Effect of superplastic deformation on precipitation behavior of sigma phase in 3207 duplex stainless steel

Progress in Natural Science: Materials International

Yanling Zhang¹  Hongliang Hou²  Xiaodan Gao²  Xueping Ren³  Jingkun Li³ 

[1] Corresponding author.;AVIC Manufacturing Technology Institute, Beijing, 100024, China;School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, China;

关键词: Duplex stainless steel;    Superplastic deformation;    Sigma phase (σ);    Precipitation mechanism;    Hardening effect;   

DOI  :  

来源: DOAJ

【 摘 要 】

Owing to excellent strength, toughness and corrosion resistance, duplex stainless steels (DSS) are widely used in constructional and petrochemical applications. Sigma phase, which has detrimental impact on the properties, is readily precipitated during hot working of DSS. However, precipitation behavior of sigma phase during superplastic deformation, which is the most significant processing method of DSS, is still unclear. In the current study, the effect of superplastic deformation on the precipitation behavior of sigma phase was investigated in 3207 duplex stainless steel. The result shows that superplastic deformation could prevent sigma phase precipitation generally by increasing mobility of grain boundaries and decreasing misorientation of the sigma phase boundaries, resulting in some sigma phase precipitated on the twin boundaries. Most of the sigma phase precipitated on ferrite-austenite interface with misorientation of 20–25°, while it precipitated in ferrite or austenite with the misorientation of 40°–45°. The orientation relationship between sigma phase and matrix matched well in austenite and on the ferrite/austenite interfaces, while it showed a small misfit in ferrite. The prevention effect of the superplastic deformation on the sigma phase precipitation was beneficial to quasi stable deformation stage, resulting in longer elongation.

【 授权许可】

Unknown