Material Properties Learning Intention: Understand the terms used to describe the properties of materials

Material Properties Different materials have different properties Designers have to consider these properties when selecting the most suitable material for a specific product

Selecting Appropriate Materials When mass producing a product you would need a material that can be permanently shaped and easily formed

If you were building a bridge, you would need a material with the ability to withstand high forces

When describing a material’s properties we can refer to either its Mechanical Properties or its Physical Properties

Mechanical Properties The Mechanical Properties of materials are linked to how they react to the application of force

Mechanical Properties - Strength The strength of a material is its ability to withstand an applied force without breaking or bending permanently Materials can have different types of strength – thinking of the different types of force what do you think they are? Here’s the first one

Tensile Strength

Bending Strength

Compressive Strength

Shear Strength

Torsion Strength

Mechanical Properties - Durability The ability to resist wear and tear over a period of time, materials begin to weather and suffer wear and tear

Mechanical Properties - Toughness The ability to withstand sudden shocks or blows without breaking

Mechanical Properties - Brittleness The opposite of toughness – little or no resistance – acrylic is very brittle unless heated

Mechanical Properties - Malleability The ability of a material to be permanently deformed in all directions – hammering, rolling or pressing

Mechanical Properties - Ductility Ability of a material to be cold-formed by being pulled (drawn) into thinner sections of wire (without breaking)

Mechanical Properties - Elasticity Ability to flex and bend but return to original form when force is removed

Physical Properties The Physical Properties of materials are unaltered by the application of force

Physical Properties - Hardness The ability of a material to resist abrasive wear or scratching

Physical Properties - Density The mass per unit volume – often has an effect on other properties such as hardness

Physical Properties - fusibility Ability of a material to change into a liquid at a certain temperature – important for fabrication and forming processes

Physical Properties – thermal conductivity Ability to allow heat to pass through a material

Physical Properties – Electrical conductivity Ability to allow electricity to pass through the material

Physical Properties – Environmentally friendly Materials that can be reused, recycled or are biodegradable

Examiner’s Tip You must be able to describe the properties of materials Be able to describe the terms used in relation to a variety of materials using notes and sketches Examiner’s Tip You must be able to describe the properties of materials Be able to describe the terms used in relation to a variety of materials using notes and sketches

Check your understanding the ability of a material to conduct heat or electrical energy ?

Check your understanding Give an example of a material with good thermal conductivity ?

Check your understanding Give an example of a material that is a good thermal insulator ?

Check your understanding Give an example of a material that is a good electrical insulator ?

Check your understanding the ability of a material to withstand a force without breaking or bending ?

Check your understanding Why would this I beam be used?

Check your understanding the ability of a material to bend and then to return to its original shape and size ?

Check your understanding Many wooden tool handles and sports equipment are made from Ash. Why?

Check your understanding the ability of a material to permanently deform in all directions without cracking ?

Check your understanding Give an example of a malleable metal

Check your understanding the ability of a material to deform, usually by stretching along its length ?

Check your understanding Name a metal that is ductile – what is it used to make? ?

Check your understanding the ability of a material to resist wear, scratching and indentation ?

Check your understanding the ability of a material to withstand blows or sudden shocks without breaking ?

Check your understanding What’s the opposite of tough? Give some examples ?

Check your understanding is the ability of a material to withstand wear, especially as a result of weathering ?

Check your understanding the ability of a material to change into a liquid or molten state when heated to its melting point ?

Homework Task Design some simple tests you could carry out in the school workshop to find out the relative properties of a range of materials