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

RAPOSO, M.; MARTIN, M.; GIORDANA, M. F.; FUSTER, V.; MALARRIA, J.

METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE

SPRINGER

Año: 2019

1073-5623

A fullyaustenitic Fe-18Mn-2Si-2Al transformation-induced plasticity (TRIP) steel wastensile tested from quasi-static to low-dynamic regime at three differentstrain rates: 4.7 x 10-4, 1.3 x 10-1, and 8.3 x 100s-1. Typical two-stage transformation mechanism, TRIP γ → ε → α?,was observed for samples tested at 4.7 x 10-4 s-1. Athigher strain rates, the increase in temperature due to adiabatic plastic workshifts the stacking fault energy (SFE) towards a twinning-induced plasticity?SFE-rangemodifying the mechanical behavior of the alloy. This change on the deformationmechanism leads to a lower work hardening capacity and a higher elongation torupture in samples tested at 1.3 x 10-1 and 8.3 x 100 s-1.In this context, the alloy maintains its energy absorption capability with amaximum reduction of 3.6 pct according to the Rm x A parameter. The Md temperature, experimentallydetermined in the present study, proved to be a useful tool for understandingthe material?s behavior.