The effect of particle shape on mechanical properties of perlite/metal syntactic foam

In a previous work, a natural porous volcanic glass, expanded perlite (EP), was introduced for fabrication of cost-efficient metallic syntactic foams. Perlite metal syntactic foams (P-MSF) were produced by counter gravity infiltration of a packed bed of porous expanded perlite (EP) particles with molten aluminium. In the current study, the effect of EP particles shape on the mechanical and structural properties of foams were investigated. The irregular shape and coarse surface of raw EP particles were turned to near spherical shape with smooth surface using a tumbling process. Foams containing rounded EP particles showed higher mechanical strength at a constant density. The superior mechanical properties of foams with rounded EP particles are likely due their regular positioning and less structural defects.