In situ experiments
Study of metals by transmission electron microscopy (TEM) - Microscope, samples and diffraction

In situ experiments using electron microscopy were carried out very early on. It's interesting to be able to see directly the effects you want to study. In the early 1960s, and right up to the present day, a number of studies of ion irradiation, phase transformation or plastic deformation have been developed.

In in-situ plastic deformation experiments, the behavior of samples subjected to mechanical stress and/or a particular environment is directly observed in real time. In transmission electron microscopy, specially designed sample holders can be used to heat, cool and/or deform the sample - a thin slide in a vacuum - inside the microscope.

For in situ observations, you need an electron microscope with a large distance between the polar parts of the objective lens (a few millimeters or so), allowing a special sample holder to be inserted...