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.