Metal-based materials

Types of metal-based materials and their uses

Selecting materials

Materials can be selected based upon their working properties. It is important to know and understand which materials can be used for a specific purpose:

  • How do they look?
  • What are they commonly used for?
  • How can they be manufactured?
  • How do they perform in use?
  • What makes them unique - are they the most durable, the lightest etc?

Many products are made from metal, and understanding the way each metal will function is vital. For example, if a metal is needed for strength and lightweight properties, then aluminium could be a possibility. Many sports cars are made of aluminium, as are aeroplane shells and wings.

Alloys are made by combining different metals to produce another that is more useful for a specific task. Stainless steel is an alloy of iron and chromium (from 10.5 per cent to 27 per cent). The chromium produces an oxide layer on the outer surface of the steel and prevents corrosion. Stainless steel is often used for kitchen utensils as it will not rust and can be wiped and cleaned with ease.

A close-up image of a stainless steel spatula used for cooking.

Metals offer a wide variety of aesthetic qualities - some, like lead, are dull, and some can be polished to a mirror-like finish. Metals can be smooth after machining or textured after being cast.

Metals come from an ore that is mined from the ground. A huge amount of heat energy is needed to extract the metal from the ore - this energy often comes from fossil fuels. Metal ores are non-renewable, meaning they are a finite resource and therefore recycling metal is important.

A heap of small clusters of natural iron ore in a red shade, isolated on a white background.
Iron ore

The cost of metal varies massively and some metals will become harder to obtain in future years. Common metals, such as steel, are relatively cheap, whereas gold and platinum are considerably more expensive.

A detailed close-up image of a collection of intricate gold bangles.
Gold used for jewellery

Metals can be used for all methods of production, from bespoke pieces of jewellery to continuously produced cars. Bulk buying of metal will reduce the cost. Most stock sizes of metals will have a price that is based on the weight of the metal.

Example

If aluminium costs £1,450 per tonne, calculate the cost of a 1 m length of 20 mm2 section aluminium bar that weighs 1 kg.

A 1 kg aluminium section measuring 20 mm x 20 mm x 1 m for calculating material costs.
curriculum-key-fact
Cost = cost per tonne X weight required (in tonnes)

There are 1000kgs in one tonne.

To convert 1kg to tonnes we need to divide 1kg by 1000.

1kg ÷ 1000 = 0.001 tonnes

The cost per kg is £1450

Cost = cost per tonne X weight required (in tonnes)

1450 x 0.001 =1.45

Cost for the metre length = £1.45

Remember to read questions carefully to identify the information that is relevant to the calculations.

Question

Aluminium weighs approximately 2,600 kg per cubic metre (m3).

Based on this, how much would a 1 m length of 20 mm2 section aluminium weigh?

Convert the square section into metres:

20 ÷ 1,000 = 0.002 m

Calculate the surface area of the end:

0.002 m × 0.002 m = 0.0004 m2

The length of the bar is 1 m, so:

0.0004 m2 × 1 m = 0.0004 m3

The weight per cubic metre (m3) is 2,600 kg, so:

2,600 × 0.0004 = 1.04 kg