Characteristics properties of materials Flashcards
Density
The mass of a material (its weight) divided by its volume (size)
Strength
The strength of a material is its ability to withstand forces that try to bend or break it
- some materials might be strong against one type of force but weak against another
Tenacity
The strength of textiles and fabrics
Compressive strength
Withstanding compressive/ squashing forces
Yield strength
Withstanding forces before being permanently deformed
Impact strength
Withstanding sudden force
Tensile strength
Withstanding tension/ stretching force
What materials have a high tensile strength but low compressive strength?
Composite materials, timber and some polymers
What has tensile and compressive strength?
Metals usually have tensile and compressive strength
Hardness
The hardness of a material is how resistant it is to pressure from cutting, scratching or wear (metals are harder than polymers and textiles
Brittle
A material that will shatter or break rather than bend and deform when a force is applied
Durability
The ability of a material to withstand wear, pressure or damage
Strength to weight ratio
A measure of a material’s strength compared to its weight
What materials have a high strength to weight ratio
Most polymers
Carbon fibres
Glass fibre
Alloys (e.g. titanium)
Stiffness
The ability of a material to resist being deformed when a force is applied to it (its rigidity)
Examples of rigid materials and examples of materials with poor stiffness…
RM Ceramics Glass Steel PS Polymers like foam and rubber
Elasticity
The ability of a material to return to original shape when forces are applied that will make it bend or flex out of shape
What will materials with low elasticity do?
Deform very little before breaking
Impact resistance
The ability of a material to withstand a force or shock applied to it
What materials have good impact resistance?
Soft metals such as mild steel
Polymers such as rubber and nylon
Plasticity
The ability of a material to permanently change in shape when a force is applied to it
Corrosive resistance
How susceptible a material is to degradation from oxygen, moisture and other chemicals
What is rust?
A form of corrosion that affects ferrous metals when they are exposed to oxygen and moisture
What materials are resistant to corrosion?
Oak and dense hardwoods
What materials will rot when exposed to elements and left untreated?
Softwood
What can be affected by the weather?
Car and bicycle tyres will crack and split if left in the sun
Flammability
The ability of a substance to burn or ignite
What types of materials are flammable?
Most timbers
Polymers
Fabrics
Papers and boards
What is not flammable?
Metals
Absorbency
The ability of a material to absorb / take in moisture
What materials have good absorbency?
Natural fibres (e.g. cotton, linen, wool)
Cardboard
Foam
Thermal conductivity
Materials with good thermal conductivity allow heat to be transferred through then easily
What are good conductors of heat/electricity ?
Metals
Thermal resistance
Materials with good thermal resistance will not let heat be transferred through the easily - good insulators
Porous
A material that has tiny holes that allow moisture to seep through Porous materials (Styrofoam and softwoods) are good insulators
Thermal fabrics
E.g. acrylic, wool and viscose
Have good insulation (material that prevents heat, electricity or sound from escaping) properties.
Used to keep clothing warm, keep things cool in cool bags
Electrical conductivity
Refers to how easy it is for electricity to flow through a material
Good electrical conductor
Metals
Bad electrical conductor
Wood and rubber
Magnetic properties
A material with magnetic properties will emit forces that attract or repulse other materials
