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839 KiB

Open AccessArticle

Behavior of Metallic Foam under Shock Wave Loading

by Matej Vesenjak, Matej Borovinšek, Zoran Ren, Seiichi Irie and Shigeru Itoh

Metals 2012, 2(3), 258-264; https://doi.org/10.3390/met2030258 - 03 Aug 2012

Cited by 16 | Viewed by 8100

In this manuscript, the behavior of metallic foam under impact loading and shock wave propagation has been observed. The goal of this research was to investigate the material and structural properties of submerged open-cell aluminum foam under impact loading conditions with particular interest [...] Read more.

In this manuscript, the behavior of metallic foam under impact loading and shock wave propagation has been observed. The goal of this research was to investigate the material and structural properties of submerged open-cell aluminum foam under impact loading conditions with particular interest in shock wave propagation and its effects on cellular material deformation. For this purpose experimental tests and dynamic computational simulations of aluminum foam specimens inside a water tank subjected to explosive charge have been performed. Comparison of the results shows a good correlation between the experimental and simulation results. Full article

(This article belongs to the Special Issue Metal Foams)

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879 KiB

Open AccessArticle

The Role of Foaming Agent and Processing Route in the Mechanical Performance of Fabricated Aluminum Foams

by Alexandra Byakova, Svyatoslav Gnyloskurenko and Takashi Nakamura

Metals 2012, 2(2), 95-112; https://doi.org/10.3390/met2020095 - 23 May 2012

Cited by 24 | Viewed by 7117

Abstract

The results of the present study highlight the role of foaming agent and processing route in influencing the contamination of cell wall material by side products, which, in turn, affect the macroscopic mechanical response of closed-cell Al-foams. Several kinds of Al-foams have been [...] Read more.

The results of the present study highlight the role of foaming agent and processing route in influencing the contamination of cell wall material by side products, which, in turn, affect the macroscopic mechanical response of closed-cell Al-foams. Several kinds of Al-foams have been produced with pure Al by the Alporas melt process and powder metallurgical technique, all performed either with conventional TiH₂ foaming agent or CaCO₃ as an alternative. Mechanical characteristics of contaminating products induced by processing additives, all of which were presented in one or another kind of Al-foam, have been determined in indentation experiments. Damage behavior of these contaminations affects the micro-mechanism of deformation and favors either plastic buckling or brittle failure of the cell walls. It is justified that there is no discrepancy between experimental values of compressive strengths for Al-foams comprising ductile Al + Al₄Ca eutectic domains and those prescribed by theoretical models for closed-cell structure. However, the presence of low ductile Al + Al₃Ti + Al₄Ca eutectic domains and brittle particles/layers of Al₃Ti, fine CaCO₃/CaO particles, Al₂O₃ oxide network, and, especially, residues of partially reacted TiH₂, results in reducing the compressive strength to values close to or even below those of open-cell foams of the same relative density. Full article

(This article belongs to the Special Issue Metal Foams)

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3258 KiB

Open AccessArticle

Method of Preventing Shrinkage of Aluminum Foam Using Carbonates

by Takuya Koizumi, Kota Kido, Kazuhiko Kita, Koichi Mikado, Svyatoslav Gnyloskurenko and Takashi Nakamura

Metals 2012, 2(1), 1-9; https://doi.org/10.3390/met2010001 - 23 Dec 2011

Cited by 14 | Viewed by 7086

Abstract

Metallic foams are commonly produced using titanium hydride as a foaming agent. Carbonates produce aluminum foam with a fine and homogenous cell structure. However, foams produced using carbonates show marked shrinkage, which is clearly different from those produced using titanium hydride. It is [...] Read more.

Metallic foams are commonly produced using titanium hydride as a foaming agent. Carbonates produce aluminum foam with a fine and homogenous cell structure. However, foams produced using carbonates show marked shrinkage, which is clearly different from those produced using titanium hydride. It is essential for practical applications to clarify foam shrinkage and establish a method of preventing it. In this research, cell structures were observed to study the shrinkage of aluminum foam produced using carbonates. The cells of foam produced using dolomite as a foaming agent connected to each other with maximum expansion. It was estimated that foaming gas was released through connected cells to the outside. It was assumed that cell formation at different sites is effective in preventing shrinkage induced by cell connection. The multiple additions of dolomite and magnesium carbonate, which have different decomposition temperatures, were applied. The foam in the case with multiple additions maintained a density of 0.66 up to 973 K, at which the foam produced using dolomite shrank. It was verified that the multiple additions of carbonates are effective in preventing shrinkage. Full article

(This article belongs to the Special Issue Metal Foams)

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2698 KiB

Open AccessArticle

Impact Response of Aluminum Foam Sandwiches for Light-Weight Ship Structures

by Vincenzo Crupi, Gabriella Epasto and Eugenio Guglielmino

Metals 2011, 1(1), 98-112; https://doi.org/10.3390/met1010098 - 15 Dec 2011

Cited by 49 | Viewed by 11447

Abstract

The structures realized using sandwich technologies combine low weight with high energy absorbing capacity, so they are suitable for applications in the transport industry (automotive, aerospace, shipbuilding industry) where the “lightweight design” philosophy and the safety of vehicles are very important aspects. While [...] Read more.

The structures realized using sandwich technologies combine low weight with high energy absorbing capacity, so they are suitable for applications in the transport industry (automotive, aerospace, shipbuilding industry) where the “lightweight design” philosophy and the safety of vehicles are very important aspects. While sandwich structures with polymeric foams have been applied for many years, currently there is a considerable and growing interest in the use of sandwiches with aluminum foam core. The aim of this paper was the analysis of low-velocity impact response of AFS (aluminum foam sandwiches) panels and the investigation of their collapse modes. Low velocity impact tests were carried out by a drop test machine and a theoretical approach, based on the energy balance model, has been applied to investigate their impact behavior. The failure mode and the internal damage of the impacted AFS have also been investigated by a Computed Tomography (CT) system. Full article

(This article belongs to the Special Issue Metal Foams)

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5418 KiB

Open AccessArticle

The Manufacture and Characterisation of Aluminium Foams Made by Investment Casting Using Dissolvable Spherical Sodium Chloride Bead Preforms

by Apichart Jinnapat and Andrew Kennedy

Metals 2011, 1(1), 49-64; https://doi.org/10.3390/met1010049 - 04 Nov 2011

Cited by 28 | Viewed by 9693

Abstract

Open cell Al foams have been made by infiltrating molten Al into preforms made from porous salt spheres. Infiltration has been effected using simple pressure-assisted vacuum investment casting where the maximum infiltration pressure difference was less than 36 psi. The preform and resulting [...] Read more.

Open cell Al foams have been made by infiltrating molten Al into preforms made from porous salt spheres. Infiltration has been effected using simple pressure-assisted vacuum investment casting where the maximum infiltration pressure difference was less than 36 psi. The preform and resulting foam density decreased with increasing compaction pressure and the foam density increased with increasing infiltration pressure. For low pressure infiltration, and high density preforms, salt dissolution was rapid due to the porous nature of the salt spheres. Infiltration of molten Al occurred into the beads and, for high density preforms and higher infiltration pressures, the volume of metal in the beads exceeded that in the cell walls, drastically decreasing the NaCl dissolution rate. A simple approach is shown whereby the data from mercury porosimetry can be used to predict the resulting foam density, thereby aiding the design of preform and beads structures. Full article

(This article belongs to the Special Issue Metal Foams)

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Review

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1546 KiB

Open AccessReview

Metal Foaming Investigated by X-ray Radioscopy

by Francisco Garcia-Moreno, Manas Mukherjee, Catalina Jiménez, Alexander Rack and John Banhart

Metals 2012, 2(1), 10-21; https://doi.org/10.3390/met2010010 - 27 Dec 2011

Cited by 38 | Viewed by 10040

Abstract

The use of X-ray radioscopy for in-situ studies of metal foam formation and evolution is reviewed. Selected results demonstrate the power of X-ray radioscopy as diagnostic tool for metal foaming. Qualitative analyses of foam nucleation and evolution, drainage development, issues of thermal contact, [...] Read more.

The use of X-ray radioscopy for in-situ studies of metal foam formation and evolution is reviewed. Selected results demonstrate the power of X-ray radioscopy as diagnostic tool for metal foaming. Qualitative analyses of foam nucleation and evolution, drainage development, issues of thermal contact, mold filling, cell wall rupture and more are given. Additionally, quantitative analyses based on series of images of foam expansion yielding coalescence rates, density distributions, etc., are performed by dedicated software. These techniques help us to understand the foaming behavior of metals and to improve both foaming methods and foam quality. Full article

(This article belongs to the Special Issue Metal Foams)

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