Propiedades mecánicas y mecanismos de deformación en aleaciones del sistemas Fe-xMn-3,2Al-0,2C (12 ≤ x ≤ 43)

Abstract

Microstructure and mechanical properties of Fe-xMn-3,2 Al-0,23 C alloys with 12 ≤ x ≤ 43 (mass %) at 77 and 290 K have been studied to determine the mechanisms controlling plastic deformation. Austenitic alloys (Mn ≥ 22) show an increase of elongation to failure with decreasing temperature of testing (inverse ductility). This behavior has been related to formation of deformation twins, which is favored at 77 K. Alloys with manganese content lower than 17% present a two-phase microstructure (α′ + γ). The martensite volume fraction increases as the manganese content decreases. These alloys show a loss of ductility, especially at 77 K. In contrast to asutenitic alloys, this different mechanical behavior has been associated with a TRIP mechanism (transformation-induced plasticity).