B对Mo等合金元素在γ-Fe∑9、∑11晶界偏析行为的影响  

Effect of B on Segregation Behavior of Mo at γ-Fe Σ9 and Σ11 Grain Boundarie

作　　者：闫新[1] 张翊[1] 杨静 陈津[1] 韩培德[1] YAN Xin;ZHANG Yi;YANG Jing;CHEN Jin;HAN Peide(College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学材料科学与工程学院,太原030024

出　　处：《太原理工大学学报》2023年第6期1055-1062,共8页Journal of Taiyuan University of Technology

基　　金：国家自然科学基金资助项目(518171159)。

摘　　要：【目的】超级奥氏体不锈钢中Cr、Mo等元素的严重偏析,使得其在热轧过程中析出大量富Mo、Cr第二相,从而引发轧制开裂、分层等问题,B微合金化有利于遏制σ相的析出。【方法】在实验的基础上对比分析了B对S31254超级奥氏体不锈钢基体、析出相的影响及其Cr、Mo等元素分布,并结合实验结果,以γ-FeΣ9(221)、γ-FeΣ11(113)两种晶界结构模型为研究对象,分析了Cr、Ni、Mn、Mo、Cu、Si在两种晶界处的偏析倾向,探讨了B处于晶界时,对以上元素晶界偏析行为的影响。【结果】研究发现以上合金元素均可固溶于γ-FeΣ9、γ-FeΣ11晶界结构体系,Cr、Mo均有在γ-FeΣ9、γ-FeΣ11晶界偏析的倾向,Mo在晶界处偏析倾向最为严重;而B处于晶界时,可抑制Cr、Mo在γ-FeΣ11晶界的偏析,对Mo在γ-FeΣ9晶界偏析的抑制作用较弱。【结论】从原子层次上诠释了实验中B在超级奥氏体不锈钢中抑制富Mo析出相析出的本质,为后续超级奥氏体不锈钢的成分优化奠定了基础。【Purposes】Owing to the serious segregation of Cr and Mo in super austenitic stainless steel,a large number of Mo-and Cr-rich second phases precipitate during the hot rolling process,which leads to rolling cracking and delamination.Boron microalloying is helpful for preventing theσphase precipitation.【Methods】The matrices and precipitate structures of boron-free and boron-containing S31254 super austenitic stainless steels and the distribution of elements such as Cr and Mo were analyzed experimentally.Combined with the experimental results,two grain boundary structure models ofγ-FeΣ9(221)andγ-FeΣ11(113)were taken as the research objects.The segregation tendency of Cr,Ni,Mn,Mo,Cu,and Si at grain boundaries was analyzed,and the influence of B on the segregation behavior of these elements at grain boundaries was discussed.【Findings】It was found that all of these alloying elements can be solid soluble in the grain boundary structure model ofγ-FeΣ9 andγ-FeΣ11.Both Cr and Mo tend to segregate at the grain boundary ofγ-FeΣ9 andγ-FeΣ11,and Mo tends to segregate most seriously at the grain boundary.When B is at the grain boundary,the segregation of Cr and Mo at theγ-FeΣ11 boundary is inhibited,but the segregation of Mo atγ-FeΣ9 boundary is weakly inhibited.【Con-clusions】The essential reason why the precipitated phase can be inhibited by the addition of super austenitic stainless steel to B is explained from the atomic level,which lays a foundation for the composition optimization of super austenitic stainless steel in the future.

关 键 词：铁 第一性原理 晶界 偏析 

分 类 号：TG142.71[一般工业技术—材料科学与工程]