| The deformation-induced transformation behavior of an austenitic Fe-25Mn-0.2C steel has been investigated in this study. The recently proposed transformation-kinetics equation between the volume fraction (f) of transformed phase and the inelastic strain (ε), which is in the form of (f/f_s) = 1 - exp(-βε^n), has been employed to analyze the transformation behavior during deformation of the Fe-25Mn-0.2C steel at various temperatures ranging from 7.5℃ to 177℃. In the equation above, f_s, denotes saturation value of f and parameters β and n characterize the stability of austenite and formation rate of nucleation sites to inelastic strain, respectively. The deformation-induced phases in this steel below and above 100℃ were ε-martensite and deformation twin, respectively. The formation rates of nucleation site to inelastic strain, n, for the ε-martensite and deformation twin were obtained as 1.4 and 1.0, respectively. The values of f_s and β appeared to decrease with increasing temperature for both (-martensite and deformation twin. A new method to determine the M_d temperature, above which the deformation-induced phase cannot be formed regardless of the amount of inelastic strain, was suggested and obtained as 67℃ and 290℃ for the formation of the ε-martensite and deformation twin, respectively. These values appear to be very close to previously reported ones. |
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