Engineering materials and their properties · GCSE Engineering

Metals

Ferrous metals contain iron and most will rust. Mild steel (low carbon) is tough and easy to work; high carbon steel is harder, for tools; cast iron is hard but brittle; stainless steel contains chromium and resists corrosion.
Non-ferrous metals contain no iron: aluminium (light, corrosion resistant), copper (excellent electrical conductor) and zinc (used to coat steel).
Alloys are mixtures of a metal with other elements to improve properties. Brass is copper and zinc; bronze is copper and tin.

Thermoplastics soften when heated and can be reshaped and recycled, such as acrylic, ABS, nylon, PVC and polypropylene.
Thermosetting polymers set permanently when first heated and can't be reshaped, such as epoxy resin, polyester resin and urea formaldehyde (used in electrical fittings).
Composites combine materials to get better properties: carbon fibre reinforced polymer (strong and light), glass-reinforced plastic (GRP) and reinforced concrete.

Strength: resisting a force without breaking (tensile strength for pulling, compressive strength for squashing).
Hardness: resisting scratching, wear and indentation. Toughness: absorbing energy without breaking (the opposite of brittleness).
Ductility: being drawn out into wire. Malleability: being hammered or pressed into shape without cracking.
Elasticity: returning to the original shape after a force is removed. Plasticity: staying permanently deformed.

Density = mass ÷ volume. Aluminium is about 2.7 g/cm³; steel is about 7.8 g/cm³.
Electrical and thermal conductivity, melting point, and resistance to corrosion.

Ferrous metal: A metal that contains iron.
Non-ferrous metal: A metal that contains no iron.
Alloy: A metal mixed with other elements to improve its properties.
Thermoplastic: A polymer that can be reheated and reshaped.
Thermosetting polymer: A polymer that sets permanently and can't be reshaped.
Composite: A material made by combining two or more materials.
Toughness: The ability to absorb energy without breaking.
Ductility: The ability to be drawn out into a wire.
Malleability: The ability to be hammered or pressed into shape without cracking.