Tensile failure observations in sintered steel foam struts revealed by sub-micron contrast-enhanced microtomography

被引:24
作者
Kaya, Ali Can [1 ]
Zaslansky, Paul [2 ]
Nikolaus, Anneke [1 ]
Fleck, Claudia [1 ]
机构
[1] Tech Univ Berlin, Dept Mat Engn, Str 17 Juni 135 Sekr EB 13, D-10623 Berlin, Germany
[2] Charite, Julius Wolff Inst, Augustenburger Pl 1, D-13353 Berlin, Germany
关键词
Synchrotron radiation mu CT; Metal foam; Micro-tensile testing; Finite-element simulation; Crack propagation; Microporosity; OPEN-CELL; ALUMINUM FOAMS; MECHANICAL-PROPERTIES; DEFORMATION-BEHAVIOR; WALL MICROSTRUCTURE; FRACTURE;
D O I
10.1016/j.matdes.2016.05.069
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Powder metallurgical open-cell steel foams made of hollow struts are of great interest for impact resistance. Here we report experimental results of high-resolution characterisation of single struts, extracted from a commercially available steel foam. Synchrotron radiation X-ray microtomography reveals that the hollow struts are made of triplets of lens shaped rods, connected to each other along the long axis, appearing triangular in cross-sections. The struts have a non-uniform geometry and they include macro and micropores as well as high-density inclusion powder particles, poorly fused with the matrix. Micro-tensile testing showed that tensile failure is accompanied by longitudinal unzipping due to shear along the thinner material found near the hollow corners. Included, higher-density powder particles deflect crack propagation along the interface with the matrix, where much porosity is observed. Results of finite element simulations well match our mechanical tests, revealing plastic deformation due to bending and significant shear stresses arising between neighbouring rods within the same strut. The failure behaviour and the mechanical response of sintered struts in steel foams produced using non-uniformly coated polyurethane templates is the result of an interplay between the triplet geometry, sub-micron pores, precipitates and high-density inclusions. (C) 2016 Elsevier Ltd. All rights reserved.
引用
收藏
页码:190 / 200
页数:11
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