Metal foams have drawn an increasing interest especially in applications where weight and energy absorption are critical. Despite the extensive studies available on their characterization and enhanced fabrication techniques, limited work was found on the possibility of producing a porous composite foam. The objective of this article is to investigate two new synthesis techniques for manufacturing metal matrix composite foam that is, powder metallurgy and melt infiltration. Both techniques are studied using Sodium Chloride (NaCl) as a space holder in an aluminum-based metal matrix and graphene nanoparticles as reinforcements. The effect of the quantity added of both the space holder and graphene is studied using designed experiments. Although powder metallurgy provided lower baseline hardness, experimentation results suggest the superiority of the process over melt infiltration in terms of porosity and hardness. Results suggest that baseline aluminum hardness can be increased by up to 21.5% using powder metallurgy and 15% using melt infiltration. In terms of porosity, powder metallurgy porosity increased baseline more than ten folds while melt infiltration only doubled the baseline porosity. Moreover, it is easier to control the macroscopic shape, density, and distribution of the pores using powder metallurgy. It is also easier to disperse the reinforcement homogenously. Results will support several industries such as military, automotive, medical, and aerospace in developing this innovative material with superior properties and coping with their need for advanced applications.
Hierarchically structured, highly porous nickel synthesized in sintering–evaporation process from a metal nanopowder and a space holder
