Fretting of Single Crystal/Polycrystalline Nickel Contacts at Elevated Frequency and Temperature

2004 ◽  
Author(s):  
John Matlik ◽  
Thomas Farris
Keyword(s):  
Single Crystal ◽  
Polycrystalline Nickel ◽  
Elevated Frequency

Fretting fatigue of single crystal/polycrystalline nickel subjected to blade/disk contact loading

2005 ◽  
Vol 57 (1) ◽  
pp. 1-9 ◽  
Author(s):  
H. Murthy ◽  
Daniel B. Garcia ◽  
John F. Matlik ◽  
Thomas N. Farris
Keyword(s):  
Single Crystal ◽  
Fretting Fatigue ◽  
Polycrystalline Nickel ◽  
Contact Loading ◽  
Disk Contact

Microstructural Investigations of Nickel-Based Superalloys with Different Structure

2013 ◽  
Vol 592-593 ◽  
pp. 557-560
Author(s):  
Maciej Pytel ◽  
Andrzej Nowotnik ◽  
Dariusz Szeliga ◽  
Jan Sieniawski
Keyword(s):  
Chemical Composition ◽  
Single Crystal ◽  
Primary Dendrite ◽  
Nickel Superalloy ◽  
Vacuum Furnace ◽  
Polycrystalline Nickel ◽  
X Ray ◽  
Dendrite Arm Spacing ◽  
Before And After ◽  
Primary Dendrite Arm Spacing

This paper presents the results of analysis of superalloys microstructures with different structures: polycrystalline nickel-based superalloy René 80, Mar-M 200Hf directionally solidified with columnar grains and single crystal CMSX-4. Microstructure studies were performed using a scanning electron microscope Hitachi FE-SEM SU-70 and S-3400N equipped with a Thermo Scientific Noran System for analysis of chemical composition by X-ray dispersion. Metallographic microsections of the rods before and after heat treatment was performed, which were electrolytically etched using different reagents. The morphology of γ phase precipitates in the interdendritic areas and dendritic cores was analyzed. Single crystal rods of nickel superalloy CMSX-4 were cast by Bridgman technique in a vacuum furnace of ALD Vacuum Technologies. Rods were withdrawn with rate: 1mm/min and 5mm/min. EDS X-ray microanalysis showed significant differences in chemical composition between the cores dendrites and eutectic regions. Significant differences in the number of dendrites, the shape and length of the arms were observed. A lower speed rate causes that amount of eutectic is lower but value of primary dendrite arm spacing is higher, while a higher withdraw rate increases the amount of eutectic and decreases primary dendrite arm spacing.

Adsorption on single crystal and polycrystalline nickel

Vacuum ◽  
1967 ◽  
Vol 17 (3) ◽  
pp. 169-170
Author(s):  
David Lichtman ◽  
R.B. McQuistan ◽  
T.R. Kirst
Keyword(s):  
Single Crystal ◽  
Polycrystalline Nickel

scholarly journals Total secondary electron emission from a single crystal face of nickel

1930 ◽  
Vol 128 (807) ◽  
pp. 57-62 ◽  
Keyword(s):  
Single Crystal ◽  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Experimental Results ◽  
X Rays ◽  
Polycrystalline Nickel ◽  
Crystal Face ◽  
Nickel Crystal

In an accompanying paper, secondary electron experiments on ordinary nickel are described. These were conducted mainly to study the conditions of secondary electron emission and to find how far the experimental results of Retry on a polycrystalline nickel target could be reproduced. It was found that a large number of inflections were obtained some of which coincided with Petry’s values. Most of these inflections had corresponding values in Thomas’s results for soft X-rays from nickel. In this paper, the results of experiments on total secondary electron emission from the 100 face of a nickel crystal are given.

scholarly journals Microstructure and Texture of Hydrostatic Extrusion Deformed Ni Single Crystals and Polycrystal

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
D. Jakubowska ◽  
J. Zdunek ◽  
M. Kulczyk ◽  
J. Mizera ◽  
K. J. Kurzydłowski
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Single Crystal ◽  
Single Crystals ◽  
Relevant Literature ◽  
Hydrostatic Extrusion ◽  
Total Deformation ◽  
Polycrystalline Nickel ◽  
Before And After

The differences in the microstructure and texture of two Ni single crystals, with different initial orientations (100and110), and of polycrystalline nickel, before and after severe plastic deformation (SPD) produced by hydrostatic extrusion (HE), have been investigated. The crystals were deformed by a two-step HE process with a total deformation value ofε=1.2. The global texture, mechanical properties, and microstructure were examined after the deformation. In every investigated sample, the presence of111fibre texture was noted, while the starting orientation of a100Ni single crystal was preserved in 50% of the volume. The results obtained were compared with the relevant literature data.

A Preparation of High Resolution Standards for Electron Microscopy. Part II

1971 ◽  
Vol 29 ◽  
pp. 160-161
Author(s):  
Akira Tanaka ◽  
David F. Harling
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Carbon Black ◽  
Single Crystal ◽  
Dark Field ◽  
Graphitized Carbon Black ◽  
Graphitized Carbon ◽  
Dark Field Imaging ◽  
Crystal Films ◽  
Micro Holes

In the previous paper, the author reported on a technique for preparing vapor-deposited single crystal films as high resolution standards for electron microscopy. The present paper is intended to describe the preparation of several high resolution standards for dark field microscopy and also to mention some results obtained from these studies. Three preparations were used initially: 1.) Graphitized carbon black, 2.) Epitaxially grown particles of different metals prepared by vapor deposition, and 3.) Particles grown epitaxially on the edge of micro-holes formed in a gold single crystal film.The authors successfully obtained dark field micrographs demonstrating the 3.4Å lattice spacing of graphitized carbon black and the Au single crystal (111) lattice of 2.35Å. The latter spacing is especially suitable for dark field imaging because of its preparation, as in 3.), above. After the deposited film of Au (001) orientation is prepared at 400°C the substrate temperature is raised, resulting in the formation of many square micro-holes caused by partial evaporation of the Au film.

Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates

1970 ◽  
Vol 28 ◽  
pp. 456-457
Author(s):  
L. E. Murr ◽  
G. Wong
Keyword(s):  
Single Crystal ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
High Rate ◽  
Flash Evaporation ◽  
Optimum Load ◽  
Single Crystal Films ◽  
Crystal Films ◽  
A Current

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.

Dislocations, Ordering and Antiferromagnetic Domains in MnO

1970 ◽  
Vol 28 ◽  
pp. 522-523
Author(s):  
D. J. Barber ◽  
R. G. Evans
Keyword(s):  
Electron Diffraction ◽  
Single Crystal ◽  
Optical Microscopy ◽  
Defect Chemistry ◽  
Magnetic Structures ◽  
Optically Transparent ◽  
Magnetic Features ◽  
Antiferromagnetic Domains

Manganese (II) oxide, MnO, in common with CoO, NiO and FeO, possesses the NaCl structure and shows antiferromagnetism below its Neel point, Tn∼ 122 K. However, the defect chemistry of the four oxides is different and the magnetic structures are not identical. The non-stoichiometry in MnO2 small (∼2%) and below the Tn the spins lie in (111) planes. Previous work reported observations of magnetic features in CoO and NiO. The aim of our work was to find explanations for certain resonance results on antiferromagnetic MnO.Foils of single crystal MnO were prepared from shaped discs by dissolution in a mixture of HCl and HNO3. Optical microscopy revealed that the etch-pitted foils contained cruciform-shaped precipitates, often thick and proud of the surface but red-colored when optically transparent (MnO is green). Electron diffraction and probe microanalysis indicated that the precipitates were Mn2O3, in contrast with recent findings of Co3O4 in CoO.

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