Ultrafine-Grained 6wt% Mn TRIP steel

Abstract

Multi-Phase, Ultra-fine grained TRIP steel (MP-UFG-TRIP) containing 6 mass-%Mn was obtained by cold rolling and intercritical annealing of an initially fully martensitic microstructure. Ultrafine grained microstructures with a mean grain size less than 300nm were obtained. The fraction of reverse transformation austenite in the dual phase microstructure was controlled by changing the intercritical annealing temperature. The tensile properties were found to be strongly influenced by the volume fraction of reverse transformation austenite. The presence of UFG reverse austenite also resulted in a pronounced localization of the deformation. Brief study on the localized band was conducted to find the way to improve the mechanical property of the steel.