The mechanical behavior of a pearlitic steel was studied by means of tensile tests performed in the temperature interval from 298 to 773 K, at strain rates from 10 Ϫ4 to 10 Ϫ2 s Ϫ1, aiming to analyze the role of cementite decomposition in the dynamic strain aging (DSA) phenomena occurring in these steels. Typical features of DSA were observed: serrated flow (the Portevin-LeChatelier-PLC effect), the presence of a maximum and a minimum in ultimate tensile strength and reduction of area versus temperature curves, respectively, and a less evident maximum in the yield strength versus temperature curve. Apparent activation energies were calculated based on the onset of the PLC effect, the maximum in ultimate tensile strength and the minimum in reduction of area. Results suggest that changes in mechanical properties associated with DSA in pearlitic steels are related to cementite decomposition. Differences on the phenomenological aspects regarding DSA in pearlitic and in low carbon steels are discussed, based on the kinetics of the process.KEY WORDS: dynamic strain aging; Portevin-LeChatelier effect; pearlitic steels; cementite decomposition.sized that, for the values of e˙and T in between the end of the PLC effect and the maximum in s t , the work hardening rate was high and the ductility was very low, irrespectively of the content of soluble nitrogen in the steel. However, the mechanism responsible for these effects was not discussed in their work.The PLC effect and a maximum in the 10 % flow stress versus temperature was also observed by Tsuzaki et al.,18) in a pearlitic steel tested between 293 and 623 K, at strain rates of 3.3ϫ10 Ϫ4 and 3.3ϫ10 Ϫ3 s Ϫ1. The activation energies for these phenomena were not determined in their work and the observed DSA effects were associated with the interaction of carbon atoms in solid solution with dislocations in ferrite.The present work was undertaken to provide a more complete description of the phenomenological and kinetic aspects of dynamic strain aging in pearlitic steel. The aim was to verify if cementite decomposition plays an important role in DSA phenomena taking place in pearlitic steels, as it does in static strain aging, as well as to compare the behavior of this steel with that generally observed in low carbon steels. ExperimentalThe commercial grade pearlitic steel studied was received as a lead patented, 5.5 mm in diameter wire rod. Its chemical composition (in weight percent) was: 0.80 % C, 0.76% Mn, 0.0015% P, 0.005% S, 0.25% Si, 0.019% Al, 0.0038 % N. Tensile-test specimens 2.5 mm in diameter and with a gauge length of 25.0 mm were machined from wire rod samples spheroidized at 953 K for 24 h. After machining, the specimens were heated at 1 153 K for 20 min and lead patented in laboratory conditions at 793 K for 10 min. According to Fisher,21) the mean true interlamelar spacing, Sp, of pearlite formed at this temperature should be equal to 77 nm. Atomic force microscopy (AFM) images taken from the transverse section of patented test specimens confirmed that the...