9Cr-ODS钢中纳米析出相的SAXS和TEM研究<sup>*</sup>

金属学报, 2016, 52(9): 1053-1062. doi: 10.11900/0412.1961.2016.00164

9Cr-ODS钢中纳米析出相的SAXS和TEM研究^*

谢锐 ^1, , 吕铮 ^1,2, , 卢晨阳 ^1, , 李正元 ^1,3, , 丁学勇 ^2, , 刘春明 ^2,

1.1 东北大学材料科学与工程学院材料各向异性与织构教育部重点实验室, 沈阳 110819

2.2 东北大学冶金学院, 沈阳 110819

基金项目: * 国家自然科学基金项目51471049和高等学校博士学科点专项科研基金课题项目20130042110014资助

关键词： 9Cr-ODS钢 , 金属气雾化 , 小角X射线散射(SAXS) , 富Y-Ti-O纳米团簇 , Y2Ti2O7 , 屈服强度

CHARACTERIZATION OF NANOSIZED PRECIPITATES IN 9Cr-ODS STEELS BY SAXS AND TEM

Rui XIE ^1, , Zheng LU ^1,2, , Chenyang LU ^1, , Zhengyuan LI ^1,3, , Xueyong DING ^2, , Chunming LIU ^2,

1.) Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China

2.) School of Metallurgy, Northeastern University, Shenyang 110819, China;

Keywords： 9Cr-ODS steel , metal gas atomization , SAXS , Y-Ti-O-rich nano-cluster , Y2Ti2O7 , yield strength

对球磨不同时间的雾化合金粉采用热等静压烧结方法制备9Cr-ODS钢. 利用高能同步辐射小角X射线散射(SAXS), 配合高分辨透射电镜(HRTEM), 高角环形暗场(HAADF)像和电子背散射衍射(EBSD)研究了不同球磨时间合金粉制备的9Cr-ODS钢中纳米析出相的特征及其对组织和性能的影响. SAXS和TEM实验结果表明, 9Cr-ODS钢中富Y-Ti-O纳米团簇的尺寸随着球磨时间的延长不断下降, 分布密度峰值逐渐升高, 球磨20 h样品中富Y-Ti-O纳米团簇的分布密度峰值达到2.93×10²³ m^-3; 烧绿石结构Y₂Ti₂O₇相的分布密度峰值在球磨8 h样品中最高(1.03×10²² m^-3); 少量大尺寸富Ti, Al和O的析出相的分布密度随着球磨时间延长而增加, 出现核壳结构. 晶粒尺寸随着球磨时间的延长而细化, 屈服强度随着球磨时间的延长而升高. 富Y-Ti-O纳米析出相对材料强度的贡献占主导地位.

Oxide dispersion strengthened (ODS) steels are the leading candidate structural materials for fast reactor and fusion reactor application due to excellent radiation tolerance and high temperature creep strength. High number density nanoscale oxides play a key role in controlling microstructure and properties. Atomized alloy powders with different ball-milling times were employed to produce 9Cr-ODS steels by hot isostatic pressing (HIP). Nanosized precipitates in 9Cr-ODS steels with different ball-milling times were characterized by synchrotron small angle X-ray scattering (SAXS) together with high resolution transmission electron microscopy (HRTEM). Grain morphology and size were observed by electron backscatter diffraction (EBSD). The effects of nanosized precipitates on grain size and mechanical properties were analyzed. SAXS and TEM results indicated that the size of Y-Ti-O-rich nano-clusters in 9Cr-ODS steels decreases with the increasing milling time, while the distribution density increases. The maximum value of distribution density is about 2.93×10²³ m^-3 in 9Cr-ODS steel ball milled for 20 h. The maximum value of distribution density of pyrochlore structure Y₂Ti₂O₇ is the highest (1.03×10²² m^-3) in 9Cr-ODS steel ball milled for 8 h. Some large-scale Ti-Al-O-rich precipitates are observed and show core/shell structure. Their distribution density increases with ball milling time. With increasing ball milling time, the grain size decreases and the yield strength increases. The contribution of Y-Ti-O-rich nanosized precipitates to yield strength is dominated.

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