Warm ductility of 0.2% C–1.5% Si–5% Mn TRIP-aided steel

Autor: Junya Kobayashi, Koh-ichi Sugimoto, Hikaru Tanino
Rok vydání: 2017
Předmět:
Zdroj: Materials Science and Engineering: A. 688:237-243
ISSN: 0921-5093
DOI: 10.1016/j.msea.2017.02.018
Popis: Warm tensile properties of 0.2% C–1.5% Si–5.0% Mn transformation-induced plasticity (TRIP)-aided steel sheets with annealed martensite matrix and retained austenite of 39.4 vol% were investigated for automotive applications. The product of tensile strength and total elongation (TS×TEl) of the TRIP-aided steel was enhanced to 50 GPa% by warm deformation at 150 and 200 °C which is significantly higher than that (30 GPa%) required for third generation advanced high-strength steels. The thermal stability of the retained austenite was low, because the low stacking fault energy promotes the e-martensitic transformation. The mechanical stability of the retained austenite, however, increased with an increase in the deformation temperature of the steel, because the e-martensitic and the strain-induced α′-martensitic transformations were suppressed with increasing deformation temperature. Therefore, the high value of the TS × TEl of the steel subjected to warm deformation is principally associated with the high volume fraction of the retained austenite and its optimum metastability which maximizes the TRIP effect.
Databáze: OpenAIRE