Effects of transmutation elements on the defect structure development of W irradiated by protons and neutrons

A series of W–Re–Os alloys were fabricated by arc melting for investigating the effects of transmutation elements of tungsten on the defect structure development. Transmutation electron microscopy has been used to investigate the defect structure for proton-irradiated (E = 1 MeV) W, W–3Re, W–3Os and 0.15 dpa neutron-irradiated (E > 1 MeV) W–5Re–3Os and W, W–3Re, W–5Re and W–26Re. The irradiation-induced voids and dislocation loops which directly cause the irradiation hardening were observed. The results show the combination of W with Re or Os effectively restrains irradiation damage since the number density and radius of both voids and dislocation loops remarkably decrease with increasing Re or Os content.