Microstructural characterization and mechanical behavior of a low-carbon 17%Mn steel

• Autor(a) principal: Spindola,Mirelle Oliveira
• Data de Publicação: 2014
• Outros Autores: Dafé,Sara Silva Ferreira de, Carmo,Denilson José do, Santos,Dagoberto Brandão
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Materials research (São Carlos. Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392014000300022
• topic: 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 700º and 800ºC. 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/m². 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 ε- and α'-martensites was confirmed using X-ray diffraction (XRD) analyses and dilatometry. Increasing the rate of cold reduction resulted in the formation of a α'-martensite phase and a decrease in the volume fraction of the ε-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 α'-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.