Microstructural, physical, and mechanical characteristics of bulk nanocrystalline copper synthesised using powder metallurgy

Abstract

In the present study, elemental Cu powder was mechanically milled to reduce the grain (crystalline) size to the nanorange (< 100 nm). The powder was consolidated by die cold compaction. Omitting the sintering process, the powder compacts of 10 h mechanically milled powder and elemental powder without mechanical milling (0 h mechanically milled) were hot extruded at different temperatures to maintain a crystallite size within the nanoregime. Characterisation revealed that samples with relatively lower grain size (63 nm/10 h mechanically milled) exhibited reduced density and ductility, similar dimensional stability, and significantly enhanced hardness, 0·2% yield strength, and ultimate tensile strength. Particular emphasis was placed on correlating the properties of the samples with their microstructural features.