Compressive properties and energy absorption of aluminum composite foams reinforced by in-situ generated MgAl2O4 whiskers

Al composite foams reinforced by in-situ generated MgAl2O4 spinel whiskers were fabricated via sintering and dissolution processes, using sodium chloride particles as a space holder material. The MgAl2O4 spinel whiskers with diameters ranging from 50 to 300 nm were uniformly distributed in the composite foams and formed well-bonded interface with the Al matrix. The mean pore sizes and the average thickness of the cell wall are about 450 μm and 20 μm, respectively, while the relative density is 0.3. Compressive tests verified that the plateau stress is in the range of 5.4-18.7 MPa at the pore size of 0.45 mm, while the relative density increases from 0.2 to 0.5. Especially, the composite foams showed superior plateau stress (18.7 MPa) and energy absorption capacity (17.5 MJ/m3) by adding 10 wt% Mg powder in starting materials.