COUPLED DIFFUSIONAL DISPLACIVE TRANSFORMATIONS - EFFECT OF CARBON CONCENTRATION

S. A. Mujahid and H. K. D. H. Bhadeshia

Abstract

The nonequilibrium growth of partially supersaturated ferrite plates in Fe-C alloys is examined as a function of the carbon concentration, using a published theory for ''coupled diffusional/displacive transformations''. It is found that the theory correctly predicts the variation in the martensite-start temperature with carbon concentration, but fails to estimate the corresponding variations in the bainite-start temperatures of the same steels. This is attributed to the fact that the model does not include any variations in stored energy as a function of transformation temperature. The nature of the required variation in stored energy has been calculated by fitting against available data.

ACTA METALLURGICA ET MATERIALIA, 1993, Vol.41, No.3, pp.967-973

Bainite

Surface relief due to bainite
[Surface Relief due to Bainite]

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