Electron microscopies


Mechanical tests followed by microstructural investigations provide engineers information to computationally predict the mechanical performance of components. Electron microscopy is one of the most well known techniques for analyzing deformation features of materials allowing understanding their response to exterior solicitations.Two kinds of electron microscopes are generally used and bring complementary information: at micro/nano-scale, Transmission Electron Microscopy (TEM) and at macro/meso-scopic scale, Scanning Electron Microscopy (SEM).


The TEM is one of the most well-known techniques for observing and characterizing crystalline defects on one hand at the sub-micronic, and on the other hand, at the nanoscales in electron transparent thin foils (thickness of ≈ 100 nm). Such comprehensive studies at microscopic scale bring valuable information for extrapolating to the macroscopic response of materials.

Characterization of a configuration of dislocations observed by TEM (Guitton et al., Philos. Mag., 2012)


The SEM uses a thin beam of electrons, emitted by an electron gun. Electromagnetic lenses focus the electron beam on the sample. The interaction between the electrons and the sample causes the formation of new electrons. Then they are detected and converted into an electrical signal. This process is carried out at each point of the sample by scanning. The collection of signals allows to reconstruct the topography of the surface of the sample.

Cracks observed by SEM (Guitton, Thesis, 2013)

Some of my publications on the subject

Evidence of dislocation cross-slip in MAX phase deformed at high temperature.
A. Guitton, A. Joulain, L. Thilly, C. Tromas
SCIENTIFIC REPORTS, 2014, 4 (6358)
DOI: 10.1038/srep06358

Dislocation analysis of Ti2AlN deformed at room temperature under confining pressure.
A. Guitton, A. Joulain, L. Thilly, C. Tromas
PHILOSOPHICAL MAGAZINE, 2012, 92 (36), 4536–4546
DOI: 10.1080/14786435.2012.715250