Theory and Computation of Two-Metal and Higher Order Predominance Area Diagrams

Abstract

Algorithms which calculate the classical one-metal predominance area or phase stability diagram are briefly reviewed. The “Constrained Chemical Potential Method”, which has been used to calculate one-metal predominance area diagrams, is adapted to calculate two-metal and higher order systems. The topologies of the resulting diagrams are analyzed and general guidelines are proposed for constructing multi-metal predominance area diagrams. Examples are presented for systems containing one metal, Fe–S–O, Ca–C–O–S–H, Cu–S–o, Zn–S–O, Al–S–O; two metals, Al–Zn–S–O, Al–Si–C–O, Cu–Fe–S–O; and three metals, Al–Fe–Zn–S–O.

Résumé

Les algorithmes calculant les diagrammes de stabilité ou d'aires de prédominance d'un métal sont présentés briévement. La méthode des potentials chimiques imposés, qui a été utilisée pour calculer de tels diagrammes, a été modifiée pour permettre le calcul de systèmes où plus d'un métal est présent. La topologie des diagrammes résultant est analysée et les principes de construction de tels diagrammes sont présentés. Des exemples de diagrammes sont donnés pour des systèmes contenant un métal, Fe–S–O, Ca–C–Q–S–H, Cu–S–O, Zn–S–O, Al–S–O; deux metaux, Al–Zn–S–O, Al–Si–C–O, Cu–Fe–S–O; et trois métaux, Al–Fe–Zn–S–O.     

Glass-Forming Ability of Mg–Cu–Ni–Gd Bulk Metallic Glasses with High Strength

The glass-forming ability (GFA) of Mg–Cu–Ni–Gd alloy system was evaluated using copper mold casting. A three-dimensional composition map of Mg–Cu–Ni–Gd system with GFA over 6 mm was revealed, confirming that the Ni addition decreased the GFA of Mg–Cu–Gd system. The maximum Ni tolerance was about 6 at.% for the Mg–Cu–Ni–Gd BMGs with GFA over 6 mm. The compressive tests displayed that the Ni addition as small as 3.45 at.% could result in higher strength for the Mg–Cu–Gd BMGs. The Mg–Cu–Ni–Gd system with small Ni content can be balanced candidates for the Mg-based BMGs with both acceptable GFA and high strength.     

Über die Vorausbestimmung der Wasserstofflöslichkeit in binären Eisenschmelzen

Statistisches Modell der Wasserstofflöslichkeit in Eisenschmelzen. Berechnungsgleichungen. Berechnung der Wasserstofflöslichkeit der Systeme Fe–H–AI, Fe–H–Co, Fe–H–Ge, Fe–H–Ni und Fe–H–Si bei 1600°C und 0,101 MPa. Vergleich des Modells mit dem Experiment.     

Multiscale Characterization of the Work Hardening Mechanisms in Fe–Mn Based TWIP Steels

When strained in tension, high‐manganese austenitic twinning induced plasticity (TWIP) steels achieve very high strength and elongation before necking. The main hypotheses available in the literature about the origin of their excellent work hardening include deformation twinning and dynamic strain ageing. In order to provide some answers, various experiments at different scales were conducted on Fe–Mn–C steels and the Fe–28 wt%Mn–3.5 wt%Al–2.8 wt%Si alloy. At a macroscopic scale, tensile tests were performed on all the studied grades. It was shown that, though the Fe–Mn–Al–Si based alloy retains very high elongation, the Fe–Mn–C steels properties are even more extraordinary. Tensile tests at different strain rates with the help of digital image correlation were also performed on the Fe–20 wt%Mn–1.2 wt%C steel to study the PLC effect occurring in this type of steel. It is suggested that supplementary hardening could come from reorientation of Mn–C pairs in the cores of the dislocations. At a microscopic scale, the Fe–20 wt%Mn–1.2 wt%C TWIP steel and the Fe–Mn–Al–Si grade were thoroughly investigated by means of in situ TEM analysis. In the Fe–Mn–C steel, the formed twins could also lead to a composite effect, since they contain plenty of sessile dislocations. In the Fe–Mn–Al–Si alloy, mechanical twins are thicker and contain fewer defects, leading to a lower work hardening than the other grade.     

Development of the γ′ Stability in Co–Al–W Alloys at 800 °C by Alloying with Carbon

Metallurgical and Materials Transactions A - The microstructures and hardnesses of Co–10Al–9W–1C, Co–7Al–5W–1C, and Co–7Al–5W (at. pct) alloys are...     

Tendency Towards Strain Ageing of Sheet Steel EH36 150 mm Thick for Marine Applications

Metallurgist - The effect of strain ageing parameters on the impact strength of low-carbon microalloyed C–Mn–Si–Nb–V–Ni–Cu-steel on the example of rolled product...     

The prediction of the nitrogen solubility in binary iron melts

Statistical model of nitrogen solubility in iron melts. Equations. Calculation of nitrogen solubility of the systems Fe–Co–N, Fe–Cr–N, Fe–Mn–N and Fe–Ni–N in the liquid state at 0.101 MPa. Comparison between model and experiments.     

特种钨合金电极材料制备工艺及组织性能研究

制备了W–Ni–Ca、W–Ni–Sr、W–Ni–Ba三种钨合金电极材料,研究了三种钨合金电极材料的组织性能。结果表明:W–Ni–Ca电极材料难烧结,组织不均匀,性能较差;W–Ni–Ba在烧结过程中生成的钨酸钡熔点较低,对电极抗烧蚀性能不利;通过对三种电极材料进行比较分析,认为W–Ni–Sr具有最佳的组织和性能。     

Die Gleichgewichte zwischen Eisen und kalkgesättigten,schwefelhaltigen Eisenoxydschlacken bei 1400 und 1600°C

Versuchsdurchführung. Schlackengleichgewichte im System Fe–O–Ca–S sowie im Teilsystem FeO_n–CaO–CaS–FeS. Metall-Schlacken-Gleichgewichte. Mikroskopische Untersuchungen. Raummodell Fe–O–Ca–S für 1600 und 1400°C. Erörterung der Ergebnisse im Hinblick auf die Entschwefelung unter oxydierenden Bedingungen.     

Measurement of the phase equilibrium temperatures of high-entropy metallic alloys by a viscometric method

The Cu–Pb, Cu–Ga, Cu–Bi, Cu–Sn–In–Bi–Pb, and Cu–Sn–Ga–Bi–Pb melts of equiatomic compositions, i.e., high-entropy melts have been studied by the method of damped torsional vibrations of a crucible with a melt. The experiments are performed on heating with subsequent cooling of the samples in the maximum possible temperature range. The logarithmic decrement of the suspension system of the Shvidkovskii viscometer is measured. The results are used to determine the phase equilibrium temperatures.     

A microstructural characterization of scale formed on austenitic Fe–29.7Mn–8.7Al–1.04C and duplex Fe–29Mn–10Al–0.4C alloys in oxidizing-sulfidizing environments

Austenitic Fe–29.7Mn–8.7Al–1.04C and duplex Fe–29Mn–10Al–0.4C alloys were exposed to the SO₂–O₂ mixed gas environments at 900 °C. The morphology of the scales formed on these alloys under oxidizing-sulfidizing conditions were examined by SEM and X-ray mapping techniques. The results showed that the addition of carbon up to 1 wt.% to the Fe–29.7Mn–8.7Al–1.04C alloy led to the formation of internal sulfidation and intergranular oxidation in the mixed oxidant gas environments. On the other hand, no evidence of intergranular oxidation could be detected in the duplex Fe–29Mn–10Al–0.4C alloy with lower carbon concentration.     

Interaction of Titanium Diboride with Nickel and Ni–20% Cr Alloy (Nichrome)

Powder Metallurgy and Metal Ceramics - The interaction in the Ni–Ti–B and Ni–Ti–B–Cr systems along the Ni–TiB2 and (Ni–20% Cr)–TiB2 sections was...     

Thermodynamic modeling of the interaction of high-level element and oxygen in iron-based melt

The main reactions of calcium, cerium, lanthanum, silicon, and complex alloys with the active additive Ca–Si, Ca–Al, Ce–Si, La–Si, Ce–La, or Ce–Ca–Al are subjected to thermal analysis. On the basis of binary and ternary fusibility diagrams, the thermodynamic data are refined for the main reactions between complex alloys with rare-earth elements and the oxygen present in the liquid metal. Solubility surfaces are plotted for components of the Fe–Si–Ce–O, Fe–Si–La–O, Fe–Ce–La–O, and Fe–Ca–Al–Ce–O systems. From those diagrams, optimal compositions of complex alloys with rare-earth elements in terms of nonmetallic-inclusion formation are established by plotting the consumption of the active components. For each group of steels, the quantitative elementary composition of the active components used for reduction and modification of the nonmetallic inclusions must be calculated. The chemical and phase composition of the nonmetallic inclusions may be very complex even in the final stages of the reduction of oxides. A method is developed for taking account of the polyvalency of cerium in reduction processes. The thermodynamic data and diagrams obtained help provide a better understanding of the complex heterogeneous processes within multicomponent systems that contain liquid metals. In combination with experimental data for the solubility surfaces of the components and the consumption diagrams, it is possible to track the transitions from the nonequilibrium state of the metallurgical system to the equilibrium state. In other words, the degree of refining of the metal and the equilibrium composition of the nonmetallic inclusions may be determined.     

Processability and Structure Formation of the Al–Zn–Mg–Ca–Fe–Zr–Sc Alloy upon Hot Rolling and TIG Welding

Russian Journal of Non-Ferrous Metals - Technological regimes for producing wrought products (2 and 1 mm) from the Al–4.5%Zn–2.5%Mg–2.5%Ca–0.5%Fe–0.2%Zr–0.1%Sc...     

Viscosity of the liquid Al–6Mg–1Mn–0.2Sc–0.1Zr alloy

The microstructure and the phase composition of as-cast Al–Mg–Mn–Sc–Zr alloy samples are studied by electron microscopy and electron-probe microanalysis. The processes of solidification and melting of this alloy are described. The temperature dependence of the kinematic viscosity of the Al–Mg–Mn–Sc–Zr melts is studied during heating and subsequent cooling of the samples. The measurement results are used to determine the temperature at which inherited microheterogeneities in the melts are destroyed irreversibly.     

Untersuchung der α/γ-Umwandlung in hochreinen Zweistofflegierungen des Eisens mit Molybdän,Vanadin, Wolfram,Niob, Tantal,Zirkon und Kobalt

Suszeptibilitätsmessungen an eisenreichen Zweistofflegierungen bei Temperaturen bis su 1400°C. Ermittlung der Grenzen des Zweiphasengebietes in den Systemen Eisen–Molybdän, Eisen–Vanadin, Eisen–Wolfram, Eisen–Niob, Eisen–Tantal, Eisen–Zirkon und Eisen–Kobalt. Ermittlung des Existenzbereiches der ?-Phase in den Systemen Eisen–Niob, Eisen–Tantal und Eisen–Zirkon. Errechnung thermodynamischer Gröβen aus den ermittelten Phasengrenzen. Ihre Zuordnung zu der Ordnungszahl der Legierungselemente im periodischen System. Vergleich der Untersuchungsergebnisse mit den Angaben des Schrifttums.     

Interaction of Components in Glass-Forming Melts of Iron and Nickel with Titanium,Zirconium, and Hafnium I. Mixing Enthalpies of Liquid Alloys

Powder Metallurgy and Metal Ceramics - The mixing enthalpies of glass-forming Fe–Ni–Ti, Fe–Ni–Zr, and Fe–Ni–Hf liquid alloys were investigated at 1873 K by...     

Thermal stability of the cellular structure of an austenitic alloy after selective laser melting

The thermal stability of the cellular structure of an austenitic Fe–17% Cr–12% Ni–2% Mo–1% Mn–0.7% Si–0.02% C alloy produced by selective laser melting in the temperature range 20–1200°C is investigated. Metallographic analysis, transmission electron microscopy, and scanning electron microscopy show that structural changes in the alloy begin at 600-700°C and are fully completed at ~1150°C. Differential scanning calorimetry of the alloy with a cellular structure reveals three exothermic processes occurring upon annealing within the temperature ranges 450–650, 800–1000, and 1050–1200°C.     

Some components and consequences of a babyface.

Obtained physical measurements and subjective ratings from 80 undergraduates of various facial features for 20 adult male stimulus faces, and these faces were also rated on 5 personality dimensions, physical attractiveness, age, and "babyfacedness" by Ss, to investigate components and consequences of a babyface. The personality dimensions were designated as warm–cold, honest–dishonest, irresponsible–responsible, kind–cruel, and naive–shrewd; physical measurements included narrow–wide nose, full–thin cheeks, close set–wide set eyes, narrow–broad chin, low–high eyebrows, angular–soft face, long–short nose, high–low forehead, round–narrow eyes, small–large eyes, and not attractive–attractive designations. Results show that large, round eyes, high eyebrows, and a small chin yielded the perception of a babyish facial appearance. A weighted linear composite derived from the measures of eye size and chin width accounted for 57% of the variance in ratings of babyfacedness. Both measured composite and subjective babyfacedness ratings were positively correlated with perceptions of the stimulus person's naivete, honesty, kindness, and warmth. Findings suggest that the adaptive value of recognizing natural covariations between certain appearance cues and behavioral affordances may provide an explanation for appearance-based stereotyping. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermodynamic modeling of the reaction of lanthanum with components of iron-based melts

Thermodynamic analysis of binary and ternary oxide systems containing the oxide La₂O₃ permits the formulation of a database of energy parameters in the theory of subregular solutions for oxide melts adjacent to the region of existence of metallic melts in the phase diagram of the system. The temperature dependence of the equilibrium constants for the heterogeneous reduction of steel is established. The solubility surfaces of components in oxygen-bearing steel are plotted for the Fe–Al–La–O–C, Fe–Ca–La–O–C, Fe–Mg–La–O–C, Fe–Si–La–O–C, and Fe–Cr–La–O–C systems. Diagrams are plotted for the complex reduction of steel by alloys and mixtures containing active and alloying elements: Ca, Mg, Si, Al, Cr, and La. Analysis is undertaken for thoroughly reduced and sulfur-free steel. With the usual reduction system, in which rare-earth metals are added to the steel after the introduction of calcium, silicon, and aluminum, the inclusions that form—consisting of a conglomerate of calcium and magnesium aluminates—provide the substrate for the deposition of small fractions, actively interact with the liquid component of the inclusions, and dissolve in the liquid component. Therefore, La₂O₃ is not present as an independent phase in the metallic inclusions.