Materials in the New Millennium: Responding to Society's Needs (2001)

The third topical session examined the role of materials in national security. The overview talk in this session was presented by David O.Swain of the Boeing Company. Dr. Swain is president of Phantom Works, Boeing’s research and development organization. Before the merger of Boeing and McDonnell Douglas, he held a variety of positions at McDonnell Douglas, starting in 1964 as an engineer on the manned Gemini project. His goal for Phantom Works is to advance Boeing’s competitiveness through technology development, process improvement, and new product development, with a special focus on making products more affordable and more capable.

C.Paul Robinson presented next. Dr. Robinson is president of Sandia Corporation and laboratory director of Sandia National Laboratories. He spent most of his early career as a physicist at Los Alamos National Laboratory, where he led the laboratory’s defense programs. From 1988 to 1990, he served as the chief negotiator and head of the U.S. delegation to the U.S.-U.S.S.R. nuclear testing talks in Geneva. Dr. Robinson is a member of the National Academy of Engineering.

Maxine Savitz of Honeywell was the next speaker. Dr. Savitz joined Honeywell (previously AlliedSignal) in 1985. From 1987 until June 1999, she was general manager of AlliedSignal Ceramics Components, the only U.S.-owned manufacturer of silicon-nitride structural ceramic for gas turbine applications. She is currently general manager for technology/partnerships. Prior to joining Honeywell, Dr. Savitz was with the Department of Energy and its predecessors, where she was deputy assistant secretary for conservation for four years. She is a member of the National Academy of Engineering and a former member of the National Materials Advisory Board.

Lewis E.Sloter II of the U.S. Department of Defense gave the view from the Pentagon. Dr. Sloter is the Department of Defense staff specialist for materials and structures and is currently assigned to the Office of the Deputy Under Secretary (Science and Technology). He is responsible for technical oversight of Defense Department science and technology activities in materials, processes, and structures and for technical assessments associated with materials manufacturing and engineering applications.

The session ended with a panel discussion. The following are summaries prepared by the editors who adapted them from the remarks made by the individual presenters.

The aerospace industry is a giant. Boeing has more than 6,000 military planes in the field, and more than 10,000 commercial craft. Each day 3 million people fly on 43,000 flights on these planes. Over the past 50 years,

the challenges facing the aerospace industry have changed significantly. Initially, performance was the focus of both customers and manufacturers. Beginning in about 1982, the focus of customers changed to value— obtaining the same or better value at reduced cost—but until 1987, the industry stayed focused exclusively on performance, resulting in an imbalance between customer and supplier. Since 1997, customer and supplier have converged again, this time aiming for reduced cost, equal or better performance and quality, and shorter cycle time.

To reduce cycle time and cost, the aerospace industry has relied on innovative technologies, such as three-dimensional modeling and simulation and integrated tool sets. One example is the Delta IV launch vehicle, the first new U.S. rocket in 25 years. During the development of this rocket, various trade-offs were carefully considered, including trade-offs among requirements and between cost and performance. The result of paying so much attention to these issues was a shorter than historical development time, half the historical development cost, and a reduction in the parts count by 70 to 80 percent. The launch vehicle makes extensive use of technology that was previously demonstrated on other platforms, such as friction stir welding (which ultimately resulted in inspection-free joints) and cast titanium (which reduced cycle time and cost).

Another example is the C-17 transport plane, for which McDonnell Douglas originally won the contract in 1981. The secrets of this project’s success include the use of fiber-reinforced composites and high-speed machining. Particular attention was paid to designing the tail section for affordability, leading to a new horizontal tail made of composite and metal, with a 20 percent weight reduction and an 80 to 85 percent part reduction. Paying extremely close attention to cost, especially in the high-cost areas, led to other improvements. For example, the aircraft contains more than 43,000 fasteners, each of which originally required wetting before installation. The introduction of prewetting saved $2 million.

On a cautionary note, the aerospace industry is reaping the rewards of 10 to 20 years of technology development. At present, only incremental improvements are being pursued vigorously because of the perception that technology leads only to improved performance, which is not currently in as much demand as are reduced cost and cycle time. We must remember that science and technology are also key to lower cost and cycle time for both defense and commercial aviation. For this reason, we need continued investment in the science and technology base. Science and technology make products more affordable.

Our national security concerns have changed profoundly in recent years. The Cold War has ended, and we find ourselves in a multipolar, rather than bipolar, world. Rogue states and groups have appeared. New threats, such as chemical and biological agents, are of great concern. The terrorist chemical

attack on the Tokyo subway in 1995 sounded a warning of this change. Had the temperature been a few degrees different, several thousand people could have died, with no prior warning or appropriate emergency response.

Meanwhile, the arsenal we rely on for our national security continues to age. New capabilities are being added in some areas, but other parts of our defense are slated to remain in service many decades past their original design lives. The nuclear stockpile is one example. Another is the aging of our aircraft, both military and commercial, as illustrated dramatically by the Aloha Airlines disaster in 1988.

To address these issues, we need new approaches to detecting, identifying, and neutralizing new threats and to certifying the continued performance of the aging components of our national defense system. New materials and processes will be critical to these tasks. For example, detection and identification will require systems that are smaller, more highly integrated, and more complex than have ever before been fielded. Here are some examples of materials and processing needs:

• New materials, such as amorphous diamond, with the wear resistance of crystalline diamond as well as tailorable stress characteristics. This material may be useful in ultrareliable microsystems that perform either mechanical or sensing functions.

• New ways to process materials that, for example, result in entirely new surface properties through new ion beam processing techniques or that allow incorporation of motion into silicon devices to enable microelectromechanical systems (MEMS) with the same reliability, low cost, and high functionality that we take for granted in silicon-based microelectronics.

• New ways to integrate materials into a component or system such as a chemistry laboratory on a chip. An example is a gas analysis capability in a few-square-centimeter area which includes a preconcentrator, a 1-meter separation column, and an output sensor that can perform a chemical analysis in a matter of a few seconds.

• Fabrication of structures at smaller dimensions than we thought possible not so very long ago. A new form of silicon, the photonic crystal, has the potential to dramatically increase the functionality of this ubiquitous material by introducing the ability to control photons.

• Understanding of materials and processes throughout their life cycle through modeling and simulation. The phenomena of interest occur at multiple length scales, requiring a sophistication in the approach to modeling and simulation that is just beginning to be possible.

• Application of materials science and engineering approaches and techniques to new areas such as detecting and responding to biological threats.

These materials needs are not unique to national security. They have been reiterated in much of what we have heard at this forum. In fact, they are echoed in a recent study, Condensed Matter and Materials Physics: Basic

Research for Tomorrow’s Technology (National Academy Press, 1999). Some of the strategic research themes identified in that study are the very materials research and engineering needs outlined here:

• the synthesis and processing of new materials

• the drive to reduced dimensionality and nanofabrication

• the inexorable march toward increasing complexity

• the foray of materials research approaches and techniques into soft condensed matter and biological arenas

• the move from empiricism toward predictability in the simulation of materials properties and processes

More than 20 years of ceramic materials technology development for gas turbines has led to improved high-temperature ceramic materials, component manufacturing technology, design and life prediction methodologies, and ceramic integration experience for a variety of applications. Honeywell’s ceramic development programs have accelerated commercialization of ceramics for industrial engines, aerospace applications, and hybrid vehicles.

Ceramics exceed the capabilities of metallic components. Because they have one-third the density of superalloys, they offer significant weight savings, improved metallic disk life, faster rotor response, and reduced containment requirements. They can operate uncooled at up to 2500 °F, leading to increased power and lower specific fuel consumption, as well as lower emissions. They also have five to ten times higher resistance to wear and erosion/corrosion and at least twice the thermal low-cycle fatigue life.

Today’s ceramics are very different from their predecessors. They have in-situ reinforced microstructure, giving high strength, high fracture toughness, and excellent thermal shock resistance. Their high Weibull modulus gives low variability and high predictability. Advanced computer design tools produce robust designs. High volume can drive the costs into a competitive regime, and production parts are now in commercial service.

Microelectromechanical systems (MEMS) are based on three principles combined on an integrated chip or single substrate: miniaturization of mechanical structures, microelectronics, and massively parallel architectures. These allow sensing, computation, actuation, and control to be merged in a single device. Features can include thin-film sensors and materials, optical detectors and emitters, and monolithic integrated microstructures. Applications under current study and development include fluid flow sensors, fluid property sensors, flame detection and combustion controls, ultraviolet detectors, gas analyzers, biological sensors, low-cost infrared sensors, and infrared sensor testing.

New materials on the horizon may have a significant impact on future devices. One class of promising new materials is single-wall carbon

nanotubes that may be used as actuator materials. The properties of these materials are truly extraordinary: modulus of 6 million kg/cm²; surface area of 1,500 m²/g; strength of 0.3 million kg/cm²; conductivity of 5,000 S/cm. An actuator has been fabricated that operates at about 1 volt in seawater or blood, suggesting possible marine and medical applications.

Materials developed in the twentieth century are slowly entering military systems when they can solve a problem that conventional materials cannot. The challenge for the future is to accelerate their insertion into production hardware so that it takes less than the current 15 to 20 years. Tools must be developed that will lead to more rapid acceptance by designers. There are many exciting materials for the new millennium with potential roles in national security, including piezo materials, such as aluminum silicates and other smart materials, and catalytic systems for remediating environmental hazards. It will be critical to search for materials that can play a dual role— materials with both military and commercial applications.

Although there is support for science and technology (S&T) at the highest levels of the Department of Defense, the S&T budget is raided rather regularly to pay for other matters that arise, such as operations in Kosovo.

We live in an increasingly complex world. Revolutionary capabilities have entered the defense arena, including stealth, night vision, global positioning systems, adaptive optics and lasers, and phased-array radar. These technologies originated in the basic research program of the DOD. In fiscal year 2000, the DOD S&T budget is $7.4 billion: $1.1 billion for basic research (6.1), $3.0 billion for applied research (6.2), and $3.3 billion for advanced technology development (6.3). The total DOD budget for research, development, testing, and evaluation (6.1 through 6.7) is $34.4 billion. About $340 million of this is for materials and processes, not including some contributions from environmental research and development and compliance and about $100 million of materials-related work in the SBIR program.

It is critical for materials scientists and engineers to remember that materials are chosen for the function they provide. There has been a dramatic change in the use of materials over time. Particularly impressive changes have taken place in the use of aluminum (reduced from 49 percent in older aircraft to 31 percent in newer ones), titanium (increased from 13 percent to 21 percent), and carbon/epoxy-based materials (increased from 10 percent to 19 percent). The F-22 aircraft now in development contains 40 percent titanium, 15 percent aluminum, and a large proportion of thermoset materials. The V-22 aircraft is slated to contain 33 percent graphite/epoxy materials by weight. These changes were made to reduce weight and cost while improving strength and reliability.

Advanced materials play a critical role in our national security and will continue to do so.

Question: What about rapid prototyping at Sandia?

Robinson: Interconnectedness is increasingly important in the design and development of systems. A particularly vivid example is the work on extreme ultraviolet lithography, which involves staff at both Sandia locations (New Mexico and California), at Lawrence Livermore National Laboratory and Lawrence Berkeley National Laboratory, and at several companies and universities. The interconnectedness of these locations has advanced to the point that location is no longer important. The work can be done equally well at a distance.

Q: Is there a way to commercialize developments in the national laboratories quickly?

Robinson: Sandia has many industrial partners and in fact has completed about 500 cooperative research and development agreements (CRADAs). Sandia also has an active licensing program.

Savitz: The gel-casting technology used by Honeywell (formerly AlliedSignal) was originally developed at Oak Ridge National Laboratory. A senior scientist at Oak Ridge came to AlliedSignal for two years to transfer the technology.

Q: Is U.S. dependence on foreign sources of critical raw materials a national security issue?

Sloter: The base for defense acquisition and the vulnerability of critical supplies are matters of concern, but we must remember that we are now living in a global economy.

Savitz: Honeywell’s supply of silicon nitride comes from Japan and Germany. The technical capability exists in the United States, but there is no economic incentive to manufacture it in this country.

Q: What is the relationship between the drive to reduce costs and the resulting quality?

Swain: We never settle for lower quality. In fact, the quality often goes up.

Q: What about life prediction?

Swain: One must view quality in the context of functionality. One should not substitute materials or processes if one is not sure that the quality will remain at least as high. It is imperative to go slowly.

Robinson: It is impossible to inspect out defects. Instead, one must design quality in, using such things as in-process sensors and controls and designing with operational models that include processing and the full life cycle of the system or component.

Q: Are MEMS reliable enough for use in national security applications?

Robinson: We have a long way to go. We must move slowly and do our homework to make sure we do it right. Some new materials, such as amorphous diamond, are very interesting because they offer the promise of extremely high reliability.

Q: Are you considering the environmental effects on materials, for example the pronounced effect of fog in the Los Angeles basin on the fatigue life of some materials?

Sloter: Yes. The Navy in particular is extremely concerned about such effects. Remember that a carrier deck in the middle of the Indian Ocean is exposed to one of the most corrosive environments one encounters.

Q: The cause of the Aloha Airlines disaster was determined to be holes drilled through the aluminum structure that were not properly passivated. This resulted in exposure of the substrate.

Robinson: At the time, the military was using an epoxy for passivation that would have prevented the problem, but it had not yet been approved by the Federal Aviation Administration for use on commercial aircraft. That epoxy has subsequently been approved.