Controlled Shrinkage of Expanded Glass Particles in Metal Syntactic Foams

Area of Science:

• Materials Science
• Metallurgy
• Foam Technology

Background:

• Metal matrix syntactic foams (MMSFs) offer tunable properties for various applications.
• Recycled expanded glass (EG) presents a sustainable filler material for lightweight foams.
• Optimizing filler properties is crucial for enhancing MMSF performance.

Purpose of the Study:

• To fabricate metal matrix syntactic foams using recycled expanded glass particles (EG) and A356 aluminum alloy.
• To investigate the effect of particle shrinkage on the mechanical properties of EG-MMSFs.
• To characterize the microstructure and mechanical behavior of the developed foams.

Main Methods:

• Counter-gravity infiltration of packed beds of EG particles with A356 aluminum alloy.
• Controlled thermal treatment (shrinkage) of EG particles at 700 °C for 20 min.
• Uni-axial compression testing to evaluate mechanical properties and stress-strain behavior.

Main Results:

• Particle shrinkage effectively doubled the crushing strength of expanded glass particles.
• The resulting EG-MMSFs exhibited low densities (1.03–1.19 g/cm³).
• Particle shrinkage increased the average plateau stress of the foam from 15.5 MPa to 26.7 MPa.

Conclusions:

• Particle shrinkage is a viable method to enhance the mechanical strength of expanded glass/metal syntactic foams.
• The developed EG-MMSFs demonstrate potential for lightweight structural applications requiring improved mechanical performance.
• Recycled expanded glass is a promising material for sustainable and high-performance metal foams.