Current status of ductile tungsten alloy development by mechanical alloying

2004 ◽  
Vol 329-333 ◽  
pp. 775-779 ◽  
Author(s):  
Y Ishijima ◽  
H Kurishita ◽  
K Yubuta ◽  
H Arakawa ◽  
M Hasegawa ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Current Status ◽  
Tungsten Alloy ◽  
Alloy Development

Synthesis of Nanocrystalline Tungsten Alloy by Mechanical Alloying and Annealing

2005 ◽  
Vol 23 ◽  
pp. 239-242 ◽  
Author(s):  
Z.G. Liu ◽  
L. Lu ◽  
M.O. Lai
Keyword(s):  
Mechanical Alloying ◽  
Structural Characterization ◽  
Amorphous Matrix ◽  
Amorphous Structure ◽  
Tungsten Alloy ◽  
Tungsten Alloys ◽  
Iron Powders ◽  
Nanocrystalline Phases

Formation of partial nanocrystal and amorphous tungsten alloys was synthesized via crystallization of a completely amorphized tungsten alloy synthesized by mechanical alloying. Structural characterization shows formation of amorphous structure from mechanical alloying of a mixture of elemental tungsten and iron powders after about 150 hours. Partial nanocrystalline phases within the amorphous matrix were formed through annealing the amorphous tungsten alloy at 1075°C.

Current status of special planetary and lunar theories and ephemerides

1966 ◽  
Vol 25 ◽  
pp. 266-267
Author(s):  
R. L. Duncombe
Keyword(s):  
Observational Data ◽  
Current Status ◽  
Numerical Errors

An examination of some specialized lunar and planetary ephemerides has revealed inconsistencies in the adopted planetary masses, the presence of non-gravitational terms, and some outright numerical errors. They should be considered of temporary usefulness only, subject to subsequent amendment as required for the interpretation of observational data.

Current Status of Solid-State X-Ray Systems

1985 ◽  
Vol 43 ◽  
pp. 158-161
Author(s):  
Martin Peckerar ◽  
Anastasios Tousimis
Keyword(s):  
Solid State ◽  
Electric Fields ◽  
Spectral Lines ◽  
Current Status ◽  
Mobile Charge ◽  
Electron Hole ◽  
X Ray ◽  
Sensing Systems ◽  
Transmission Electron ◽  
Electron Microscopes

Solid state x-ray sensing systems have been used for many years in conjunction with scanning and transmission electron microscopes. Such systems conveniently provide users with elemental area maps and quantitative chemical analyses of samples. Improvements on these tools are currently sought in the following areas: sensitivity at longer and shorter x-ray wavelengths and minimization of noise-broadening of spectral lines. In this paper, we review basic limitations and recent advances in each of these areas. Throughout the review, we emphasize the systems nature of the problem. That is. limitations exist not only in the sensor elements but also in the preamplifier/amplifier chain and in the interfaces between these components.Solid state x-ray sensors usually function by way of incident photons creating electron-hole pairs in semiconductor material. This radiation-produced mobile charge is swept into external circuitry by electric fields in the semiconductor bulk.

Microstructure of mechanically alloyed and hot-pressed Al5CuZr2

1990 ◽  
Vol 48 (4) ◽  
pp. 970-971
Author(s):  
T. E. Mitchell ◽  
P. B. Desch ◽  
R. B. Schwarz
Keyword(s):  
Mechanical Alloying ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Rapid Quenching ◽  
Hardened Steel ◽  
Alloyed Powder ◽  
Ion Milling ◽  
Mechanical Grinding ◽  
Mechanically Alloyed ◽  
Steel Container

Al3Zr has the highest melting temperature (1580°C) among the tri-aluminide intermetal1ics. When prepared by casting, Al3Zr forms in the tetragonal DO23 structure but by rapid quenching or by mechanical alloying (MA) it can also be prepared in the metastable cubic L12 structure. The L12 structure can be stabilized to at least 1300°C by the addition of copper and other elements. We report a TEM study of the microstructure of bulk Al5CuZr2 prepared by hot pressing mechanically alloyed powder.MA was performed in a Spex 800 mixer using a hardened steel container and balls and adding hexane as a surfactant. Between 1.4 and 2.4 wt.% of the hexane decomposed during MA and was incorporated into the alloy. The mechanically alloyed powders were degassed in vacuum at 900°C. They were compacted in a ram press at 900°C into fully dense samples having Vickers hardness of 1025. TEM specimens were prepared by mechanical grinding followed by ion milling at 120 K. TEM was performed on a Philips CM30 at 300kV.

Electron-deficient boron-based catalysts for C–H bond functionalisation

2021 ◽  
Author(s):  
Yuanhong Ma ◽  
Shao-Jie Lou ◽  
Zhaomin Hou
Keyword(s):  
Review Article ◽  
Current Status ◽  
Comprehensive Overview

This review article provides a comprehensive overview to recognise the current status of electron-deficient boron-based catalysis in C–H functionalisations.

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