Microstructural characterization of a silicon carbide whisker reinforced 2014 aluminum metal matrix composite

Microstructural development in a powder metallurgy 2014 aluminum alloy -SiC whisker composite subject to controled and systematic aging treatments was investigated using analytical transmission electron microscopy and matrix microhardness measurements. In order to build a basis for comparison, the precipitation characteristics of the unreinforced matrix material with an identical processing history were also examined. The results indicate that the matrix of the composite material has a much greater density of dislocations than the control alloy. This high density of dislocations is due to the substantial difference on thermal expansion of Al matrix with respect to the SiC particles. (orig.)