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Taylor & Thornton, ALSTOM Power, Rugby. 0.5 µm. a. b. V V . dV = ( 1 - ) dV . e. V. V V . dV = ( 1 - ) dV . e. V. Robson, Jones & Bhadeshia, 1996. 2.25Cr1Mo 600 °C. M 3 C. M 2 X. M 23 C 6. Time / h. 1000 h. 3Cr1 .5Mo 600 °C.
E N D
a b
VV dV = (1 - ) dV e V VV dV = (1 - ) dV e V
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 3 0.02000 0.01500 0.01000 Laves M X 0.00500 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) y = a + b (%C) +c (%Mn) + d(%C x %Mn)
y = a + b (%C) +c (%Mn) y = a + b (%C) +c (%Mn) + d(%C x %Mn) y =sin (%C) + tanh (%Mn)
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
GTA weld at 823 K (data from Nippon Steel) 600 500 400 300 200 100 0 20000 30000 40000 Life / hours Cole & Bhadeshia, 1999
Linkweld Project, Siemens Power Generation o W5397 Weld Metal Rupture at 570 C 500 400 300 200 100 0 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 0 0 1 2 3 4 5 log (life / h) Cole and Bhadeshia, 2000
600 °C As-welded 700 °C 650 °C Cool, 1996
Coarsening diffusion r r 2 1 flux a q q concentration aq c r aq 1 c r 2 distance
-6 10 -7 10 -8 10 -9 10 2 3 4 5 6 7 8 9 10 10 10 10 10 10 10 10 10 10 4 2 0 2 3 4 5 6 7 8 9 10 10 10 10 10 10 10 10 10 10 1/3 Mean radius / m 1/2 Time / s -3 Number density 18 10 m Time / s Fujita & Bhadeshia, 2000
1 10 0 10 -1 10 -2 10 1 2 3 4 10 10 10 10 Data from Abe, 1999 Fe-9Cr-W alloys 0W 1W 2W 4W M_23C_6 size / µm Time at 600 °C / h
1.8e-19 1.7e-19 1.6e-19 1.5e-19 0 1 2 3 4 5 Coarsening accelerated by tungsten! -1 chromium alone 2 Effective diffusivity / m s multicomponent Tungsten / wt% Bhadeshia, 2000
0.03 0.02 0.01 0.00 0 1 2 3 4 5 M_23 C_6 Mole fraction of phase Laves phase 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) Gelletly, Phil. Trans. Roy. Soc. Lond. A, 356 (1998) 1952. Quark (10-18 cm)
Multicomponent coarsening Venugopalan & Kirkaldy, 1978