If you’re interested in how to make the most of the huge variety of materials available to us in construction, design and art, then we have the perfect course for you right here. However, if you’d like to dip your toe in the water then here’s a quick taster of what you’re in for!
Mankind has never had such a diverse variety of materials available with which to make things. Factories and workshops today make everything from cars, clothing and hoses, to kitchen appliances, electronic devices and children’s toys. These things are made using all sorts of raw and manufactured materials.
Things may be manufactured at one extreme on a large scale (producing very large numbers of identical products in a factory), or at the other extreme, they may be manufactured on a bespoke scale for a specific customer or job (one item at a time in a small workshop).
Properties of Materials
We choose to make things out of one type of material rather than another because of its properties, and there may be a whole range of physical properties to consider e.g. chemical, electrical and mechanical properties. These are then balanced against each other to help decide which material to choose. Understanding materials begins with understanding their properties. For construction materials, the following are some of the important considerations but bear in mind we are mostly concerned with solids (although liquids and gases may be used to manufacture certain materials). Also, bear in mind that this is not an exhaustive list.
Mechanical Properties
Strength – there are various measures of strength including: tensile strength (the maximum stress a material can endure before it breaks), compressive strength (the maximum stress a material can endure under compression before it fails), shear stress (the maximum shear stress a material can tolerate under shear load), yield strength (the stress under which a material yields), flexural strength (the stress in a material just before it yields) specific strength (the strength in each unit of density).
Elasticity – ability to be stretched by a tensile force and return to original shape and size after the force is removed.
Malleability – ability to be moulded or flattened under heat or cold without splitting or cracking to create different shapes.
Toughness – this is a combination of strength and plasticity refers to the ability of a material to resist fracture under impact or bending i.e. shock absorption.
Brittleness – lack of ability of a material to resist fracture.
Plasticity – ability of a material to deform whilst resisting fracture.
Ductility – ability to undergo significant plastic deformation before rupturing.
Hardness – resistance to surface erosion and marking (particles becoming dislodged from the mass).
Creep – physical deterioration of a material over time.
Thermal Properties
Thermal conductivity – thermal conductivity is the ability of a material to conduct heat.
Thermal diffusivity – the rate of transfer of heat form the hot part to the cold part of a material.
Thermal expansion – the ability of a material to change shape in response to temperature changes.
Fusibility – capability of a material of being melted and fused together, or the heat or temperature needed to achieve this.
Combustibility – the ease with which a material catches fire. Flammable materials are highly combustible i.e. they set alight when exposed to flames.
Melting point – temperature at which a solid material changes to a liquid.
Electrical Properties
Electrical conductivity – electrical conductivity is the ease with which a material can conduct electricity. The inverse is electrical resistance.
Capacitance – ability of a material to store an electric charge.
Environmental Properties
Environmental friendliness – ability to be recycled or decompose without adverse environmental effects.
Embodied energy – the total of all the energy needed to produced materials or goods.
Sustainability – of materials, this is the ability to continue to exist whether renewable or non-renewable i.e. the material will not run out.
Environmental sustainability – the harvesting, production or manufacture of the material causes little or no damage to the environment.
Manufacturing Properties
Machinability – ease with which materials can be cut leaving a good finish.
Cost & availability – sometimes the best materials may be unavailable or too costly to use; and compromises may need to be made. It may be better to use a less desirable material, because in doing so you can manufacture more products faster to meet demand, and/or produce products that can be sold for a far lower price.
Economic Properties
Cost – sometimes the raw materials are costly and sometimes the refinement of raw materials to produce a usable material can be costly. Even after you have the material you are going to use, the difficulty and cost of working with materials can vary. Some may require highly specialised skills to work with.
Availability – Even if cost is not an issue, some materials may be difficult to get.
