Compressive Behavior of Al-TiB₂ Composite Foams Fabricated under Increased Pressure

The application of increased pressure was used as a strategy to investigate the effect of different cell structures on the mechanical properties of Al-TiB₂ composite foams. In situ Al-xTiB₂ (x = 5, 10 wt.%) composites were foamed under three different pressures (0.1 MPa, 0.24 MPa, 0.4 MPa) through the liquid melt route. The macro-structure of the composite foams was analyzed in terms of cell size distribution measured by X-ray microcomputed tomography (micro-CT). It was found that the mean cell size decreases, and the cell size distribution range narrows with increasing pressure. Uniaxial compression tests revealed that the stress fluctuation (R_sd) of 10TiB₂ foams is larger than that of 5TiB₂ foams under the same pressure. Moreover, cell size refinement causes the simultaneous deformation of multi-layer cells, which leads to an enhancement in the energy absorption efficiency and specific energy absorption. The comparison of experimental data with theoretical predictions (G&A model) is discussed.