Researching nitrogen solubility in nitrogen-containing austenitic steels at melting and recrystallization by CALPHAD method

2019 ◽  
pp. 53-66 ◽  
Author(s):  
L. A. Smirnov ◽  
I. I. Gorbachev ◽  
V. V. Popov ◽  
A. Yu. Pasynkov ◽  
A. S. Oryshchenko ◽  
...  
Keyword(s):  
Global Minimum ◽  
Nitrogen Solubility ◽  
Thermodynamic Description ◽  
Solidus Temperature ◽  
Liquidus Line ◽  
Calphad Method ◽  
Austenitic Steels ◽  
Nitrogen Transfer ◽  
Fixed Nitrogen ◽  
System Phase

The CALPHAD method has been employed to compose thermodynamic description of the Fe–Cr–Mn–Ni–Si–C–N system. Using an algorithm based on finding a global minimum of Gibbs energy, the calculations of system phase composition were performed in the temperature range from 1750°C to hardening and in the range of compositions corresponding to 04Kh20N6G11M2AFB steel. Calculations showed that at temperatures above liquidus line, Cr and Mn increase nitrogen solubility in the melt, while Ni and Si reduce it. With an increase in the content of Cr, Mn, Ni, and Si in steel in the studied composition range, both liquidus and solidus temperature decrease. The degree of influence on these temperatures of Cr, Mn, Ni and Si within the steel grade is different and ranges from ~3 to ~14°C. Calculations taking into account the possibility of nitrogen transfer between steel and the atmosphere of air showed that the amount of fixed nitrogen in the alloy under study varies, depending on the composition of the steel and temperature, from ~0.3 to ~0.6 wt%. As the temperature decreases from liquidus to solidus, the amount of fixed nitrogen increases, with the exception of those steel compositions when ferrite and not austenite is released from the liquid phase.

Calphad description of the Ge-Mn system

2014 ◽  
Vol 1642 ◽  
Author(s):  
Alexandre Berche ◽  
Jean-Claude Tédenac ◽  
Philippe Jund ◽  
Stéphane Gorsse
Keyword(s):  
Phase Diagram ◽  
Liquid Phase ◽  
Thermodynamic Properties ◽  
Gibbs Energy ◽  
Critical Review ◽  
Thermodynamic Description ◽  
Calphad Method ◽  
Review Of The Literature ◽  
Solid Phases

ABSTRACTThe germanium-manganese system has been experimentally studied but no Calphad description is available yet. After a critical review of the literature concerning the phase diagram and the thermodynamic properties, a thermodynamic description of the Gibbs energy of the phases is performed using the Calphad method. The liquid phase is described with an associated model and the variation to the stoichiometry of the solid phases is taken into account.

Corrosion of T91 Steel in LBE: Contribution to the Study of the Pb–Bi–O–Fe–Hg System - Thermodynamic Description of PbO–Fe2O3

2008 ◽  
Vol 595-598 ◽  
pp. 473-481 ◽  
Author(s):  
Ibra Diop ◽  
N. David ◽  
J.M. Fiorani ◽  
Renaud Podor ◽  
Michel Vilasi
Keyword(s):  
Thermodynamic Assessment ◽  
Isothermal Annealing ◽  
Nuclear Reactors ◽  
Thermodynamic Description ◽  
Calphad Method ◽  
Experimental Investigations ◽  
Degradation Mechanisms ◽  
Spallation Target ◽  
Thermocalc Software

The knowledge of the quinary Pb–Bi–O–Fe–Hg is necessary for understanding the degradation mechanisms of the T91 steel used as structural material in future ADS nuclear reactors. In this device, the steel will be in direct contact with the liquid spallation target (which is constituted by lead or lead-bismuth eutectic) surrounded by a reduced oxygen pressure atmosphere. In the present work, the characterization of the pseudo-binary PbO–Fe2O3 cut has been performed. In order to complete the available data in the literature, some experimental investigations by DTA, isothermal annealing, SEM and EPMA have been done. These results have allowed proposing a thermodynamic assessment using the Calphad method by the ThermoCalc software.

scholarly journals Thermodynamic description of the C-Ge and C-Mg systems

2010 ◽  
Vol 46 (1) ◽  
pp. 97-103 ◽  
Author(s):  
B. Hu ◽  
Y. Du ◽  
H. Xu ◽  
W. Sun ◽  
W.W. Zhang ◽  
...  
Keyword(s):  
Thermodynamic Parameters ◽  
Enthalpy Of Formation ◽  
Thermodynamic Modeling ◽  
First Principles ◽  
Thermodynamic Description ◽  
Calphad Method ◽  
Thermodynamic Calculations ◽  
First Principles Calculation ◽  
System A ◽  
The Enthalpy Of Formation

The thermodynamic modeling for the C-Ge and C-Mg systems is performed by the CALPHAD method. The enthalpy of formation for Mg2C3, the experimental value of which is not available in the literature, is obtained via first-principles calculation to refine the thermodynamic modeling of the C-Mg system. A comparison of the thermodynamic calculations with the available literature data shows that the presently obtained two sets of thermodynamic parameters for the C-Ge and C-Mg systems can well describe the these two systems.

scholarly journals Phosphate availability affects fixed nitrogen transfer from diazotrophs to their epibionts

2019 ◽  
Vol 13 (11) ◽  
pp. 2701-2713 ◽  
Author(s):  
Niels J. Schoffelen ◽  
Wiebke Mohr ◽  
Timothy G. Ferdelman ◽  
Julia Duerschlag ◽  
Sten Littmann ◽  
...  
Keyword(s):  
Nitrogen Transfer ◽  
Fixed Nitrogen ◽  
Phosphate Availability

scholarly journals Thermodynamic description of the Al-Cu-Yb ternary system supported by first-principles calculations

2016 ◽  
Vol 52 (2) ◽  
pp. 177-183 ◽  
Author(s):  
G. Huang ◽  
L. Liu ◽  
L. Zhang ◽  
Z. Jin
Keyword(s):  
Ternary System ◽  
First Principles ◽  
Thermodynamic Description ◽  
Theoretical Data ◽  
Intermetallic Phases ◽  
Calphad Method ◽  
First Principles Calculations ◽  
Self Consistent ◽  
Ternary Intermetallic Compounds ◽  
Phase Relationships

Phase relationships of the ternary Al-Cu-Yb system have been assessed using a combination of CALPHAD method and first principles calculations. A self-consistent thermodynamic parameter was established based on the experimental and theoretical information. Most of the binary intermetallic phases, except Al3Yb, Al2Yb, Cu2Yb and Cu5Yb, were assumed to be zero solubility in the ternary system. Based on the experimental data, eight ternary intermetallic compounds were taken into consideration in this system. Among them, three were treated as line compounds with large homogeneity ranges for Al and Cu. The others were treated as stoichiometric compounds. The calculated phase diagrams were in agreement with available experimental and theoretical data.

Uptake of soil nitrogen by legumes in mixed swards

1977 ◽  
Vol 28 (3) ◽  
pp. 413 ◽  
Author(s):  
I Vallis ◽  
EF Henzell ◽  
TR Evans
Keyword(s):  
Soil Nitrogen ◽  
The Other ◽  
Nitrogen Transfer ◽  
Soil Mineral ◽  
Soil Mineral Nitrogen ◽  
Fixed Nitrogen ◽  
15N Uptake ◽  
Digitaria Decumbens ◽  
Chloris Gayana ◽  
Macroptilium Atropurpureum

The partitioning of uptake of soil nitrogen between legumes and grasses in mown, mixed swards was studied at two sites in south-eastern Queensland. The swards contained either Lotononis bainesii, Desmodium intortum or Trifolium repens with Digitaria decumbens at one site, and either L. bainesii, T. repens, Macroptilium atropurpureum, Vigna luteola or Stylosanthes guyanensis with Chloris gayana at the other site. (15NH4)2SO4 equivalent to c. 0.3 kg nitrogen ha-1 was added every 4 weeks in an attempt to label the soil mineral nitrogen, and the partitioning of 15N uptake between species used as an estimate of the partitioning of uptake of soil nitrogen. Although two of the legumes (L. bainesii and T. repens) obtained 70–100% of the total 15N uptake at some of the spring harvests, when growth of the associated tropical grasses was limited by low temperatures, none of the legumes obtained more than c. 25% of the annual 15N uptake over a 2-year period. Proportional 15N uptake by the legumes was curvilinearly related to the proportion of legume dry matter yield in the mixtures. Annual 15N uptake by the grass-legume mixtures was up to 360% as high as by the grass control. This had only a small effect on estimates of the proportion of legume nitrogen derived from symbiotic fixation, but caused a large discrepancy in isotopic estimates of nitrogen transfer. The proportion of fixed nitrogen in the legumes averaged 94% at one site and 92% at the other, nearly always exceeded 80%, and was independent of legume yield.

Thermodynamic description of Ge-Mn-Si

2014 ◽  
Vol 1642 ◽  
Author(s):  
Alexandre Berche ◽  
Jean-Claude Tédenac ◽  
Philippe Jund ◽  
Stéphane Gorsse
Keyword(s):  
Solid Solution ◽  
Gibbs Energy ◽  
First Principles ◽  
Thermodynamic Description ◽  
Intermetallic Phases ◽  
Calphad Method ◽  
Enthalpies Of Formation ◽  
Mixing Enthalpy ◽  
First Principles Calculations ◽  
First Time

ABSTRACTLiterature data of the Mn-Si system is analyzed and discordances are pointed out. First principles calculations are performed to clarify the enthalpies of formation of the intermetallic phases. Especially the enthalpies of formation of the various possible structures of the MnSix are discussed. On the basis of these new data, a thermodynamic description of the Gibbs energy of the phases is performed using the Calphad method. The system Ge-Mn is also assessed using the Calphad method for the first time.The mixing enthalpy in the D88 solid solution is calculated between Mn5Ge3 and Mn5Si3 by DFT calculations.Finally a thermodynamic description of the ternary system is suggested. Especially the solubility of germanium in MnSix is modeled.

scholarly journals Experimental and thermodynamic description of ternary Bi-Cu-Ga system

2017 ◽  
Vol 53 (3) ◽  
pp. 189-201 ◽  
Author(s):  
D. Minic ◽  
Y. Du ◽  
M. Premovic ◽  
D. Manasijevic ◽  
N. Talijan ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Ternary Phase ◽  
Energy Dispersive Spectrometry ◽  
Thermodynamic Description ◽  
Calculated Phase Diagram ◽  
Calphad Method ◽  
Experimental Result ◽  
Liquidus Phase ◽  
Ternary Phase Diagrams ◽  
Good Agreement

Phase diagram of the Bi-Cu-Ga ternary system has been investigated experimentally with 27 alloys and analytically by using a Calphad method. Thirteen annealed alloys at 200?C were investigated by using scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS), and X-ray powder diffraction (XRD) methods. Temperatures of phase transformation were determined with 14 alloys which are lying along three vertical sections Bi-Cu0.5Ga0.5, Cu-Bi0.5Ga0.5 and Ga-Bi0.5Cu0.5 by using differential thermal analysis (DTA). Based on the experimental result and by using Calphad method, ternary phase diagrams were constructed with a new description of liquidus phase. Calculated phase diagram and experimentally obtained results are in good agreement. Liquidus projection and invariant reaction were calculated by using new thermodynamic parameters for liquidus phase.

Thermodynamic description of the Cu–Sn system

2007 ◽  
Vol 22 (11) ◽  
pp. 3158-3165 ◽  
Author(s):  
Wojcieh Gierlotka ◽  
Sinn-wen Chen ◽  
Shih-kang Lin
Keyword(s):  
Binary System ◽  
Thermodynamic Description ◽  
Electronics Packaging ◽  
Experimental Information ◽  
Calphad Method ◽  
Energy Models ◽  
Recent Developments ◽  
Packaging Industry ◽  
Two Phases ◽  
Good Agreement

The Cu–Sn binary system is important for various applications, especially for recent developments in the electronics packaging industry. The ϵ-Cu3Sn and η-Cu6Sn5 (η′ phases) phases are frequently encountered in electronics products. However, the two phases have been described as line compounds in previous thermodynamic modeling, and their compositional homogeneities were not considered. In this study, the thermodynamic properties of the Cu–Sn binary system are modeled and the phase diagram is calculated by the CALPHAD method, using experimental information reported in the literature. The ϵ and η (η′) phases are described using compound energy models with two and three sublattices, respectively, so that their compositional homogeneities could be calculated. Good agreement was observed between the calculated result and the existing experimental data.

Sign in / Sign up

Export Citation Format

Share Document