抄録
Beryllium has long been noted as nuclear reactor materials due to its excellent nuclear properties and thermal and mechanical properties for high temperature. In submitting beryllium to the serious stress conditions at reactor core, however, the brittleness of this material even at comparatively lower temperature has been the most urgent problem with beryllium as fuel cladding material in the high temperature gas cooled reactor. However it does not seem to have been made clear yet what can contribute to solving the problem so as to bring out its strength and ductility to full utility. In this study, test specimens were produced from the sheets of hot pressed and unidirectionally rolled beryllium. Then two factors, i.e. the three grain sizes in the powder metallurgy of typical electrolytic flake beryllium and the anisotropy by the hot rolled fabrication were considered as affecting the mechanical properties of beryllium at elevated temperatures. The experiments were conducted to measure and discuss the various mechanical properties as a function of temperature and neutron irradiation effect on the two factors.
