Production and testing of syntactic metal foams with graded filler volume

This paper proposes an innovative multi-material approach for introducing auxetic behaviour to syntactic foams (SFs). By carefully designing the size, shape, and orientation of the SFs, auxetic deformation behaviour was induced. Re-entrant hexagon-shaped SF elements were fabricated using expanded perlite (EP) particles and a plaster of Paris slurry first. Then, an auxetic pattern of these SF elements was arranged within a stainless-steel casting box. The empty spaces between the SF elements were filled with molten aluminium alloy (A356) using the counter-gravity infiltration casting technique. The cast auxetic composite had a bulk density of 1.52 g/cm3. The cast composite was then compressed under quasi-static loading to characterise its deformation behaviour and to determine the mechanical properties, especially the Poisson’s ratio. The cast composite deformation was auxetic with a Poisson’s ratio of −1.04. Finite Element (FE) simulations were conducted to understand the deformation mechanism better and provide means for further optimisation of the geometry.

Section: Introductionmentioning

confidence: 99%

Introducing Auxetic Behavior to Syntactic Foams

Novak,

Kolar,

Movahedi

et al. 2024

“…Foamed metallic materials (FMM) are materials that have a foam structure and contain a large of number of cells in the base metal materials. Owing to the abundant cells, foamed metallic materials possess unique functional properties, such as light weight, damping, energy absorption, heat dissipation, colation, etc., therefore drawing significant attention from the industrial field [1][2][3][4][5][6][7][8]. In particular, Al and Al alloys are typically used for foamed metallic materials due to their excellent castability and industrial significance [6].…”

Section: Introductionmentioning

confidence: 99%

“…Owing to the abundant cells, foamed metallic materials possess unique functional properties, such as light weight, damping, energy absorption, heat dissipation, colation, etc., therefore drawing significant attention from the industrial field [1][2][3][4][5][6][7][8]. In particular, Al and Al alloys are typically used for foamed metallic materials due to their excellent castability and industrial significance [6]. Extensive studies have been conducted to investigate the mechanical property, energy absorption capability and damping property of uniform Al foams [9][10][11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

“…Extensive studies have been conducted to investigate the mechanical property, energy absorption capability and damping property of uniform Al foams [9][10][11][12][13][14][15][16][17][18]. To optimize the functional properties of foams, functionally graded foams have been widely studied for higher performance and effectiveness [4,6,[19][20][21][22][23] instead of uniform foam. The graded foams consist of a gradual change in their property from one location to another.…”

Section: Introductionmentioning

confidence: 99%

“…Many methods for preparing uniform metal foams can be used to prepare metal foams with a gradient structure. According to the cell structure, gradient metal foams can be divided into open-cell structure metal foams [22,23], metal matrix syntactic foams [6,24,25] and closed-cell structure metal foams [20,21,[26][27][28]. At present, a gradient is usually introduced to foam materials by changing the relative density distribution.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Compressive Properties and Failure Mechanisms of Gradient Aluminum Foams Prepared by a Powder Metallurgy Method

Huang

Liu

et al. 2021

A layered gradient aluminum foam was prepared by powder sintering with sodium thiosulfate (Na2S2O3) particles as the cell-forming agent. By cutting, polishing and observing under a microscope, it was found that the aluminum powder particles were not completely melted after sintering but were only combined by surface melting. Based on the quasi-static compression test and the macroscopic diagram of the sample during deformation, the mechanical properties of gradient aluminum foam were studied, and their deformation characteristics and mechanism were analyzed and discussed.

Influence of Melt Infiltration Parameters on Structural and Mechanical Properties of Al-4.3wt.%Cu-EP Syntactic Foam

Niroumand,

Jazini Dorcheh

2023

The present research concerns fabrication of Al-4.3wt.%Cu metal syntactic foams using expanded perlite particles (EPPs). A gas pressure infiltration technique was employed to fabricate the aluminium syntactic foams under different infiltration temperatures and pressures. Ambient air pressure and 750 °C were identified as the favoured processing conditions for full infiltration of the melt. The average density and EP volume percentage of the fabricated foams were measured to be about 1.55 g/cm3 and 50.3%, respectively. Melt infiltration is believed to be mainly controlled by the breakage of the aluminium oxide layer on the melt surface and melt viscosity. Preferential infiltration of the melt between the mould wall and the EP particles bed complemented by radial melt infiltration toward the centre of the samples was identified. The effects of EP particles on growth of the nucleated primary α-aluminium phase were discussed. XRD and EDS analyses suggested some chemical reactions at the interface of EPPs with the molten aluminium. T6 heat treatment in the ambient atmosphere improved the average compressive tensile strength, plateau stress, and absorption capacity of the syntactic foams by more than 100%. Uniform deformation and similar densification strains (about 40%) of the as-fabricated and heat-treated syntactic foams during the compression test suggested uniform distribution of EP particles and metallic struts in the aluminium alloy matrix.