Abstract
The experimental evidence for the realization of a superplastic behavior with 900% elongation in V-alloyed high-nitrogen austenitic Fe-19Cr-22Mn-1.5V-0.3C-0.6N steel was proposed. Using thermomechanical processing, a misoriented grain/subgrain austenitic microstructure with a high density of deformation-assisted defects and precipitates was developed in the steel. During high-temperature tensile deformation in a temperature interval from 850 to 1000 °C and strain-rate range from 4 × 10−4 s−1 to 6 × 10−3 s−1, this microstructure demonstrated the characteristics of superplastic flow: elongation in the interval 400–900%, strain-rate sensitivity exponent m = 0.40–0.49, grain boundary sliding mechanism. The maximum elongation to failure (900%) was reached at deformation temperature 950 °C and strain rate 4 × 10−4 s−1.
Highlights
Superplasticity (SP) is an ability of a material to undergo significant tensile plastic elongation prior to failure [1,2]
Steel microstructure contained large particles of vanadium-based nitrides/carbonitrides, which were microstructure contained large particles of vanadium-based nitrides/carbonitrides, which were homogeneously distributed both in grain bodies and along grain boundaries. These coarse particles homogeneously distributed both in grain bodies and along grain boundaries. These coarse particles are peculiar for V-high-nitrogen steels (HNS), and they do not dissolve during solid-solution treatment [25,26,27]
A deformation-assisted austenitic microstructure with the high volume fraction of nitrides was designed in V-alloyed Fe-19Cr-22Mn-1.5V-0.3C-0.6N steel, which demonstrated the superplastic behavior with 900% elongation to failure at deformation temperature 950 ◦ C and strain rate of 4 × 10−4 s−1
Summary
Superplasticity (SP) is an ability of a material to undergo significant (more than 300–400%) tensile plastic elongation prior to failure [1,2]. Fine-grained structure (typically less than 10–15 μm), relatively low strain rates (about 10−2 –10−4 s−1 ), and elevated deformation temperatures (commonly above half of a melting temperature) are the principal well-established requirements for the superplastic flow of polycrystalline metals [1,2,3]. Concerning the iron-based alloys, the majority of the papers are directed to the study of superplastic behavior in duplex steels, medium carbon steels, high carbon steels, and new medium-Mn steels [5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21] These steels demonstrate a perspective of Fe-based materials for practical superplastic forming because of their superior superplastic-assisted elongation-to-failure higher than
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
