ABSTRACT
An important tool in processing materials is to subject them to high temperatures and to use the resulting change in properties, which includes softening or melting, and changes in chemical and material phase. Thus, it is feasible to perform desired modifications in the material shape and characteristics. Other applications of high temperatures include heating, power harvesting, and other energy-related tasks. As covered in the various chapters of this book, there are many examples of operations that are implemented when materials are subjected to high temperatures, including forming and casting. To operate at extremely high temperatures, there is a need for devices, tools, structures, and mechanisms that are used to operate at such conditions. High-temperature materials have been used by humans as early as the primitives have started using fire and heat. The materials that are used have grown in capability and sophistication from as simple as rocks to the enormous selection that is available today (Bar-Cohen, 2003; Spear et al., 2006). The pool of high temperature (HT) materials that are available nowadays includes metal alloys such as stainless steels, superalloys, and refractory metals as well as ceramics, composites,
CONTENTS
17.1 Introduction ........................................................................................................................ 499 17.2 Operating Underground and at Great Earth Depths ...................................................500
