RAPID QUENCHING OF MELTS IN THE SYSTEM ZrO2-SiO2-Al2O3

1986 ◽  
Vol 47 (C1) ◽  
pp. C1-473-C1-477
Author(s):  
M. YOSHIMURA ◽  
M. KANEKO ◽  
S. SŌMIYA
Keyword(s):  
Author(s):  
T. E. Mitchell ◽  
R. B. Schwarz

Traditional oxide glasses occur naturally as obsidian and can be made easily by suitable cooling histories. In the past 30 years, a variety of techniques have been discovered which amorphize normally crystalline materials such as metals. These include [1-3]:Rapid quenching from the vapor phase.Rapid quenching from the liquid phase.Electrodeposition of certain alloys, e.g. Fe-P.Oxidation of crystals to produce amorphous surface oxide layers.Interdiffusion of two pure crystalline metals.Hydrogen-induced vitrification of an intermetal1ic.Mechanical alloying and ball-milling of intermetal lie compounds.Irradiation processes of all kinds using ions, electrons, neutrons, and fission products.We offer here some general comments on the use of TEM to study these materials and give some particular examples of such studies.Thin specimens can be prepared from bulk homogeneous materials in the usual way. Most often, however, amorphous materials are in the form of surface films or interfacial films with different chemistry from the substrates.


Author(s):  
W. A. Chiou ◽  
N. L. Jeon ◽  
Genbao Xu ◽  
M. Meshii

For many years amorphous metallic alloys have been prepared by rapid quenching techniques such as vapor condensation or melt quenching. Recently, solid-state reactions have shown to be an alternative for synthesizing amorphous metallic alloys. While solid-state amorphization by ball milling and high energy particle irradiation have been investigated extensively, the growth of amorphous phase by cold-rolling has been limited. This paper presents a morphological and structural study of amorphization of Cu and Ti foils by rolling.Samples of high purity Cu (99.999%) and Ti (99.99%) foils with a thickness of 0.025 mm were used as starting materials. These thin foils were cut to 5 cm (w) × 10 cm (1), and the surface was cleaned with acetone. A total of twenty alternatively stacked Cu and Ti foils were then rolled. Composite layers following each rolling pass were cleaned with acetone, cut into half and stacked together, and then rolled again.


Author(s):  
T. E. Mitchell ◽  
P. B. Desch ◽  
R. B. Schwarz

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.


1985 ◽  
Vol 46 (C8) ◽  
pp. C8-533-C8-537
Author(s):  
J. Chevrier ◽  
P. Sainfort ◽  
P. Germi ◽  
D. Pavuna

1992 ◽  
Vol 63 (6) ◽  
pp. 3425-3430 ◽  
Author(s):  
Kenichi Nishiuchi ◽  
Noboru Yamada ◽  
Nobuo Akahira ◽  
Mutsuo Takenaga ◽  
Ryutaro Akutagawa

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Tiebao Wang ◽  
Chunxiang Cui ◽  
Kuo Jia ◽  
Lichen Zhao

The nanostructured Fe-V-Nb master alloy was prepared in vacuum rapid quenching furnace and then was added in the steel melts as modificators before casting. Next, the effects of the nanostructured Fe-V-Nb modificators on the microstructure and mechanical properties of the steel were studied. The results show that the grain size of the steel has been effectively refined, which is mainly because the dispersed nanoscale particles can produce more nucleation sites during the solidification of the liquid steel. Tensile properties and fracture morphology reveal that the yield strength and toughness of the steel modified by nanostructured Fe-V-Nb modificators are better than that of the microalloyed steel. TEM analysis shows that vanadium and niobium in the modificators exist in the form of (V, Nb) C which effectively increases the nucleation rate and leads to better mechanical properties of the steel.


Fuel ◽  
2021 ◽  
Vol 306 ◽  
pp. 121658
Author(s):  
Bin Li ◽  
Xing Xie ◽  
Lei Zhang ◽  
Dan Lin ◽  
Shuaijun Wang ◽  
...  

Author(s):  
Keiichi N. ISHIHARA ◽  
Shigeto R. NISHITANI ◽  
P. Hideo SHINGU
Keyword(s):  

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