The Mechanisms of Cavitation Erosion of the Elektron21 Magnesium Alloy

2015 ◽  
Vol 229 ◽  
pp. 99-104 ◽  
Author(s):  
Bartłomiej Dybowski ◽  
Mirosław Szala ◽  
Andrzej Kiełbus ◽  
Tadeusz Hejwowski
Keyword(s):  
Solid Solution ◽  
Cross Sections ◽  
Cavitation Erosion ◽  
Water Environment ◽  
High Hardness ◽  
Intermetallic Phases ◽  
The Other ◽  
Casting Alloy ◽  
Magnesium Casting ◽  
Scanning Electron

Magnesium and its alloys may be applied as cathodic protection for steel constructions. As the protectors work in water environment, one of the main degradation factors is cavitation erosion. The paper presents results of research on the cavitation erosion of magnesium casting alloy – Elektron 21. The cavitation erosion tests were performed using vibratory apparatus. After the cavitation tests eroded surface and the cross-sections of the specimens were observed by means of scanning electron microscopy. Elektron 21 did not exhibit distinct incubation period of cavitation erosion. The cavitation pits are observed mainly in the α-Mg solid solution grains and on the interfaces between intermetallic phases and the α-Mg. On the other hand, the Mg3(Nd, Gd) eutectic phases are more resistant to cavitation erosion than α-Mg. They are protecting the solid solution from degradation. However, due to their high hardness they undergo cracking and detachment of from the surface. After longer times of cavitation tests, cracks begin to propagate into the material, which leads to crushing of bigger parts of the material.

Microstructure and Hydrogen Permeability of Duplex Phase M-ZrNi (M=V, Nb, Ta) Alloys

2006 ◽  
Vol 980 ◽  
Author(s):  
Kazuhiro Ishikawa ◽  
Naoshi Kasagami ◽  
Tomoyuki Takano ◽  
Kiyoshi Aoki
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
High Performance ◽  
Gas Flow ◽  
Hydrogen Permeation ◽  
Hydrogen Permeability ◽  
The Other ◽  
Cast State ◽  
X Ray ◽  
Scanning Electron

AbstractIn order to develop non-Pd based high performance hydrogen permeation alloys, microstructure, crystal structure and hydrogen permeability of duplex phase M-ZrNi (M=V and Ta) alloys were investigated using a scanning electron microscope, an X-ray diffractometer and a gas flow meter. These results were compared with those of Nb-ZrNi ones which have been previously published. The hydrogen permeation was impossible in the V-ZrNi alloys, because they were brittle in the as-cast state. On the other hand, duplex phase alloys consisting of the bcc-(Ta, Zr) solid solution and the orthorhombic ZrNi (Cmcm) intermetallic compound were formed and hydrogen permeable in the Ta-ZrNi system. The Ta40Zr30Ni30 alloy shows the highest value of hydrogen permeability of 4.1×10-8 [molH2m-1s-1Pa-0.5] at 673 K, which is three times higher than that of pure Pd.

scholarly journals Effect of Mould Components on the Cooling Rate, Microstructure, and Quality of We43 Magnesium Casting Alloy/ Wpływ Zastosowanych Elementów Formy Na Szybkość Chłodzenia, Mikrostrukturę I Jakość Stopu Magnezu We43

2014 ◽  
Vol 59 (4) ◽  
pp. 1527-1532 ◽  
Author(s):  
B. Dybowski ◽  
A. Kiełbus ◽  
R. Jarosz
Keyword(s):  
Solid Solution ◽  
Shrinkage Porosity ◽  
Casting Alloy ◽  
Sand Cast ◽  
Feeding Method ◽  
Magnesium Casting ◽  
Metallic Inclusions ◽  
The Impact ◽  
We43 Magnesium Alloy

Abstract We investigated the impact of the applied cooling and feeding method on the microstructure and metallurgical quality of castings made from WE43 magnesium alloy. Six identical plates with dimensions of 100x50x20 mm were sand cast for use as samples. Each casting was fed and cooled in a different way. The solid solution grain size was evaluated quantitatively using the Met-Ilo software program, and casting defects were observed using a scanning electron microscope Hitachi S3400N. The finest solid solution grain was observed in the castings with only the coolers applied. Non-metallic inclusions were observed in each plate. The smallest shrinkage porosity was observed in the castings with feeders applied.

scholarly journals Laser Cleaning Tests on Archaeological Copper Alloys Using an ND:YAG Laser

2006 ◽  
Vol 2006 ◽  
pp. 1-7 ◽  
Author(s):  
Capucine Korenberg ◽  
Alexandra Baldwin
Keyword(s):  
Cross Sections ◽  
Nd:Yag Laser ◽  
Copper Alloy ◽  
Copper Alloys ◽  
Laser Cleaning ◽  
The Other ◽  
Original Surface ◽  
Surface Laser ◽  
Mechanical Cleaning ◽  
Scanning Electron

Laser cleaning tests were performed on five archaeological copper alloy objects using a Q-switched Nd:YAG laser at 1064 nm. As a comparison, a section of each object was cleaned mechanically. Prior to cleaning, cross-sections were prepared to characterise the corrosion crust and help to locate the position of the original surface. Laser cleaning was not successful at removing burial deposits on two of the objects. For the other three objects, the laser removed most of the corrosion crust. This was not always satisfactory, as cleaning was sometimes accompanied by the loss of the original surface. In addition, laser-cleaned surfaces were matt compared to mechanically cleaned surfaces. In some instances, the former had a disfiguring purple hue which was attributed to the formation of particles that could be seen when examining the surface using scanning electron microscopy. For all the objects examined here, superior results were obtained by mechanical cleaning.

scholarly journals Properties and Structure of Cellulosic Membranes Obtained from Solutions in Ionic Liquids Coagulated in Primary Alcohols

2018 ◽  
Vol 18 (3) ◽  
pp. 232-242
Author(s):  
Beata Fryczkowska ◽  
Małgorzata Kowalska ◽  
Dorota Biniaś ◽  
Czesław Ślusarczyk ◽  
Jarosław Janicki ◽  
...  
Keyword(s):  
Cross Sections ◽  
Phase Inversion ◽  
Composite Membranes ◽  
Skin Layer ◽  
The Other ◽  
Inversion Method ◽  
Primary Alcohols ◽  
Membrane Surfaces ◽  
Phase Inversion Method ◽  
Scanning Electron

Abstract This paper presents the results of studies on the preparation of cellulosic membranes, from a solution in 1-ethyl-3- methylimidazolium acetate (EMIMAc), using the phase inversion method. Initially, the membranes were obtained by coagulation of the polymer film in water and primary alcohols (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol), 1-hexanol, 1-octanol) resulting in membranes with significantly differing morphologies. Subsequently, composite membranes were produced, with the support layer being a membrane with the largest pores, and the skin layer a membrane with smaller pores. The resulting membranes were tested for physicochemical and transport properties. The morphology of the membrane surfaces and their cross-sections were investigated by using a scanning electron microscope (SEM). The structure of the membranes, on the other hand, was investigated by FTIR spectroscopy and WAXS structural analysis.

scholarly journals Microstructure and Cavitation Erosion Resistance of HVOF Deposited WC-Co Coatings with Different Sized WC

Coatings ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 307 ◽  
Author(s):  
Xiang Ding ◽  
Du Ke ◽  
Chengqing Yuan ◽  
Zhangxiong Ding ◽  
Xudong Cheng
Keyword(s):  
Fracture Toughness ◽  
Electron Microscope ◽  
Cavitation Erosion ◽  
Erosion Resistance ◽  
The Other ◽  
Fuel Spray ◽  
X Ray ◽  
Cavitation Erosion Resistance ◽  
Scanning Electron ◽  
Conventional Coating

Conventional, multimodal and nanostructured WC-12Co coatings with different WC sizes and distributions were prepared by high velocity oxy-fuel spray (HVOF). The micrographs and structures of the coatings were analyzed by scanning electron microscope (SEM), X-ray diffractometer (XRD) et al. The porosity, microhardness and fracture toughness of the WC-Co coatings were measured. The coating resistance to cavitation erosion (CE) was investigated by ultrasonic vibration cavitation equipment and the cavitation mechanisms were explored. Results show that there is serious WC decarburization in nanostructured and multimodal WC-Co coatings with the formation of W2C and W phases. The nanostructured WC-Co coating has the densest microstructure with lowest porosity compared to the other two WC-Co coatings, as well as the highest fracture toughness among the three coatings. It was also discovered that the nanostructured WC-Co coating exhibits the best CE resistance and that the CE rate is approximately one-third in comparison with conventional coating.

The Morphological Characteristics and Composition of Body Surface of Ant and its Relation to Reducing Soil Adherence

2010 ◽  
Vol 139-141 ◽  
pp. 872-876
Author(s):  
Dian Wu Zhang ◽  
Yu Xing Wang ◽  
Yan Qin Tang ◽  
Wen Zeng
Keyword(s):  
Cross Sections ◽  
Surface Composition ◽  
Morphological Characteristics ◽  
The Body ◽  
The Other ◽  
X Ray ◽  
Soil Adherence ◽  
Energy Spectrometer ◽  
Abundant Element ◽  
Scanning Electron

The surface of ants was observed, analyzed and tested by using of scanning electron microscopy and X-ray energy spectrometer technology. On different surface of the ants, the waveform characteristics which were formed by different sizes of grooves were found. These cross sections of waveform surface were waveform curves which had continuous periods and amplitudes. Their sizes varied with different part of the ant. In addition, there was distribution of setae of various sizes on surface of the body. Under higher multiple of electron microscope, the bigger setae had the waveform surface of smaller periods and amplitudes. The results of composition analyzing indicated that the surface of ants contained multi-elements. Among these elements, the most abundant was O which content was over 57%. The following abundant element was C which content was more than 23%. The other elements such as Na, Mg, Zn, Si, P, S, Cl, K, Ca remained less than 3% respectively. The distribution of morphological characteristics and surface composition may contribute to the property of reducing soil adherence.

scholarly journals Fabrication and Microstructure of Layers Containing Intermetallic Phases on Magnesium

2013 ◽  
Vol 13 (1) ◽  
pp. 99-102 ◽  
Author(s):  
R. Mola
Keyword(s):  
Solid Solution ◽  
Powder Mixture ◽  
Intermetallic Phase ◽  
Intermetallic Phases ◽  
Vacuum Furnace ◽  
X Ray Diffraction ◽  
Surface Layers ◽  
X Ray ◽  
Al Powder ◽  
Scanning Electron

Abstract Al- and Al/Zn-enriched layers containing intermetallic phases were deposited on the Mg substrate by heating the Mg specimens in contact with the powdered materials in a vacuum furnace. The Al-enriched surface layers were produced using Al powder, whereas the Al/Znenriched layers were obtained from an 80 wt.% Al + 20 wt.% Zn powder mixture. The microstructure and composition of the layers were analyzed by optical microscopy, scanning electron microscopy and X-ray diffraction. The results showed that the Al-enriched layer comprised an Mg17Al12 intermetallic phase and a solid solution of Al in Mg. The layer obtained from the Al+Zn powder mixture was composed of Mg-Al-Zn intermetalic phases and a solid solution of Al and Zn in Mg. Adding 20% of Zn into the Al powder resulted in the formation of a considerably thicker layer. Moreover, the hardness of the surface layers was much higher than that of the Mg substrate.

scholarly journals Analysis of interdiffusion of Dy, Nd, and Pr in Mg

2001 ◽  
Vol 16 (11) ◽  
pp. 3287-3292 ◽  
Author(s):  
Y. Xu ◽  
L. S. Chumbley ◽  
G. A. Weigelt ◽  
F. C. Laabs
Keyword(s):  
Solid Solution ◽  
Rare Earth ◽  
Intermetallic Phases ◽  
Diffusion Couples ◽  
X Ray ◽  
Diffusion Characteristics ◽  
Composition Profiles ◽  
Point Composition ◽  
Interdiffusion Coefficients ◽  
Scanning Electron

The diffusion characteristics of Mg–rare-earth diffusion couples were studied. Cylinders of pure Mg and rare earth (Dy, Nd, and Pr) were abutted and annealed at 500 °C for 100 h or 300 h. Point-by-point composition profiles were collected starting in pure Mg, across the diffusion zone, and ending in the pure rare earth, using energy dispersive x-ray spectroscopy with a scanning electron microscope. The intermetallic phases that resulted due to diffusion were identified and compared to existing phase diagrams, for which the data is limited. For each diffusion couple, a plot of concentration versus distance perpendicular to the original plane of contact was obtained and analyzed using the Boltzman–Matano method. The interdiffusion coefficients for each set of phases were then calculated. The results show that diffusion through the intermetallic phases is much slower than is expected in a solid solution.

The Alteration of the Pore Spaces in Sandstones

1973 ◽  
Vol 31 ◽  
pp. 210-211
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
The Other ◽  
Coarse Grained ◽  
Depositional Fabric ◽  
Soluble Components ◽  
Scanning Electron ◽  
Shape And Size

The pore spaces in sandstones are the result of the original depositional fabric and the degree of post-depositional alteration that the rock has experienced. The largest pore volumes are present in coarse-grained, well-sorted materials with high sphericity. The chief mechanisms which alter the shape and size of the pores are precipitation of cementing agents and the dissolution of soluble components. Each process may operate alone or in combination with the other, or there may be several generations of cementation and solution.The scanning electron microscope has ‘been used in this study to reveal the morphology of the pore spaces in a variety of moderate porosity, orthoquartzites.

Electron Irradiation Effects in Polyoxymethylene Crystals Grown Inside Trioxane Crystals

1971 ◽  
Vol 29 ◽  
pp. 78-79
Author(s):  
J. P. Colson ◽  
D. H. Reneker
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Detailed Examination ◽  
The Other ◽  
Electron Micrograph ◽  
Irradiation Effects ◽  
Threefold Axis ◽  
Typical Sample ◽  
Polymer Crystals ◽  
Chain Axis

Polyoxymethylene (POM) crystals grow inside trioxane crystals which have been irradiated and heated to a temperature slightly below their melting point. Figure 1 shows a low magnification electron micrograph of a group of such POM crystals. Detailed examination at higher magnification showed that three distinct types of POM crystals grew in a typical sample. The three types of POM crystals were distinguished by the direction that the polymer chain axis in each crystal made with respect to the threefold axis of the trioxane crystal. These polyoxymethylene crystals were described previously.At low magnifications the three types of polymer crystals appeared as slender rods. One type had a hexagonal cross section and the other two types had rectangular cross sections, that is, they were ribbonlike.

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