Modification of V-4Cr-4Ti alloy under 308 MeV Xe ion irradiation

In the 1960s and 1970s, heavy ion irradiation was developed for the purpose of simulating neutron damage in support of the fast breeder reactor program. Vanadium alloy (V-alloy) is a candidate of fusion blanket structural materials because of its excellent mechanical properties at high temperature and low activation in a 14 MeV neutron environment. In this study, we focused on the damage effects in a typical V-alloy V-4Cr-4Ti induced by 308 MeV Xe ion irradiations. The sample with dimensions 1 x 10 x 10 mm3 was cut from a plate of V-4Cr-4Ti V-alloy (China production). The composition of the alloy was Cr: 3.61%, Ti: 4.11%, Al: 0.21%, Si: 0.023, N:0.046%, O:0.09% and V:in balance. The V-alloy samples were irradiated at room temperature by 308 MeV Xe ions produced by HIRFL, Lanzhou. The irradiation fluences were 3.30 x 1014, 1.10 x 1015, 1.96 x 1015, 3.57 x 1015 ions/cm2, respectively. Subsequently, the samples were analyzed by XRD and TEM. Fig.1 shows theoretical damage level in V-alloy under different Xe-ion irradiation fluences which indicated that the peak damage level for 3.57 x 1015 ions/cm2 irradiation can reach up to about 11 dpa. The XRD patterns shown in Fig.2 suggested that V-4Cr-4Ti alloy has excellent radiation resistant properties. The modification of micro-structure of V-4Cr-4Ti alloy will be analyzed by TEM and the damage process of V-4Cr-4Ti alloy under high-energy Xe ion irradiations will be briefly discussed. (authors)