Nanocrystalline materials have improved mechanical and electrical properties in comparison to their microcrystalline counterparts due to their reduced crystallite or grain size. Loss of these unique properties due to grain growth under the affect of high temperature and stress are a limitation to their use in potential applications. This issue of grain boundary stability has been under discussion for several years. Recently it has been proposed to use dopants (alloying elements) to reduce the system energy leading to improved microstructural stability and resistance to deformation. Also, inclusion of dopants has shown to alter properties of nanocrystalline materials. Recent molecular dynamic studies have reported that deformation mechanisms in nanocrsytalline materials are dominated by grain boundary sliding, grain rotation and grain coalescence rather than traditional dislocation nucleation and movement although this observation depends strongly on grain size. In this review article, work done in the domain of stability of crystalline materials using dopants and their application in nanocrystalline materials and the role of molecular dynamic simulations is discussed. Also, recent reported deformation mechanisms of pure and doped nanocrystalline materials mainly copper, aluminum & nickel under monotonic and cyclic loading using molecular dynamics simulations will be discussed.
Journal: TechConnect Briefs
Volume: 4, Technical Proceedings of the 2007 NSTI Nanotechnology Conference and Trade Show, Volume 4
Published: May 20, 2007
Pages: 543 - 546
Industry sector: Advanced Materials & Manufacturing
Topicss: Advanced Manufacturing, Nanoelectronics