J. Mater. Sci. Technol. ›› 2015, Vol. 31 ›› Issue (3): 311-319.DOI: 10.1016/j.jmst.2013.04.028

• Orginal Article • Previous Articles     Next Articles

Microstructure Stability of V and Ta Microalloyed 12%Cr Reduced Activation Ferrite/Martensite Steel during Long-term Aging at 650 °C

Xiang Xiao1, 2, Guoquan Liu1, 3, *, Benfu Hu1, Jinsan Wang1, Wenbin Ma1   

  1. 1 School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China; 2 Chinalco Research Institute of Science and Technology, Beijing 102209, China; 3 Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing 100083, China
  • Received:2013-03-21 Online:2015-03-20 Published:2015-07-23
  • Contact: Corresponding author. Prof., Ph.D.; School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China. Tel.: +86 10 82377611.E-mail address: g.liu@ustb.edu.cn (G. Liu).
  • Supported by:
    This work was supported by the National Basic Research Program of China (Grant No. 2007CB209801), the National Natural Science Fundation of China (Grant No. 51371030), and the National High Technology Research and Development Program of China (Grant No. 2013AA031601).

Abstract: In view of developing novel alloys for applications in supercritical water-cooled reactor fuel cladding and in-core components, a 12%Cr reduced activation ferrite/martensite (RAFM) steel with good corrosion resistance and irradiation performance was developed. V and Ta were added to form fine MX type carbonitrides and enhance the high temperature creep rupture strength. Microstructure stability of the steel during long-term aging at 650 °C was studied experimentally combined with the simulation of Thermo-Calc and DICTRA software. The results show that the precipitates in the steel during long-term aging contain M23C6, MX and Laves phase. M23C6 carbides play a major role in the stabilization of the tempered martensite lath structure by exerting a large Zener pinning force as compared with MX and Laves phase. Adding V and Ta in the steel can not only promote MX precipitation, but also refine M23C6 carbides and thus improve the thermal stability of lath/subgrains, which is beneficial to the improvement of high temperature microstructure stability of the 12%Cr RAFM steel.

Key words: 12%Cr reduced activation ferrite/martensite steel, Aging, Microstructure evolution