1. B. B. Rath Symposium Thermodynamics of Interfaces in Mechanically Alloyed Metals

2. Mechanically Alloyed Oxide Dispersion Strengthened Metals

3. Atom probe image of MA957

4. MA956 Chou & Bhadeshia, 1994

5. MA956 Chou & Bhadeshia, 1994

6. o o A B A B 1-x Gibbs free energy per mole Concentration x of B   free energy of mechanical mixture G* x Mechanical Mixture

7. o o A B A B x Gibbs free energy per mole Composition   G{x} free energy of mechanical mixture ∆G M free energy of solution G*

8. Entropy P P / 2

9. +=

10. For a random mixture, number of configurations given by:

11. Boltzmann

12. Badmos and Bhadeshia, 1997

13. Classical theory for entropy of mixing

14. Solution-like behaviour when particles about 1000 atoms in size Free energy of mixing due to configurational entropy alone

15. Enthalpy

16. Surface per unit volume SvSv Particle size Solution formation impossible!

17. coherent incoherent

18. Single barrier to solution formation when components attract Badmos and Bhadeshia, 1997

19. Double barrier to solution formation when components immiscible Badmos and Bhadeshia, 1997

20. o o A B A B Gibbs free energy per mole   Concentration x of B Paradox at concentration extremities vanishes in the discrete model of concentration

21. Amorphous phase formation during mechanical alloying of Cu and Cd powders Zhang & Massalski Metall. & Mater. Trans. 29A (1998) 2425 ….contribution from Cu/  interfaces, and accompanying increase in free energy, provide additional driving force for amorphisation….

22. Capdevila & Bhadeshia, 2000 MA957, 1330 - 30 °C

23. Sub Micron Grain Size Normal Grain Size Grain junctions powerful pinning points for small grains, which are no longer topologically independent

24. Evolution of Solutions Thermodynamics of Mechanical Alloying A. Badmos and H. K. D. H. Bhadeshia, Metall. & Mater. Trans. A, 18A (1997) 2189. H. K. D. H. Bhadeshia, Proceedings of the Royal Microscopical Society, 35 (2000) 95. Materials Science and Technology, 16 (2000) 1404. H. K. D. H. Bhadeshia & H. Harada, Applied Surface Science, 67 (1993) 328.