Correlation among a variety of miniaturized mechanical tests and their application to D-T neutron-irradiated metals

Tensile, disk bulge and microhardness tests with miniaturized specimens have been performed on a variety of metals and alloys. Both the bulge fracture load and the microhardness test strongly correlate with the tensile strength. Specimens as thin as 0.1 mm generally fulfil the requirements for obtaining bulk properties from miniaturized tensile tests, for materials where the grain size can be properly controlled. The tensile and bulge tests were carried out on Ni, Au, Cu and austenitic stainless steel irradiated with D-T fusion neutrons from RTNS-II. Au and Cu showed a large increase in yield strength up to factors of 7 and a reduction of ductility down to 50% by the irradiation of 1.7 x 1022 n/m2. The increase of the yield strength for Ni and stainless steel is about half that of Cu and Au, and the decrease of ductility is small for stainless steel. Variation of deformation mode with increasing neutron fluence has been detected by optical and electron microscopy. (orig.)