Compressive behavior of Cu-Ni alloy foams: Effects of grain size, porosity, pore directionality, and chemical composition

Abstract

Experiments were conducted to study the compression behavior of Cu-Ni foams prepared using freeze casting. The struts of the foam samples were solid-solutioned with differing Cu/Ni ratios, after which the grain size in the struts was measured using scanning electron microscopy. The compression performance of the samples was studied in both parallel and perpendicular directions to the temperature gradient, and compared with model calculations. It was confirmed that alloying increased the yield strength of the struts. The experimentally determined yield strength and elastic modulus were compared with model calculations, which revealed that the elastic modulus of the foams was lower than the values calculated from the classical compression and Gibson-Ashby models due to variation in the thickness of the struts. It was also found that the alloying of Cu and Ni improved the mechanical performance of the alloy foams because the absorbed energy for the alloys was considerably higher than that for the pure foams.