Tailoring the Deformation Behaviour of a Medium Mn Steel through Isothermal Intercritical Annealing

TL;DR

This study investigates how varying the intercritical annealing duration affects the deformation behavior of medium Mn steel, revealing relationships between austenite stability, Mn enrichment, and strain hardening.

Contribution

It introduces a novel approach to tailor deformation behavior by controlling intercritical annealing time, linking microstructural stability to mechanical properties.

Findings

Austenite stability inversely relates to annealing duration.

Maximum strain hardening rate correlates linearly with austenite stability.

Mn enrichment during annealing influences phase stability.

Abstract

A novel concept of varying the strain hardening rate of a medium Mn steel with 8 wt\% Mn by varying the duration of the intercritical anneal after hot rolling was explored. It was found that the stability of the austenite phase showed an inverse square root relationship with intercritical annealing duration and that the maximum strain hardening rate showed a linear relationship with austenite stability. The change in austenite stability was attributed to continuous Mn enrichment with increasing intercritical annealling duration. Twinned martensite was also found to be the most likely product of the martensitic transformation during deformation.