A study on kinetics of Al2O3 inclusion absorbed by mold slag used for non-manganese steel

2017 ◽  
Author(s):  
Zhiyang Li ◽  
Weican Zhou ◽  
Mindong Chen
2013 ◽  
Vol 212 ◽  
pp. 157-162
Author(s):  
Roman Przeliorz ◽  
Jaroslaw Piątkowski

Studies were conducted on the kinetics and mechanism of oxidation of chromium-manganese steel under partial oxygen pressure pO2from 10-11to 10-2Pa at a temperature of 1173 K. The low oxygen partial pressure was produced in a gas mixture of CO-CO2and helium containing 0.2 ppm of oxygen. The kinetics of oxidation was examined by thermogravimetry using a thermobalance made by Setaram Company. Scale growth mechanism was determined with the use of markers. The oxidation products were analyzed by scanning electron microscopy (SEM, EDS). It was found that at low partial pressure of oxygen, MnO oxide was forming on the steel surface. From an analysis of the curves of the steel weight growth per unit surface in function of time it followed that the oxidation assumed a parabolic course. A relationship has been determined between the coefficient of self-diffusion of manganese in MnO and the oxygen partial pressure.


Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7116
Author(s):  
Valery Shabashov ◽  
Kirill Lyashkov ◽  
Kirill Kozlov ◽  
Vladimir Zavalishin ◽  
Andrey Zamatovskii ◽  
...  

A narrow temperature range of changes in the mechanism and kinetics of structural-phase transformations during mechanical alloying under deformation in rotating Bridgman anvils was determined by the methods of Mössbauer spectroscopy, electron microscopy, and mechanical tests in the high-nitrogen chromium-manganese steel FeMn22Cr18N0.83. The experimentally established temperature region is characterized by a change in the direction of nitrogen redistribution—from an increase in the N content in the metal matrix during cold deformation to a decrease with an increase in the temperature and degree of severe plastic deformation. The change in the direction of nitrogen redistribution is due to the acceleration of the decomposition of a nitrogen-supersaturated solid solution of austenite with the formation of secondary nanocrystalline nitrides. The presence of a transition region for the mechanism of structural-phase transitions is manifested in the abnormal behavior of the mechanical properties of steel.


Author(s):  
J. F. DeNatale ◽  
D. G. Howitt

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.


Author(s):  
R. J. Lauf

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.


Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization


Author(s):  
L. J. Chen ◽  
L. S. Hung ◽  
J. W. Mayer

When an energetic ion penetrates through an interface between a thin film (of species A) and a substrate (of species B), ion induced atomic mixing may result in an intermixed region (which contains A and B) near the interface. Most ion beam mixing experiments have been directed toward metal-silicon systems, silicide phases are generally obtained, and they are the same as those formed by thermal treatment.Recent emergence of silicide compound as contact material in silicon microelectronic devices is mainly due to the superiority of the silicide-silicon interface in terms of uniformity and thermal stability. It is of great interest to understand the kinetics of the interfacial reactions to provide insights into the nature of ion beam-solid interactions as well as to explore its practical applications in device technology.About 500 Å thick molybdenum was chemical vapor deposited in hydrogen ambient on (001) n-type silicon wafer with substrate temperature maintained at 650-700°C. Samples were supplied by D. M. Brown of General Electric Research & Development Laboratory, Schenectady, NY.


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