Materials Testing


Materials testing laboratoryThe reliability and performance of gears is greatly influenced by material quality and condition. The most common mode of failure is fatigue and is dependant on:

  • Steel composition, cleanliness, grain size, hardenability and heat treatment;
  • Post heat treatment finishing processes such as shot blasting, shot peening, grinding and superfinishing;
  • The effect of lubricants and lubricant additives.

The Materials Laboratories at Design Unit support industrial gear research and consultancy projects in three main areas:

  • Metallography and evaluation of material properties.
  • Quality control (eg gear manufacture and heat treatment).
  • Characterisation and analysis of gear failures.


A range of up-to-date laboratory equipment is used to study the metallurgy of gears and the factors affecting fatigue performance. The facilities available include:

  • Sectioning, mounting and polishing equipment for metallographic sample preparation;
  • Video imaging and analysis software connected to stereo and reflected light microscopes;
  • Micro- and macro-Vickers testers for hardness and case depth measurement;
  • X-ray diffraction equipment for measurement of residual stress and retained austenite;
  • Barkhausen Noise analysis for detection of grinding burn;
  • Eddy Current crack detection equipment.

Design Unit also has access to the University's scanning electron microscopes fitted with EDX analysers, an optical profilometer for characterisation of surface topography.