Processing of magnetic materials enhanced by electric fields or currents

通过电场或电流增强磁性材料的加工

• 批准号: 319418944
• 负责人: Professor Dr. Christian Elsässer
• 金额: --
• 依托单位: Fraunhofer-Institut für Werkstoffmechanik (IWM)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/319418944?language=en
• 关键词: Processing; magnetic; materials; enhanced; electric

This continuation proposal for period two of this SPP aims to extend our results and experiences from period one to a conclusive picture of electric current processing of binary hard magnetic alloys. Our key question is: what is the essential link from the observed atomic diffusion and phase transition phenomena to the atomic level migration processes under the influence of an electric field or current? To answer this question, the influence of microstructure and alloy composition on diffusion and transformation will be explored by experiments and simulations, linking migration of atoms and chemical ordering of phases. We will focus on these issues to further develop the understanding of electromigration and phase ordering. For this continuation, we will orient experimental and theoretical work to a common size scale using different binary material systems. This will be done from both sides: by using advanced processing and characterization techniques and by employing a deterministic, macro-scale diffusion model based on atomistic point-defect formation and migration data. Through this combination, we are confident to connect the current annealing experiments on the chosen rare-earth-free material systems to atomic scale ordering mechanisms. By a systematic study of the alloys, we will describe influences of compound and element properties on the current induced formation of the hard magnetic phases. This work plan relies on the synergy of ideas and results of the joint efforts of the two groups.On the experimental side of the project, we will expand and refine the processes and setups developed the first period to the four proposed material systems (Mn-Al, Mn-Ga, Fe-Pt and Fe-Ni). With this approach, we intend to identify the driving forces and obtain quantitative data on the electric current assisted processing of these magnetic materials. Moreover, intensified investigations of the effects caused by microstructural features (defect structures, misfits or misorientations) in the observed current driven atomic diffusion and phase formation are planned.The theoretical tasks will be guided by the experimental activities on the chosen model systems. Quantitative data from phase transition and diffusion pair experiments will be compared with features of diffusion models constructed from atomistic simulation results. An important feature of the models will be the discrimination of diffusion (by temperature) and drift (by electric field or current), addressing the problem of separating Joule heating from electromigration. Theoretical results on crystal and interface orientations relative to the electric field or current will complement experimental results on interfaces, layered precursors and grain-orientation resolved current annealing.

该SPP的两个时期的延续建议旨在将我们的结果和经验从第一期扩展到二元硬磁合金电流处理的结论性图。我们的关键问题是：在电场或电流的影响下，观察到的原子扩散和相变现象到原子水平迁移过程的基本联系是什么？为了回答这个问题，将通过实验和仿真来探索微结构和合金组成对扩散和转化的影响，将原子的迁移和相位的化学排序联系起来。我们将重点介绍这些问题，以进一步发展对电气移民和相排序的理解。为了进行这种延续，我们将使用不同的二元材料系统将实验和理论工作定向到共同的尺寸尺度。这将从双方进行：通过使用高级处理和表征技术，并采用基于原子点 - 缺陷形成和迁移数据的确定性的宏观扩散模型。通过这种组合，我们有信心将所选无稀土材料系统的当前退火实验与原子规模排序机制联系起来。通过对合金的系统研究，我们将描述化合物和元素特性对当前诱导的硬磁相形成的影响。该工作计划依赖于两组的思想和结果的协同作用。在项目的实验方面，我们将扩展和完善过程和设置为四个拟议的材料系统（MN-AL，MN-GA，MN-GA，FE-PTN和FE-NI）开发了第一阶段。通过这种方法，我们打算确定驱动力并获得有关这些磁性材料的电流辅助处理的定量数据。此外，计划了对当前驱动的原子扩散和相形成的微观结构特征（缺陷结构，不适或不良）引起的影响的加强研究。理论任务将由所选模型系统的实验活动指导。从相变和扩散对实验中的定量数据将与原子模拟结果构建的扩散模型的特征进行比较。模型的一个重要特征是歧视扩散（按温度）和漂移（按电场或电流），解决了将焦耳加热与电气移民分离的问题。相对于电场或电流的晶体和界面取向的理论结果将补充界面，分层前体和晶粒方向的实验结果。