1. Case Study: Creep-Resistant Steels cml.postech.ac.kr/teaching.html Graduate Institute of Ferrous Technology (GIFT)

3. Z-phase, inaccurate data

6. Thermodynamics Cannot win, can only break even Cannot reach absolute zero Can only break even at absolute zero

7. Goal Increase as far as is possible, the maximum temperature in the cycle i.e. better materials & engineering

10. Taylor & Thornton, ALSTOM Power, Rugby

11. 0.5 µm

15. time = t time = t+∆t  

17. 2.25Cr1Mo 600°C

19. Yamasaki & Bhadeshia, 2003

24. x

27. diffusion flux distance concentration c  r c r 1 2 r 1 r 2    Coarsening

28. 10 9 8 7 6 5 4 3 2 -9 10 -8 10 -7 10 -6 Time / s Mean radius / m 1/3 1/2 10 9 8 7 6 5 4 3 2 0 2 4 Number density 10 m 18 -3 Fujita & Bhadeshia, 2000 Time / s

29. 10 4 3 2 1 -2 10 10 0 1 Time at 600 °C / h M_23C_6 size / µm 0W 1W 2W 4W Data from Abe, 1999 Fe-9Cr-W alloys

30. 543210 0.00 0.01 0.02 0.03 Tungsten / wt% Mole fraction of phase Laves phase M_23 C_6

31. Multicomponent coarsening Venugopalan & Kirkaldy, 1978

32. 543210 1.5e-19 1.6e-19 1.7e-19 1.8e-19 Tungsten / wt% Effective diffusivity / m s multicomponent chromium alone 2 Coarsening accelerated by tungsten

33. distance concentration in ferrite Laves   Multiphase coarsening ?

35. Cole & Bhadeshia, 2002 650 o C