Microstructural Characterization and Mechanical Behavior of a Low-Carbon 17% Mn Steel

作者：Spindola Mirelle Oliveira^*; Ferreira de Dafe Sara Silva; do Carmo Denilson Jose; Santos Dagoberto Brandao

来源：Materials Research, 2014, 17(3): 694-699.

DOI：10.1590/S1516-14392014005000066

• manganese
• warm rolling
• cold rolling
• recrystallization
• EBSD analysis

Steels containing high levels of Mn, Si and Al exhibit high plasticity when deformed, owing to twinning-induced plastitity (TWIP) and transformation-induced plasticity (TRIP) effects. In this study, we investigated the microstructural evolution of samples of samples of a 17% Mn steel subjected to war rolling at 700 degrees and 800 degrees C. We also studied the effects of the microstructure of the steel samples on their mechanical behavior. Using a mathematic model the stacking fault energy of the steel was estimated to be 14.5 mJ/m(2). This value was indicative of a martensitic transformation. The presence of martensite and twinned austenite was verified using optical microscopy, scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) analyses. The presence of austenite and epsilon- and alpha%26apos;-martensites was confirmed using X-ray diffraction (XRD) analyses and dilatometry. Increasing the rate of cold reduction resulted in the formation of a alpha%26apos;-martensite phase and a decrease in the volume fraction of the epsilon-martensite phase. The volume fractions of the various phases were measured by integrating the areas under the XRD peaks. The sample subjected to a cold-rolling reduction of 81% and a subsequent annealing treatment did not contain a alpha%26apos;-martensite phase, indicating that it was fully recrystallized. The Vickers microhardness of the samples increased with an increase in the cold-rolling reduction rate. However, the microhardness values of the cold-rolled samples decreased after the annealing treatment.

• 出版日期2014-6