Effects of particle size on the microstructure and mechanical properties of expanded glass-metal syntactic foams

Our new article Effects of particle size on the microstructure and mechanical properties of expanded glass-metal syntactic foams  has been published in MSEA. For the next 50 days, the manuscript can be downloaded for free.

Abstract

The effect of particle size on the microstructure and mechanical properties of expanded glass-metal syntactic foams (EG-MSF) was investigated. The foams were fabricated via counter gravity infiltration of a packed bed of recycled expanded glass (EG) particles. The metallic matrix of all foam samples was A356 aluminium. Different particle sizes were considered, i.e. diameters between 1–1.4, 2–2.8 and 4–5.6 mm. The microstructures of EG-MSF were investigated by optical and scanning electron microscopy and the grain size of the aluminium alloy was found to increase with EG particle size. Uni-axial compression testing of EG-MSF indicated that its mechanical properties depend both on foam density and particle size. Smaller particles were found to dampen plateau stress oscillation and improve the energy absorption characteristics of EG-MSF.

Controlled Shrinkage of Expanded Glass Particles in Metal Syntactic Foams

Our research on metal matrix syntactic foams with expanded glass particles has been published in Materials (PDF version).

Abstract Metal matrix syntactic foams have been fabricated via counter-gravity infiltration of a packed bed of recycled expanded glass particles (EG) with A356 aluminum alloy. Particle shrinkage was studied and has been utilized to increase the particles’ strength and tailor the mechanical properties of the expanded glass/metal syntactic foam (EG-MSF). The crushing strength of particles could be doubled by shrinking them for 20 min at 700 ◦C. Owing to the low density of EG (0.20–0.26 g/cm^3), the resulting foam exhibits a low density (1.03–1.19 g/cm^3 ) that increases slightly due to particle shrinkage. Chemical and physical analyses of EG particles and the resulting foams were conducted. Furthermore, metal syntactic foam samples were tested in uni-axial compression tests. The stress-strain curves obtained exhibit three distinct regions: elastic deformation followed by a stress plateau and densification commencing at 70–80% macroscopic strain. Particle shrinkage increased the mechanical strength of the foam samples and their average plateau stress increased from 15.5 MPa to 26.7 MPa.

 

2.5 Ton Drop Test

In June 2017 we have successfully tested a P-MSF impact module. A 2.5 ton drop test was conducted to replicate conditions encountered in an automotive impact. The work has been supported by Transurban with an Innovation Grant.

P-MSF, a novel material invented and developed by our research group was used to manufacture a cylindrical crash element. Its controlled deformation allowed to safely arrest a 2.5 ton concrete block released from an elevation of 5 meters. A short video of the Project can be found below.

 

Visit Prof. Rossmanek

Prof. Rossmanek (second from the left) visited our group to discuss a possible collaboration between the University of Newcastle and the University of Applied Sciences Stralsund. Prof. Rossmanek has been driving the development of Formula SAE in Germany and will support img_20161206_125017this year’s event in Melbourne as a judge.

Visit Prof. Vesenjak

In the framework of an ongoing collaboration with the University of Maribor (Slovenia) Prof. Matej Vesenjak (on the right) visited our research team in November 2016. Work was focused on the dynamic testing of metallic foam material and the creation of an editorial for a special issue in Materials. matej

On the compressive behaviour of high porosity expanded Perlite-Metal Syntactic Foam (P-MSF)

Our paper entitled “On the compressive behaviour of high porosity expanded Perlite-Metal Syntactic Foam (P-MSF)” has been accepted for publication in the Journal of Alloys and Compounds 691 (2017) 690-697:

A high porosity Perlite-Metal Syntactic Foam (P-MSF) is produced by the pre-compaction of a packed bed of expanded perlite particles prior to counter gravity infiltration with molten aluminium. The density of the resulting high porosity (>70 vol%) syntactic foam is in the range of 0.72e0.98 g/cm3, depending on the particle pre-compaction pressure and the number of compaction steps. Compressive testing is carried out following the ISO 13314 standard to characterise the mechanical properties of this novel material. Furthermore, micro-computed tomography scans are performed in order to investigate its mesostructure. The geometrical analysis revealed that the densification procedure generates a porosity gradient in the direction of the compressive force. This gradient is found to affect the deformation mechanism and thus the mechanical properties of high porosity P-MSF.