TENSILE PROPERTIES AND FRACTURE-BEHAVIOR OF V-CR-TI ALLOYS AFTER NEUTRON-IRRADIATION AT 330-DEGREES-C

Results of irradiation effects in the fast neutron spectrum of the BOR -60 reactor on the mechanical properties and fracture behaviour of van adium as well as on binary and ternary alloys (including V-4Cr-4Ti and V-5Cr-10Ti) are presented. The irradiation was carried out at 330 deg rees C in a Li-7 isotope environment to a damage dose of 18 dpa. It is shown that all alloys without exception experienced severe radiation embrittlement. Most specimens failed without discernible traces of duc tile strain at room temperature. At a test temperature of 350 degrees C, ductility was observed but the total elongation, as a rule, did not exceed 1%. The fracture was mixed: transgranular brittle cleavage and ductile dimple rupture. As the test temperature was increased from 20 degrees C to 350 degrees C, the brittle fracture fraction decreased. At 600 degrees C only ductile fracture was observed. The behaviour of V-4Cr-4Ti alloys of American and Russian production is analyzed in the 275-530 degrees C temperature range, where a shift in behaviour from brittle to ductile failure is observed. (C) 1998 Elsevier Science B.V. All rights reserved.