Multi length-scale characterisation of microstructure/geometry interactions for tailoring properties of open-cell Al alloy foams

微观结构/几何相互作用的多长度尺度表征，用于定制开孔铝合金泡沫的性能

• 批准号: 434241711
• 负责人: Professor Dr.-Ing. Andreas Bührig-Polaczek
• 金额: --
• 依托单位: Fachgebiet Werkstofftechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/434241711?language=en
• 关键词: Multi; length; scale; characterisation; microstructure

Metal foams are promising candidates for energy absorption and light weight construction applications. On the μm- to the cm-length-scale, phases, struts and cells are hierarchical structural elements. Thus, the base material and its microstructure, e.g. the shape and amount of second phases, as well as geometry, topology and size of struts and cells, determine the mechanical properties. Here, size effects play an important role, both regarding solidification and mechanical properties. Control of these variables is the basic condition for the development of a metal foam with well defined quasi-static and dynamic properties We aim at modifying the hierarchical structural elements and their interactions under consideration of metallurgical and geometrical aspects. Our scientific goal is the understanding of the mechanisms acting on the different length-scales, how these ineract between the hierarchical structural elements, and their influence on the mechanical properties, on the example of open porous Al-alloy foams. The microstructure of the mm-sized struts will be adjusted by adaptation of the alloy composition, the content of modifying elements and through heat treatments. Here, we will consider size and geometry effects both of precipitates and of the dendrite arm distance. The geometry, length and thickness of the struts will be varied to change the stiffness of the struts, and the cell topology of the foams will be modified by introduction of closed cell walls or additional struts. The metal foams will mainly be produced by the block moulding casting process, on the basis of foamed polyurethane or additive-manufactured wax models. Additionally, metallic open-cell foams, produced in-house by additive manufacturing, as well as commercially available sintered open-cell and closed-cell foams, will be included in the investigations. The microstructure and the development of mechanically induced damage will be observed on the length-scales of the foams, cells and struts, by a variety of high resolution 2D and 3D imaging methods, such as SR-μCT, SEM or TEM. The results will help us better understand whether and to what extent metallurgical and mechanistic knowledge of bulk Al-alloys can be transferred to the mm-sized struts and the foams themselves. The results will be summarised in a model describing the microstructure/property-relationship of open-cell metal foams for an application-adapted modulation of the deformation behaviour.

金属泡沫是能够吸收能量和轻质构造应用的候选候选物。在μm-到CM长度尺度上，相位，支柱和细胞是分层结构元素。那就是基本材料及其微观结构，例如第二阶段的形状和数量以及支柱和细胞的几何形状，拓扑和大小决定了机械性能。在这里，尺寸效应在固化和机械性能方面起着重要作用。对这些变量的控制是开发具有良好定义的准静态和动态特性的金属泡沫的基本条件，我们旨在修改层次结构元素及其相互作用，以考虑冶金和几何方面。我们的科学目标是对作用于不同长度尺度的机制的理解，分层结构元素之间的这些intact及其对机械性能的影响，以开放的多孔Al-Al-Al-Al-Al-Al-Al-Al-Al-Aly泡沫为例。 MM大小的支撑杆的微观结构将通过适应合金组成，修饰元件和热处理的含量来调节。在这里，我们将考虑沉淀物和树突臂距离的大小和几何影响。支柱的几何形状，长度和厚度将变化以改变支柱的刚度，并且通过引入闭孔壁或其他支撑杆来修改泡沫的细胞拓扑。金属泡沫将主要由块状铸造过程，基于泡沫的聚氨酯或添加的制造蜡模型产生。通过添加制造业以及市售的烧结开放式泡沫和闭孔泡沫，将包括在内部生产的其他金属开放式泡沫。将通过各种高分辨率2D和3D成像方法（例如SR-μCT，SEM或TEM）观察到在泡沫，细胞和支柱的长度尺度上观察到的微观结构和机械诱导损伤的发展。结果将有助于我们更好地理解散装Al-Alsoys的冶金和机械知识是否可以转移到MM大小的支柱和泡沫本身。结果将汇总在一个模型中，以描述开放型金属泡沫的微观结构/属性关系，以进行变形行为的应用调节调制。