Experimental investigation of mechanical properties of metallic hollow sphere structures

Autor(en)

Oliver Friedl, Christian Motz, Herwig Peterlik, Stephan Puchegger, Norbert Reger, Reinhard Pippan

Abstrakt

Metallic foam was fabricated from 316L stainless steel spheres, where the bonding of the spheres was achieved by a sintering process. The mechanical behavior of a low-density material (0.3 g/cm3) with 2- and 4-mm sphere diameter and a high-density material (0.6 g/cm3) with 4-mm sphere diameter was investigated in compression and tension. The cell wall material of this hollow sphere structure (HSS) had different morphologies: dense and porous sintered walls were investigated. The cell wall morphology affects the Young’s modulus (stiffness) and the ductility of the HSS material. Defects, such as the cell wall porosity, lower the ductility of the material. Besides the quasi-static measurements, the HSS material was tested with a resonance frequency method (dynamic measurement), to obtain detailed information on the stiffness at different temperatures up to 700 °C. In-situ compression and tension tests were carried out to understand the deformation mechanisms on the scale of the single hollow spheres. The failure mechanisms in the vicinity of the sintering neck of the spheres was investigated. A doubling of the density leads to an increase of the plateau stress and the ultimate tensile stress of the material, whereas the ductility (strain to fracture) depended mainly on the cell wall morphology. Due to the mainly tensile loading of the cell walls in the vicinity of the sinter neck, the ultimate tensile strength doubled for the high-density HSS, in good agreement with theoretical considerations. In compression, the gain in the plateau stress was not as distinctive compared with the theoretical considerations assuming a bending dominated deformation. The influence of structural parameters, such as cell wall morphology, cell wall thickness, and sphere diameter, on the mechanical behavior is discussed.

Organisation(en)

Dynamik Kondensierter Systeme

Externe Organisation(en)

Montanuniversität Leoben, Österreichische Akademie der Wissenschaften (ÖAW), PLANSEE Metall GmbH

Journal

Metallurgical and Materials Transactions B - Process Metallurgy and Materials Processing Science

Band

39

Seiten

135-146

Anzahl der Seiten

12

ISSN

1073-5615

DOI

https://doi.org/10.1007/s11663-007-9098-2

Publikationsdatum

2008

Peer-reviewed

Ja

ÖFOS 2012

103009 Festkörperphysik, 210006 Nanotechnologie, 103018 Materialphysik

Link zum Portal

https://ucris.univie.ac.at/portal/de/publications/experimental-investigation-of-mechanical-properties-of-metallic-hollow-sphere-structures(13f7003e-4f47-4370-b05f-acb4cc4e4397).html