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Materials Science and Engineering and National Economic and Strategic Security

This chapter examines the impact of materials science and engineering on U.S. society. The committee evaluated the impact of materials science and engineering by surveying its role in industries considered important for commerce and defense and then looking briefly at needs of the public sector, particularly of governmental units whose missions involve defense, energy, transportation, and space.

SIGNIFICANCE OF MATERIALS SCIENCE AND ENGINEERING IN INDUSTRY

Eight industries that represent different aspects of the use of materials were chosen to be surveyed, including the aerospace, automotive, biomaterials, chemical, electronics, energy, metals, and telecommunications industries. The scope of each of the eight surveys is shown in Table 2.1.

The surveys of the eight industries were carried out by people with senior management and technical responsibilities in their respective industries. Hence the results of the surveys are particularly important in two respects. First, they represent a sample of industry views regarding materials science and engineering and its impact. Second, they represent technical management views on how materials science and engineering should be structured by policymakers to fully exploit the opportunities that lie ahead. The results of the surveys show that materials science and engineering is viewed as vital by all eight industries. The idea also emerged that it is important for government to play a leadership role in helping to identify research areas of



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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials 2 Materials Science and Engineering and National Economic and Strategic Security This chapter examines the impact of materials science and engineering on U.S. society. The committee evaluated the impact of materials science and engineering by surveying its role in industries considered important for commerce and defense and then looking briefly at needs of the public sector, particularly of governmental units whose missions involve defense, energy, transportation, and space. SIGNIFICANCE OF MATERIALS SCIENCE AND ENGINEERING IN INDUSTRY Eight industries that represent different aspects of the use of materials were chosen to be surveyed, including the aerospace, automotive, biomaterials, chemical, electronics, energy, metals, and telecommunications industries. The scope of each of the eight surveys is shown in Table 2.1. The surveys of the eight industries were carried out by people with senior management and technical responsibilities in their respective industries. Hence the results of the surveys are particularly important in two respects. First, they represent a sample of industry views regarding materials science and engineering and its impact. Second, they represent technical management views on how materials science and engineering should be structured by policymakers to fully exploit the opportunities that lie ahead. The results of the surveys show that materials science and engineering is viewed as vital by all eight industries. The idea also emerged that it is important for government to play a leadership role in helping to identify research areas of

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials TABLE 2.1 Industries Surveyed in This Study Industry Scope of Survey Aerospace Airframe and engine materials (not electronics) Automotive Primarily automobiles Biomaterials Primarily materials used in contact with human body tissue Chemical Traditional chemicals, polymers, advanced ceramics Electronics Materials for computers, commercial and consumer electronics Energy Electricity, coal, oil, natural gas, nuclear, solar, geothermal Metals Production and forming of primary metals Telecommunications Materials for telephone and data transfer equipment national importance, so that materials science and engineering can be more fully exploited. The eight industries collectively employed 7 million people and had sales of $1.4 trillion in 1987 (Table 2.2). In addition, they were critical to many millions of jobs and to huge sales in ancillary manufacturing industries, for example, in the manufacture of materials for electronic applications that drive the computer hardware industry. TABLE 2.2 Economic Impact of the Eight Industries Industry 1987 Employmenta (thousands) 1987 Sales ($ billion) Aerospace 835 105.6 Automotive 963 222.7 Biomaterials – >50 Chemical 1004 195.2 Electronics 1394 155.4 Energy 1229 375.8 Metals 629 (1230)b 98.9 Telecommunications 1007 146.0 aThe statistics are taken from the U.S. Industrial Outlook 1989, published by the Department of Commerce, International Trade Administration, Washington, D.C. bThe 1980 to 1985 average based on a broader definition of the metals and mining industry used in Employment Prospects for 1995, Bulletin 2197 published by the Bureau of Labor Statistics, Washington, D.C. (1984).

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials The recent economic performance of the eight industries has varied widely. The U.S. metals industry, which is still very large, has declined significantly overall in employment and sales over the last decade. Nonetheless, in 1988 much of the industry was operating at capacity, and exports were once again on the increase. At the other extreme, the biomaterials industry, which started from a very small base, is in a period of very rapid growth. Table 2.3 shows the international trade balances for seven of the eight industries surveyed. The aerospace and chemical industries are healthy exporters and contribute substantially to the U.S. position in international trade. Although the trade balance for the chemical industry has declined somewhat as production of petrochemicals has grown in the Middle East and manufacture of synthetic apparel fibers has shifted to the Far East, this negative trend seems to have slowed recently. As is well known, imports of automobiles and petroleum have had an extremely negative effect on the U.S. balance of payments. A particularly worrisome trend is the decline in the trade balance for high-technology industries such as electronics and telecommunications. The biomaterials industry, in which the United States has a strong position, is omitted from the table because the industry is comparatively small. Of the eight industries surveyed, two are primarily producers of materials. The metals industry has a well-defined traditional role as a producer of bulk and formed metals. However, the chemical industry, which historically has been a supplier of bulk chemicals and polymers, is undergoing rapid change. American chemical companies are diversifying into biotechnology, materials for the electronics industry, ceramics, and specialty metals (such as amorphous metals prepared by rapid solidification techniques). In fact, they are becoming broad-spectrum producers of materials, with an emphasis on high-value products. To some extent, the growth of the biomaterials industry is occurring under the wing of the chemical industry. TABLE 2.3 International Trade Balances for Seven Selected Industries (billions of dollars) Industries 1982 1984 1985 1986 1987 Aerospace +11.1 +10.2 +12.3 +11.7 +15.1 Automotive –10.4 –20.7 –26.5 –35.8 –42.4 Chemical +12.4 +10.7 +8.5 +8.5 +9.3 Electronics +6.7 +2.5 +2.6 +0.6 –0.1 Energy –53.3 –52.7 –44.2 –30.8 –38.3 Metals –9.5 –12.9 –11.6 –9.6 –10.8 Telecommunications +0.2 –1.0 –1.2 –1.3 –1.7   SOURCE: Data are abstracted from U.S. Industrial Outlook 1989, published by the International Trade Administration, Department of Commerce, Washington, D.C.

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials The metals, chemical, and biomaterials industries are also consumers of materials. The processing equipment for metals and chemicals often requires materials resistant to high temperatures and to corrosive environments. New materials with outstanding resistance to heat and corrosion can be critical to the success of a new process technology. In the chemical industry, selectively permeable polymeric membranes are beginning to have an impact in new separation processes based on dialysis and reverse osmosis. In industries that might be considered primarily consumers of materials, the roles of materials vary widely. The aerospace, automotive, and energy industries are most concerned with structural materials, whereas the electronics and telecommunications industries emphasize development of materials that have an active function. Biomaterials generally serve both structural and functional roles. The more rapidly evolving segments of these industries are active in the development of new materials such as composites. The aerospace industry and, to a lesser extent, the automotive industry have a major interest in reducing the weight of their structural materials to increase fuel economy and performance. Although approximately half the cost of a modern aircraft lies in its electronic gear, reducing the weight of the airframe can significantly reduce the cost of its operation. There is a similar interest in high-temperature materials for highly efficient aircraft engines that will also decrease fuel consumption. Because of the large economic impact of improvements in these areas, the aerospace industry has become a major developer of advanced materials. The energy industry has many different segments with different materials needs. On the one hand, coal, petroleum, and natural gas production has only marginal, incremental needs for new materials. On the other hand, the fossil and nuclear power and solar energy segments can benefit greatly from materials with improved performance. New developments such as high-temperature superconductivity may have a profound influence on the production, transmission, and use of electricity. Because improvements in performance in the electronics and telecommunications industries are closely tied to improved electronic and optical properties of materials, these industries play a dynamic role in developing new materials and processes. The link to materials is especially close because fabrication of a semiconductor device, for example, often involves synthesis of functional materials in situ. The biomaterials industry is unique in that its products must be compatible with body tissue, and new materials must be approved for use by the Food and Drug Administration. These requirements present special challenges for materials developers. Some of the generic materials needs of the eight industries are summarized in Table 2.4. These needs, in turn, represent opportunities to improve the economic performance of the industries, as discussed below.

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials TABLE 2.4 Materials Needs of the Eight Industries Desired Characteristic Industry Aero. Auto. Bio. Chem. Elec. Energy Metals Telecom. Light/ strong ✓ ✓ ✓   High temperature resistance ✓   ✓   ✓ ✓   Corrosion resistance ✓ ✓ ✓ ✓   ✓ ✓   Rapid switching   ✓ ✓   ✓ Efficient processing ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ Near-net-shape forming ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ Material recycling   ✓   ✓   ✓   Prediction of service life ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ Prediction of physical properties ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ Materials data bases ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ These findings are consistent with the results of an international survey, discussed in Chapter 7, that clearly shows that many of the major trading partners of the United States have targeted research in materials science and engineering, along with biotechnology and computer and information technology, as one of three principal areas for special growth. They have also targeted specific areas within materials science and engineering for development in their nations. Aerospace Industry Scope of the Industry The aerospace industry is large and dynamic. In 1987, it employed 835,000 workers (a figure that doubles when supplier companies are included) and had sales of $105.6 billion (see Table 2.2). The industry has had a consistently positive balance in international trade, including $15.1 billion in 1987 (see Table 2.3). Despite the traditional technological leadership of the U.S. aerospace industry, however, extremely stiff foreign competition has developed. Beyond its role in the civilian economy, the industry is critical to the national defense. The survey of the aerospace industry covered both military and civilian airframe and engine production as well as materials needs for spacecraft. Electronic materials for aircraft applications were excluded from this survey, because they were included in the electronics industry survey. Role of Materials in the Aerospace Industry The aerospace industry is both a user and a developer of high-performance materials. Aerospace systems push structural materials capabilities to their limits.

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials The industry must constantly revise its practices to ensure continued system reliability and safety and structural integrity. Advanced materials such as composites are used extensively in military aircraft, helicopters, and business planes. In large civilian transport aircraft, the introduction of such materials is much slower (Table 2.5); they appear primarily in secondary structures. Broader use of composite materials will require large changes in design and in manufacturing plants. Advances in turbine airfoil materials are illustrated in Figure 2.1. The volume of materials consumed by the industry is not large (e.g., about 80,000 tons/year for large commercial aircraft), but the value is extraordinary. The cost of a commercial airframe is approximately the value of its weight in silver. The cost of a spacecraft approximates the value of its weight in gold. Because of these economic factors, substantial costs can be tolerated for materials that possess the desired combination of properties. Needs and Opportunities Some principal determinants in the selection of materials for the aerospace industry are life cycle cost, strength-to-weight ratio, fatigue life, fracture toughness, survivability, and reliability. Additional considerations for spacecraft include high specific stiffness and strength, a low coefficient of thermal expansion, and durability in a space environment. The payoff for successful materials development can be large. In a shuttlelike orbiter, for example, replacement of conventional aluminum airframes with currently unobtainable aluminum/silicon carbide or magnesium-graphite composites would yield a severalfold increase in pay load capability. Similarly, a major reduction in airframe weight could lead to an increase in fuel efficiency that would make an aircraft attractive to commercial airlines. Lifetime sales for a successful new generation of commercial transport planes could be expected to amount to about $45 billion. Conventional materials (e.g., metals, alloys, ceramics, and polymer composites) are approaching developmental limits in terms of properties for aerospace applications. This limit is based on fatigue (or service life) criteria TABLE 2.5 Use of Materials in Civil Transport Airframes   Percentage of Structural Weight by Year Material 1987 2000 (projected) Aluminum 71 55.5 Composites 7.2 24.8

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials FIGURE 2.1 Progress in casting techniques for turbine blades. Standard methods produce a polycrystalline blade (left). With directional solidification, the crystalline structure is oriented in the direction of the stresses encountered in operation, imparting greater strength and creep resistance to the blade (center). The blade on the right is a single crystal, which is even stronger. (Reprinted, by permission, from Bernard H.Kear, 1986, Advanced Metals, Sci. Am. 255:159–167. Copyright © 1986 by Pratt & Whitney Aircraft.) as well as on strength at elevated temperatures. Innovative research and engineering are needed to provide high-strength and/or heat-resistant ultralight structures for use in advanced subsonic, supersonic, and transatmospheric aircraft. Opportunities exist to develop and use composites of all types, including new alloys and intermetallics as well as multilithic composites such as metal matrix, ultrafine metal-metal, cermets, ceramic-ceramic thermoplastic, thermoset-thermoplastic, and molecular polymeric types. Designs must be modified to accommodate these materials in a cost-effective way. New metallic alloys such as aluminum-lithium, intermetallics like titanium aluminides, and high-temperature alloys derived from rapid solidification technology (e.g., aluminum-iron-vanadium-silicon) offer promising avenues for research on materials with good strength-to-weight ratios. Metal matrix composites are an especially ripe area for development, with applications in layered metal structures and especially in ceramic-reinforced metals.

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials Ceramics appear to be very attractive for high-temperature applications such as radiant burner tubes and leading edge structures for wings. With respect to polymeric materials, carbon-carbon composites retain high strength at high temperatures in hostile atmospheres. A wide range of properties for use at lower temperatures is accessible from combinations of polymeric binders and reinforcing materials. So-called molecular composites offer many opportunities. Stiff, strong, chemically compatible reinforcing materials continue to find increasing use in high-performance composites. This description of materials and the possible opportunities they offer strongly emphasizes composite materials and suggests the consequent requirement for major advances in our understanding of the chemistry and physics at the interfaces between dissimilar materials. In addition to this understanding at the molecular and microstructural level, major advances in processing and fabrication technology are required. The simultaneous development of materials, processing, and fabrication is essential if the new technology is to be used in an efficient and timely fashion. Cost-effective, high-quality processing technology is essential. Real-time, on-line process control systems, computer modeling, and advanced sensor development must complement fundamental materials science. As in other industries, materials development requires a systems approach encompassing materials preparation, processing, fabrication, quality assurance, and in-service monitoring. The research on processing must be coordinated among the aerospace users and developers and the materials suppliers who will ultimately produce the materials. Automotive Industry Scope of the Industry The production of automotive products is one of the largest components of the U.S. economy. The industry had sales of $223 billion in 1987 and employed about 1 million persons directly, as well as many others in supporting businesses. As noted below, the production of motor vehicles makes the industry one of the largest consumers of materials. The automotive industry is a major cause of the current U.S. trade deficit. In 1986, automobile imports cost $46.5 billion and resulted in a net trade imbalance of –$35.8 billion. Clearly, if these imported vehicles had been made in the United States or if there had been offsetting exports, the U.S. economy and the U.S. automotive and metals industries would have been much healthier. The international competitiveness of the automotive industry is crucial to the whole U.S. materials industry. The survey done for this study covered materials requirements for the production of cars, trucks, and buses in the United States.

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials TABLE 2.6 Use of Materials in the Automotive Industry in 1984 Material Percentage of Total U.S. Consumption Steel 17.5 Aluminum 16.0 Copper 9.7 Lead 59.0 Platinum 46.9 Zinc 26.0 Synthetic rubber 55.1 Natural rubber 76.6 Role of Materials in the Automotive Industry The production of motor vehicles consumes 60 million tons of metals, polymers, ceramics, and glasses per year. Table 2.6 lists the automotive industry’s share of total U.S. consumption of basic materials in 1984: As a consumer product, the automobile must be made from materials that are cheap and easy to process, and it must have long life and high reliability under extremely adverse conditions. In recent years, there has been additional pressure to make vehicles lighter in the interest of fuel economy. This new requirement has led to extensive substitution of aluminum and plastics for steel and heavy metals and has led to extensive changes both in vehicle design and in manufacturing processes. Needs and Opportunities Improvements in materials can have a large impact on the economic health of the automotive industry. One important need is the development of complete materials systems that take into account the cost of production and fabrication of a material along with specific design criteria. The survey identified four major needs that may be considered driving forces for automotive technology. These basic requirements and their implications for materials science and engineering are listed in order of priority in Table 2.7. A fifth requirement, reusability of materials, is significant because it also emerged in the metals industry survey as a high priority. Research Opportunities The survey identified R&D needs for 11 major classes of materials used in automobiles: sheet steels, specialty steels, structural plastics and composites, nonstructural plastics and composites, elastomers, paint, nonferrous

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials TABLE 2.7 Materials Needs for the Automotive Industry Generic Drivers of Automotive Technology Implications for Materials R&D 1. Need for reliability Emphasis on production of materials with minimal variation in properties and dimensions Emphasis on processes that can be used to convert materials to components with minimal variation in size and shape Development of processes simultaneously with materials Development of sensors and control systems of materials production and fabrication processes Development of materials data bases including variation of properties 2. Need for low cost Emphasis on low-cost (including energy) and in particular low-cost materials production systems Emphasis on development of materials that can be processed at low cost and emphasis on low-labor and high-throughput and low-waste process development Development processes simultaneously with materials Research on existing as well as “new” materials systems 3. Need for functional improvement Emphasis on weight-reducing materials Materials with improved conductivity and catalysis Development of functional characteristics and design studies simultaneously with materials and process development (a “materials” systems approach) Materials with improved sound absorption, toughness, transparency, dent resistance, etc. 4. Need for durability Research on durability-related failure mechanisms (wear, fatigue, and corrosion) Research on methods of predicting durability 5. Need for reusability Research on technical and economic factors in recycling wrought metals, castings, ceramics, tool and die materials, and metal matrix composites. Plate 1 illustrates where some of these materials are used in an automobile. Research is needed to increase understanding and accessibility of materials properties in all classes of materials, polymers and composites as well as metals. Predictive models for both properties and processing can have a significant impact. Intense R&D effort directed to composites could lead to a clear U.S. competitive advantage. The United States currently leads in this area but must work hard to maintain its lead. Ceramics have important roles as tool and die materials as well as in engine components such as turbo-chargers. Sheet steels, castings, plastics, and structural composites—particularly their processing—offer the largest potential opportunities to improve automotive technology.

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials Biomaterials Industry Scope of the Industry The biomaterials industry encompasses the design, fabrication, and manufacture of materials for the health and life sciences fields. It has been estimated that the industry has sales of over $50 billion annually and is growing at a rate of 13 percent per year. The industry’s products include disposable hospital supplies, artificial organs, personal care products, diagnostic devices, drug-delivery systems, and separation systems for biotechnology. Its participants range from operating divisions of Fortune 500 companies to small, family-operated businesses. The industry has a positive balance of payments in international trade. The United States has had a leading role in the development of the biomaterials industry and is a strong exporter, as exemplified by its dominant market share in the European Economic Community countries. To counter U.S. dominance, Japan, South Korea, Italy, and Sweden are moving aggressively to build their biomaterials and biodevice industries. The industry can be divided into market segments as follows: Artificial organs Biosensors (diagnostic devices) Biotechnology Cardiovascular and blood products Drug delivery Equipment and devices Maxillofacial prostheses, materials for plastic surgery Ophthalmology Orthopedics Packaging (including hospital supplies and consumer products) Wound management Role of Materials in the Biomaterials Industry The biomaterials industry develops, produces, and uses materials of extraordinary diversity. Currently used materials include synthetic polymers (degradable and nondegradable), water-soluble polymers, biopolymers, metals, ceramics, glasses, glass-ceramics, carbons, and biologically derived materials. Figure 2.2 shows artificial skin composed of a layer of silicone rubber and a layer of modified collagen. In specialized applications such as artificial organs, ophthalmic lenses, and specialty catheters, very high costs can be tolerated for materials whose physical and biological properties are satisfactory. However, consumable items such as hospital supplies and personal care products are price sensitive, and the cost of materials becomes a significant factor. Figure 2.3 shows a drug-delivery system that employs a microporous membrane to introduce drugs through the skin.

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials to about $16.1 billion; the service sector reported revenues of $130 billion. The downstream leverage of telecommunications is even greater—modern banking, airline travel, and commerce of almost every kind have been profoundly altered by the availability of inexpensive data manipulation and transport. Our modern information-based society results from a blending of the computer with telecommunications to provide the essential infrastructure for the information society. The telecommunications industry is being reshaped by governmental deregulation in the United States and many other countries. International trade is increasing rapidly. Since approximately half of the world market is in the United States, foreign companies are trying vigorously to enter the U.S. market. The United States imports substantial amounts of communications equipment, which resulted in an unfavorable trade balance ranging from about $1 billion to $1.7 billion per year for the period from 1984 to 1987 (see Table 2.3). Recent technology for data transfer and voice communication has blurred the distinction between the communications and the computer industries. The survey of the telecommunications industry emphasized the role of materials in equipment for telephone and data transfer operations. The findings parallel those of the electronic industry survey, except that a much greater role is played by optical technology in telecommunications. Role of Materials in the Telecommunications Industry The telecommunications industry is a major user and developer of new electronic and optical materials. In fact, it may be taken as a paradigm of a high-technology industry critically dependent on materials. As in the computer and electronics industries, most current devices are based on high-quality, dislocation-free, single-crystal silicon. The processing steps include masking, photolithography, diffusion, implantation, metallization, and etching. The packaging materials used to mount and seal the integrated circuits are commonly ceramics similar to those used in other electronic devices. Quartz is crucially important to the industry for devices used for frequency control. Synthetic quartz has allowed the United States to become independent of overseas suppliers and is superior to natural quartz in cost, availability, and quality. The shift from electronic to optical technology has required the development, production, and fabrication of many new materials. The development of new process technology resulted in silica optical fibers with transmission losses approaching the theoretical minimum. For optical emitters and detectors, III–V semiconductors are the materials of choice. Indium phosphide substrates with gallium-indium-arsenic-phosphorus epitaxial layers are used to generate radiation at 1.3 and 1.5 µm as input to optical fibers.

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials Needs and Opportunities The telecommunications industry offers outstanding opportunities in materials science and engineering as the industry shifts toward optical technology. The United States has been a leader in this area, but vigorous effort will be required to maintain our position. Achieving the economic opportunities inherent in the telecommunications industry is dependent on new materials. The modern central telephone office is essentially a large, special purpose, “switching” computer. A truly integrated optical switching system (all-photonic) with optical logic gates and memory could be much faster and cheaper than present electronic systems. It might be as great an advance as the electronic telephone office was over the electromechanical office. The materials challenges to an all-photonic switching system are massive. Fully optical devices are scarcely at a laboratory prototype stage. Many promising photonic phenomena have been demonstrated, but current understanding and methods are inadequate to produce an all-optical system. Improved materials and processes are needed to make integrated optics a technological reality. Even in electrooptic systems, in which electrical fields are used to switch light signals, circuitry on III–V semiconductors has reached only a rudimentary level of integration because materials capable of a full range of functions are not available. For electrooptic switching, lithium niobate is useful, but better electrooptic materials that allow more elaborate switching circuits on smaller substrate areas would make this technology advance rapidly. In the transmission of optical signals, silica-based optical fibers are approaching the theoretical limits of performance. If improvements in fiber transmission are to be made, new materials, possibly mixtures of metal fluorides, will be needed. In principle, fibers of these materials could provide transoceanic communications without repeater units because the optical losses are so low. Conversion to fluoride fibers will require new light sources and detectors, because transmission frequencies will move further into the infrared region. A variety of new technologies will be needed if silicon very large scale integrated (VLSI) circuits are to be pushed to the limit of approximately 0.1 µm features. New families of photoresists, improved dry processing, new dielectrics, and new metallization technology will be needed. Research Opportunities and Issues Progress in the telecommunications industry has been a direct consequence of materials synthesis, processing, characterization, and analysis. Exceptionally promising areas for continued progress are superlattices, fibers, high-

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials temperature superconductors, and neural networks (with circuitry analogous to that in the brain). With techniques such as molecular beam epitaxy, precise control of semiconductor layers has been achieved. Despite this precision in fabrication, the chemistry and physics at the interfaces are scarcely understood. Multiple quantum-well structures have opened a new area of physics and have great potential for use in devices. The growth of III–V semiconductors on silicon and of II–VIs on III–Vs offers exciting new possibilities. Germanium-silicon superlattices may afford the opportunity to develop lasers and detectors based on silicon. Optical fibers are now made at the theoretical loss limit. Devices such as Raman and Brillouin amplifiers and stress optic-effect sensors in which interaction lengths can be as long as kilometers should be possible. Single-crystal fibers of niobate, garnet, sapphire, and other oxides have potential, and electrooptic applications may follow. Current research results on high-temperature superconductors are truly unprecedented. Although the fabrication of these oxide materials into useful configurations may be difficult, the promise of the materials is enormous, especially in tunneling technology and high-speed data busses. In addition, biological information storage and retrieval systems hold great fascination. Addressing and reading out molecules are formidable tasks, but the scanning tunneling microscope may prove to be a useful probe. SIGNIFICANCE OF MATERIALS SCIENCE AND ENGINEERING FOR THE PUBLIC SECTOR Government—federal, state, and local—is critically dependent on materials in fulfilling its many missions related to defense, energy, transportation, space, and safety. While the materials science and engineering needs of the federal government are very diverse, they can be broadly divided into two regimes that often present quite different demands—one associated with providing new systems that can perform at the leading edge, and the other associated with incrementally improving the performance of existing systems. Needs for leading edge systems exist in such programs as the strategic defense initiative and the national aerospace plane. In addition, more conventional planes need to fly faster and higher; submarines need to be faster and quieter and to have greater range; aircraft interiors should not burn following a crash; and computer capability is a frequent limitation in the ability to describe the behavior of complex systems and structures. In these and similar areas, successful development frequently depends on materials that have specific and definable characteristics either through inherent electrical, structural, or thermophysical properties or through engineering design that compensates for limitations of materials. While these demands are often

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials difficult to achieve, the mission requirements present clear goals that the materials must meet. Incrementally improving existing systems involves meeting numerous demands and setting goals that are often difficult to specify. Many federal units—including the Department of Defense (DOD), Department of Energy (DOE), Department of the Interior (DOI), Department of Transportation (DOT), Department of Health and Human Services (DHHS), National Aeronautics and Space Administration (NASA), and the regulatory agencies—are concerned with achieving optimum use and extended life of state-of-the-art structures, vehicles, processes, and devices. Many of the issues are common to several agencies. Corrosion limits the performance of ships, aircraft, bridges, concrete reinforcement, mining and drilling equipment, and vehicles of all types. The fuel efficiency of all vehicles can be improved by the use of lightweight materials. Energy availability and acceptability depend on developing reliable processes that are cheaper and less polluting than current processes. The useful lifetime of vehicles, tracks, roads, and structures can all be influenced by nondestructive testing methods. In common with industry, the federal government needs improved generic techniques, such as synthesis and processing, and new techniques for the evaluation of performance. There are, however, significant differences in the impact of materials on the public sector and the private sector. Most importantly, national security is often a motivating factor for governmental involvement in materials science and engineering. The federal government devotes a large share of its materials R&D budget to the development of high-performance and high-cost materials for military applications that do not have a large impact on the civilian sector. The implications of this emphasis on defense-related needs are discussed in Chapter 7. The following sections deal with materials requirements of four government units, illustrating needs for materials in the four areas of defense, energy, transportation, and space. Department of Defense Since the end of World War II, the United States has adopted the strategy that it will use technology to offset the numerical advantage that the Warsaw Pact nations have in manpower and conventional weapons. Materials science and engineering is intimately involved in maintaining the technological lead inherent in this policy. The broad range of activities covered under the mission of DOD demands high performance from an exceptionally broad range of materials. Although hardware for weapons systems such as ships, tanks, and planes is most visible, materials for construction of buildings, roads, and runways; electronic and optical materials for communication and control; and clothing for climate

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials and environmental protection are indispensable for many missions. Performance is, of course, paramount; but because the most severe demands occur during infrequent crisis situations, other considerations such as availability, reliability, and durability are important. Environmental protection is often necessary, and provisions for in-service inspection or evaluation are essential. To provide more effective weapons and to minimize the risk to personnel, weapons systems are constantly provided with more intelligence. This intelligence requires microelectronics, sensors, displays, and software systems. Artificially structured materials and artificial intelligence are just two examples of areas in which research efforts support the diverse needs of the military. In addition, present and future weapons systems are carefully examined to identify performance or economic issues that are limited by the capabilities of existing materials. When deficiencies are found, research programs are initiated to eliminate these limitations. The use of lightweight carbon-epoxy composite materials in military and civilian aircraft is an outgrowth of such an evaluation by the Air Force. Many of the materials needed by DOD are unique to military applications. Therefore the development process must include the processes for producing materials, often to exacting tolerances. Strong attention is thus paid to manufacturing techniques. Although DOD maintains numerous specialized laboratories and weapons centers, most of the actual R&D on new weapons systems is done by private contractors working under DOD direction. Many basic research programs in areas related to defense needs are carried out through contracts with universities. Department of Energy The Department of Energy has a mission that is much broader than its name suggests. It is responsible not only for R&D in support of advanced energy technologies and energy conservation, but also for the design, development, and production of nuclear weapons. It is therefore concerned with issues that are critical both to defense and to the economic well-being of the civilian sector. Materials issues affect most DOE activities. DOE supports a large basic research program that provides scientific support for the energy technologies that are longer range than those described earlier for the energy industry. Examples of such long-range technologies are fusion power, advanced fission reactors, and improved techniques for coal conversion and combustion. Many of these new technologies are used in very severe environments that place unusual demands on materials. The Department of Energy is also concerned with energy conservation

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials issues, some of them near-term and others involving the development of longer-term technologies. These often involve materials and include establishment of standards for usage, development of new materials, and development of new systems that use both new and traditional materials. In the case of new energy sources for transportation, a major effort is under way to develop efficient electric vehicle power systems, including new and revolutionary batteries, new fuel cells, and ceramic turbines. The Department of Energy is also charged with assuring that the United States continues to have the capability to maintain a credible nuclear deterrent, which includes the design and certification of new weapons and their production in stockpile quantities. For nuclear weapons to be a deterrent, they must threaten those targets that an enemy considers essential. Thus, as an enemy’s strategy and its related targets change with time, so must the capabilities of our nuclear weapons, a condition that often requires development and qualification of new materials. For example, earth penetrator or nuclear-directed energy weapons present severe materials challenges. Hardening of weapons systems against enemy attack must be considered as well. Economic and environmental forces also have an impact on weapons research; for example, improved processing technologies for plutonium are required to reduce the amount of transuranic waste produced. The safe disposal of radioactive waste presents a series of unusually difficult and challenging materials problems. The Department of Energy maintains several large national facilities for materials research, such as the National Synchrotron Light Source and several centers for neutron scattering research. Much of the short- and long-term research on materials is carried out in the multidisciplinary national laboratories supported by DOE. Department of Transportation The major needs of DOT are reflected in two mission requirements: enhancement of the safety of all modes of transportation and promotion of the efficiency of the transportation system. Improving the safety of the air traffic control system; ensuring the safety of bridges, pipelines, and ship hulls; establishing standards for performance of vehicles used in transportation; and providing for the safe transport of potentially dangerous substances all involve materials in a variety of ways. Improving the efficiency of the transportation system also involves materials and materials systems. The efficiency of the vehicles that move along the nation’s highways, airways, waterways, and railways is continually being improved as a result of the introduction of new materials into their power plants and structures. The efficient operation of the transportation system also depends on the ease with which freight and humans are transferred to

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials vehicles. Efficient transfer depends significantly on the creation of efficient interfaces between the various modes of the transportation system. Since these interfaces are frequently concerned with handling materials, they also are critically dependent on the progress that results from research on materials. It is also worth noting that the need for control of large amounts of information, often in real time, places increasing demands on the control systems and the computers that support these systems. From the materials science and engineering perspective, the main materials of interest can be classified according to type and weight. They are (1) bulk materials such as concrete, asphalt, and aggregate, which form the over-whelming percentage of the weight of railbeds and roadbeds; (2) structural metals (primarily steel), which perform critical structural functions in the form of rail tracks, railcars, bridges, ships, pipelines, and concrete reinforcement and in new metal alloys and reinforced plastics that are being used increasingly in aircraft and ground vehicles; and (3) specialized materials such as polymeric materials used for protective clothing, coatings, adhesives, and vehicle interiors and exteriors. Although the relevant missions of DOT have been categorized as safety and efficiency, these two functions are clearly intertwined. Deterioration, when unchecked, leads either to unsafe conditions or to less than optimal use of infrastructure capacity. Overall evaluation of the needs and opportunities for research in the U.S. transportation sector indicates that new materials technologies offer substantive possibilities for improving all areas related to the transportation infrastructure. National Aeronautics and Space Administration The National Aeronautics and Space Administration is charged with assuring that the United States remains a preeminent world power in space science, space operation, and space exploration, and with creating the necessary research and technology bases needed for the United States to maintain a competitive position in civilian and military aeronautics. Materials issues pervade all aspects of NASA’s mission. Many of the challenges are unique and particularly difficult. Special emphasis is placed on weight reduction to enhance pay load capabilities. This includes not only lightweight materials, but also innovative processing and design concepts that can reduce weight while maintaining the desired level of performance. High-temperature materials are required to enhance fuel efficiency in combustion and to ensure protection during reentry. Cryogenic materials and insulation are needed for containment of cryogenic fuel and liquid oxygen. High-efficiency energy sources for space applications present critical materials problems. Environmental conditions include the high-vacuum conditions of outer space and the effects of atomic oxygen encountered in low

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials earth orbit. Reliability is an important issue, since maintenance is often difficult or impossible. NASA is also responsible for exploring effects of the space environment, including microgravity, on materials processing. The National Aeronautics and Space Administration also has a special role in assuring the continuing availability of advanced technology for ground-based aeronautics systems. This includes concern with improving the efficiency of turbine engines, the design of low-noise, high-thrust turbines, the examination of new structural designs that increase lift and reduce weight, and the development of new avionic systems that improve reliability and provide needed assistance to their human operators. Materials issues thus are of critical concern to the mission of NASA. Economics, safety, and performance all depend on innovative use and development of materials. To meet the myriad demands for advanced sensors for earth-based and planetary missions; for on-orbit and deep space power; for micro- to mega-thrust propulsion systems; for extraterrestrial structures and vehicles; and for improved airframes and propulsion systems for the commercial aircraft industry, NASA supports a wide spectrum of materials research in its in-house laboratories and through contracts with industry. NASA also maintains a wide range of unique test facilities that are used by government and industry for the evaluation and testing of new designs and concepts. FINDINGS The surveys of the eight industries show critical needs of these industries for new, improved, and more economical materials and processes. Similar needs are evident in the public sector in areas including defense, energy, transportation, space, and health. Some important crosscutting materials needs are summarized in Table 2.4. An overriding theme for all the industries surveyed was the primary importance of synthesis and processing of new materials and traditional materials, and fabrication of these materials into useful components and devices. Materials science and engineering, and processing in particular, plays a uniquely important role in these industries and in their ability to help maintain and improve the U.S. position in international competitiveness. In every industry surveyed, there is a clear need to produce and fabricate new and traditional materials more economically, and with higher reproducibility and quality, than is done at present. The opportunities in synthesis range from preparation of totally new materials to development of methods for recycling scrap metals and polymers. For all materials, there is an acute need for better ways to produce objects in shapes approaching the desired final form (near-net-shape forming). Equally important is a need for ways to determine the quality of products on the production line and to feed back

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials the information to operators in real time. Computers and computer modeling are beginning to play an important role in this area and are also reducing the time needed to take new materials, processes, and designs from the laboratory to the production floor. Throughout manufacturing, the integration of synthesis, processing, fabrication, and testing is a challenge to materials science and engineering. Industry needs in other areas of materials science and engineering are also evident from the industry surveys outlined above. These include needs for new materials with new properties, especially composites, and new materials synthesized at the nanostructural level. Outstanding opportunities exist to improve the production and use of materials through computation as a complement to experimentation. A challenge is to use our understanding of structure, bonding, and properties to develop predictive models from the behavior of materials in use. There is a critical need for better ways to predict the mechanical behavior and useful lifetime of materials and objects in various applications. Another theme that emerged in some of the industry surveys was that the federal government should help to identify industries of current or projected strategic national importance. Such identification should then influence the emphasis and direction of major national research activities. It was also felt that the government should play a role in helping to bring industry, universities, and federal laboratories together to address these research priorities. The industry survey participants saw a number of opportunities to improve the effectiveness of the various institutions involved in materials science and engineering. Their views, and those of the committee as a whole, represent important themes of this report and are as follows: Industry clearly has the major responsibility for maintaining the competitiveness of its products and its production operations. Greater emphasis on materials science and engineering and, in particular, on integration of materials science and engineering with other business operations is necessary to improve the competitive positions of U.S. firms in domestic and international competition. The incentives (e.g., money and prestige) for top-quality people to become involved in production should be increased. Intelligent collaborations with researchers in the universities and in government laboratories can enhance the effectiveness of R&D in industry. Industrial consortia can provide a mechanism to conduct R&D programs too large for any one company. Universities traditionally have had a dual role in educating personnel for industry and in conducting innovative fundamental research. The universities can promote the general welfare through encouragement of the interdisciplinary teaching and interdisciplinary research characteristic of materials science and engineering. Both industry and the nation need materials

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials scientists and engineers broadly trained in the range of disciplines needed for effective research, development, and production. Greater emphasis is needed on teaching and research relevant to processing and manufacturing operations. Universities will often provide the best sites for the science and technology centers discussed below. Government laboratories, which include hundreds of laboratories funded by federal and sometimes by state governments, have many capable employees and large capital resources that could benefit industry. The DOE-funded national laboratories, in particular, have many scientists and engineers with special talents in materials science and engineering. Reorientation of the missions of the national laboratories toward industrial materials science and engineering interests could have a valuable effect on U.S. industrial competitiveness. (The role of the National Institutes of Health laboratories as an asset to the pharmaceutical industry is illustrative.) To be effective in helping industry, federal R&D must be directed intelligently to problems of genuine interest to industry. Exchange of personnel between industry and the government laboratories would help focus the work and assist technology transfer. The federal laboratories, especially the National Institute for Standards and Technology in its new role, could play a valuable role in establishing test procedures, setting standards, assembling data collections, and transferring technology to industry. Centers, including the materials research laboratories and engineering research centers funded by the National Science Foundation, play an important part in bringing together people from the many science and engineering disciplines that constitute materials science and engineering. Likewise, centers can be a focal point for bringing together people from universities, industry, and government laboratories in materials science and engineering programs of mutual interest. This combination of many talents and the extensive instrumentation and equipment available in a center can be extremely effective in advancing R&D programs. Relevant models exist in the interdisciplinary teams at large industrial laboratories and at the Max Planck and Fraunhofer Institutes in West Germany. As with the national laboratories, significant input from industry will be needed to direct centers in work relevant to industry. Consortia of industrial research groups, such as the Microelectronics and Computer Technology Corporation and the Semiconductor Research Corporation, and consortia in steel, machine tools, and components may play a significant role in preliminary research on new technologies such as “beyond VLSI” circuitry. There are few U.S. models of demonstrated effectiveness. Industrial consortia guided by the Ministry of International Trade and Industry seem to be effective in Japan but need refinement as models for U.S. use. Leadership and initiative to establish such mutual materials science and engineering ventures should be encouraged.

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Materials Science and Engineering for the 1990s: Maintaining Competitiveness in the Age of Materials People who are well trained and well motivated, and who have effective leadership skills, are the basis for success in any technological endeavor. The universities, industry, and government all have important roles in ensuring the availability and intelligent employment of materials science and engineering personnel. Communication and personnel interchange are fundamental to successful technology transfer within a company or between institutions. All parties in materials science and engineering should work to encourage communication and a sense of community in ventures aimed at enhancement of U.S. industrial competitiveness.