Effects of damage rate on Cu precipitation in Fe-Cu model alloys under neutron irradiation

The formation of Cu precipitates and point defect clusters was investigated in two Fe-Cu binary model alloys, Fe-0.3Cu and Fe-0.6Cu, irradiated at 573K at three different damage rates, namely 3.8 x 10(-10), 1.5 x 10(-8) and 5 x 10(-8) dpa (displacements per atom)/s, up to about 1.6 x 10(-2) dpa. Results of positron annihilation experiments indicated that Cu precipitates were formed in these irradiations with different damage rates. The growth of Cu precipitates does not increase monotonously with increasing irradiation dose, but it rather depends on the nucleation and growth of microvoids. It is also clear that the nucleation and growth of microvoids are influenced by the irradiation dose rate.