1. Long and the short of steels

2. hexagonal close-packed cubic close-packed
Christian, 1951

3. Brooks, Loretto and Smallman, 1979

4. Swallow and Bhadeshia, 1996

5. Fe-2Si-3Mn-C wt% 800 B 600 Temperature / K 400 M 200 0.2 0.4 0.6 0.8 1
0.2
0.4
0.6
0.8 1
1.2
1.4
Carbon / wt%

6. Fe-2Si-3Mn-C wt% 1.E+08 1 month Time / s 1.E+04 1.E+00 0.5 1 1.5
1 year
1 month
Time / s
1.E+04
1.E+00
0.5 1
1.5
Carbon / wt%

7. wt% Low transformation temperature Bainitic hardenability
Reasonable transformation time
Elimination of cementite
Austenite grain size control
Avoidance of temper embrittlement
wt%

8. Homogenisation Austenitisation Isothermal transformation Temperature
1200 o C
2 days
1000 o C
15 min
Temperature
Air
125 o C -
325 o C
slow
cooling
hours -
months
cooling
Quench
Time

10. retained austenite bainitic ferrite Percentage of phase Temperature/ C
100
retained austenite 80
X-ray diffraction results 60
Percentage of phase 40
bainitic ferrite 20
200
250
300
325
Temperature/ o C

12. a g a g g
50 nm

13. g g a a a
20 nm

15. Scifer, 5.5 GPa with ductility!
Kobe Steel

16. 50-10 Denier Scifer is 9 Denier
1 Denier: weight in grams, of 9 km of fibre
50-10 Denier
Scifer is 9 Denier

17. Faster Transformation
Cobalt (1.5 wt%) and aluminium (1 wt%) increase the stability of ferrite relative to austenite
Refine austenite grain size

18. 200oC
250oC
300oC

20. Long and the short of steels

21. TRANSPARENT STEEL by Harry Bhadeshia
Materials World, March 1995, p. 128

22. Why is iron opaque?
opaque
transparent

23. 1991 Sumio Iijima studied soot, found nanotubes, nested like Russian dolls.
Nanotubes grow efficiently from gas with iron as catalyst.

24. blobby iron particle
Kinloch, 2002

27. Long and the short of steels

28. Perception of smell
template model
spectroscopic model
Luca Turin

29. nickel in cage molecule
iron in cage molecule
Luca Turin

30. Long and the short of steels

31. Bhor magnetons
Iron atom in ferrite
Iron atom in thin film 3.1
Iron atom in austenite or 0.6

32. Fe Ru
6d 2s Os Hs

33. Iron [Ar] + 8 e- b.c.c
Ruthenium [Kr] + 8 e- h.c.p
Osmium [Xe] + 14f + 8 e- h.c.p
Hassium [Rn] + 14f + 8 e- ???

34. more electric systems

36. 50-50 cobalt iron alloys strengthened with very fine particles of yttrium oxide?

37. Oxide Dispersion Strengthened Metals
Mechanically Alloyed
Oxide Dispersion Strengthened Metals

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

39. Fe-20Cr-5Al-0.5Ti-0.3 yttria wt%
90% reduction
Capdevila & Bhadeshia, 2000

41. Helical grains
Capdevila & Bhadeshia, 2000

42. Capdevila & Bhadeshia, 2000