Structure of metals Metals exhibit different properties Malleable

Structure of metals • Metals exhibit different properties • Malleable, ductile and bear high temperatures • Why they are like this it can be answered by studying their structures • Structure greatly influence their properties and • Understanding structure allows us to understand properties • In addition to this various other factors affect properties that are impurities , grain size and methods by which metals or alloys are made into useful products

Ladle and molds

Different metallic structures When in a furnace the metals are melted they are put into molds in molten state and are cooled , upon cooling atoms of these metals arrange themselves in a regular repeating pattern

Crystalline structures • When metals solidify from a molten state the atoms arrange themselves into various orderly configuration called crystals • This arrangement of atoms in the crystal is called crystalline structure • The smallest group of atoms showing the characteristic lattice(arrangement of material in a geometric pattern) structure of a particular metal is unit cell. it is building block of a crystal and a single crystal can have many unit cells

Amorphous structure • These are those structures in which there is no orderly manner of atoms in a unit cells

Metallic crystal structure • Metallic bonding is non directional in nature so there is minimal restriction to the number and position of nearest neighbor atoms this leads to large no. of neighboring atoms and a dense packing

Three simple crystal structures • Three relatively simple crystal structures are found for most of the common metals 1. face centered cubic (FCC) 2. body centered cubic (BCC) 3. Hexagonal closed pack (HCP)

Face centered cubic structure • A crystal structure in which atoms are located at each of the corners and centers of all the cube faces is called FCC structure Like Fe, Al, Cu, Ni, Pb, Ag, Hg