Development of Lightweight Magnesium/Glass Micro Balloon Syntactic Foams Using Microwave Approach with Superior Thermal and Mechanical Properties

Magnesium matrix syntactic foams (MgMSFs) are emerging lightweight materials with unique capabilities to exhibit remarkable thermal, acoustic, and mechanical properties. In the current study, lightweight glass micro balloon (GMB)-reinforced Mg syntactic foams were synthesized via the powder metallurgy technique using hybrid microwave sintering. The processing employed in the study yielded MgMSFs with refined grain sizes, no secondary phases, and reasonably uniform distributions of hollow reinforcement particles. The developed MgMSFs exhibited densities 8%, 16%, and 26% lower than that of the pure Mg. The coefficient of thermal expansion reduced (up to 20%) while the ignition resistance improved (up to 20 degrees C) with the amount of GMB in the magnesium matrix. The MgMSFs also exhibited a progressive increase in hardness with the amount of GMB. Although the MgMSFs showed a decrease in the yield strength with the addition of GMB hollow particles, the ultimate compression strength, fracture strain, and energy absorption capabilities increased noticeably. The best ultimate compression strength at 321 MPa, which was similar to 26% higher than that of the pure Mg, was displayed by the Mg-5GMB composite, while the Mg-20GMB composite showed the best fracture strain and energy absorption capability, which were higher by similar to 39 and 65%, respectively, when compared to pure Mg. The specific strength of all composites remained superior to that of monolithic magnesium. Particular efforts were made in the present study to interrelate the processing, microstructural features, and properties of MgMSFs.

Automated summary

In this study, lightweight glass micro balloon (GMB)-reinforced Mg syntactic foams were synthesized using hybrid microwave sintering, resulting in MgMSFs with refined grain sizes, no secondary phases, and reasonably uniform distributions of reinforcement particles. The addition of GMB led to reduced coefficient of thermal expansion and improved ignition resistance, while increasing hardness. Ultimate compression strength, fracture strain, and energy absorption capabilities also increased, with the Mg-5GMB and Mg-20GMB composites showing the best performance compared to pure Mg. Overall, the developed MgMSFs exhibited superior specific strength compared to monolithic magnesium.