Interpenetrating phase composites obtained by silicone rubber infiltration of Cu–Al–Ni shape memory foams

Abstract

Starting with the 3D structure of interconnected pores of a shape memory metal foam, interpenetrating phase composites were obtained by filling its cells with a viscoelastic polymer. A powder metallurgy method to obtain a highly porous Cu-14Al-3Ni shape memory foam with millimeter size cells is detailed. Composites were then fabricated infiltrating silicone rubber with different viscosities under vacuum. A complete structural characterization with the aid of x-ray tomography is presented, identifying the best combination of foam porosity and silicone viscosity required to achieve full foam impregnation. The mechanical response under compression of the metal foam is compared with that of the composites. The presence of a polymer phase inside the cells, subjects the foams to a combined compression–tension stress state, diminishing their load bearing capacity.However, the silicone rubber improves the strain resistance of the foam by supporting the cellsduring crack propagation within the metal phase.