NEWS
CALPHAD Best paper 2010 Award
Volume 33, Issue 1, March 2009, Pages 227-232
Experimental and Computational investigation of intermetallic systems: A Special Issue Dedicated to Prof. Riccardo Ferro
Parameters in the compound energy formalism for ionic systems
M. Hillerta, L. Kjellqvista, H. Maoa, M. Selleby, a, and B. Sundmana
Department of Materials Science and Engineering, KTH, SE-10044 Stockholm, Sweden
Received 11 April 2008; revised 26 May 2008; accepted 26 May 2008. Available online 17 July 2008. Abstract
The compound energy formalism, CEF, involves many model parameters. They are evaluated to give the best fit to the experimental information.
The optimisation is simpler if less parameters need to be adjusted. The maximum number of independent parameters that can be evaluated depends on the information available. The best choice of parameters is first discussed for simple ionic substances with an internal variable, then for solutions of two or four such substances. To reduce the number of parameters, independent parameters are conveniently defined as combinations of primary model parameters. That may be possible when there is an internal variable, which can take only one value, the value that minimizes the Gibbs energy. Such combinations may be regarded as the true optimisation parameters and they may be used actively during an optimisation. The present discussion deals with substances with an internal variable and mixtures, which may have more than one internal variable.
The conclusions apply equally well to non-ionic systems if the information is limited to stoichiometric compositions.
The optimisation parameters should then be defined for stoichiometric overall compositions.
Keywords: Thermodynamics; Modelling; Compound energy; Stoichiometric substances; Ionic substances
CALPHAD Annual Awards:
The Best Paper Award for papers published in the CALPHAD journal The paper for the Best Paper Award will be voted for by the CALPHAD Advisory and Editorial Board members. The Best Paper Award consists of $500 from CALPHAD and a certificate.
TCSAB - New office
After 13 years in the same building Thermo-Calc Software AB has a new office at a new location from May 3:rd, 2010. New directions here.
The new office is designed to meet our present and future activites.
It would be a pleasure to see you as a visitor at our new address:
Norra Stationsgatan 93, Plan 5
SE-113 64 Stockholm
Sweden
Cooperation
Thermo-Calc Software AB and QuesTek Innovations LLC agree to cooperatively develop new precipitation modeling software.
Newsletter 34 out July 2:nd 2009
New Databases
· ION3: TCS Ionic Solutions Database
· STBC2: SGTE Thermal barrier coatings database
· TTAL7: Thermotech Al-based Alloys Database
· TTNI8: Thermotech Ni-based Super-alloys Database:
· MOBFE: TCS Steels/Fe-Alloys Mobility Database
Read more in the database descriptions here.
New Software Versions
The new versions of Thermo-Calc, DICTRA and Programming Interfaces are available.
All our Maintenance & Support Subscribers have received their new versions and we hope they are enjoying the improvements as much as we do.
For more information please read the release notes for the new versions.
