UPPER BAINITE

1. Carbon supersaturated plate Carbon diffusion into Carbon diffusion into austenite and carbide austenite precipitation in ferrite Carbide precipitation from austenite LOWER BAINITE UPPER BAINITE (Low Temperature) (High Temperature)

2. 0.2 µm

3. with carbides

4. Carbide-free alloys wt %

5. 1 µm

6. Very poor toughness!

7. 50 µm

9. T-zero curves

10. 50 µm

12. 70 0.4C-3Mn-2Si 0.4C-4Ni -2Si 60 0.2C-3Mn-2Si 50 40 30 20 10 0 -200 -100 0 100 200 Impact Energy Test temperature / °C

14. 20 µm

16. Bainite Martensite Pearlite 0 200 400 600 800 1000 1200 kilocycles to Crack Initiation Yates, Jerath

17. Yates, Jerath

19. 180 160 140 120 100 80 60 40 20 1000 1500 2000 2500 Advances in carbide-free bainitic steels 18 wt% Ni maraging steel Fracture toughness / MPa √m QT Ultimate tensile strength / MPa

20. an apple weighs 1 Newton = 1 Pa 1 m

21. 180 to 220 °C Cooking temperature?

22. 200 °C for 20 days 2.5 GPa Caballero, Mateo & Bhadeshia

23. a g a g g 50 nm

24. g g a a a 20 nm

25. Low temperature transformation: 0.25 T/Tm Fine microstructure: 20 nm thick plates Carbide-free Designed using theory alone Typical mechanical properties:

27. 180 160 140 120 100 80 60 40 20 1000 1500 2000 2500 Very Strong, Low Temperature Bainite m1/2 18 wt%Ni maraging steel MPa Fracture toughness / QT Ultimate tensile strength / MPa