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.

本SPP第二阶段的延续建议旨在将我们的结果和经验从第一阶段扩展到关于二元硬磁合金电流处理的确凿图景。我们的关键问题是：在电场或电流的影响下，从观察到的原子扩散和相变现象到原子能级迁移过程的本质联系是什么？为了回答这个问题，我们将通过实验和模拟，将原子的迁移和相的化学有序联系起来，探索微观组织和合金成分对扩散和相变的影响。我们将围绕这些问题来进一步加深对电迁移和相序的理解。在本教程中，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规模。这将从两个方面进行：使用先进的处理和表征技术，以及采用基于原子点缺陷形成和迁移数据的确定性宏观扩散模型。通过这种结合，我们有信心将目前在选定的无稀土材料体系上的退火实验与原子尺度的有序化机制联系起来。通过对合金的系统研究，我们将描述化合物和元素性质对电流诱导形成硬磁相的影响。这项工作计划依赖于两个小组共同努力的思想和成果的协同作用。在项目的实验方面，我们将把一期开发的工艺和装置扩大和完善到四个拟议的材料系统(Mn-Al、Mn-Ga、Fe-PT和Fe-Ni)。通过这种方法，我们打算确定驱动力，并获得电流辅助加工这些磁性材料的定量数据。此外，还计划加强研究微观结构特征(缺陷结构、失配或错位)对观察到的电流驱动的原子扩散和相形成的影响。理论任务将通过在选定的模型系统上的实验活动来指导。来自相变和扩散对实验的定量数据将与由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将是区分扩散(通过温度)和漂移(通过电场或电流)，解决将焦耳加热与电迁移分开的问题。晶体取向和界面取向与电场或电流的关系的理论结果将补充界面、层状前驱体和晶体取向分辨电流退火的实验结果。