Production of Ni-GNP/AlSi12 Composite Foams and Investigation of Their Properties

Abstract

In this study, Ni-GNP/AlSi12 composite foams were produced by using powder metallurgy process using aluminum powder as matrix material, silicon (12%) for alloying, titanium hydride (1%-TiH₂) as foaming agent and graphene nanoplatelets (0%, 0.4%, 0.8% and 1.2%-GNP) as reinforcement. The powders were mixed at specified ratios, cold compressed and extruded at different ratios to produce precursor samples with diameters of 6 mm and 12 mm. Foaming experiments were carried out at 750 °C in open atmosphere by measuring the expansion rates volumetrically. After foaming, the samples were analyzed in terms of their cellular structure, relative density and cell wall hardness. The results showed that the addition of Ni-GNP decreased the expansion rates but increased the relative density and stability, and the optimum reinforcement effects were observed at 0.4% Ni-GNP concentration. Therefore, the addition of Ni-GNP provides improved stability and hardness, albeit at the expense of reduced expansion, for applications requiring structural strength.