On the Superplastic Deformation in Vanadium-Alloyed High-Nitrogen Steel

• Published in: Metals
• Main Authors: Elena Astafurova, Valentina Moskvina, Marina Panchenko, Galina Maier, Eugene Melnikov, Kseniya Reunova, Nina Galchenko, Sergey Astafurov
• Format: Article
• Language: English
• Published: MDPI AG 2019-12-01
• Subjects: superplasticity; vanadium-alloyed high-nitrogen steel; austenite; precipitate hardening
• Online Access: https://www.mdpi.com/2075-4701/10/1/27
• ISSN: 2075-4701

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.