Complex Metallic Alloys: Plasticity and Defects

帕克坦特拉格将复杂金属合金(CMA)作为材料科学中的一个新领域，其主要目标是确定和了解各种CMA相的物理性质。帕克坦特拉格是对欧洲卓越网络“复杂金属合金”的科学补充。在本提案的框架内，我们将继续研究复杂金属合金的塑性性能和缺陷，这两者都是由这些材料的显著结构特征直接决定的。传统的变形机制由于其较大的晶格参数而容易失效，另一方面，由于复杂金属合金特殊的局域有序性，使得新的变形机制成为可能。首先，我们将利用Jülich最先进的像差校正显微镜，结合斯图加特合作伙伴的相应理论工作，对变质核心结构进行原子水平的电子显微镜研究。其次，我们将对新体系中涉及的塑性行为和缺陷进行全面的表征，例如笼状结构、相关系列的镁锌Laves相及其等结构化合物，以及泰勒相，这些都是以前从未研究过的。第三，关于在第一个资助期开展的工作，我们将对相关系统(例如Bergman相变化、复杂程度不同的六边形CMA相)进行比较研究，以深入了解CMA中局部有序与变形机制之间的关系。

The Paketantrag addresses Complex Metallic Alloys (CMAs) as a novel field in materials science with the primary goal to determine and understand the physical properties of a wide range of CMA phases. The Paketantrag scientifically complements the European Network of Excellence “Complex Metallic Alloys”. In the framework of the present proposal we will continue investigating the plastic properties and defects of complex metallic alloys, which are both directly determined by the salient structural features of these materials. Due to their large lattice parameters, conventional deformation mechanisms are prone to failure, and, on the other hand, due to the particular local order in complex metallic alloys, novel deformation mechanisms are possible.The work in the forthcoming period will basically follow three tracks. First, we will carry out an atomic-level transmission electron microscopy study of metadislocation core structures, taking advantage of the availability of state-of-the-art aberrationcorrected microscopes in Jülich, in conjunction with corresponding theoretical work by the partner in Stuttgart. Second we will carry out a full characterization of the plastic behaviour and the defects involved in new systems, such as clathrates, related series of Mg-Zn Laves phases and their isostructural compounds, as well as Taylor phases, which have not been approached before. Third, relating to work carried out in the first funding period, we will carry out comparative studies of related systems (e.g. Bergman-phase variations, hexagonal CMA phases of varying complexity) in order to gain insight into the relations between the local order and the deformation mechanism in CMAs.