Effect of dissolved cerium on austenite grain growth in an Fe-0.20 mass%C-0.02 mass%P alloy

Abstract

The effects of dissolved cerium on the kinetics of austenite grain growth and on the grain size and grain shape distributions were studied at 1 473, 1 573, and 1 673 K in an Fe-0.20 mass%C-0.02 mass%P alloy containing a limited amount of second-phase particles as a function of holding time. The mean planar grain diameter (Dmean) for a given holding time decreased considerably with the addition of dissolved Ce up to 300 mass ppm and then decreased gradually. The parabolic law kinetics was observed and its apparent rate constant was inversely proportional to the content of dissolved Ce in atomic pct. The spatial grain size distribution obtained by the Johnson-Saltykov transformation could be best described by the log-normal distribution function and normal grain growth was observed. The Dmax/Dmean (Dmax: the maximum grain diameter) value was independent of the content of dissolved Ce and holding time. The distribution of the number of grain sides was observed to be holding time-invariant and was not affected by the presence of dissolved Ce.