Nanoengineering of metallic materials

Nanoengineering, by definition, is the science and technology involved with modifying or manipulating the microstructure of bulk materials on a nanoscale. Such materials may display enhanced mechanical, physical, or chemical properties, and hence nanoengineering is of paramount importance to the evolution of new metallic materials. Rather than dealing with milligrams or grams of material, tones of materials are processed, at prices that are economical and sustainable for modern manufacturing. This chapter discusses the principles underlying the nanoengineering of metallic materials in terms of those criteria that have the most significant effect on the mechanical properties of metals and alloys—namely, the effect of grain size and the role of obstacles that retard deformation by the process of crystallographic slip. It discusses relationships between processing, microstructure, properties, and cost and presents an introduction to manufacturing routes used in the processing of metallic materials. It also describes four examples in which microstructures are manipulated on the nanoscale in order to improve properties. These examples are concerned with the precipitation strengthening of aluminum alloys, the development of high strength low alloy steels, mechanical alloying, and rapid solidification processing.