Taylor & Thornton, ALSTOM Power, Rugby

0.5 µm

b a

dV = (1 - ) dV VV e V dV = (1 - ) dV VV e V

Robson, Jones & Bhadeshia, 1996

2.25Cr1Mo 600 °C M3C M2X M23C6 Time / h 1000 h

3Cr1.5Mo 600 °C M23C6 Time / h

0.02500 NF616 600 °C M23C6 M C 0.02000 3 0.01500 0.01000 Laves 0.00500 M X 2 0.00000 1e-03 1e+00 1e+03 Time / h

Empirical Equations y = a + b (%C) +c (%Mn) + d (%Ni) .... 1223

y = a + b (%C) +c (%Mn) + d(%C x %Mn)

y = a + b (%C) +c (%Mn) + d(%C x %Mn) y = sin (%C) + tanh (%Mn)

Hyperbolic Tangents

The complexity of the model is given by the number of hidden units, i The complexity of the model is given by the number of hidden units, i.e. the number of hyperbolic tangent functions included

y A B x

Brun, Robson, Narayan, MacKay & Bhadeshia, 1998

Components of Creep Strength, 2.25Cr1Mo iron + microstructure 550 °C solid solution 600 °C precipitates Murugananth & Bhadeshia, 2001

elements in solution Murugananth & Bhadeshia, 2001

Cole & Bhadeshia, 1999

GTA weld at 823 K (data from Nippon Steel) 600 500 400 300 200 100 20000 30000 40000 Life / hours Cole & Bhadeshia, 1999

Cole & Bhadeshia, 1999

Linkweld Project, Siemens Power Generation W5397 Weld Metal Rupture at 570 C 500 400 300 200 100 2 3 4 5 6 log(life / h) Cole and Bhadeshia, 2000

Data from Manoir Industries 9Cr 1Mo type steel (Z1092, 600 °C) 300 200 Rupture stress / MPa 100 1 2 3 4 5 log (life / h) Cole and Bhadeshia, 2000

Cool, 1996

Cool, 1996

600 °C As-welded 700 °C 650 °C Cool, 1996

Coarsening diffusion r r flux concentration q a q aq c r aq c r 1 2 flux q a q concentration aq c r 1 aq c r 2 distance

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

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

Coarsening accelerated by tungsten! -1 chromium alone 2 Effective diffusivity / m s multicomponent 5 4 3 2 1 Tungsten / wt% Bhadeshia, 2000

Mole fraction of phase 0.00 0.01 0.02 0.03 M_23 C_6 Laves phase 5 4 3 Tungsten / wt% Bhadeshia, 2000

Multiphase coarsening Laves concentration in ferrite q q distance Bhadeshia, 2000

The microscopic world Atom (10-8 cm) Nucleus (10-12 cm) Nucleon (10-13 cm) Quark (10-18 cm) Gelletly, Phil. Trans. Roy. Soc. Lond. A, 356 (1998) 1952.

Multicomponent coarsening Venugopalan & Kirkaldy, 1978