ABSTRACT
Throughout history, civilizations have been distinguished according to their ability to produce and work with superior materials that perform better than the previously available ones. In fact, the different eras in our prehistory are dežned by the materials available to our ancestors: stone, bronze, and then iron, where clearly the newer materials proved to be far better than the previous ones in terms of mechanical strength, durability, and workability. The search for new and superior materials has always been a crucial matter in the advancements of humanity and is still in fact an ongoing process. Since the beginning of the twentieth century, research in materials science resulted in massive developments that made possible the big advances in the communications and transport industries, among others. In particular, the last three decades have seen an increased interest in designing, discovering, and synthesizing
10.1 Introduction .................................................................................................. 135 10.1.1 Materials Exhibiting Negative Poisson’s Ratios (Auxetic) ............... 136 10.1.2 Negative Thermal Expansion ........................................................... 138 10.1.3 Causes of Negative Poisson’s Ratios and Negative Thermal
Expansion ......................................................................................... 139 10.2 Modeling and Experimental Work on the Thermo-Mechanical
Properties of Natrolite .................................................................................. 140 10.2.1 Mechanical Behavior of NAT-Type Systems .................................... 140 10.2.2 Thermal Behavior of NAT-Type Systems ......................................... 144
10.3 Results and Discussion ................................................................................. 147 10.4 Conclusion .................................................................................................... 149 Acknowledgments .................................................................................................. 149 References .............................................................................................................. 149
new materials that exhibit highly unusual properties. For example, although one normally expects that a lateral contraction should occur when a material is uniaxially stretched, it has been shown that not all materials behave like this and some materials can actually get fatter when uniaxially stretched (auxetic) (Lakes 1987; Evans et al. 1991; Wojciechowski 1989). Similarly, although one normally expects a material to expand when heated, some materials actually shrink in size, that is, they undergo negative thermal expansion (NTE). As discussed below, such properties usually arise as a result of the manner in which particular features in the nano-or microstructure of the material deform upon stretching or heating and result in the materials having superior qualities when compared with their conventional counterparts.
