C. Atkinson et al., THEORY FOR REAUSTENITIZATION FROM FERRITE CEMENTITE MIXTURES IN FE-C-X STEELS/, Acta metallurgica et materialia, 43(5), 1995, pp. 2013-2031
Citations number
57
Categorie Soggetti
Material Science","Metallurgy & Metallurigical Engineering
Phase transformation theory for the formation of austenite from substi
tutionally alloyed ferrite/cementite mixtures is discussed. The local
equilibrium assumption is adopted. Diffusion of carbon in ferrite and
cementite is ignored, together with the ternary diffusional interactio
ns. The ferrite and cementite phases are assumed to be semi-infinite i
n extent, so that soft impingement effects are not accounted for. Subj
ect to these assumptions, exact solutions are presented for one-dimens
ional (planar) growth. The solution method involves the determination
of the appropriate tie-lines at the cementite/austenite and austenite/
ferrite interfaces. Potential numerical difficulties which arise in de
termining the solution are discussed. It is found that for reasonable
values of the diffusion coefficients involved, the governing equations
can be simplified. The results are presented in the form of reverse t
ime-temperature-transformation diagrams, and comparisons with recent r
esults for reaustenitisation from binary Fe-C steels are made. The eff
ects of silicon and manganese as ternary alloying additions are quanti
fied.