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Investment Casting of AZ91 Magnesium Open-Cell Foams

Kapłon Honorata, Dmitruk Anna, Naplocha Krzysztof

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 1

11--16

EN

The process of investment casting of AZ91 magnesium alloy open-cell porosity foams was analysed. A basic investment casting technique was modified to enable the manufacturing of magnesium foams of chosen porosities in a safe and effective way. Various casting parameters (mould temperature, metal pouring temperature, pressure during metal pouring and solidifying) were calculated and analysed to assure complete mould filling and to minimize surface reactions with mould material. The foams manufactured with this method have been tested for their mechanical strength and collapsing behaviour. The AZ91 foams acquired in this research turned out to have very high open porosity level (>80%) and performed with Young’s modulus of ~30 MPa on average. Their collapsing mechanism has turned out to be mostly brittle. Magnesium alloy foams of such morphology may find their application in fields requiring lightweight materials of high strength to density ratio or of high energy absorption properties, as well as in biomedical implants due to magnesium’s high biocompatibility and its mechanical properties similar to bone tissue.

2

Mechanical and Thermal Properties of Aluminum Foams Manufactured by Investment Casting Method

Dmitruk Anna, Kapłon H., Naplocha K.

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 1

37--42

EN

A method for the open-cell aluminum foams manufacturing by investment casting was presented. Among mechanical properties, compressive behaviour was investigated. The thermal performance of the fabricated foams used as heat transfer enhancers in the heat accumulator based on phase change material (paraffin) was studied during charging-discharging working cycles in terms of temperature distribution. The influence of the foam on the thermal conductivity of the system was examined, revealing a two-fold increase in comparison to the pure PCM. The proposed castings were subjected to cyclic stresses during PCM’s subsequent contraction and expansion, while any casting defects present in the structure may deteriorate their durability. The manufactured heat transfers enhancers were found suitable for up to several dozen of cycles. The applied solution helped to facilitate the heat transfer resulting in more homogeneous temperature distribution and reduction of the charging period’s duration.

3

Geometrical and mechanical properties of polyamide PA 12 bonds in composite advanced pore morphology (APM) foam structures

Kovačič A., Novak N., Vesenjak M., Dubrovski P. D., Ren Z.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 4

1198--1206

EN

Adhesive bonds have very strong influence on mechanical properties of composite particulate metal foams. This study experimentally investigates for the first time the geometrical and mechanical properties of PA 12 adhesive bonds between spherical advanced pore morphology (APM) elements made of AlSi10 foam. A new experimentation setup for mechanical testing of bonds in APM structures is based on APM element puncturing. The results show that mechanical behaviour of adhesive bonds differs much from the basic mechanical behaviour of adhesive. Two different bond failure modes are identified, depending on the bond geometry. The geometrical and mechanical results are statistically interpreted for simpler representation, applicability, and modelling of bonds in APM composites in the future.

4

Manufacturing of cellular A2011 alloy from semi-solid state

Robert M. H., Delbin D.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 24, nr 1

115-122

EN

Purpose: The work presents a new method to produce cellular metallic material by pressing the alloy in the thixotropic semi-solid state into a layer of space holder particles, which are removed from the product after the forming operation. Design/methodology/approach: It is investigated the influence of the thixoforming temperature and the size of space holder particles, in the ability of penetration of the slurry in the porous preform as well as the structure of the obtained porous material (general aspect, quantitative and qualitative characterization of porosity microstructure of cells walls and density of the product). Findings: Cylindrical samples presenting three different ranges of porosity were produced. The cellular material obtained contains open porosity, being characterized as sponge. Products were analyzed by tomography and metallographic techniques. Results show that the proposed process is able to produce acceptable porous material, in a simple and low cost technique. The quality of the product depends rather on the processing temperature than on the size of space holder particles. Low liquid fraction in the thixotropic slurry can lead to incomplete infiltration and deformation of the preform. In the analyzed conditions influence of the size of space holder particles could be observed neither in the processing ability nor in the quality of the product. Density of produced porous material increases as processing temperature increases, due to the increase of cells walls thickness. Research limitations/implications: The investigated process is suitable only for alloys with a significant solidification range. Practical implications: The new method to produce cellular metals can represent energy savings and is highly operational when compared to conventional methods based on liquid infiltration, since lower temperatures are involved and no need of liquid handling is required. Originality/value: the process proposed is a new one; no techniques based on thixoforming of the alloy into porous preforms are known so far.

5

Recent powder metallurgy research in Institute of Nonferrous Metals.

Missol W.

Rudy i Metale Nieżelazne

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2002

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R. 47, nr 12

627-632

EN

The paper is related to Institute's research activity over the last few years concerning powder metallurgy (P/M) in the fields of: electric contact tips manufactured by P/M techniques (excluding tips and rivets obtained by mechanical working), modern fine-grained hard metals for instruments, metal foams, self-lubricating bearings for high load rating conditions and soft and hard magnetic materials prepared by metallic powder consolidation.

6

Metallic foams - ultra light materials for structural applications.

Simancik F.

Inżynieria Materiałowa

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2001

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R. XXII, nr 5

823-828

EN

Metallic foams are relatively unknown structural materials, however with enormous future potential for applications where lightweight combined with high stiffness and acceptable manufacturing costs are of prime interest. The performance of metallic foams, in particular those made of aluminium, in various prototypes, such as foamed panels, sandwiches, complex 3-D parts, foamed hollow profiles as well as castings with foamed cores, has been discussed with respect to the expected and achieved goals. The important contributions of aluminium foam to the improvement of the product's properties are highlighted and most promising utilisation is suggested.