Microtensile testing of open-cell metal foams - Experimental setup, micromechanical properties
Microtensile testing of open-cell metal foams - Experimental setup, micromechanical properties
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DOI：
10.1016/j.matdes.2015.09.091
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发表时间：
2015-12-25
影响因子：
8.4
通讯作者：
Seibert, H.
中科院分区：
文献类型：
--
作者：
Jung, A.;Wocker, M.;Seibert, H.
泡沫金属是多孔材料，通常用于轻质结构或作为能量吸收剂。开孔泡沫涂层通过形成Ni/Al混合泡沫提高了力学性能。性能由微结构、支柱材料的性能及其几何形状决定。散装材料的性能显着不同，在单一支柱的测量。对于有意义的模拟，确定单支柱的微观力学性能是必要的。由于新型多相Ni/Al混杂泡沫的尺寸小、支撑体曲率大，其微力学性能测试具有挑战性，目前还没有对新型多相Ni/Al混杂泡沫的支撑体进行测试。一个具有挑战性的方面是小样本尺寸和铝和镍的屈服强度之间的巨大差异。为了确定真实的应力-应变曲线，使用基于CCD相机的光学系统通过非接触测量来计算支柱横截面。使用数字图像相关性评价局部菌株。提出了一种在合适尺寸的单支杆上产生散斑图的方法。研究概述了泡沫铝和Ni/Al混合泡沫的微观力学性能的评价。(C)2015爱思唯尔有限公司版权所有。
Metal foams are cellular materials often used for lightweight construction or as energy absorbers. Coating of open-cell foams improves the mechanical properties by the formation of Ni/Al hybrid foams. The properties are determined by the microstructure, the properties of the strut material and its geometry. The properties of bulk materials significantly differ from those measured at single struts. For meaningful simulations, the determination of micromechanical properties on single struts is necessary. According to the small dimensions and the strut curvature, the micromechanical testing is challenging and has not been performed on struts of the new multi-phase Ni/Al hybrid foams, yet.In this study, a microtensile setup for aluminium and Ni/Al hybrid foams is developed. A challenging aspect was the small sample dimensions and the large discrepancy between the yield strength of aluminium and nickel. To determine true stress-strain curves, an optical system based on CCD cameras was used to calculate the strut cross section by means of a non-contact measurement. Local strains were evaluated using digital image correlation. A method to produce speckle pattern on single struts in an appropriate size was developed. The study outlines the evaluation of micromechanical strut properties of aluminium foams and Ni/Al hybrid foams. (C) 2015 Elsevier Ltd. All rights reserved.