Material Science and Metallurgy

4

Plastic Deformation in Crystalline Materials

4.1 INTRODUCTION

The most ideal representation of a material is in the form of its single crystal. The mechanical behaviour of a single crystal is described on the basis of crystal structure and defects in the crystal. However, the use of single crystal is limited to electronic and semiconductor devices as single crystals of germanium and silicon are grown in laboratory and the chips are cut in preferred orientations.

But in a polycrystalline material, a grain or crystal is not free to deform independently because of the constraints imposed on it by the surrounding crystals, which may have different crystallographic orientations. Even if slip has started in one crystal, it is not carried through ...