# Temperature-Dependent Charpy Impact Toughness and Deformation Mechanisms of Austenitic Fe-32Mn-0.6C Steel

## TL;DR

This study examines how temperature affects the impact toughness and deformation behavior of a high-manganese steel from room temperature to cryogenic levels.

## Contribution

The paper reveals a unique deformation mechanism in Fe-32Mn-0.6C steel under cryogenic conditions, differing from conventional FCC alloys.

## Key findings

- Impact energy drops sharply from 120 J at 25 °C to 13 J at −196 °C.
- A critical temperature transition occurs between −100 °C and −150 °C.
- Dislocation slip and twinning are suppressed at low temperatures, limiting plasticity.

## Abstract

The Charpy impact toughness of single-phase austenitic Fe-32Mn-0.6C steel was systematically investigated across a wide temperature spectrum from 25 °C to −196 °C using Charpy V-notch impact tests. The material exhibited a remarkable temperature dependence of impact energy, decreasing dramatically from 120 J at ambient temperature (25 °C) to 13 J under cryogenic conditions (−196 °C). Notably, a steep transition in impact energy occurred within the critical temperature window of −100 °C to −150 °C. Microstructural analysis revealed that synergistic effects of high strain rates and low temperatures significantly restrict dislocation slip and multiplication mechanisms, while also suppressing deformation twinning activation. This restricted plasticity accommodation mechanism fundamentally differs from the deformation characteristics reported in conventional low-carbon high-manganese steels and other face-centered cubic (FCC) alloy systems.