chapter  1
10 Pages

Introduction

The search for new and advanced materials has been the major preoccupation of materials scientists during the past several years. Recent investigations have focused on the improvement of the properties and performance of existing materials and/or synthesizing and developing completely new materials. Signicant improvements have been achieved in the mechanical, chemical, and physical properties of materials by the addition of alloying elements, microstructural modication, and by subjecting the materials to thermal, mechanical, or thermo-mechanical processing methods. Completely new materials, unheard of earlier, have also been synthesized. These include metallic glasses [1-3], quasicrystals [4,5], nanocrystalline materials [6-10], and high-temperature superconductors [11], to name a few. The high-tech industries have provided the opportunity andllip to develop these novel materials. An added side benet of the synthesis of these materials is the development of newer and improved techniques to characterize these materials with better resolution capabilities to determine the crystal structure and microstructure at different levels (nanometer, micrometer, and gross level), phase identication, and compositionofphasesofever-decreasingdimensionsandwithhigherandhigher resolutions, down to the atomic level.