Miedema's Model

Miedema's model is a semi-empirical approach developed by the Dutch scientist Andries Rinse Miedema ( 15 November 1933 - 28 May 1992 [1] ) while working at Philips Research Laboratories Philips_Natuurkundig_Laboratorium for estimating the heat of formation of solid or liquid metal alloys and /or compounds in the framework of thermodynamic calculations for metals and minerals.[2] It may provide or confirm basic enthalpy data that have always been needed for the calculation of phase diagrams of metals, and that are now currently approached by CALPHAD. The method has been introduced by Miedema in a couple of papers appeared in 1973 in Philips Technical Review Magazine entitled "A simple model for alloys".[3][4] While Miedema himself or with collaborators produced many scientific papers we report here in his own words the genuine motivation of his approach "Reliable rules for the alloying behaviour of metals have long been sought. There is the qualitative rule that states that the greater the difference in the electronegativity of two metals, the greater the heat of formation - and hence the stability. Then there is the Hume-Rothery rule, which states that two metals that differ by more than 15% in their atomic radius will not form substitutional solid solutions. This rule can only be used reliably (90 % success) to predict poor solubility; it cannot predict good solubility. The author has proposed a simple atomic model, which is empirical like the other two rules, but nevertheless has a clear physical basis and predicts the alloying behaviour of transition metals accurately in 98 % of cases. The model is very suitable for graphical presentation of the data and is therefore easy to use in practice." There are several free web bases applications like Entall [5] or Miedema Calculator.[6] The latter has been recently reviewed and improved, with an extension of the method in a scientific publication.[7] A simple presentation of the method is in the appendix B of the book,[8] while the original Algol program [9] has been ported in a fortran code [10]

References

  1. ↑ "Huygens Institute - Royal Netherlands Academy of Arts and Sciences (KNAW) : Q.H.F. Vrehen, Levensbericht A.R. Miedema, in: Levensberichten en herdenkingen, 1993, Amsterdam" (PDF). Dwc.knaw.nl. pp. 61–66. Retrieved 2017-02-28.
  2. ↑ "Thermodynamic Data for Mineral Technology" (PDF). Bulletin 677 US Mines. Check date values in: |date= (help)
  3. ↑ Miedema, A.R. (1973). "A simple model for alloys. I. Rules for the alloying behaviour of transition metals" (PDF). Philips Technical Review. 33: 149–160.
  4. ↑ Miedema, A.R. (1973). "A simple model for alloys. Il, The influence of ionicity on the stability and other physical properties of alloys" (PDF). Philips Technical Review. 33: 196–202.
  5. ↑ "Miedema calculator of standard formation enthalpy". Entall.imim.pl. Retrieved 2017-02-28.
  6. ↑ "Welcome to >>> Miedema Calculator | Homepage organized by Dr. Zhang". Zrftum.wordpress.com. Retrieved 2017-02-28.
  7. ↑ Zhang, R.F.; Zhang, S.H.; He, Z.J.; Jing, J.; Sheng, S.H. (2016). "Miedema Calculator: A thermodynamic platform for predicting formation enthalpies of alloys within framework of Miedema's Theory". Computer Physics Communications. 209: 58–69. Bibcode:2016CoPhC.209...58Z. doi:10.1016/j.cpc.2016.08.013.
  8. ↑ Gokcen, N. A. (1986). "Appendix B" (PDF). Statistical Thermodynamics of Alloys. pp. 255–76. ISBN 978-1-4684-5053-8.
  9. ↑ A.K. Niessen, F.R. de Boer, R. Boom, P.F. de Châtel, W.C.M. Mattens, A.R. Miedema (1983). "Model predictions for the enthalpy of formation of transition metal alloys II". Calphad. 7 (1, January–March): Pages 51–70 – via Elsevier Science Direct.
  10. ↑ "Hex, Bugs and More Physics | Emre S. Tasci » Blog Archive » Miedema et al.’s Enthalpy code — 25 years after..". www.emresururi.com. Retrieved 2017-03-04.

See also

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