TOPICS IN IN-SITU EXPERIMENTS IN THE HVEM

Current topics in in-situ experiments with HVEM are presented, with emphasis on the work that has been carried out with a 2 MV (routine) HVEM at Osaka University. A hot stage capable of operation at temperatures of up to 2300 K has been developed, exhibiting its performance when applied to the study of various annealing phenomena in refractory materials. With the use of a window-type environmental cell, the nucleation and growth process of transition metal hydrides, which resulted from a gas (hydrogen)-solid (transition metals) reaction, have successfully been observed. Through systematic experiments it is revealed that the electron-irradiation-induced C-A transition is a phenomenon of wide generality and occurs not only in metallic compounds but also in non-metallic compounds and that the amorphization tendency is closely related with the position of the compounds in the T-C phase diagram. A unique foreign atom implantation technique, in which irradiation effects of MeV electrons are utilized, has been developed. It is confirmed that with the use of this technique such foreign atoms as lead and gold can successfully be implanted into the substrate material on an extensive scale.