Structure and plastic deformation of metastable Ag–Cu metal-matrix composites produced by a bottom-up way from Cu@Ag core–shell powders

Abstract

To understand mechanical behavior of metastable metal-matrix composites, Cu@Ag core–shell powders of two compositions, 51:49 and 80:20 (Cu:Ag in wt%), were compacted by spark plasma sintering. The microstructures of these metastable metal-matrix composites are characterized by single spherical particulates of pure Cu in the matrix of pure Ag in the former case while by aggregates of Cu particulates in Ag matrix in the latter one. The plastic deformation showed enhancement of the ultimate tensile strength compared to both pure component metals by a factor of ca. 3. It is shown that a part of plastic deformation can be correlated by a logarithmic dependence but a possibility to apply a polynomial (quadratic) correlation is suggested. As expected, the shape of the particulate changes during plastic deformation and depends on the level and type of the plastic deformation. A model is proposed showing that this dependence is of a hyperbolic character.