Magnesium-Based Foams: Fabrication Methods and Properties

Innovative applications such as lightweight structural and energy-absorbing uses have been found for magnesium-based foams due to their exceptional properties, such as low density, high specific strength, and excellent energy absorption. This review explores the influence of various space holder materials and manufacturing methods on the structural, mechanical, and thermal properties of magnesium-based foams. Key observations indicate that specific energy absorption is improved with certain space holders and manufacturing techniques, while corrosion resistance is significantly enhanced with higher space holder fractions. However, increasing porosity reduces thermal conductivity and peak compressive strength, highlighting the trade-offs in foam design. Comparisons among stir casting, powder metallurgy, and melt foaming methods reveal notable differences in density, mechanical strength, and corrosion resistance. Stir casting produces Mg foams with a density of 1.57 g/cc and a porosity of 16.5%, offering moderate mechanical strength (peak compressive stress ~208 MPa) and corrosion resistance. Powder metallurgy yields highly porous foams (up to 84.5%) with lower density (0.28 g/cc) but reduced strength (~30 MPa) and corrosion resistance. Melt foaming balances porosity (44.6%) and strength (56.97 MPa), making it suitable for energy absorption, though corrosion resistance varies with processing conditions. Furthermore, thermal conductivity studies suggest that magnesium foams can be tailored for applications requiring thermal insulation. The results underscore the need for optimized manufacturing techniques and tailored space holder materials to achieve the desired balance of properties. Optimization can be achieved by carefully controlling porosity levels, selecting suitable space holder materials, and fine-tuning processing parameters, such as sintering temperature and infiltration conditions, to balance mechanical strength and thermal insulation. This review provides a comprehensive understanding of the current advancements in magnesium foam research and outlines the pathways for developing next-generation magnesium foams for diverse industrial and biomedical applications.