This book focuses on the emerging class of new materials characterized by ultra-fine microstrucures. The NATO ASI which produced this book was the first international scientific meeting devoted to a discussion of the mechanical properties and deformation behavior of materials having grain sizes down to a few nanometers. Topics covered include superplasticity, tribology, and the supermodulus effect. Review chapters cover a variety of other themes including synthesis, characterization, thermodynamic stability, and general physical properties. Much of the work is concerned with the issue of how far conventional techniques and concepts can be extended toward atomic scale probing. Another key issue concerns the structure of nanocrystalline materials, in particular, what is the structure and composition of the internal boundaries. These ultra-fine microstructures have proved to challenge even the finest probes that the materials science community has today.

In an attempt to meet the demand for new ultra-high strength materials, the processing of novel material configurations with unique microstructure is being explored in systems which are further and further from equilibrium. One such class of emerging materials is the so-called nanophased or nanostructured materials. This class of materials includes metals and alloys, ceramics, and polymers characterized by controlled ultra-fine microstructural features in the form oflayered, fibrous, or phase and grain distribution. While it is clear that these materials are in an early stage of development, there is now a sufficient body of literature to fuel discussion of how the mechanical properties and deformation behavior can be controlled through control of the microstructure. This NATO-Advanced Study Institute was convened in order to assess our current state of knowledge in the field of mechanical properties and deformation behavior in materials with ultra fine microstructure, to identify opportunities and needs for further research, and to identify the potential for technological applications. The Institute was the first international scientific meeting devoted to a discussion on the mechanical properties and deformation behavior of materials having grain sizes down to a few nanometers. Included in these discussions were the topics of superplasticity, tribology, and the supermodulus effect. Lectures were also presented which covered a variety of other themes including synthesis, characterization, thermodynamic stability, and general physical properties."