Tensile elongation of lean-alloy austenitic stainless steels: transformation-induced plasticity versus planar glide

ABSTRACT

An Fe–13Cr–3.4Mn–0.47C lean-alloy stainless steel was made austenitic by solution annealing at 1250°C. Tensile tests between 20 and 200°C indicated enhancement of ductility at higher temperatures. At 200°C where planar glide, manifested as deformation twinning, was the dominant deformation mechanism, a uniform tensile elongation of 102% was achieved. At 20°C where deformation-induced α′-martensitic transformation replaced deformation twinning as the dominant deformation mechanism, tensile elongation was significantly impaired. The tensile elongation contribution by the planar glide was estimated to be at least four times that of the α′-TRIP (transformation-induced plasticity) mechanism. The results indicate that inexpensive lean-alloy austenitic stainless steels exhibiting pronounced α′-formation at room temperature could become highly formable at higher temperatures.

KEYWORDS:

• Austenitic stainless steel
• planar glide
• α′-TRIP effect
• tensile elongation
• deformation twinning

Acknowledgements

Thanks are extended to Mr Reza Rahimi for the ECCI micrographs and Dr Christian Schimpf for the XRD measurements.

ORCID

Javad Mola http://orcid.org/0000-0002-9057-3114

Additional information

Funding

The authors would like to thank the German Research Foundation (Deutsche Forschungsgemeinschaft) for the financial support of this research under the grant number MO 2580/1-1.