3.1 Types of Materials

• Force


  • A power that produces a strain on a material
  • And that changes the materials shape, or has the potential to change its shape
  • There are five forces that act on materials: Compression, tension, torsion, sheer and bending.
• Physical Property


  • An observable or measurable characteristic of a material
  • Common physical properties are: mechanical, electrical, chemical, thermal, magnetic, permeability, aesthetic and tactile
• Prototype


  A working model, in the early stages of development

  Which, through testing against the specification, is used to help refine the product; before beginning final or larger scale production
• Stiffness


  Resistance to forces of bending or torsion
• Stress or Strain


  • A force created by pressure on an object or material
  • That has the potential to damage the object or material by changing its shape
• Working Properties


  The way a material behaves when being worked or shaped or while being used within a product

  Helps determine the tools or processes that will be used when making or manufacturing and how a product will function
• Mechanical 


  • Shows how the material will react to physical forces
  • Some materials can become brittle when bent or flexed
• Electrical


  • Shows how conductive a material is, including its insulation
  • Example: a screwdriver has a polymer handle to prevent electric shocks
• Chemical


  • Shows how a material reacts to other chemicals
  • Example: metals oxidise when exposed
• Thermal


  • Shows how a material responds at different temperatures

  Example: freezing, melting, and boiling points
• Magnetic


  • Shows if they are attracted to magnets or can be magnetised
  • Example: most ferrous metals (metals that contain iron) materials are attracted to magnets or can be magnetised
• Permeability


  • The degree to which liquids or gases can pass through a material

  Example: woods that have been varnished having low permeability to liquids and water resistance
• Aesthetic


  • The visual sensory properties of the surface / form of a material

  Example: colour and shine
• Tactile


  • The touch or sensory properties of a material

  Example: texture
• Strength


  The ability to withstand a constant external force without failing
• Hardness


  • The ability to resist wear and tear, scratching and dents
  • Is usually related to surfaces
• Toughness


  The ability to withstand blow or momentary shocks (live forces)
• Durability


  • The ability to resist wear
  • Example: weathering over time
• Elasticity 


  The ability to bend and then return to its original shape or size
• Plasticity 


  • The ability to permanently change shape or form
  • Applies to materials other than polymers
• Malleability

  The ability to permanently change shape, in all directions, while retaining integrity
• Ductility


  The ability to change shape by stretching along its length without snapping