Izod Charpy Impact ASTM D256, ISO 180

The Izod Charpy impact test is an ASTM and ISO standard method of determining the impact resistance of thermoplatic and composite materials and is an important test for characterization of materials. The test is very much similar to the Charpy impact test but uses different type of specimens for testing. The Izod impact test differs from the Charpy impact test in that the test sample is held in a cantilevered beam configuration as opposed to a three-point bend configuration. Both notched and un-notched  Izod Charpy impact test  provide important material properties.

The testing conditions are governed by many parameters, as below:

  • the dimensions of the usually rectangular cross section of the sample below the notch;
  • the height of the hammer at the start position, determining its velocity at impact;
  • the mass of the hammer which together with the velocity determines its kinetic energy at impact;
  • the sharpness, or tip curvature, of the notch;
  • the temperature of the sample.

Results of impact tests are expressed in terms of:

  • Amount of energy absorbed (N-m) or 
  • Amount of energy absorbed per unit cross sectional area (N-m/cm2)

Applications include:

  • Measure of the energy required to crack the material.
  • Test materials and grade them as per their impact property and use the grading for different applications.
  • Develop new materials suitable for use in automotive and aerospace impact applications.