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

作　　者：Pan-Pan Xu Jin-Yao Ma Zhou-Hua Jiang Yi Zhang Chao-Xiong Liang Nan Dong Pei-De Han 无 徐攀攀;马晋遥;姜周华;张翊;梁超雄;董楠;韩培德;无(College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Instrumental Analysis Center,Taiyuan University of Technology,Taiyuan 030024,China;Taiyuan Iron and Steel(Group)Company Ltd,Taiyuan 030024,China;School of Metallurgy,Northeastern University,Shenyang 110167,China)

机构地区：[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

出　　处：《Chinese Physics B》2022年第11期445-454,共10页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant Nos.U1860204 and 51871159)。

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 theσphase 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 theσphase 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 ofσphase precipitates by suppressing Mo migration to grain boundaries.It is found that B and Mo are inclined to segregate atΣ5 andΣ9 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 

分 类 号：O469[理学—凝聚态物理]