipitated during the solidification. The high Cu-containing alloy with optimum levels of Ni (1.8 wt.%), Fe (0.75 wt.%), and Mn (0.3 wt.%) has the highest tensile strength (250 MPa) and hardness (110 BHN) among the other alloys.

Mechanical Alloying Synthesis of K2Bi8Se13– type Solid Solutions

2007 ◽  
Vol 1044 ◽  
Author(s):  
Nikolaos Toumpas ◽  
Theodora Kyratsi ◽  
Euripides Hatzikraniotis ◽  
Andreas Tsiappos ◽  
Eleni Pavlidou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Scanning Electron Microscopy ◽  
Electrical Properties ◽  
Mechanical Alloying ◽  
Solid Solutions ◽  
Structural Features ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

AbstractSolid solutions of β-K2Bi8-xSbxSe13are an interesting series of materials for thermoelectric investigations due to their very low thermal conductivity and highly anisotropic electrical properties. In this work, we aimed to synthesize solid solutions of β-K2Bi8-xSbxSe13type materials using powder techniques. The synthesis was based on mechanical alloying as well as sintering procedures. The products were studied in terms of structural features, composition and purity with powder x-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. Preliminary results on thermoelectric properties as well as IR reflectivity measurements are presented.

Electron Microscopic Observation of the Longitudinal Organization of Poly (p-Phenylene Terephthalamide) Fibers

1982 ◽  
Vol 40 ◽  
pp. 680-681
Author(s):  
Li Li-Sheng ◽  
L.F. Allard ◽  
W.C. Bigelow
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Microscopic Observation ◽  
Electron Microscopic Observation ◽  
Electron Microscopic ◽  
Aromatic Polyamides ◽  
Radial Arrangement ◽  
Scanning Electron ◽  
Better Than

The aromatic polyamides form a class of fibers having mechanical properties which are much better than those of aliphatic polyamides. Currently, the accepted morphology of these fibers as proposed by M.G. Dobb, et al. is a radial arrangement of pleated sheets, with the plane of the pleats parallel to the axis of the fiber. We have recently obtained evidence which supports a different morphology of this type of fiber, using ultramicrotomy and ion-thinning techniques to prepare specimens for transmission and scanning electron microscopy.

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