These powders
can be consolidated using various techniques such as hot
rolling, hot extrusion, compaction, sintering, and spark
plasma sintering (SPS) [11e15]. SPS processing is a useful
method for densifying hard-to-sinter materials such as CNTs
[16]. Furthermore, sound interfacial bonding between the
matrix and the reinforcements can be achieved by spark
plasma sintering [17]. SPS processed Al has a porous structure
with large surface area; its porosity can be easily controlled by
changing the applied uniaxial stress.