Investigation of mechanical and physical properties of particle reinforced functional graded aluminum foam

In this study, particle (SiC) reinforced aluminum foams were produced using the space holder technique and the mechanical and physical properties of the produced foams were compared. In the production of foams, 99.5% pure Al powder (<44 µm), SiC particles with an average diameter of 7 µm and urea granules with sizes ranging from 1-5 mm were used as starting materials. Experimental studies started with mixing aluminum and SiC particles (3%, 5% and 7% by weight). Then, 75% by volume urea granules were added to the Al-SiC mixture as space holder. The prepared mixture was mixed in a three-dimensional mixer for 30 minutes. Then, the mixture was compressed under 600 MPa pressure in a uniaxial hydraulic press. To dissolve the ureas in the pressed compacts, the samples were kept in a water bath at 80 °C for 3 hours and then subjected to sintering in the oven at 650°C for 2 hours. Compression test was applied to determine the crushing behavior of the produced samples under compression forces. In addition, microhardness tests were applied to determine the hardness change in the cell walls, while the pore morphologies and density changes of the foam structures were characterized. Accordingly, the amount of porosity obtained in all three foam types (Al foam, 5% SiC-Al foam and FD-Al foam) was proportionally compatible with the amount of urea used (75%). In addition, the effect of SiC particles on the cell morphology of foams is negligible. On the other hand, it has a very important effect in terms of the development of mechanical performance. The foam type with the highest collapse stress (4.48 MPa), plateau stress (5.01 MPa) and energy absorption capacity (2.47 MJ/m3) is FD-Al foams.