The research center for ultra-high voltage electron microscopy at Osaka University.

High-voltage electron microscopy has shown itself advantageous for the study of natural science, including biology, but especially for materials science. The most important advantage for materials science is for in situ experiments about the detailed processes of the phenomena that occur in bulk materials. The present paper is mainly concerned with several types of in situ experiments that have been carried out in the Research Center for Ultra-High Voltage Electron Microscopy, Osaka University. The following subjects have been studied: a) fundamental problems, such as the conditions necessary for in situ experiments, functional features of specimen treatment devices, and the effects of electron irradiation; b) the dislocation behavior of crystals under various conditions; c) high-temperature behavior of refractory materials, mainly ceramic composites; d) new applications of electron irradiation effects, such as amorphization of crystalline materials and electron-irradiation-induced foreign-atom implantation; e) environment-matter interaction, mainly chemical amorphization of alloys; and f) future trends of the in situ experiment, such as combinations with Auger valency electron spectroscopy and high-resolution electron microscopy.