Y2Ti2O7纳米颗粒对含铝ODS钢微观结构和力学行为的作用机理

项目名称： Y2Ti2O7纳米颗粒对含铝ODS钢微观结构和力学行为的作用机理

项目编号： No.U1560106

项目类型： 联合基金项目

立项/批准年度： 2016

项目学科： 矿业工程

项目作者： 刘彤

作者单位： 北京航空航天大学

项目金额： 54万元

中文摘要： 氧化物弥散强化钢（ODS钢）具有优异的高温蠕变强度和抗辐照性能，是新一代核反应堆的重要候选结构材料。添加铝能够提高ODS钢的耐蚀性能，但铝在ODS钢制备过程中首先与钢中的Y2O3反应生成易长大的Y-Al-O复合氧化物，阻止了钛与Y2O3形成细小而稳定的Y-Ti-O纳米颗粒，导致强化效果降低。申请人前期通过添加纳米Y2Ti2O7以替代Y2O3，在含铝ODS钢中成功获得Y2Ti2O7纳米弥散相，有效抑制了Y-Al-O相产生，显著提高了弥散强化效果。本项目拟进一步研究ODS钢制备过程中Y2Ti2O7的结构和尺寸演变规律，确立氧化物与ODS钢基体的界面关系，揭示Y2Ti2O7纳米颗粒的形核和长大机制及其抑制Y-Al-O相产生的机理；研究ODS钢的基体微观结构、氧化物尺寸及结构与力学行为的相关性，阐明纳米Y2Ti2O7对ODS钢微观结构和力学行为的作用机理，为研发高强含铝ODS钢奠定理论和实验基础。

中文关键词： 氧化物弥散强化钢；复合氧化物；纳米颗粒；微观结构；强化机理

英文摘要： Oxide dispersion strengthened (ODS) steels with good creep strength and high radiation resistance are considered as one of the most important candidates for constructing the next-generation nuclear energy system. The addition of Al greatly improves the corrosion resistance of the ODS steels. However, this induces the formation of large Y-Al-O complex oxide particles in the matrix due to the reaction of Al with Y2O3 during the fabrication of the ODS steels, prevents Ti from reacting with Y2O3 to form the small and stable Y-Ti-O complex oxide nanoparticles (NPs), and deteriorates the mechanical properties of the ODS steels. Recently, by adding the Y2Ti2O7 NPs to substitute the conventional Y2O3 NPs, we successfully obtained Y2Ti2O7 NPs in the Al-alloyed ODS steels, which effectively inhibited the formation of the Y-Al-O particles and significantly improved the dispersion strengthening effect. In this project, we intend to further study the evolutions of microstructure and size of Y2Ti2O7 NPs during the fabrication of ODS steels, investigate the interface relationship between the oxide NPs and the matrix, elucidate the mechanisms for the nucleation and growth of Y2Ti2O7 NPs and their inhibition for the formation of Y-Al-O phase. In addition, the relationships of the microstructure of the matrix, the size and structure of the complex oxides with the mechanical properties of the ODS steels are systematically investigated, and the effects of Y2Ti2O7 NPs on the microstructure and mechanical behaviors of the Al-alloyed ODS steels are clarified. This project will establish the theoretical and experimental foundations for developing the high performance ODS steels.

英文关键词： Oxide dispersion strengthened steels;Complex oxide;Nanoparticles;Microstructure;Strengthening mechanism