排序方式: 共有6条查询结果,搜索用时 0 毫秒
1
1.
Dépinoy S. Marini B. Toffolon-Masclet C. Roch F. Gourgues-Lorenzon A.-F. 《Metallurgical and Materials Transactions A》2017,48(5):2289-2300
Metallurgical and Materials Transactions A - Austenite grain size has been experimentally determined for various austenitization temperatures and times in a 2.25Cr-1Mo vanadium-free steel. Three... 相似文献
2.
A new numerical tool has been developed by coupling the diffusion code “EKINOX” (Estimation Kinetics Oxidation) and the thermodynamic database “ZIRCOBASE” using TQ (ThermoCalc program interface). The aim of this tool is to calculate the oxygen diffusion during oxidation of Zr based alloys. The simulation results of the oxide growth kinetics and the induced oxygen diffusion profiles in the [1100-1250 °C] temperature range, at different times, are presented and compared to previous experimental results. An estimation of the diffusion coefficient in the α phase is deduced from this comparison. The results are discussed in comparison to previous models based on an analytical treatment and the influence of the choice of the thermodynamic data set on the final oxygen diffusion profile is explored.Finally, it is shown that the present modeling is able to predict quite accurately the “critical” oxidation time corresponding to the overall ductile-to-brittle transition of the high temperature (HT) oxidized clad. 相似文献
3.
Sylvain Dépinoy Caroline Toffolon-Masclet Stéphane Urvoy Justine Roubaud Bernard Marini François Roch Ernst Kozeschnik Anne-Françoise Gourgues-Lorenzon 《Metallurgical and Materials Transactions A》2017,48(5):2164-2178
The effect of the tempering heat treatment, including heating prior to the isothermal step, on carbide precipitation has been determined in a 2.25 Cr-1 Mo bainitic steel for thick-walled applications. The carbides were identified using their amount of metallic elements, morphology, nucleation sites, and diffraction patterns. The evolution of carbide phase fraction, morphology, and composition was investigated using transmission electron microscopy, X-ray diffraction, as well as thermodynamic calculations. Upon heating, retained austenite into the as-quenched material decomposes into ferrite and cementite. M7C3 carbides then nucleate at the interface between the cementite and the matrix, triggering the dissolution of cementite. M2C carbides precipitate separately within the bainitic laths during slow heating. M23C6 carbides precipitate at the interfaces (lath boundaries or prior austenite grain boundaries) and grow by attracting nearby chromium atoms, which results in the dissolution of M7C3 and, depending on the temperature, coarsening, or dissolution of M2C carbides, respectively. 相似文献
4.
Benoît Mazères Clara Desgranges Caroline Toffolon-Masclet Daniel Monceau 《Oxidation of Metals》2013,79(1-2):121-133
Previous studies have shown that the numerical model EKINOX-Zr was able to simulate with accuracy oxide growth and oxygen diffusion into the matrix during high-temperature oxidation of Zy-4. In this study, the aim of the development was to evaluate if the observed effect of hydrogen cladding content on the increase of oxygen solubility in the high-temperature βZr was only a thermodynamic effect. Previous experimental studies have shown that hydrogen induces an evolution of equilibrium oxygen concentration at the αZr/βZr interface. The present work showed that EKINOX-Zr linked with the thermodynamic database Zircobase reproduced the evolution induced by hydrogen during the high-temperature steam oxidation. However, the results showed also that additional studies are necessary to better understand hydrogen behavior during high-temperature oxidation of Zr. 相似文献
5.
Benoît Mazères Clara Desgranges Caroline Toffolon-Masclet Daniel Monceau 《Oxidation of Metals》2018,89(5-6):517-529
The numerical tool EKINOX-Zr has been upgraded to simulate oxygen tracer experiments during the high-temperature oxidation of a metal with a high oxygen solubility limit. The penetration of 18O tracer is calculated during the dynamic evolution of the ZrO2-x/αZr(O )/βzr system. The numerical approach allows to explicitly take into account the variation of the tracer diffusion coefficient through the oxide scale as a function of the vacancy concentration. A classical two-stages 16O2/18O2 tracer experiment has been simulated. It is shown that a classical fitting procedure on the 18O concentration profile obtained for short-time experiments leads to the identification of the oxygen chemical diffusion coefficient. The second type of tracer experiment is proposed using a three-stages 16O2/18O2/16O2 oxidation. It allows the direct estimation of the diffusion coefficient from the transport of 18O peak in the growing oxide scale. 相似文献
6.
The Zr–Sn binary system has been reinvestigated by several experimental techniques: X-ray diffraction, electron probe micro-analysis, mass density and calorimetry measurements. The existence of a miscibility gap inside the homogeneity domain of the η phase (Zr5Sn3–Zr5Sn4) has been confirmed. It has been also shown that Zr substitution on the Sn sublattice is responsible for the non-stoichiometry of the A15 phase (Zr4Sn). The temperature of the peritectoid reaction βZr+A15↔αZr has been determined to be at 1216 K that is 40° below the temperature reported in the literature. All these new experimental data have been taken into account for a new thermodynamic assessment of this system. 相似文献
1