Copper can be stronger, but retain ductility

Research undertaken at the Technical University of Denmark, in association with the Shenyang National Laboratory for Materials Science and the Chinese Academy of Sciences, has shown that it is possible to produce copper which is four times stronger than commercially available material whilst retaining ductility.

According to the researchers, because the thermal and electrical conductivity of the metal are also good, the development holds the prospect of manufacturing of conductors with improved mechanical properties. The work examined the concept that the strength of a metal depends on its microstructure; the finer the structure, the stronger the metal. The researchers also addressed whether this fundamental principle also applied to extremely fine structures. Although similar work has been undertaken around the world, the Chinese-Danish collaboration is said to have made a breakthrough. As expected, the strength of copper material was seen to increase when the structure becomes finer. But when the structure dimension became smaller than 15nm, the metal became unexpectedly softer. The physical processes giving rise to this softening have been identified using electron microscopy.