The diversities in crystalline structure and the hierarchical features of the structures in metals lead to their distinguished deformation behaviour, elastic properties, magnetic properties, electric properties, mechanical properties, etc. In the research of metallic materials, the linkage of structure-processing-property is considered as the very important principle to understand the alloys. Following this basic principle, one can further design, select and assess suitable materials for a specific application. Over the last decades, based on multi-scale understanding of the metallic materials - from metre (components) to micrometre (grains and phases) and further down to nanometre (second phases and stacking faults), a number of extraordinary metallic materials have been successfully developed and commonly applied, e.g. ultra-strong steels for automotive and aerospace applications, orthopaedic medical materials, etc.

New material design concepts speed up the development of novel alloys with superior properties. For many newly developed steels, it is the fact that their microstructures can no longer be sufficiently described on the micrometre-scale, but a full description has to consider structure features on the nanometre-scale. With the recent development and application of the theoretical simulation tools and the advanced characterization methods, it has been found that it is necessary to understand the underlying mechanisms of phase transformations and deformation behaviours of the metallic materials at nano-scale, even atomistic scale and scale it up, so that one could figure out the key controlling parameters and to tune the materials properties.

This research work will present several nano-engineering concepts that offer new opportunities to design and engineer the novel metallic materials into hierarchical structures with tailored properties, in particular for bio-applications. The multi-scale characterization of the hierarchical features in metals in a correlative manner from atomic scale to millimetre scale will be focused. New methods that aid controlling the process of phase transformation during deformation and/or thermal treatment in the steels will be discussed.