Advanced synthesis and multifaceted characterization of Al-Mg alloy foams reinforced with TiH2 incorporation through friction stir processing

This study reports the fabrication and characterization of aluminium 5052 (Al-5052) alloy foams using TiH2 as a foaming agent processed through friction stir processing (FSP). A multi-pass FSP strategy was utilized to ensure uniform incorporation of TiH2 particles. Results reflected that TiH2 particles were evenly dispersed throughout the Al-5052 matrix using multi-pass FSP, then activated to promote foaming under specific thermal conditions. Phase analysis via XRD confirmed the coexistence of aluminium and titanium phases, while microstructural examinations revealed homogeneous particle dispersion and significant grain refinement. Mechanical characterization illustrated the improvement in tensile strength (from 263.2 MPa to 318.3 MPa) and microhardness (from 85 HV to 103 HV). Foaming heat treatment at 725 °C and 750 °C led to the formation of uniform pore structures, with average pore diameters of 256 μm and 219 μm, respectively. A foam density of 1,266 kg/m³ and porosity of 53.28% were achieved, validating the effectiveness of TiH2-induced gas expansion. These findings establish Al-5052/TiH2 foams produced by FSP as a promising pathway for lightweight, high-performance materials suitable for aerospace, automotive, and thermal management applications.