Experimental and FEA evaluation of the Young´s modulus for Al2O3/Al(OH)3 reinforced aluminum foams: effect of the interfacial bonding

In this work, the compressive Young´s moduli of metallic aluminum foams reinforced with spherical ceramic particles were both experimentally determined and predicted using Finite Element Analysis (FEA). Different combinations pore/reinforcement were used, keeping 4 mm in diameter pores and 2 mm reinforcements, which were Al 2 O 3 or Al(OH) 3 . Volume ratios pore/reinforcement of 4:1, 2:1, and 1:1 were selected. For validation purposes, experimental foams were manufactured through infiltration, using NaCl as space holders that generate pores upon dissolution. A wide distribution of characteristics was obtained for both experimental foams and FEA models, with porosities ranging from 35 to 51%, and reinforcement percentages from 11 to 37%. Results showed FEA estimations well aligned with experimental findings, but only after the correct selection of the bonding characteristics for the matrix-reinforcement interface, which depended on the use of Al 2 O 3 or Al(OH) 3 . Such a linkage is associated with the formation of a SiO 2 layer at the Al(OH) 3 -matrix interface, observed during the characterization of the experimental foams. This led to simulating interfacial regions with complete bonding, but only when Al(OH) 3 was used as reinforcement. Contrarily, in the FEA analysis of the foams reinforced with Al 2 O 3 these particles were simulated completely de-bonded with matrix, because of the total lack of interfacial reaction products observed for the experimental foams. Although the Young´s modulus of Al 2 O 3 is significantly higher than for Al(OH) 3 , total debonding Al 2 O 3 -matrix caused a significant decrease in the mechanical properties of these foams. It was demonstrated the importance of selecting appropriate reinforcements and accurately defining boundary conditions for reliable simulation results.