Assessment of phase diagrams

1 Assessment ofphase diagrams. Selection, designing and planning of materials are relevant subjects from a fundamental point of view but, of course, are also interrelated basic topics in material science and engineering. Study and classification of preparation methods and of constitutional and fundamental properties followed by an investigation of application and performance characteristics are essential aspects of such topics and procedures. 

We may mention the activity of several institutions and bodies such as IAEA (International Atomic Energy Agency, Vienna) which, in special issues of its Atomic Energy Review dedicated to various metals of nuclear interest, has published critical collections of physico-chemical properties of their compounds and alloys. 

As a conclusion to these notes on the assessment and compilation of intermetallic data, we mention a few examples of papers in which criteria to be followed in order to extract from literature data the best version of a phase diagram have been discussed. These are Morral and Gupta (1991) (a figure of merit for predicted phase diagram), Okamoto and Massalski (1991, 1993) (thermodynamically improbable phase diagrams and guidelines for binary phase diagram assessment). See also various comments in several chapters in Cahn (2001). 

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Critical assessment of phase-diagram data employing the thermodynamics of the phase equilibria in the form of phase-diagram modeling provides consistent thermochemical data (including also the liquid solution) for binary metal-boron systems such as V—B Cr—B, Mn—B, Fe —B, Co—B, Ni—Mo—B and Nb—B, W—B, A1 — B Despite these efforts, reinvestigation of binary systems is... 

The assessment of phase diagram of CsF-Cap2 system (relative stability of KNiFs-type and K2NiF4-type structures) ... 

The assessment of phase diagrams of some alkali halide systems... 

Rycerz L, Gong W, Gaune-Escard M (2013) The TbBr3- LiBr binary system experimental thermodynamic investigation and assessment of phase diagram. J Chem Thermodyn... 

The vast quantity of metallurgical data on phase equilibria have been reviewed " - , including a handbook of phase diagrams . Structural data for inter-metallic phases and compounds have been critically assessed ". ... 

As for many other materials, phase diagrams are roadmaps not only for the description of these substances and of their reactions, but also for their processing and for research and development planning. The systematic experimental determination of phase diagrams, their assessment and compilation and their thermodynamic optimization and calculation are the essential steps in the development of materials science and make up one of the bases of the intermetallic disciplines. 

The book begins with a chapter describing the history and growth of CALPHAD. This provides a useful point of departure for a more detailed account of the various strands which make up the CALPHAD approach. Chapters 3 and 4 then deal with the basic thermodynamics of phase diagrams and the principles of various experimental techniques. This is because one of basic pillars of the CALPHAD approach is the concept of coupling phase diagram information with all other available thermodynamic properties. It is a key factor in the assessment and characterisation of the lower-order systems on which the properties of the higher-... 

It is possible in many cases to predict highly accurate phase equihbria in multi-component systems by extrapolation. Experience has shown extrapolation of assessed (n — 1) data into an nth order system works well for n < 4, at least with metallurgical systems. Thus, the assessment of unary and binary systems is especially critical in the CALPHAD method. A thermodynamic assessment involves the optimization of aU the parameters in the thermodynamic description of a system, so that it reproduces the most accurate experimental phase diagram available. Even with experimental determinations of phase diagrams, one has to sample compositions at sufficiently small intervals to ensure accurate reflection of the phase boundaries. 

A—B—A block copolymers assessment of samples, 23—24 construction of phase diagrams, 24 light-scattering measurements, 24—25 preparation of samples, 23 Adsorbed polymer layer around a sphere, self-similar picture, 32132 323 Ammonia—ammonium thiocyanate mixtures, solvents for cellulose, 157 Amphiphilic lipopeptides advantages, 117... 

Lattice stabilities can also be obtained from computer calculations of phase diagrams (Pt-W, Ir-W so-called CALPHAD assessments) [1.25-1.27]. This approach is semi-... 

Riv] Rivhn, V.G., Assessment of Phase Equihbria in Ternary Alloys of Iron , J. Less-Common Met., 114(1), 111-121 (1985) (Phase Diagram, Phase Relations, Assessment, 4)... 

Cou] Counsell, J.F., Lees, E.B., Spencer, P.J., Computer Calculations of Phase Boundaries in the Fe-Cu-Ni and Fe-Cr-Ni Systems in Metallurgical Chemistry , HMSO, London, 451-458 (1972) (Assessment, Calculation, Phase Diagram, Phase Relations, 21)... 

Chu] Chuang, Y.-Y, Chang, Y.A., A Thermodynamic Analysis and Calculation of the Fe-Ni-Cr Phase Diagram , Met. Trans. A, 18A(5), 733-745 (1987) (Assessment, Calculation, Phase Diagram, Phase Relations, 36)... 

Hil] Hillert, M., Qiu, C., A Reassessment of the Cr-Fe-Ni System , Met. Trans. A, 21(6), 1673-1680 (1990) (Assessment, Calculation, Phase Diagram, Phase Relations, 40) [1990Yam] Yamada, A., Umeda, T., Kimura, Y, Calculation of Liquidus and Solidus Surfaces of the Iron Rich Comer of the Fe-Cr-Ni System , J. Iron Steel Inst. Jpn., 76(12), 2137-2143 (1990) (Calculation, Phase Diagram, Phase Relations, 25)... 

Tom] Tomiska, J., The System Fe-Ni-Cr Revision of the Thermodynamic Description , J. Alloys Compd., 379(1-2), 176-187 (2004) (Assessment, Calculation, Phase Diagram, Phase Relations, Thermodyn., 38)... 

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