The cover illustration depicts a diamond-anvil cell that can exert pressures of hundreds of gigapascals. Adapted from an image from A. Correa, Lawrence Livermore National Laboratory. * _________________________ * R. J. Hemley, A pressing matter, Phys. World 19, 26-30 (2006).
BASIC RESEARCH NEEDS FOR MATERIALS UNDER EXTREME ENVIRONMENTS
Report of the Basic Energy Sciences Workshop for Materials under Extreme Environments
Chair:Jeffrey Wadsworth, Oak Ridge National Laboratory
Co-chairs:George W. Crabtree, Argonne National Laboratory Russell J. Hemley, Carnegie Institution of Washington
EXECUTIVE SUMMARY EXECUTIVE SUMMARYNever has the world been so acutely aware of the inextricably linked issues of energy, environment, economy, and security. As the economies of developing countries boom, so does their demand for energy. Today nearly a quarter of the world does not have electrical power, yet the demand for electricity is projected to more than double over the next two decades. Increased demand for energy to power factories, transport commodities and people, and heat/cool homes also results in increased CO 2 emissions. In 2007 China, a major consumer of coal, surpassed the United States in overall carbon dioxide emissions. As global CO 2 emissions grow, the urgency grows to produce energy from carbon-based sources more efficiently in the near term and to move to non-carbon-based energy sources, such as solar, hydrogen, or nuclear, in the longer term. As we look toward the future, two points are very clear: (1) the economy and security of this nation is critically dependent on a readily available, clean and affordable energy supply; and (2) no one energy solution will meet all future energy demands, requiring investments in development of multiple energy technologies.Materials are central to every energy technology, and future energy technologies will place increasing demands on materials performance with respect to extremes in stress, strain, temperature, pressure, chemical reactivity, photon or radiation flux, and electric or magnetic fields. For example, today's state-of-the-art coal-fired power plants operate at about 35% efficiency. Increasing this efficiency to 60% using supercritical steam requires raising operating temperatures by nearly 50% and essentially doubling the operating pressures. These operating conditions require new materials that can reliably withstand these extreme thermal and pressure environments. To lower fuel consumption in transportation, future vehicles will demand lighter weight components with high strength. Next-generation nuclear fission reactors require materials capable of withstanding higher temperatures and higher radiation flux in highly corrosive environments for long periods of time without failure. These increasingly extreme operating environments accelerate the aging process in materials, leading to reduced performance and eventually to failure. If one extreme is harmful, two or more can be devastating. High temperature, for example, not only weakens chemical bonds, it also s...