Next Article in Journal
The Impact of the Composition Effect on Ferromagnetic Properties of Tb2Co2Ga
Next Article in Special Issue
The Influence of Alloy Composition and Liquid Phase on Foaming of Al–Si–Mg Alloys
Previous Article in Journal
Synthesis of Zeolite Using Aluminum Dross and Waste LCD Glass Powder: A Waste to Waste Integration Valorization Process
Previous Article in Special Issue
Mechanical, Thermal, and Acoustic Properties of Aluminum Foams Impregnated with Epoxy/Graphene Oxide Nanocomposites
Article

Effects of Eutectic Modification and Grain Refinement on Microstructure and Properties of PM AlSi7 Metallic Foams

1
Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Wiener Straße 12, 28359 Bremen, Germany
2
Rolls-Royce Deutschland Ltd. & Co KG, Eschenweg 11, 15827 Blankenfelde-Mahlow, Germany
3
Deutsche Bahn AG, DB Systemtechnik GmbH, Bahntechnikerring 74, 14774 Brandenburg-Kirchmöser, Germany
4
TU Bergakademie Freiberg, Gustav-Zeuner-Straße 5, 09599 Freiberg, Germany
*
Author to whom correspondence should be addressed.
Metals 2019, 9(12), 1241; https://doi.org/10.3390/met9121241
Received: 14 October 2019 / Revised: 12 November 2019 / Accepted: 13 November 2019 / Published: 20 November 2019
(This article belongs to the Special Issue Cellular Metals: Fabrication, Properties and Applications)
For AlSi7 foams, microstructure modification by variation of solidification rates and addition of Sr, B and TiB2/TiAl3 was investigated and its transfer to powder metallurgical metal foaming processes demonstrated. Microstructural characterization focused on grain size and morphology of the eutectic phase. Cooling rates during solidification were linked to secondary dendrite arm spacing, establishing a microstructure-based measure of solidification rates. Effects of refining and modification treatments were compared and their influence on foam expansion evaluated. Studies on foams focused on comparison of micro- and pore structure using metallographic techniques as well as computed tomography in combination with image analysis. Reference samples without additives and untreated as well as annealed TiH2 as foaming agent allowed evaluation of pore and microstructure impact on mechanical performance. Evaluation of expansion and pore structure revealed detrimental effects of Sr and B additions, limiting the evaluation of mechanical performance to the TiB2 samples. These, as well as the two reference series samples, were subjected to quasi-static compression testing. Stress-strain curves were gained and density-dependent expressions of ultimate compressive strength, plateau strength and tangent modulus derived. Weibull evaluation of density-normalized mechanical properties revealed a significant influence of grain size on the Weibull modulus at densities below 0.4 g/cm3. View Full-Text
Keywords: aluminum foam; metal foam; aluminum alloys; grain refinement; modification; microstructure; mechanics of materials; metallurgy; melt treatment; powder metallurgy aluminum foam; metal foam; aluminum alloys; grain refinement; modification; microstructure; mechanics of materials; metallurgy; melt treatment; powder metallurgy
Show Figures

Graphical abstract

MDPI and ACS Style

Lehmhus, D.; Hünert, D.; Mosler, U.; Martin, U.; Weise, J. Effects of Eutectic Modification and Grain Refinement on Microstructure and Properties of PM AlSi7 Metallic Foams. Metals 2019, 9, 1241. https://doi.org/10.3390/met9121241

AMA Style

Lehmhus D, Hünert D, Mosler U, Martin U, Weise J. Effects of Eutectic Modification and Grain Refinement on Microstructure and Properties of PM AlSi7 Metallic Foams. Metals. 2019; 9(12):1241. https://doi.org/10.3390/met9121241

Chicago/Turabian Style

Lehmhus, Dirk, Daniela Hünert, Ulrike Mosler, Ulrich Martin, and Jörg Weise. 2019. "Effects of Eutectic Modification and Grain Refinement on Microstructure and Properties of PM AlSi7 Metallic Foams" Metals 9, no. 12: 1241. https://doi.org/10.3390/met9121241

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop