Lecture 1- Metals and Alloys Notes

High stiffness and strength

Metals can be alloyed for high rigidity, strength, and hardness; thus, they are used to provide the structural framework for most engineering products

Toughness

Metals have the capacity to absorb energy better than other classes of materials

Good electrical conductivity

Metals are conductors because of their metallic bonding that permits the free movement of electrons as charge carriers

Good thermal conductivity

Metallic bonding also explains why metals generally conduct heat better than ceramics or polymers

Alloy

A metal composed of two or more elements

Solid Solution

an alloy in which one element is dissolved in another to form a single-phase structure

phase

any homogenous mass of materials, such as a metal in which the grains all have the same crystal lattice structure

substitutional solid solution

atoms of the solvent element are replaced in its unit cell by the dissolved element

interstitial solid solution

atoms of the dissolving element fit into the vacant spaces between base metal atoms in the lattice structure

Intermediate Phase

It describes the chemical composition is intermediate between the two pure elements, its crystalline structure is also different from those of the pure metals

Phase Diagram

a graphical means of representing the phases of a metal alloy system as a function of composition and temperature

eutectic alloy

a particular composition in an alloy system for which the solidus and liquidus are at the same temperature