Effective grain size refinement of an Fe-24Ni-0.3C metastable austenitic steel by a modified two-step cold rolling and annealing process utilizing the deformation-induced martensitic transformation and its reverse transformation

Journal of Materials Research and Technology

Myeong-heom Park¹  Nobuhiro Tsuji²  Si Gao³  Akinobu Shibata⁴  Wenqi Mao⁴  Yu Bai⁴ 

[1] Corresponding author.;Elements Strategy Initiative for Structural Materials, Kyoto University, Sakyo-ku, Kyoto, Japan;J-PARC Center, Japan Atomic Energy Agency, Ibaraki, Japan;Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto, Japan;

关键词: Ultrafine grain;    Transformation cycling;    Martensitic transformation;    Reverse transformation;    Tensile property;   

DOI  :  

来源: DOAJ

【 摘 要 】

Metastable austenitic steels having ultrafine grained (UFG) microstructures can be fabricated by conventional cold rolling and annealing processes by utilizing the deformation-induced martensitic transformation during cold rolling and its reverse transformation to austenite upon annealing. However, such processes are not applicable when the austenite has high mechanical stability against deformation-induced martensitic transformation, since there is no sufficient amount of martensite formed during cold rolling. In the present study, a two-step cold rolling and annealing process was applied to an Fe-24Ni-0.3C metastable austenitic steel having high mechanical stability. Prior to the cold rolling, a repetitive subzero treatment and reverse annealing treatment were applied. Such a treatment dramatically decreased the mechanical stability of the austenite and greatly accelerated the formation of deformation-induced martensite during the following cold rolling processes. As a result, the grain refinement was significantly promoted, and a fully recrystallized specimen with a mean austenite grain size of 0.5 μm was successfully fabricated, which exhibited both high strength and high ductility.

【 授权许可】

Unknown