Material testing

• it is necessary to test materials on their mechanical properties as this ensures the material is fit for the application - results are fairly tested meaning all other variables need to be removed
• variables that could impact the test include:

  • environmental conditions
  • size of material sample
  • testing equipment
  • force applied
  • method of force application
  • position of force application
  • individual taking measurements
• two types of testing


  • industrial testing - tests done with high quality equipment
  • workshop testing - tests done in workshop with equipment at hand
• industrial testing


  • tensile testing
  • toughness testing
  • hardness testing
  • malleability testing
  • non-destructive testing (NDT)
  • x-ray testing
  • electrical conductivity
• types of workshop testing


  • tensile testing
  • toughness testing
  • hardness testing
  • malleability and ductility testing
  • corrosion testing
  • conductivity testing
• tensile testing(IT)

  • piece of material is placed and held in a tensometre machine
  • the material is then places at constant tension
  • the yield or strength is measured before the piece breaks
• toughness testing(IT)

  • izod impact test: a piece of the material is held vertically in the machine
  • a pendulum is then released from a set potision
  • the energy is absorbed is calculated from the height the pendulum swings after hitting the material
  • the more impact it absorbs the tougher it is
• hardness testing(IT)

  there are 3 types of hardness testing:

  • rockwell test
  • brinell test
  • vickers pyramid
• rockwell hardness test(IT)

  • material is places in a diamond indenter
  • a preload is applied to the material which breaks through the surface
  • an applied load is applied to the material and held for a certain length of time
  • the distance between the preload and the applied load is then measures
• brinell hardness test(IT)

  • use a standard sized steel ball which is forced into materials surface using a pre-set load
  • the diameter of the indent is measured
  • the smaller the indent, the harder the material
• vickers pyramid hardness test(IT)

  • used for very hard materials
  • square based diamond pyramid is used to indent the surface of the material (does not deform)
  • a microscope is used to measure the indent - the smaller the indent the harder the material
• malleability and ductility testing(IT)

  • a bend test is used to see how well a material can withstand cracking during one continuous bend - a ductile material will have plastic deformation prior to failure
  • material is placed in bending machine and held at both ends
  • a plunger loads the test piece at the centre and bends to a predetermined angle - material is inspected for cracks
  • cracks on outer bend indicate ductility level
  • cracks on inner bend indicate malleability level
• non-destructive testing (IT)

  • taken out on products that are likely to have internal defects that wont be picked up by other testing methods
  • ultrasonic testing - sound waves that are pushed into the material - shows internal cracks
  • x-ray testing - a beam passes through the material and image is projected onto a screen - can show any inner deformation
• electrical conductivity(IT)

  • a 4-point probe method to determine the electrical conductivity
  • 4 diameter wires are stretched parallel to each other and across a polymer block
  • ohms law can be used to calculate
• thermal conductivity(IT)

  • using a heat flow meter a square shaped material test piece is placed between temperature controlled plates
  • the temperature increases and the heat flow rate is measured
• tensile testing (WT)


  • placing a weight on a length of material held in clamp or vice
  • weight is applied at end of material protruding from the vice
  • tension will be applied to the top of material with compression at the bottom
• toughness testing (WT)


  • placing test material in a vice and hitting with hammer
  • the more impact it withstands the tougher the material
  • problem of maintaining consistent amount of pressure
• hardness testing (WT)


  • can use a file on the surface of the material - least scratches is the hardest
  • a dot punch can be placed on the material and hit with a hammer - the bigger the circle the softer the material
  • problem of maintaining a constant amount of pressure
• malleability and ductility testing (WT)


  • test piece is placed in vice and attempted to bend 90 degrees with a hammer or mallet
  • cracks on outside indicate ductility
  • cracks on inside indicate melleability
• corrosion testing (WT)

  • exposing the material to environmental effects
  • inspected for signs of surface corrosion
  • other tests can be taken out to see if it has changed
• conductivity testing (WT)


  • electrical conductivity - using a multimeter - the higher the resistance the lower the conductivity
  • thermal conductivity - using a thermometer which is placed at one end of the material while the other end has a bunsen burner placed under - the time for the thermometer to change is measured