Compressive strength and hardness of metal matrix syntactic foams

Abstract

Six types of metal matrix syntactic foams (MMSFs) were produced by pressure infiltration technique. The foams were investigated by upsetting tests at increased (220°C) and at room (25°C) temperature. The parameters were the constituents of the composites and the aspect ratio (height-diameter ratio, H/D) of the specimens. The characteristic properties were: the compressive strength, the fracture strain, the structural stiffness of the foams and the absorbed energy. The strength, the strain and the energy were decreased while the stiffness was increased by increasing the H/D. Increased temperature caused ∼25 % drop in the strength and in the stiffness. Macrohardness, depth sensitive and dynamic hardness tests were also performed on MMSF blocks: macrohardness is a structural property and independent from the matrix material. The depth sensitive hardness is sensitive to the deformation capability of the matrix and to a possible change reaction. The dynamic hardnesses of the MMSFs were higher than the hardness of the matrices and this is a microballoon related property. © 2010 IOP Publishing Ltd.