Ｎ元素偏聚对2205双相不锈钢微观组织结构的影响
李 明，卢焕明，陈惠锋，陈国新，孙 洁，马永存，李 勇Ｎ元素偏聚对2205双相不锈钢微观组织结构的影响
李 明，卢焕明*，陈惠锋，陈国新，孙 洁，马永存，李 勇
（中国科学院宁波材料技术与工程研究所，测试中心，浙江 宁波315201）
摘 要 采用金相、SEM、XRD和EBSD等分析方法，对双相不锈钢管N元素偏聚区域组织进行成分及结构的分析。结果表明：双相不锈钢管有100μm宽的带状N元素偏聚区，中心开裂，该区域基本为奥氏体单相组织，内部晶粒粗大且为等轴晶，以Σ3重位点阵（CSL）晶界为主，出现频率约为40%。而远离偏聚区中，铁素体奥氏体双相组织的相比例正常，奥氏体晶粒细小呈条状，也以Σ3晶界为主，出现频率降为27%。N偏聚区奥氏体与正常区奥氏体组织均可形成<111>∥RD及<110>∥ND方向的织构，但偏聚区奥氏体织构强度较之正常区域弱。
关键词 双相不锈钢；电子被散射衍射；织构；晶界
中图分类号：TG142.71；O76；TG115.21+5.3；TG115.23 文献标识码：A doi:10.3969/j.issn.1000-6281.2016.06.002
Effect of N element segregation on microstructure of 2205 Duplex Stainless Steel
LI Ming，LU Huan-ming，CHEN Hui-feng，SUN-Jie，CHEN Guo-xin，MA Yong-cun，LI Yong
( Test Center, Ningbo Institute of Material Technology and Engineering, CAS, Ningbo Zhejiang 315201, China)
AbstractThe composition and microstructure of the N element segregation region on duplex stainless steel tube was studied by metallographic analysis, scanning electron microscopy, X-ray diffraction and electron backscatter diffraction. The results show that the 100μm wide ribbon like area along the crack direction on the duplex stainless steel tube is where N element segregation occurs. We found only single austenite phase with abnormally coarse equiaxed grains, and a relatively high frequency of Σ3 grain boundary appears in this area, the fraction of Σ3 grain boundaries reached 40%. Away from the crack area where N element content is normal, we found ferrite austenite dual phase with small strip like grains, and the austenite grains has relatively low frequency of Σ3 grain boundary, and the fraction is 27%. Austenite orientation exhibit <111>∥RD and <110>∥ND texture in both crack region and normal region, but the texture intensities in crack region is weaker than normal region.
Keywordsduplex stainless steel；electron backscattered diffraction; texture; grain boundary
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