Author(s): LIANG Mengtian, SHEN Yongfeng, XUE Wenying, LU Xingchao, Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education, State Key Laboratory of Rolling and Automation
Pages: 50-55
Year: 2017 Issue:  1
Journal: Materials Science and Technology
Keyword:  TRIP steel; Q&P process; product of strength and elongation; retained austenite; Cu precipitates;
Abstract: A Cu-TRIP steel was heat-treated by quenching and partitioning(Q&P) processes including onestep(QT = PT,Quenching Temperature,Partitioning Temperature) and two-step(QT ≠PT). Microstructures and properties differences were investigated by means of tensile tests,X-Ray diffraction(XRD),scanning electron microscopy(SEM),and transmission electron microscopy(TEM). Results show that microstructure after one-step consists of martensite,ferrite,and retained austenite while that after two-step contains bainite except for the aforementioned three microstructures. Tensile strength and elongation are 2 200 MPa and 15%respectively after one-step,accompanied with a product of strength and elongation of 33 GPa·%. As far as two-step is concerned,a combination of tensile strength of 1 300 MPa and elongation of 43% is obtained at partitioning temperature of 400 ℃ with the highest product of strength and elongation of ~ 55 GPa·% which is prior to one-step. The eminent mechanical properties benefit from relative contents of phases,TRIP effect,and interaction between Cu precipitates and dislocation in martensite.