Equilibrium segregation in a ternary solution: A model for temper embrittlement

Guttmann, M.

doi:10.1016/0039-6028(75)90125-9

Cited by 493 publications

(111 citation statements)

References 17 publications

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“…In the same way, the calculation of surface tension of liquid alloys can be performed, based on solution models and phase diagram data. In the literature, the surface tension isotherm of liquid Au-Ag-Cu alloys has been developed using perfect and regular solution models (23,26,27). Both descriptions involve the input of thermodynamic parameters of the ternary Au-Ag-Cu system, its binary subsystems (Au-Ag, Au-Cu and AgCu) and its pure components and their surface tension zero at the critical point: the variation often follows a linear function law over a limited temperature range:…”

Section: The Gold Alloys: Au-ag-cu and Au-ag-cu-znmentioning

confidence: 99%

Wetting and surface tension measurements on gold alloys

Ricci

Novaković

2001

Gold Bull

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The surface tension and the density of some gold alloys have been measured and their wetting behaviour investigated in relation to different ceramic supports. Relationships between surface tension and density as a function of temperature are proposed.The primary objective of jewellery production is the optimization of melting processes (1) and the choice of suitable ceramic materials for the crucibles is required, and this choice can be critical. Accordingly, there is a need for a range of materials with excellent thermal and mechanical properties to withstand high temperatures and, at the same time, resist attack by the molten metal, so that there is no metal-ceramic interaction (2, 3). To date, the materials used have been graphite, silicon carbide or the more common 'refractory materials', but there are still complaints about problems, principally related to the rapid consumption of the crucible, or pollution of the melt due to the detachment of particles from the crucible. A knowledge of the interaction between the ceramic and the liquid gold alloys can help in the definition of more suitable ceramic material for the melting processes used by goldsmiths. It is necessary to use materials that are highly resistant to wetting by metallic melts, thus a knowledge of the interface properties of liquid gold alloys in relation to ceramic materials is needed.The interactions between the liquid metallic material and the ceramic are usually studied using: 1 Surface tension measurements of the liquid metal in contact with the ceramic material 2 Measurements of both surface tension and contact angle as a function of temperature 3 Surface tension measurements in the presence of liquid metal vapour. Ott (4) has stated that there is insufficient data on the thermal properties of jewellery alloys in the liquid state and at solidification, including that on surface /interface tension. Surface tension is a thermophysical property that must be considered because it influences the surface structure of castings, and determines the interfacial interactions between melts and solid containers (ie interfacial tensions); and it is influenced by the presence of alloying elements such as zinc or silicon. Consequently, the study of its variation can provide useful information on the outcome of casting processes. We have therefore measured the surface tension and the density of some precious gold alloys as a function of temperature, and investigated their wetting behaviour on a number of relevant ceramic supports. THEORETICAL BACKGROUNDFor the sake of clarity, we provide some details on the nature of adhesion and wettability of liquid metals on solid substrates and the behaviour of surface tension. WettabilityOne of the basic equations which describes the behaviour of a liquid phase in contact with a solid surface is Young's equation (5):where σ SV , σ SL , σ LV are respectively the interface energies between the solid and the vapour phase, the solid and the liquid phase, and the liquid and the

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Section: The Gold Alloys: Au-ag-cu and Au-ag-cu-znmentioning

confidence: 99%

Wetting and surface tension measurements on gold alloys

Ricci

Novaković

2001

Gold Bull

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“…Furthermore, the segregation of one element can induce segregation of the other one. This model could explain why the addition of alloys enhanced impurity segregation [9,10]. Stabilization of nano-scale grain size in base binary alloys by adding suitable ternary or multi solutes has been reported in recent investigations [11].…”

Section: Introductionmentioning

confidence: 72%

“…This seriously limited the development of new NC alloys with high stabilization. In 1975, Guttmann [9] developed a model for GB segregation in non-ideal multicomponent systems and worked out an analytical solution for simple ternary alloys. If two elements strongly attract one another, they will precipitate in the matrix.…”

Section: Introductionmentioning

confidence: 99%

The thermodynamic stability induced by solute co-segregation in nanocrystalline ternary alloys

Liang

Chen

Yang

et al. 2017

International Journal of Materials Research

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The thermodynamic stability induced by solute co-segregation in nanocrystalline ternary alloysThe grain growth and thermodynamic stability induced by solute co-segregation in ternary alloys are presented. Grain growth behavior of the single-phase supersaturated grains prepared in Ni-Fe-Pb alloy melt at different undercoolings was investigated by performing isothermal annealings at T = 400 8C -800 8C. Combining the multicomponent Gibbs adsorption equation and Guttmann's grain boundary segregation model, an empirical relation for isothermal grain growth was derived. By application of the model to grain growth in Ni-Fe-Pb, Fe-Cr-Zr and Fe-Ni-Zr alloys, it was predicted that driving grain boundary energy to zero is possible in alloys due to the co-segregation induced by the interactive effect between the solutes Fe/Pb, Zr/Ni and Zr/Cr. A non-linear relationship rather than a simple linear relation between 1/D* (D* the metastable equilibrium grain size) and ln(T) was predicted due to the interactive effect.

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“…The first theory once widely accepted to explain the role of alloying elements is the cosegregation theory (38). If there exists an attractive interaction between the alloying element and phosphorus, they attract each other at grain boundaries and increase the segregation of the partner.…”

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confidence: 99%

Intergranular Fracture in BCC Metals

Kimura

1988

Trans. JIM

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The intergranular fracture (IGF) in high purity molybdenum and high purity iron are discussed together with the effects of interstitial and substitutional solutes on it.Recrystallized molybdenum is inherently susceptible to IGF. Purification does not improve it. Grain boundary segregation of carbon increases the grain boundary cohesion of general boundaries and that of oxygen decreases it.IGF occurs in recrystallized commercial high purity iron about 99.995% pure, but does not in specially prepared iron of about 99.999% or better purity. Segregation of oxygen decreases the boundary cohesion, but the effect is much smaller than usually believed. Segregation of carbon increases the grain boundary cohesion and reduces IGF caused by segregation of other impurities, such as hydrogen, phosphorus and sulfur. Molybdenum and chromium reduce IGF caused by the segregation of phosphorus as far as the alloy is in the solid solution. These elements interact with phosphorus to reduce the detrimental effect of phosphorus and also increase the boundary cohesion of iron. Nickel also reduces IGF, but the reduction is caused by the solid solution softening due to nickel.Also discussed are the chemical state of the segregated phosphorus and the dependence of the phosphorus segregation on the grain boundary character. (Received May 9, 1988) Keywords: intergranular fracture, high purity iron, high purity molybdenum, effect of carbon and oxygen, iron-phosphorus-molybdenum alloys, iron-phosphorus-chromium alloys, iron-phosphorus-nickel alloysThe intergranular fracture (IGF) is not rare in BCC metals and alloys, and causes serious technical probelems. Phosphorus and sulfur are common impurities in iron and steel and are known to embrittle them severely. In most cases IGF is caused by the segregation of impurities to grain boundaries. IGF caused by an impurity is promoted or suppressed by other kinds of impurities and alloying elements. An example is the temper-embrittlement in low alloy steels; when low alloy steels with high strength are heated at temperatures between 770 and 870K after quenching and tempering, impurities (typically phosphorus) segregate to grain boundaries and cause IGF. On the other hand, if a plain carbon steel containing a similar amount of phosphorus is subjected to the same heat treatment, no temper-embrittlement is observed. Thus, in the discussion of IGF due to impurity segregation, we have to consider not only the impurity directly responsible for the IGF, but also other impurities and alloying elements. Furthermore, effects of one kind of solute on a specific impurity may be modified by other kinds of solutes. Hence, we have to employ high purity materials with controlled compositions to investigate the behavior of a specific impurity and the effects of a specific solute without interference from other solutes.The grain boundary segregation is measured fairly accurately with Auger electron spectroscopy (AES); specimens are fractured and the revealed surface is analyzed under an ultra high vacuum without bei...

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Equilibrium segregation in a ternary solution: A model for temper embrittlement

Cited by 493 publications

References 17 publications

Wetting and surface tension measurements on gold alloys

Wetting and surface tension measurements on gold alloys

The thermodynamic stability induced by solute co-segregation in nanocrystalline ternary alloys

Intergranular Fracture in BCC Metals

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