Why we bother for imperfection The study of imperfections has a two fold purpose, namely, A better understanding of crystals and how they affect the properties of metals. Exploration of possibilities of minimizing or eliminating these defects. The term “defect” or “imperfection” is generally used to describe any deviation from the perfect periodic array of atoms in the crystal. Why we bother for imperfection PROPERTIES Structure sensitive Structure Insensitive E.g. Yield stress, Fracture toughness E.g. Density, elastic modulus Classification of Imperfection On the basis of geometry POINT IMPERFECTIONS LINE IMPERFECTIONS SURFACE IMPERFECTIONS VOLUME IMPERFECTIONS POINT IMPERFECTIONS ...
• An ideal crystal is regarded as a perfect crystal which has the same unit cell and contains the same Lattice Point (LP) throughout the crystals. • Crystals always have a regular periodic arrangement of atoms. Any deviation from this periodicity is known as defects or imperfections in crystals. • Definition: The deviation from the perfect periodicity of atomic arrays in crystals is known as crystal defects. • Any deviation from this makes it imperfect (defects) • Classification of crystal Varies from one author to another • Point defects are due to missing atoms, displaced atoms or extra atoms and ...
CRYSTAL DEFECTS AND IMPERFECTIONS An ideal crystal is a perfect crystal in which each atom has identical surroundings. Real crystals are not perfect. A real crystal always has a large number of imperfections in the lattice. One can reduce crystal defects considerably, but can never eliminate them entirely. 2 . . . . 3 Crystal defects Defects can affect Defects can affect Strength Strength Conductivity Conductivity Deformation style Deformation style Color Color 4 CRYSTAL DEFECTS AND IMPERFECTIONS The study of imperfections has a two fold purpose, namely, A better understanding of crystals and how they affect the properties of ...
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