A review of recent developments in imaging with a transmission electron microscope is proposed here. A first part is devoted to applications in the “imaging” mode: interest of field emission, “Z-contrast”, quantitative high resolution electron microscopy and reconstruction techniques. A second part will deal with the “diffraction” mode: convergent beam diffraction and “electron cristallography”.

Hardening precipitation in an intergranular-corrosion desensitized alloy, AA6056-T78, is characterized in comparison with that in AA6013 and AA6082 alloys. To extract quantitative information, image-analysis is applied to dark-field images and selected-area diffraction patterns, along with standardless EDX spectroscopy. The central result is that both needle-shaped and lath-shaped precipitates have a similar chemical composition (except for Al content remaining undetermined in this study) to each other and, furthermore, to that of most of the grain boundary precipitates, normally in a more advanced state of precipitation kinetics than those in the grains.

TEM in situ straining experiments are of high interest in evidencing the dislocation mechanisms responsible for the macroscopic behaviour of materials. The application of this technique to biphased materials is illustrated here through various examples in which deformation is controlled either by dislocation propagation (e.g. precipitate overcoming) or by dislocation nucleation (e.g. interfacial sources).

During the last 5 years, the semi-conductor industry has enhanced device performances by scaling down the feature sizes and by introduction of new technologies. Transmission electron microscopy with high resolution images (HREM) has become an indispensable tool for analyzing devices structure at nanoscale, for failures analysis, defects review and manufacture controlling. In parallel to this progress on the devices, the sample preparation techniques for MET compatible with the requirements of the industrial world were developed and open new prospects. In this paper, we present these techniques of sample preparation. Then we show examples in what high resolution images make it possible to answer industrial problems.

This paper is mainly devoted to the presentation and the illustration of chemical microananalysis methods. Four basic techniques will be successively presented: the energy dispersive X-rays spectroscopy (EDS), the wave dispersive spectroscopy of X-rays (WDS), the electron energy loss spectroscopy (EELS) and the Auger spectroscopy (AES). For each of them, the limitations and advantages will be presented.

The degradation of a thermal barrier coating is closely linked to the microstructural and chemical stability of the complex system and of its interfaces. The coating in the as-received condition as well as the modifications during isothermal oxidation at 1100 °C were characterized using TEM and spectral mapping. Significant modifications (precipitation, phase transformations) occurred as a consequence of the oxidation process and interdiffusion phenomena.

The electron microscopy and microanalysis techniques available at the CP2M Centre have been used to study the complex precipitation phenomena in a titanium-containing dual phase steel. Nitrides, carbides and carbonitrides of titanium have been characterized at microscopic and nanoscopic scales using carbon extraction replicas and thin foils. Precipitation occurred mainly heterogeneously on existing particles (CaS, TiN). Thin foils have also been examined in a new scanning electron microscope with a field emission gun.

The low energy loss spectroscopy interpretes the signal resulting from the excitation of the valence or conduction electrons of a material under the impact with an electron beam. The analysis of this signal in terms of plasmon energy, low-loss function or dielectric function gives a lot of informations about the electronic structure and the chemical bonding of the sample. When this spectroscopy is connected with a field emission gun scanning transmission electron microscope (STEM-VG HB5O1) it constitutes a very relevant tool to solve material problems for which nanoanalytical investigations are of prime importance. These performances are illustrated by three examples.

This communication presents experimental observations of plastic deformation in submicronic metallic multilayers. As the length scale decreases down to the nanometer range, we evidence a major change in deformation mechanisms, plasticity becoming less localized as in traditional slip bands of dislocations. AFM and nanoindentation techniques are used in conjonction with more standard techniques to characterize plastic deformation.

AFM microscope is used here as a surface forces apparatus at the nanometer scale. We show through several examples that the curves forces (nN) vs. distance (nm) obtained are the physico-chemical signature of the interacting surfaces. From such a curve, chemical, frictional (mobility) and mechanical top surface aspects can be studied.

Recent developments in Scanning Electron Microscopy (SEM) are reviewed paying particular attention to the modern tendency to determine quantitative data in the form of microstructure maps : of chemical composition (EDS and WDS), of crystal orientation (EBSD) and of the deformation (microextensometry). The maps are then used to provide complete, quantitative microstructural analyses in terms of the size, orientation and composition distributions. In this context the new SEM-FEGs have an important role to play.

Since its introduction in the early eighties, Environmental Scanning Electron Microscopy (ESEM) proved a particularly useful tool in the characterisation of delicate samples mainly in the field of life sciences. Now, the potential of this equipment (no or little sample preparation, possible dynamic observation and reactivity studies...) is more and more employed in traditional materials domains. Some typical applications of ESEM concerning metallic compounds are presented.

A technique, which allows characterizing the local strain field over a domain representative of the microstructure of a heterogeneous material, is described. It is based on scanning electron microscopy, microelectrolithography, image analysis and in situ mechanical tests. On one hand, in relation with a microstructure analysis, it allows characterizing the different mechanisms responsible for the plasticity or the damage of materials. On the other hand, a quantitative analysis allows comparing and validating from a local to a global scale, the different models used for the prediction of materials constitutive laws. Finally, the knowledge of the experimental displacement improves seriously the results of finite element computations, by a better determination of the boundary conditions.