Microstructural evolution and mechanical properties of Fe-12Mn-xAl-1.2C after aging treatment

Abstract This study investigates the influence of varying Aluminium contents on the microstructure and mechanical properties of high Manganese steel. Microstructural characterization was performed using optical microscopy (OM) and scanning electron microscopy (SEM). Mechanical property assessments included hardness testing, room temperature impact testing, and tensile testing. The results indicated that adding Aluminium content refines the austenite grains in high Manganese steel, causing a shift from coarse austenite to a more complex multiphase structure. The gradual increase of ferrite as well as other second-phase particles with increasing Aluminium content also has an effect on the hardness of high Manganese steel. The hardness of high Manganese steel is as high as 501.4 HBW when the Aluminium content is 11%. However, the impact and tensile properties initially increase and then decrease, which is attributed to changes in grain size and fracture mechanisms. The maximum impact toughness of high Manganese steel is 17 J at 4% Aluminium content.