Achieving ultra-high flow stress and hardness in a medium Mn stainless steel by the formation of strain-induced martensite and G-phase precipitates

Gupta, H and Kapoor, R and Shinde, D and Makineni, SK (2024) Achieving ultra-high flow stress and hardness in a medium Mn stainless steel by the formation of strain-induced martensite and G-phase precipitates. In: Scripta Materialia, 241 .

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Abstract

This work demonstrates how the deformation of a medium Mn austenitic stainless steel and its subsequent thermal treatment results in the steel having an ultra-high flow stress, and with a microstructure containing strain-induced martensite (α�) and G-phase precipitates. A 14 wt.Cr-8 wt.Mn-1 wt.Ni austenitic stainless steel was uniaxially compressed at room temperature and quasi-static strain rates to determine the evolution of strain-induced martensite with strain. Uniaxial compression resulted in a sigmoidal stress-strain curve (enhanced work-hardening) with the flow stress reaching �2.2 GPa, and the α� fraction saturating at 0.8 true strain. Atom-probe tomography showed that aging at 400 °C for 72 h formed 2�3 nm sized G-phase precipitates containing Cu-rich clusters and having a nominal composition of Ni8Si2Mn20Cu17Cr8Fe44. Such a microstructure resulted in a steel with an ultra-high tensile strength and a compressive flow stress of around 2 GPa. Though the tensile ductility was low, there was sufficient flowability in compression. © 2023 Acta Materialia Inc.

Item Type:	Journal Article
Publication:	Scripta Materialia
Publisher:	Acta Materialia Inc
Additional Information:	The copyright for this article belongs to authors.
Keywords:	Austenitic stainless steel; Martensite; Microstructure; Strain hardening; Strain rate; Stress-strain curves; Tensile strength, Co-precipitation; Cu co-precipitation; G-phase precipitate; High flow; Phase precipitate; Quasi-static strain rates; Strain-induced martensite; Stress/strain curves; Ultra-high; Uni-axial compression, Plastic flow
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	28 Feb 2024 13:16
Last Modified:	28 Feb 2024 13:16
URI:	https://eprints.iisc.ac.in/id/eprint/83700

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