中国物理B ›› 2022, Vol. 31 ›› Issue (11): 116402-116402.doi: 10.1088/1674-1056/ac744a

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Effects of B segregation on Mo-rich phase precipitation in S31254 super-austenitic stainless steels: Experimental and first-principles study

Pan-Pan Xu(徐攀攀)1, Jin-Yao Ma(马晋遥)1,2,†, Zhou-Hua Jiang(姜周华)4, Yi Zhang(张翊)1, Chao-Xiong Liang(梁超雄)1, Nan Dong(董楠)1, and Pei-De Han(韩培德)1,‡   

  1. 1 College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
    2 Instrumental Analysis Center, Taiyuan University of Technology, Taiyuan 030024, China;
    3 Taiyuan Iron and Steel(Group) Company Ltd, Taiyuan 030024, China;
    4 School of Metallurgy, Northeastern University, Shenyang 110167, China
  • 收稿日期:2022-02-28 修回日期:2022-05-26 接受日期:2022-05-29 出版日期:2022-10-17 发布日期:2022-11-01
  • 通讯作者: Jin-Yao Ma, Pei-De Han E-mail:majinyao@tyut.edu.cn;hanpeide@tyut.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. U1860204 and 51871159).

Effects of B segregation on Mo-rich phase precipitation in S31254 super-austenitic stainless steels: Experimental and first-principles study

Pan-Pan Xu(徐攀攀)1, Jin-Yao Ma(马晋遥)1,2,†, Zhou-Hua Jiang(姜周华)4, Yi Zhang(张翊)1, Chao-Xiong Liang(梁超雄)1, Nan Dong(董楠)1, and Pei-De Han(韩培德)1,‡   

  1. 1 College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
    2 Instrumental Analysis Center, Taiyuan University of Technology, Taiyuan 030024, China;
    3 Taiyuan Iron and Steel(Group) Company Ltd, Taiyuan 030024, China;
    4 School of Metallurgy, Northeastern University, Shenyang 110167, China
  • Received:2022-02-28 Revised:2022-05-26 Accepted:2022-05-29 Online:2022-10-17 Published:2022-11-01
  • Contact: Jin-Yao Ma, Pei-De Han E-mail:majinyao@tyut.edu.cn;hanpeide@tyut.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. U1860204 and 51871159).

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摘要： Precipitation in super-austenitic stainless steels will significantly affect their corrosion resistance and hot workability. The effects of Cr and Mo on precipitation behaviors were mainly achieved by affecting the driving force for precipitation, especially Mo has a more substantial promotion effect on the formation of the σ phase than Cr. In the present study, B addition to the S31254 super-austenitic stainless steels shows an excellent ability to inhibit precipitation. The effect of B on the precipitation behaviors was investigated by microstructure characterization and theoretical calculations. The experimental observation shows that the small addition of B inhibits the formation of the σ phase along grain boundaries and changes from continuous to intermittent distribution. Moreover, the inhibitory effect increased obviously with the increase of B content. The influence of B addition was theoretically analyzed from the atomic level, and the calculation results demonstrate that B can inhibit the formation of σ phase precipitates by suppressing Mo migration to grain boundaries. It is found that B and Mo are inclined to segregate at Σ 5 and Σ 9 grain boundaries, with B showing the most severe grain boundary segregation tendency. While B distribution at the grain boundary before precipitation begins, the segregation of Mo and Cr will be restrained. Additionally, B's occupation will induce a high potential barrier, making it difficult for Mo to diffuse towards grain boundaries.

关键词: super-austenitic stainless steel, precipitate, segregation, boron

Abstract: Precipitation in super-austenitic stainless steels will significantly affect their corrosion resistance and hot workability. The effects of Cr and Mo on precipitation behaviors were mainly achieved by affecting the driving force for precipitation, especially Mo has a more substantial promotion effect on the formation of the σ phase than Cr. In the present study, B addition to the S31254 super-austenitic stainless steels shows an excellent ability to inhibit precipitation. The effect of B on the precipitation behaviors was investigated by microstructure characterization and theoretical calculations. The experimental observation shows that the small addition of B inhibits the formation of the σ phase along grain boundaries and changes from continuous to intermittent distribution. Moreover, the inhibitory effect increased obviously with the increase of B content. The influence of B addition was theoretically analyzed from the atomic level, and the calculation results demonstrate that B can inhibit the formation of σ phase precipitates by suppressing Mo migration to grain boundaries. It is found that B and Mo are inclined to segregate at Σ 5 and Σ 9 grain boundaries, with B showing the most severe grain boundary segregation tendency. While B distribution at the grain boundary before precipitation begins, the segregation of Mo and Cr will be restrained. Additionally, B's occupation will induce a high potential barrier, making it difficult for Mo to diffuse towards grain boundaries.

Key words: super-austenitic stainless steel, precipitate, segregation, boron

中图分类号:  (Phase separation and segregation in alloying)

  • 64.75.Op
68.35.bd (Metals and alloys) 73.20.-r (Electron states at surfaces and interfaces) 63.20.dk (First-principles theory)