报告题目(中文)：交变磁场作用下合金体系中强化扩散现象
报告题目(英文)：Enhanced diffusivity in alloy systems under action of alternating magnetic field
报告内容简介：For applying an alternating magnetic field (AMF) in materials processing it is of high significance to understand the physical mechanisms behind the change in diffusivity in the AMF. In this report, the effect of the AMF on interdiffusion in two alloy systems of Ni-Al and Ni-Cr was investigated with a diffusion couple. The interdiffusion coefficient was found to increase with increasing AMF intensity. The faster diffusivity is a consequence of the enhancement of the dislocation density in the diffusion couples that was confirmed by the broadening of X-ray diffraction peaks. The higher dislocation density is attributed to the magnetoplastic effect (MPE). Theoretical considerations on the relation of MPE, dislocation density and diffusivity are in agreement with the experimental results. Furthermore, we applied the principle to homogenization of as-solidified superalloys and found that the AMF effectively increased the homogenization rate and reduced the microsegregation.
报告人姓名：李传军
报告人简介(中文)：李传军博士一直从事金属材料电磁制备理论及应用研究。针对磁场下金属材料加工过程中形核与生长，界面现象，扩散，偏析等关键科学问题，开展了磁场下金属凝固加工及高温合金热处理研究。开发了适用于强磁场环境的多套原位分析测量仪器。明确了磁场对金属及合金凝固过程热力学和动力学的影响规律。揭示了磁场下溶质扩散速率变化的物理本质，首次建立了磁场下扩散速率变化的物理模型及解析方程。提出了利用磁场优化高温合金热处理及制备亚稳金属材料的新方法。在Applied Physical Letters, Review of Scientific Instruments等国内外重要学术刊物上发表SCI论文46篇，影响因子3.0以上论文11篇。申报国家专利15项，其中授权7项。主持和承担国家自然科学基金项目，“973计划”项目，国家自然科学基金重大项目，上海市重大科技项目，上海市“浦江人才”计划项目等多个国家及省部级项目。相关研究工作已荣获德国洪堡研究奖学金，教育部自然科学二等奖，上海市科学技术发明一等奖，日本磁科学协会授予的优秀报告奖等荣誉。  
报告人单位(中文)：材料科学与工程学院
报告人单位(英文)：School of Materials Science and Engineering
报告时间：2018-10-15 09:00
报告地点：宝山日新楼508会议室
主办单位：上海大学材料学院
联系人：李传军
联系方式：56334042