THE INFLUENCE OF HEAT-TREATMENTS ON NEUTRON-IRRADIATED NB-1ZR ALLOY

The microstructural evolution of neutron irradiated Nb-1Zr alloy at 69 3-1003 K to doses as high as 47.2 dpa has been investigated, At all ir radiation conditions, strong void swelling resistance was found. In th e cold-worked and aged specimens, voids of about 50 nm diameter were o bserved at lower temperature (693 K) and higher temperature ranges (91 8-1003 K), but not at intermediate temperature ranges (744-842 K). The void density increased with dose, The swelling behavior obtained by d ensity measurements was revealed to be rather complex, depending on ir radiation temperature and dose. The complex role of starting condition on both microstructural evolution and density changes are presumably due to phase-related changes during irradiation.