1 / 52

Euromet 2006 Influence of impurities on the melting temperature of Aluminum

Euromet 2006 Influence of impurities on the melting temperature of Aluminum. Pr. B. Legendre & Dr S. Fries EA 401. Impurities. B, C, Cr, Cu, F , Fe, Mg, Mn, N, Ni, O , Pt S , Sc, Si, Ti, V, Zn. Al – X Optimized Al – Y Non optimized (or bad optimized), but the phase diagram is known

cerise
Download Presentation

Euromet 2006 Influence of impurities on the melting temperature of Aluminum

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Euromet 2006Influence of impurities on the melting temperature of Aluminum Pr. B. Legendre & Dr S. Fries EA 401

  2. Impurities • B, C, Cr, Cu, F, Fe, Mg, Mn, N, Ni, O, Pt • S, Sc, Si, Ti, V, Zn. • Al – X Optimized • Al – Y Non optimized (or bad optimized), but the phase diagram is known • Al – F no data

  3. Aim • Measurement of the slopes of the liquidus and of the solidus :  = (dT/dx) • l : for the liquidus s : for the solidus • The slope may be expressed in atomic fraction or in weight fraction. • Determination of K : • K = l/ s • For Al Tfus= 660.323°C

  4. Phase diagram • For this subject we are interested only by a very small region in temperature and composition of binaries Al-X, but it is absolutely necessary to have a perfect knowledge of the full diagram. And to know the Gibbs function versus of T and x for each phase at a fixed pressure.

  5. Phase diagram : Calphad Method • A phase diagram is the graphical expression of phase equilibria, for each phase in a binary system G = f(xi, T, P) • The limits of a two phase field aregiven by the common tangent of the G =f(xi)PT curves. • For a eutectic: • The three curves G=f(xi)p,T, have the same tangent.

  6. The whole process

  7. Calculating phase diagrams

  8. Al - Si

  9. Al - Si

  10. Al -Si

  11. Al - B

  12. Al - B

  13. Al - B

  14. Al - Pt

  15. Al - Pt

  16. Al - Pt

  17. Al - Pt

  18. Al - Cr

  19. Al - Cr

  20. Al - Ni

  21. Al - Ni

  22. Al - Fe

  23. Al - Fe

  24. Al - Fe

  25. Al - Cu

  26. Al - Cu

  27. Al - Cu

  28. Al - Sc

  29. Al - Sc • No data for the solidus…

  30. Al – O: not a good optimization

  31. Al - O • Why it is not possible to have a good optimization of the Al-O binary? • The oxygen forms with Al an oxide which is a thin film fixed on the surface of Al and then it is a kind of protection (aluminum pans are used on the gas in a kitchen…) after the fixation of a first layer the oxygen cannot go deeper in Al. There is no homogeneity and no equilibrium.

  32. Al - O • L  Al + Al2O3 T =~ 660°C • Van’t Hoff law • dln(aAl)/dT = H/RT2 • aAl~ XAl • H = fusH(Al) = 10711.04J/mol • T = 0.452 K XAl= .9993316 • dT/dX = 676

  33. Results

  34. Comparison of results

  35. Variation of the liquidus temperature versus of theyield of impurities • Tl = Tfus +  i • Tl = temperature of the liquidus • Tfus temperature of fusion of pure Al •  = dT/dx x : weight fraction • i : yield of impurities in ppm*10-6 • Example : for Al-Cr i = 9.9*10-2ppm •  = 466 Tl = 660.32°C

  36. Temperature of liquidus and solidus for a yield of impurity

  37. Conclusions • It has been possible to determine the influence of impurities in Al for nearly all the selected elements. • For O and S just an estimation has been possible. • The most important modifications occurs with O and N • It is possible to perform a calculation with two impurities.

  38. Acknowledgement • This work has been financially supported by LNE and BNM • We are very grateful to these organisms for their contribution.

  39. Al - Pt

  40. Al - Pt

  41. Al - Pt

  42. Al - Ni

  43. Al - Pt

  44. Applications of Gibbs energies descriptions combined to kinetic Information

More Related