be more fully integrated with research on performance and with engineering design of components or structures.

Industry-university collaboration should be strengthened. This is a particularly difficult challenge because much of the industrial base that traditionally has supported research in the performance of materials is in poor health. Industrial areas to which special attention should be paid in this regard include fossil and nuclear power technology, energy resource extraction, surface transportation, and the metals industry.

THE BROAD SCOPE OF RESEARCH IN THE PERFORMANCE OF STRUCTURAL MATERIALS

Research in the performance of materials seeks to predict and improve the way materials behave in service. The materials may be metals, ceramics, polymers, or any of the various alloys or composites that may be formed by combining such constituents. The example of performance research chosen here for detailed discussion is that of structural materials. One wants to know how such materials respond to stresses caused by service loading, mechanical contacts, or temperature variations; how they react to hostile, corrosive environments; and how they undergo internal degradation, e.g., by diffusive processes. The crucial issues are strength, reliability, durability, life prediction, and life extension. Such issues are relevant not just for the materials that are used in large structures or machines but also for those that form the structural elements in electronic, magnetic, or optical devices.

Research in performance involves all the conventional inputs that contribute to understanding relations between the structure of materials and their mechanical (and often chemical and electronic) response properties. It also involves understanding the means of manipulating structures to achieve desired properties and learning how properties, together with operating conditions, determine lifetimes. Here, structure refers not only to atomic structure of constituents and to the atomic bonding between phases, but also to structure at a variety of more macroscopic levels of organization that prove essential to understanding the strength of materials and their failure in service. These macroscopic structures include grains, preexisting cracks or pores, precipitates and inclusions that may contribute to strengthening but may also introduce cracks or voids, fibers embedded in matrices, and surface films or coatings.

Thus the relevant background for performance research includes not only the quantum mechanical concepts essential to understand matter at the atomic scale, and the thermodynamic, chemical, and kinetic concepts needed for understanding structural transformations, but also the more macroscopic concepts of deformation and transport that are relevant to processes that occur on the larger than atomic scales of materials microstructure. (The application



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement