gamma(')-Fe4N was subjected to electron irradiation with the dose rate of 6.8 x 10(23)e m(-2) s(-1) in a 400 kV transmission electron microscope. The first in situ observation of the formation of Fe3O4 (O) on Fe4N (gamma(')) with the orientation relationship of [100](O) parallel [100](gamma(')) and <001>(O) parallel <001>(gamma(')) has been made inside the microscope with the basic column vacuum of (5-6) x 10(-5) Pa. A mechanism is proposed involving the electron-stimulated dissociation of Fe-N chemical bonds, desorption of nitrogen from the surface, adsorption of oxygen to the surface, and the oxidization of excessive metallic iron on the surface.

The bonding interface of explosively-welded aluminium and steel in three explosive conditions have been investigated by using scanning electron microscopy, transmission electron microscopy, electron diffraction and electron probe microanalysis methods. The results show that all the interfaces have the shape of waves with curled front formed by process of superplasticity and some discontinuous reacted zones. They consist of amorphous and nano sized crystals and quasi-crystals as well as the compounds such as AlFe, Al2Fe, Al3Fe and Al6Fe with various shapes. The basal steel crystal near the interface has structure of martensite and perlite crystals which are deformed by the process of superplasticity. The size of reacted zone becomes large with increasing amount of explosive charge powder and separation of the driver Al plate from the basal steel plate.

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