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Mechanical Behaviour of Nanostructured Materials: Role of Structure, Defects and Microstructure
Mechanical behaviour of bulk materials, and especially the role of dislocations and interfaces in plastic deformation and failure, is altered significantly for systems at small length scales. Metals such as aluminium, which typically do not deform by stacking fault extension or twinning, do so when the grain size is reduced to nanometer scales. With advances in micro- and nano-electronic technology, materials at small length scales (ranging from 5 nm to 500 nm) are ubiquitous: nanoparticles, thin wires, thin single crystal films and thin polycrystalline films with nanosized grains. The mechanical behaviour of small systems is a field of intense contemporary research both experimentally and theoretically. While a detailed understanding of the mechanical behaviour of systems at small length scales is still under development, it is recognized that interfaces and their motion play a far more significant role in such systems than they do in bulk systems in such diverse phenomena as plastic deformation, annealing, superplasticity, recrystalization, grain growth and fracture. In this project, we will use atomistic simulations to study grain boundaries with a view to generating a firm, quantitative understanding of anisotropy effects. These simulations will provide detailed data, in particular, on the anisotropy in these fundamental properties. These data will form the input to phase field simulations of evolution of microstructures in systems with anisotropic GBs. The scope of this work is to develop a multiscale strategy bridging multiscaling methods which can be used to engineer grain boundaries via processing to expand the range of applications. |