Material Science and Metallurgy

3

Imperfections in Solids

3.1 INTRODUCTION

The study of imperfections in crystalline materials is of utmost importance because the mechanical properties such as strength, hardness and ductility are strongly dependent on imperfections. These are classified as point imperfections, line imperfections, stacking faults and volume imperfections. The influence of point imperfections as vacancies plays only a negligible role on the strength of a material because the presence of vacancy at room temperature is about 1 in 10⁷ atomic sites. But line imperfections as edge and screw dislocations play a vital role in the mechanical behaviour of crystalline materials and will be studied in detail in this chapter.

Volume imperfections such as inclusions, impurities, ...