Microstructure and mechanical behavior of
cold-rolled CMnAlSi TRIP-aided steel sheets
cold-rolled CMnAlSi TRIP-aided steel sheets
(1. School of Materials Science and Engineering, Shandong Jianzhu University, Ji’nan 250101, China;
2. School of Materials Science and Engineering, Shandong University, Ji’nan 250061, China,
3. Korea Institute of Machinery and Materials, Changwon 641010, Korea)
2. School of Materials Science and Engineering, Shandong University, Ji’nan 250061, China,
3. Korea Institute of Machinery and Materials, Changwon 641010, Korea)
Abstract: The microstructure, mechanical properties and retained austenite stability of CMnAlSi-TRIP steels were investigated. Optical microscopy and X-ray diffractometry were used to analyze the microstructure, volume fraction and carbon concentration of retained austenite, while the tensile tests were performed to study the retained austenite stability against strain-induced martensitic transformation. The results show that the mechanical properties of the CMnAlSi cold-rolled TRIP-aided steels fabricated by proper heat treatment display good combination of strength and ductility after isothermal bainitic transformation (IBT) treatment at 420−450 ℃ for 60−120 s. The austenite transformation kinetics is influenced significantly by the IBT temperature, and the high mechanical stability of retained austenite, governed by its carbon concentration, and determines high strain hardening during deformation.
Key words: transformation induced plasticity(TRIP); isothermal bainitic transformation (IBT); mechanical properties; retained austenite stability