强磁场对表面纳米化纯铁退火行为的影响

项目名称： 强磁场对表面纳米化纯铁退火行为的影响

项目编号： No.50871026

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 佟伟平

作者单位： 东北大学

项目金额： 37万元

中文摘要： 在本项目研究过程中，我们制备了纯铁表面机械研磨处理(SMAT) 样品，发现在表层形成大约10微米厚的纳米晶层，次表层形成一个强塑性变形区。当其在强磁场中退火时，表层纳米晶粒的热稳定性和次表层塑性变形区的再结晶行为都不同于无磁场退火的样品，说明强磁场对其退火行为有重要影响。本项目使用X射线、SEM和TEM等手段，深入研究了强磁场对退火过程中纳米晶粒生长动力学的影响，弄清了磁场强度和纳米晶粒生长激活能的关系，并建立了相关理论模型；同时，利用X 射线衍射宏观织构测定和EBSD 微区取向分析等手段，研究了强磁场作用下SMAT纯铁的表层织构演变过程和再结晶行为，并进行相应的理论解析、构建物理模型。 另外，我们还研究了纯铁和IF钢的变形织构以及在退火过程中，不同尺寸晶粒织构的演变过程。 与香港理工大学吕坚教授合作交流。参加国际会议2次，发表SCI收录论文7篇，EI收录8篇。

中文关键词： 强磁场;表面纳米化;热稳定性;激活能;再结晶。

英文摘要： In this project, a nanostructured surface layer and a severe plastic deformation zone on a pure iron were prepared by means of a surface mechanical attrition treatment (SMAT). The average grain size of SMAT sample was about 10 nm at the top surface layer, and gradually increased with the depth. The depth of severe plastic deformation zone was about 50 micron. We found that the annealing behavior of SMAT sample was considerably affected by high magnetic field. We investigated the thermal stability of nanostructed surface layer and the recrystallinzation behavior of deformation zone in SMAT sample under a high magnetic field in comparison with those in non-magnetic field. Samples were characterized by means of X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM-EBSD), microhardness tests and nanoindentation tests. Thermodynamics and kinetics of the nano grains growth under a high magnetic field were analyzed in terms of the experimental results. In addition, we studied the texture evolution of the pure iron sample after SMAT by means of electron backscattering and X-ray diffraction (XRD) analysis. The texture evolution and growth of differently sized grains in IF steel during annealing were also investageted. During the research work of this project, we have frequent exchange visits with Prof. Lu in The Hong Kong Polytechnic University (PolyU). We attended 2 international conferences. And 11 papers have been published, among which 7 were cited by SCI and 8 were cited by EI.

英文关键词： high magnetic field; surface nanocrystallization; thermal stability; activation energy; recrystallization