Abstract The calculated results obtained from the refined LFG model is similar to that from KRC,but there exists divergency between them in alloys with higher C contents.It seems that for treating interstitial solid solution,LFG model is more suitable over the KRC.Both the results from the two models show that △G~(γ→α+Fe_3c) is the largest,followed by △G~(γ→α+γ_1) and △G~(α-γ′) is the smallest and △G_N~(γ→α′)is far less than △G_N~(γ→α+γ_1′).At B_s,from LFG,for x_γ=0.001-0.002,△G_N~(γ→α+γ_1)△G_N~(γ→α+γ_1)- -196--237 J.mol~(-1);for x_γ=0.035,the sum of △G~(γ→α′) and △G~(α′→α″+Fe_3)is only—181 J.mol~(-1).The present work verifies again that at least at upper tem- perature range,the formation of bainite with shear mechanism is thermodynam- ically impossible.Calculation of the driving force for nucleaction(growth)gives an evidencs that the leading phase of the eutectoid reaction in hypoeutectoid steels is ferrite while that in hypereutectoid steels is cementite.
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