Influence of Re-Melting Technology on Properties and Microstructures of Ferrous Matrix Composites Reinforced with Tungsten Carbide Particle

2011 ◽  
Vol 291-294 ◽  
pp. 1389-1392
Author(s):  
Yan Pei Song ◽  
Hui Gai Wang ◽  
Zhi Ming Feng ◽  
Zhen Kai Zhao
Keyword(s):  
Volume Fraction ◽  
Centrifugal Casting ◽  
Outer Region ◽  
Casting Process ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Kg Medium ◽  
The Impact

The scrap WCP/Fe-C composites were re-melted in a 50 kg medium frequency induction furnace. A regenerated composites ring was manufactured by centrifugal casting process. The microstructure and properties of the composites before and after re-melting were investigated by SEM with energy dispersive spectroscopy and X-ray diffraction. The results showed that the microstructure of the composites after re-melting was composed of un-dissolved WCP, bainite, bone-like crystallites and graphite. The un-dissolved WCPwere uniformly distributed in the outer region of the regenerated composites ring, their volume fraction attained to about 65 vol. %, and size of the un-dissolved WCPwas obviously smaller than that of the WCPbefore re-melting. The impact toughness of the regenerated composites was below those of the composites before re-melting, the hardness and wear resistance of the regenerated composites were almost same as those of the composites before re-melting under the same test conditions.

Effects of Composition on Solidification Microstructure of Cast Titanium Alloys

2010 ◽  
Vol 649 ◽  
pp. 183-188 ◽  
Author(s):  
P.N. Andrade ◽  
A.A. Coelho ◽  
C.R.M. Afonso ◽  
R.J. Contieri ◽  
Maria Helena Robert ◽  
...  
Keyword(s):  
Centrifugal Casting ◽  
Casting Process ◽  
Arc Furnace ◽  
X Ray Diffraction ◽  
Alloying Element ◽  
Tungsten Electrode ◽  
X Ray ◽  
Precision Casting ◽  
Ti Alloys ◽  
Element Type

The high cost of processing of Ti alloys is an important limitation to their utilization in a number of applications. An approach to overcome such difficulties would be their processing by precision casting. The purpose of this work is to evaluate the centrifugal casting process of Ti-Cu and Ti-Nb alloys, analysing the influence of alloying element type and content in the obtained microstructure. Samples with different compositions were prepared in arc furnace with non-consumable tungsten electrode and water-cooled copper hearth under high purity argon atmosphere and cast in a copper mould. Microstructures were analysed by SEM, characterized by EDS and X-ray diffraction. Vickers hardness measurements helped the analysis of phases.

Microstructure of In Situ Particles/7055Al Matrix Composites with Deep Cryogenic Treatment

2012 ◽  
Vol 217-219 ◽  
pp. 114-118 ◽  
Author(s):  
Xun Yin Zhang ◽  
Gui Rong Li ◽  
Ting Wang Zhang ◽  
Lei Cao ◽  
Hong Ming Wang ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Cryogenic Treatment ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Deep Cryogenic Treatment ◽  
X Ray ◽  
Diffraction Peaks

Al2O3，Al3Ti and Al3Zr particles reinforced 7055 aluminium matrix composites were fabricated via melt reaction method. The volume fraction is controlled at about 4-5%. After extrusion and solution-aging heat treatment the sample was prepared for deep cryogenic treatment, The microstructure and evolution of mechanical properties of (Al3Ti+Al3Zr)p/7055 composites were analyzed using optical microscopy(OM),scanning electronic microscopy(SEM) and X-ray diffraction(XRD). Some θ(Al2Cu) phases with nanometer size precipitate in the inner grain. As some grains preferred orient the intensity of some main diffraction peaks increase. Compared with those of as-cast and squeezed states the micro hardness has increased by 16.8% and 10.0% separately.

The Microstructure and Properties of Restored WCP/Fe-C Composites

2011 ◽  
Vol 194-196 ◽  
pp. 2105-2108
Author(s):  
Yan Pei Song ◽  
Hui Gai Wang
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Wear Behavior ◽  
Centrifugal Casting ◽  
X Ray Diffraction ◽  
Casting Method ◽  
X Ray ◽  
Microstructure And Properties

A restored WCP/Fe-C composites is manufactured by centrifugal casting method. The microstructure and properties of the restored composites have been investigated by SEM, X-ray diffraction and properties tester. The results show that the distribution of WCP in the restored composites is even, Size of WCP is obviously reduced, and their volume fraction attained to about 70 vol.%. The mechanical properties and wear behavior of the restored composites are almost the same as those of the primary composites.

scholarly journals Microwave Synthesis of AlFeCuCrNi /TiB2 High-Entropy Alloy Matrix Composites

2018 ◽  
Vol 238 ◽  
pp. 02004 ◽  
Author(s):  
Lijuan Lan ◽  
Tianjiao Pu ◽  
Yingying Gu ◽  
Chengyan Zhu ◽  
Heguo Zhu
Keyword(s):  
Volume Fraction ◽  
High Entropy Alloy ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Alloy Matrix ◽  
X Ray ◽  
High Entropy ◽  
The Matrix ◽  
Modern Analysis ◽  
Geometric Morphology

The Al-Fe-Cu-Cr-Ni-Ti-B system was microwaved to generate high entropy alloy matrix composites reinforced by TiB2 particles. The micro structure and reaction process of the composites were observed and investigated by modern analysis methods, including X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS) and differential scanning calorimeter (DSC) analysis. The results show that AlFeCuCrNi /TiB2 composites can be prepared by microwave heating method. The matrix structure was FCC, and the reinforcement TiB2 showed regular geometric morphology in the matrix and evenly distributed in the matrix when the volume fraction of the reinforcement is 10%. When the volume fraction of the reinforcement increased to 15%, TiB2 partially aggregates in the matrix, and the system activation energy was 195.69 kJ/mol.

Impact Properties of TiC/Fe at Elevated Temperatures

2010 ◽  
Vol 434-435 ◽  
pp. 113-115
Author(s):  
Yan Rong Bao ◽  
Bin Li ◽  
Zong De Liu ◽  
Zhi Jian Bao
Keyword(s):  
Fracture Surface ◽  
Impact Test ◽  
Elevated Temperatures ◽  
Impact Fracture ◽  
X Ray Diffraction ◽  
Impact Properties ◽  
X Ray ◽  
Before And After ◽  
Different Temperatures ◽  
The Impact

The impact properties of TiC-Fe composite at different temperatures prepared by SHS / PHIP technique were investigated by impact test which was conducted in air from 20°C to 100020°C. Morphology of the impact fracture surface was observed by scanning electron microscope (SEM) and phase composition before and after the impact test was analyzed with X-Ray Diffraction. The results indicate that the impact toughness of TiC-Fe composite increases significantly with the temperature increasing above 700°C, representing a minimum value at 700°C. The impact fracture of TiC-Fe composite at room temperature, 700°C, 900°C and 1000°C is mainly brittle, showing certain plasticity with morphology of dimples as the temperature increases above 700°C. A small amount of Fe2O3 exists in the fracture surface, indicating TiC-Fe composite is oxidized partially during the impact test at elevated temperatures.

Influence of Ethanol as a Carburizing Agent on Carbon Surface Concentration and Microstructure of DIN 17NiCrMo7 Steel Gears

2015 ◽  
Author(s):  
Rogério Catalão ◽  
Omar Khayyam Ribas ◽  
José Rubens G. Carneiro ◽  
Érico Freitas ◽  
Larissa Vilela Costa ◽  
...  
Keyword(s):  
Shot Peening ◽  
Surface Concentration ◽  
Carbon Surface ◽  
Quantitative Chemical Analysis ◽  
X Ray Diffraction ◽  
Austenite Grain Size ◽  
X Ray ◽  
Transmission Electron ◽  
Before And After ◽  
The Impact

In the present work, the addition of ethanol to endothermic gas during the carburizing process of DIN 17NiCrMo7 steel gears was investigated with the objective of determining the impact on carbon surface concentration and microstructure. The materials were carburized at 870°C and 930°C, oil quenched, tempered and subsequently shot peened. Carburizing was carried out in a continuous industrial furnace for a total of 280 min. After quenching and tempering, the in-depth carbon concentrations were determined through quantitative chemical analysis and the resulting profiles were modeled in order to obtain carbon diffusivity constants. The amount of retained austenite and austenite grain size, determined by X-ray diffraction and optical microscopy, were found to increase with carburizing temperature. Residual stress profiles were also determined by X-ray diffraction before and after the shot-peening process. The microstructure of the specimens was further investigated by transmission electron microscopy, which revealed the presence of BCC martensite before and after shot-peening. The enrichment of the endothermic gas carrier with ethanol could be shown to be a viable option, allowing for surface concentrations of up to 0.8%C.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

A New Polyethylene Corrosion Protecting Coating with Ion Selectivity

2011 ◽  
Vol 314-316 ◽  
pp. 273-278
Author(s):  
Yu Hua Dong ◽  
Ke Ren ◽  
Qiong Zhou
Keyword(s):  
Ion Selectivity ◽  
Nano Particles ◽  
Ammonium Bromide ◽  
Linear Low Density Polyethylene ◽  
X Ray Diffraction ◽  
Sulfosalicylic Acid ◽  
X Ray ◽  
Chemically Modified ◽  
Before And After ◽  
Industrial Standards

Linear low density polyethylene (LLDPE) was chemically modified with grafting maleic anhydride (MAH) monomer on its backbone by melting blending. Nano-particles SiO2 was modified by cationic surfactant hexadecyl trimethyl ammonium bromide (CTAB) and anionic surfactant sulfosalicylic acid (SSA) and added to PE coating respectively. Measurement of membrane potential showed that the coating containing modified SiO2 nano-particles had characteristic of ion selectivity. The properties of the different coatings were investigated according to relative industrial standards. Experimental results indicated that PE coating with ion selectivity had better performances, such as adhesion strength, cathodic disbonding and anti-corrosion, than those of coating without ion selectivity. Crystal structure of the coatings before and after alkali corrosion was characterized by Fourier transform infrared spectra (FTIR) and X-ray diffraction (XRD). Structure of the coating without ion selectivity was damaged by NaOH alkali solution, causing mechanical properties being decreased. And the structure of the ion selective coatings was not affected.

scholarly journals The impact of point defects in n-type GaN layers on thermal decomposition of InGaN/GaN QWs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mikolaj Grabowski ◽  
Ewa Grzanka ◽  
Szymon Grzanka ◽  
Artur Lachowski ◽  
Julita Smalc-Koziorowska ◽  
...  
Keyword(s):  
Quantum Wells ◽  
High Temperatures ◽  
Point Defects ◽  
X Ray Diffraction ◽  
Helium Ions ◽  
X Ray ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
The Impact ◽  
Ingan Quantum Wells

AbstractThe aim of this paper is to give an experimental evidence that point defects (most probably gallium vacancies) induce decomposition of InGaN quantum wells (QWs) at high temperatures. In the experiment performed, we implanted GaN:Si/sapphire substrates with helium ions in order to introduce a high density of point defects. Then, we grew InGaN QWs on such substrates at temperature of 730 °C, what caused elimination of most (but not all) of the implantation-induced point defects expanding the crystal lattice. The InGaN QWs were almost identical to those grown on unimplanted GaN substrates. In the next step of the experiment, we annealed samples grown on unimplanted and implanted GaN at temperatures of 900 °C, 920 °C and 940 °C for half an hour. The samples were examined using Photoluminescence, X-ray Diffraction and Transmission Electron Microscopy. We found out that the decomposition of InGaN QWs started at lower temperatures for the samples grown on the implanted GaN substrates what provides a strong experimental support that point defects play important role in InGaN decomposition at high temperatures.

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