The Evolution of Microstructure and Defect Structure in Manganese-Aluminum-Base Ferromagnets: Pathways to Novel Processing Routes and Enhanced Properties

0092099 SOFFA本研究计划研究在MnAl基磁性材料中形成铁磁性tau-MnAl(L10)相所涉及的相变的性质。研究了控制大块合金和薄膜磁性能发展的微观组织和缺陷结构的演变。研究表明，介稳的tau-MnAl相是大规模相变的产物，其微观结构和缺陷结构的演化严重依赖于这种相变的机制。这项研究的目的是利用转变机制的基本知识作为设计新的合金化策略、热处理和加工方案的途径，以调整这些材料的结构-性能关系。这项研究还将有助于我们理解一种重要的固态转变类型。这些磁性材料在未来的永磁体应用和包括磁记录介质在内的薄膜器件方面具有巨大的潜力。由于MnAl基铁磁体的磁性能对tau-MnAl相的结构状态非常敏感，只有当其微结构和缺陷结构的演变能够得到系统的控制时，才能实现其全部潜能。

0092099 Soffa This research program studies the nature of the phase transformation involved in the formation of the ferromagnetic tau-MnAl (L1o) phase in MnAl-base magnetic materials. The evolution of microstructure and defect structure which governs the development of magnetic properties in bulk alloys and thin films is examined. The research builds on the revelation that the metastable tau-MnAl phase emerges as the product of a massive transformation and that the microstructure and defect structures which evolve depend critically on the mechanistics of this phase transformation. The goal of this investigation is to use the fundamental knowledge of the transformation mechanism as a pathway for the design of new alloying strategies, heat treatments, and processing schemes to tailor the structure-property relationships in these materials. This research should also contribute to our understanding of an important genre of solid-state transformation.%%%These magnetic materials have tremendous potential in futuristic permanent magnet applications and for thin film devices including magnetic recording media. The full potential of the MnAl-base ferromagnets will only be realized when the evolution of microstructure and defect structure can be systematically controlled since their magnetic properties are extraordinarily sensitive to the structural state of the tau-MnAl phase.***