Lead academic: Dr A Chrysanthou
Research Fellow: Dr Z Zhang
Funding body: EU under FP6
Period: October 2004 – January 2008
The project deals with the formation of metastable structures through high temperature processing, and their evolution into nanocrystalline materials by suitable thermal treatments at moderate temperatures, giving rise to structures with crystal size in the range 20–50 nm. In the metastability approach the traditional way of obtaining nanocrystalline materials from nanopowders is reversed.
While usually the thermal treatment could induce grain growth of the nanocrystals, in this case it is exploited to effectively achieve nanostructures. The main goal is the definition of a protocol for the correlation Metastability–Nanostructured materials–Properties.
The proposed approach is conceived so as to develop metastable structures for a set of systems representative of all the possible classes of nanomaterials: Al2O3–TiO2 and ZrO2–Al2O3 for structural ceramics; TiC–TiB2 for wear parts; Ti–Al2O3 for mechanical components; NbAl3 for turbine and power station systems; Ni–Ti SMAs for functional- and bio-materials.
The achievement of metastable structures is pursued through purposely-modified processes, like thermal spraying and combustion synthesis followed by rapid quenching of the powders in appropriate liquids. Both routes are S&T intensive and can yield nanocrystalline materials in powder, coating and bulk form.
The metastable nanopowders can be consolidated into nanostructured bulk materials by means of both conventional processes and advanced densification techniques like spark plasma sintering, high velocity forging/extrusion and dynamic compaction.