Crushing behavior of closed-cell metallic foams: Anisotropy and temperature effects

Abstract

Due to their lightweight features and special energy absorption properties, metal foams (MFs) are gradually replacing fully-dense solid materials in top industries. Having a porous structure with thin cell-walls, MFs are quite sensitive to various operating conditions such as temperature (TT) and loading direction (LD), aspects that should not be neglected. However, the dual TT-LD impact on the mechanical behavior of anisotropic MFs has not yet been addressed. In this regard, the temperature range 25–550 °C (in steps of 75 °C) and the three orthogonal directions (X, Y and Z) were used to experimentally investigate the compressive crushing responses of MFs under the combined temperature-anisotropy effect. The studied MFs had closed cells and were manufactured from Al alloys (AlSi12Mg0.6) through powder metallurgy route. The main strength properties and energy absorption performance of the investigated foams were found to be strongly dependent on the LD and the TT. The best mechanical characteristics are highlighted by the Z-LD, followed in order by the Y and X directions. Thus, improvements in properties were obtained by over 45% (compressive modulus), 71% (compressive strength), 28% (densification strain) and 53% (energy absorption) for Z-LD compared to the other two LDs. Finally, the failure mechanisms differ considerably depending on the imposed test condition (TT or LD).