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Microscopy is a blanket term encompassing several standard techniques for analysing samples at a microscopic level. Microscopy is a powerful tool in the study of materials, allowing the identification of the microstructural features which control the properties of different materials such as: metals, glass, ceramic, composite, polymer, organic, etc. It is also used to observe fracture surfaces and fracture path with relation to the underlying microstructures. It is a vital component of almost any metallurgy related project.

The techniques may be broadly divided into two areas:

In metallurgical microscopes, light microscopy involves the observation of the light reflected from carefully prepared metallographic specimens. This can reveal different features of the microstructure, including grain size, inclusions, presence of intermetallics, corrosion, impurities and local changes in composition.

Electron microscopy uses electrons rather than reflected light to examine samples which allows for much greater depth of field and magnifications, with up to 100,000x magnification for some samples. The reflected and diffracted electrons as well as the X-rays yielded when electrons strike the surface also give considerable information about local composition, crystal orientation and microstructure. Scanning electron microscopes are used extensively in the characterisation of microstructures and observation of micro-mechanisms of fracture.

TWI has a well-equipped microscopy and metallography suite with several highly experienced members of staff.

Our light microscopy facilities allow us to image samples at up to 1000x magnification; with different etches revealing different features of the sample structure. In addition, by analysis of these images, accurate measurements may be made of features including pits, cracks, coatings, grain sizes and volume/area fractions of the different microstructural features.

TWI possesses two high quality scanning electron microscopes. The first of these, an environmental SEM allows us to analyse relatively large samples without extensive cleaning, allowing the characterisation of surface deposits, fracture surface topography and microstructure. The attached EDX detector allows us to map chemical compositions both locally and globally. Imaging of features is possible up to 5,000x

Our FEG-SEM can image samples at up to 100,000x magnification, revealing the sample structure in extremely fine detail. Local and global elemental analysis is possible by EDX spectroscopy. The recent addition of an electron back-scattered diffraction detector means that crystal structures, crystallographic orientation, and phase identification can be characterised at a microscopic level.

The availability of state of the art equipment, operated by experienced engineers is a powerful tool for material scientists working many areas, from process optimisation, to corrosion to failure investigation and more.

For more information, please email

For more information please email: