Efficient Generation of Electricity www msm cam ac

Efficient Generation of Electricity www. msm. cam. ac. uk/phase-trans

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

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

Charpy fatigue tensile, creep critical stress intensity oxidation, corrosion

MULTIPASS ARC WELD L. -E. SVENSSON

The Variables C, Mn, Si, Ni, Mo, Cr, V, Nb, Ti, Al, N, O, P, S B, …. . Casting, forging …. . welding parameters and processes prolonged heat treatments cost

thermodynamics oxidation processing kinetics cost models microstructure bayesian neural networks alloy design validation

Nickel base alloy FT 750 dc wt%

40 mm

Tancret & Bhadeshia, 2002 Yield stress / MPa 1000 800 600 400 200 0 0 200 400 600 800 Temperature / °C 1000 1200

rupture stress / MPa Tancret & Bhadeshia, 2002 700 FT 750 dc 600 500 400 300 200 100 0 1 2 3 log (t /h) 4 5 6

ferritic alloy C wt%

650 o. C Cole & Bhadeshia, 2002

Mechanically Alloyed Oxide Dispersion

Fe-20 Cr-5 Al 0. 5 Ti-0. 3 yttria wt% 90% reduction Capdevila & Bhadeshia, 2000

Helical grains Capdevila & Bhadeshia, 2000

Capdevila & Bhadeshia, 2000

thermodynamics oxidation processing kinetics cost models microstructure bayesian neural networks alloy design validation

Problems • During the development of these models, we have discovered some fundamental difficulties with theory • In particular, theory dealing with small driving forces

diaz del Castillo & Bhadeshia, 2001 a

diaz del Castillo & Bhadeshia, 2001 a

Conclusions • There has been progress in predicting alloy behaviour • Much more progress needed in theory • Oxidation models?