Thermodynamic Assessment of Bio-Oriented Ti-Ta-Sn System

The alloying elements Ta and Sn can effectively increase the stability of β-bcc phase, reduce Young’s modulus and improve the shape-memory property of Ti-based biomedical alloys. The development of the thermodynamic database for Ti-based biomedical alloys promises thermodynamic predictions in composition design and process optimization. In this work, one key sub-ternary Ti-Ta-Sn system has been thermodynamically assessed based on critical evaluation of experimental phase equilibria. A self-consistent thermodynamic description for the Ti-Ta-Sn system including one ternary compound Ti36Ta28Sn36 and six binary compounds considering the solubility of the third element has been obtained. Two isothermal sections at 973 and 1173 K and the liquidus projection have been calculated. Comparisons between the calculated and experimental phase equilibria validate the reliability of the present thermodynamic description. The influence of Ta and Sn contents on the transformation temperature and amount of α_hcp-Ti phase in β_bcc-(Ti,Ta) phase has been investigated based on thermodynamic calculations. The solidified phases in Ti-20Ta-xSn (x = 5, 15 and 25 at.%) as-cast alloys have been thermodynamically calculated based on Scheil solidification simulations. The presently developed thermodynamic description of the Ti-Ta-Sn system would promote the establishment of muti-component Ti-based thermodynamic database and guide the development of Ti-based alloys.

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A thermodynamic description of metastable c-TiAlZrN coatings with triple spinodally decomposed domains

Journal of Mining and Metallurgy Section B Metallurgy ◽

10.2298/jmmb161017001z ◽

2017 ◽

Vol 53 (2) ◽

pp. 85-93 ◽

Cited By ~ 2

Author(s):

J. Zhou ◽

L. Zhang ◽

L. Chen ◽

Y. Du ◽

Z.K. Liu

Keyword(s):

Experimental Data ◽

Phase Equilibria ◽

First Principles ◽

Thermodynamic Description ◽

Quantitative Description ◽

Experimental Phase Equilibria ◽

Free Energies ◽

Calphad Technique ◽

Important Input ◽

Good Agreement

A critical thermodynamic assessment of the metastable c-TiAlZrN coatings, which are reported to spinodally decompose into triple domains, i.e., c-TiN, c-AlN, and c-ZrN, was performed via the CALculation of PHAse Diagram (CALPHAD) technique based on the limited experimental data as well as the first-principles computed free energies. The metastable c-TiAlZrN coatings were modeled as a pseudo-ternary phase consisting of c-TiN, c-AlN and c-ZrN species, and described using the substitutional solution model. The thermodynamic descriptions for the three boundary binaries were directly taken from either the CALPHAD assessment or the first-principles results available in the literature except for a re-adjustment of the pseudo-binary c-AlN/c-ZrN system based on the experimental phase equilibria in the pseudo-ternary system. The good agreement between the calculated phase equilibria and the experimental data over the wide temperature range was obtained, validating the reliability of the presently obtained thermodynamic descriptions for the c-TiAlZrN system. Based on the present thermodynamic description, different phase diagrams and thermodynamic properties can be easily predicted. It is anticipated that the present thermodynamic description of the metastable c-TiAlZrN coatings can serve as the important input for the later quantitative description of the microstructure evolution during service life.

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Experimental Phase Equilibria Studies in the FeO-Fe2O3-CaO-SiO2 System in Air: Results for the Iron-Rich Region

Metallurgical and Materials Transactions B ◽

10.1007/s11663-020-01886-w ◽

2020 ◽

Vol 51 (4) ◽

pp. 1587-1602 ◽

Cited By ~ 1

Author(s):

Siyu Cheng ◽

Maksym Shevchenko ◽

Peter C. Hayes ◽

Evgueni Jak

Keyword(s):

Phase Equilibria ◽

Experimental Phase Equilibria ◽

Experimental Phase ◽

Rich Region ◽

Sio2 System

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Supercritical Phase Equilibria Modeling of Glyceride Mixtures and Carbon Dioxide Using the Group Contribution EoS

Journal of Thermodynamics ◽

10.1155/2011/730960 ◽

2011 ◽

Vol 2011 ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

Tiziana Fornari ◽

Daniel Tenllado ◽

Carlos Torres ◽

Guillermo Reglero

Keyword(s):

Carbon Dioxide ◽

Phase Equilibria ◽

Extraction Process ◽

Group Contribution ◽

Experimental Phase Equilibria ◽

Extraction Column ◽

Experimental Phase ◽

Supercritical Phase ◽

Binary Group ◽

Pressure Phase

The Group Contribution Equation of State (GC-EoS) was extended to represent high-pressure phase equilibria behavior of mixtures containing mono-, di-, triglycerides, and carbon dioxide (CO2). For this purpose, the alcohol-ester and the alcohol-triglyceride binary group interaction parameters were regressed in this work, using experimental phase equilibria data from the literature. The capability of the parameters obtained was assessed by applying the GC-EoS model to simulate the supercritical CO2 fractionation of a complex glyceride mixture, which was produced by the ethanolysis of sunflower oil. Experimental data was obtained in a countercurrent packed extraction column at pressures ranging from 16 to 25 MPa and temperatures from 313 to 368 K. The GC-EoS model was applied in a completely predictive manner to simulate the phase equilibria behavior of the multistage separation process. The chemical analysis of the glyceride mixture allowed a significant simplification of its complex composition and thus, a simple and satisfactory simulation of the supercritical extraction process was achieved.

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