Effects of Strain Rate on the TRIP-TWIP Transition of an Austenitic Fe-18Mn-2Si-2Al Steel

RAPOSO, M.; MARTÍN, M.; GIORDANA, M. F.; FUSTER, V.; MALARRÍA, J.

METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE

SPRINGER

Lugar: Berlin; Año: 2019 vol. 50 p. 4058 - 4066

1073-5623

A fully austenitic Fe-18Mn-2Si-2Al transformation-induced plasticity (TRIP) steel was tensile tested from quasi-static to low-dynamic regime at three different strain rates: 4.7x10-4 s-1, 1.3x10-1 s-1, and 8.39x10+0 s-1. Typical two-stage transformation mechanism, TRIP γ→ε→α, was observed for samples tested at 4.7x10-4 s-1. At higher strain rates, the increase in temperature due to adiabatic plastic work shifts the stacking fault energy (SFE) towards a twinning-induced plasticity-SFE-range modifying the mechanical behavior of the alloy. This change on the deformation mechanism leads to a lower work hardening capacity and a higher elongation to rupture in samples tested at 1.3x10-1 s-1 and 8.39x10+0 s-1. In this context, the alloy maintains its energy absorption capability with a maximum reduction of 3.6 pct. according to the Rm x A parameter.The Md temperature, experimentally determined in the present study, proved to be a useful tool for understanding the material´s behavior.