Evaluation of the nucleation and coarsening kinetic behavior of the secondary hardening carbide of Fe-HCo-10Ni-1Mo-0.16C steel at two chromium levels, using an analytical and modeling approach: Part II

The effect of 1 % Cr addition on the resistivity during preaging and peak aging of an AF1410 based steel was examined by analytical and modeling approaches. The increased kinetics of aging resulting from a chromium addition, due to a variety of complex microstructural changes,was analyzed by Avrami-Mehl and Wert-Zener formulations, which were modified so that the exponent was a function of time. Using a eneralized Avrami equation, it was shown that the nucleation rate, N(t), at short aging times was large but became a rapidly declining function as N(t) approaches zero in a supersaturated system. A mathematical solution, using AF1410 steel carbide growth data at 510 degree C, confirmed reported experimental evidence of second-stage carbide nucleation at 1 to 2 h.