Design Technology - Topic 4.2a

Metals

Metals

Crystalline structures made up of grains

Large/Coarse Grains

Formed through slow cooling. Increases tensile strength, toughness, ductility, and malleability

Small Grains

Formed through fast cooling. Decreases tensile strength, toughness, and ductility. Increases brittleness

Alloys

The mixture of a metal with another material.

Alloying

Process of combing a metal with another material. Increases hardness and strength, but decreases malleability and ductility

Work Hardening

Process of increasing the hardness of a metal through applying a process when the metal is cold

Tempering

Application of heat after work hardening. Reduces some of the hardness and stiffness, but it increases the toughness and ductility of the metal

Super Alloys

Metal alloys that exhibit high degrees of mechanical strength, resistance to corrosion, and surface stability

Creep

Slow expansion or deformation of a material over time. Can be exaggerated by high temperatures or prolonged force

Oxidation

The reaction of metal with oxygen

Ferrous Alloys

Alloys containing iron, making them magnetic. Mild steel, stainless steel, and cast iron

Non-ferrous alloys

Alloys that do not contain iron. Aluminum, copper, silver, tin, and zinc

Galvanizing

Protective coatings that protect against corrosion