Processing of mechanically alloyed aluminum powder: A metallographic study

Elemental aluminum powder was mechanically alloyed, and then consolidated to produce bulk powder metallurgy parts. Consolidation was carried out either by a double cycle of cold pressing and sintering or by a single press-and-sinter technique. In the last case, sintering was assisted by blending the as-milled aluminum powder with a silicon-base powder, as sintering aid. The focus of this paper is on the influence of processing variables upon structural characteristics and properties. Samples consolidated with the silicon additive show a duplex microstructure consisting of soft islands of a minor structural constituent embedded in a hard matrix. Parts consolidated by any of the two methods attain a tensile strength of around 250 MPa and an elongation to failure of roughly 7.5%.