A novel approach to prepare aluminium-alloy foams reinforced by carbon-nanotubes

• New generation of closed-cell metal foams reinforced with carbon nanotubes (CNTs).
• A novel approach that combines the powder technology method with colloidal processing.
• CNTs are well-dispersed, non-agglomerated and stretched in the closed-cell Al-foams.

This paper presents an innovative approach to prepare a new class of closed-cell reinforced (nanocomposite) metal-foams that synergistically explores the remarkable properties of both metal-foams and carbon-nanotubes. This approach combines colloidal-processing (including freeze-granulation-lyophilisation) and powder technology, ensuring the retention of the tubular-structure of –COOH-functionalised multiwall carbon nanotubes (MWCNTs-COOH) and their uniform distribution in the metal-matrix. The microstructural analysis revealed non-agglomerated, well-dispersed, stretched and directionally-aligned MWCNTs within the Al-matrix of the foams. These conditions potentiate the reinforcing role of MWCNTs with Vickers microhardness increments >100%.