In this paper, we review the energy requirements to make materials on a global scale by focusing on the five construction materials that dominate energy used in material production: steel, cement, paper, plastics and aluminium. We then estimate the possibility of reducing absolute material production energy by half, while doubling production from the present to 2050. The goal therefore is a 75 per cent reduction in energy intensity. Four technology-based strategies are investigated, regardless of cost: (i) widespread application of best available technology (BAT), (ii) BAT to cutting-edge technologies, (iii) aggressive recycling and finally, and (iv) significant improvements in recycling technologies. Taken together, these aggressive strategies could produce impressive gains, of the order of a 50-56 per cent reduction in energy intensity, but this is still short of our goal of a 75 per cent reduction. Ultimately, we face fundamental thermodynamic as well as practical constraints on our ability to improve the energy intensity of material production. A strategy to reduce demand by providing material services with less material (called 'material efficiency') is outlined as an approach to solving this dilemma.
Micro-architectured materials offer the opportunity of obtaining unique combinations of material properties. First, a historical perspective is given to the expansion of material property space by the introduction of new alloys and new microstructures. Principles of design of micro-architecture are then given and the role of nodal connectivity is emphasized for monoscale and multi-scale microstructures. The stiffness, strength and damage tolerance of lattice materials are reviewed and compared with those of fully dense solids. It is demonstrated that micro-architectured materials are able to occupy regions of material property space (such as high stiffness, strength and fracture toughness at low density) that were hitherto empty. Some challenges for the development of future materials are highlighted.
Material properties of solids have values which— for a given structure and bond–type (defining a ‘class’ of solid)— lie within broadly defined ranges, characteristic of the class. Beyond this, correlations exist between the values of mechanical, thermal, electrical and other properties which derive from the underlying physics of bonding and packing of atoms in the material. Some of these correlations have a simple theoretical basis and can be expressed as dimensionless groups with much narrower value ranges; they allow a physically based consistency check on property values and allow some properties to be estimated when values for others are known. Others, empirical at this stage, can be found by an appropriate search routine; they, too, can be used to estimate missing properties, and to assign a reliability range to the estimates.The results are useful whenever calculations involving material properties are undertaken. They allow the detection of errors in the values of material properties which are used as inputs to the calculations; and they permit calculations to proceed even when some data are missing by providing intelligent estimates for the missing values. This paper assembles property ranges and dimensionless correlation–groups for commonly used properties, examines their accuracy and illustrates their utility. A companion paper develops and illustrates the empirical–correlation method.
Abstract The mechanisms by which ice can deform are described and extended. Some, like proton-rearrangement controlled glide, are unique to the structure of ice; others, like diffusional flow, are identical with those found in other polycrystalline solids. Data for each mechanism is assembled, and the results used to construct deformation-mechanism diagrams which show the regime of dominance of each mechanism, and its rate. The use of the diagrams is illustrated with two simple case studies.
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