TEM Characterization on the Nanocomposite Al 7075 and Silver Nanoparticles Synthesized by Powder Metallurgy

Aluminum-based nanocomposites have been produced by mechanical milling, introducing silver nanoparticles within the matrix of a 7075 aluminum alloy using a high energy ball mill. The milled products were compacted by uniaxial load and pressure-less sintered under argon atmosphere, and finally hot extruded. Silver nanoparticles are well dispersed into the matrix of the powder particles as well as in the matrix of the extruded material. Transmission electron microscopy (TEM) analyses are used to corroborate and understand the hypothesis that second-phase particles finely and homogeneously dispersed in the matrix give greater strength to the material. In addition to the strengthening effect, the nanoparticles act like a process control agent (PCA) since the crystallite size of the nanocomposite is smaller at higher contents of nanoparticles.