Role of stress-assisted martensite in the design of strong ultrafine-grained duplex steels

By H. Yen, S. Ooi, M. Eizadjou, A. Breen, Ching-Yuan Huang, H. Bhadeshia, Simon P. Ringer. 2014

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Abstract This work explains the occurrence of transformation-induced plasticity via stress-assisted martensite, when designing ultrafine-grained duplex steels. It is found that, when the austenite is reduced to a fine scale of about 300 nm, the initial deformation-induced microstructure can be dominated by parallel lamellae of e martensite or mechanical twinning, which cannot efficiently provide nucleation sites for strain-induced martensite. Hence, α′ martensite nucleation occurs independently by a stress-assisted process that enhances transformation-induced plasticity in ultrafine-grained austenite. This metallurgical principle was validated experimentally by using a combination of transmission Kikuchi diffraction mapping, transmission electron microscopy and atom probe microscopy, and demonstrated theoretically by the thermodynamics model of stress-assisted martensite.

Subfields: Biomedical Engineering, Materials Chemistry, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/e8cfaa69fd80705e4621fda219c43c8ef8967b12