A Review of Powder Metallurgy Techniques for the Production of Aluminium Foams

Abstract

Lightweight cellular materials with low density and appealing mechanical, thermal, acoustic, and energy-absorption qualities are known as aluminium foams. The presence of regulated pores in an aluminium or aluminium-alloy matrix gives them their distinctive qualities. Because it offers significant control over porosity, pore size, pore morphology, composition, and overall cellular architecture, powder metallurgy has become a significant technique among the various manufacturing methods. The two main methods used in powder metallurgy are space-holder techniques for creating open-cell structures and precursor foaming utilizing blowing agents. Aluminium powder and a gas-releasing agent—typically titanium hydride (TiH₂)—are combined, compressed into a dense precursor, then heated to create controlled expansion in precursor foaming. In space-holder processing, a porous metallic skeleton is created by blending aluminium powder with transient particles that are eliminated following compression and sintering. With a focus on precursor foaming, spaceholder processing, sintering-dissolution techniques, processing parameters, pore formation, mechanical properties, benefits, drawbacks, and possible applications; this review explores the fundamentals of powder-metallurgy processing of aluminium foams. Foam structure and performance are examined in relation to powder properties, compaction pressure, sintering conditions, blowing-agent concentration, and space-holder features. Although issues with oxidation, pore homogeneity, processing cost, scalability, and reproducibility still exist, the review shows that powder metallurgy offers an efficient method for creating applicationspecific aluminium foams. Sustainable processing, functionally graded structures, enhanced characterisation, computational optimization, and scalable production should be the main areas of future development.