中文摘要：

采用放电等离子烧结（SPS）技术取代传统热等静压工艺,制备出具有超细晶粒的纳米结构9Cr氧化物弥散强化（ODS）钢。利用SEM及阿基米德排水法分析了不同放电烧结温度（900,950,1050℃）对ODS钢组织形貌和致密度的影响;通过HRTEM,STEM-HAADF及EDS分析了SPS-ODS钢的微观组织特征等。结果表明机械合金化粉末在950℃时SPS效果最好,密度可达理论密度的97.7%;SPS-ODS钢由超细晶粒（≤200 nm）和大晶粒（≥1μm）混合组织构成;基体中弥散分布着高密度纳米尺寸的Y-Ti-O团簇及Y2Ti2O7相,在晶界上存在少量尺寸较大（30~100 nm）的尖晶石结构Mn（Ti）Cr2O4。

英文摘要：

Ultra-fine grain 9Cr-oxide dispersion strengthened（ODS） steel was prepared by spark plasma sintering（SPS）,instead of the traditional hot isostatic pressing（HIP）.The microstructure and density of the SPS-ODS steel with different sintering temperatures（900,950,1050 ℃） were analyzed by SEM and Archimedes＇ Principle,respectively.The grain size and precipitates characterization of the SPS-ODS steel were analyzed by HRTEM,STEM-HAADF and EDS.The results show that 950 ℃ is the optimal SPS temperature and the relative density reaches up to 97.7%.The mixture of ultra-fine nano grains（≤200 nm） and coarse grains（≥1 μm） is observed in SPS-ODS steel.High-density nano-sized Y-Ti-O clusters and Y2Ti2O7 phases are dispersed homogenously in the ODS steel.Large size spinel structured Mn（Ti）Cr2O4 precipitates（30~100 nm） are formed mainly at grain boundaries.