Radiation Effect on Material
Formation of Radiation Defect
Interstitial cluster
Dislocation loop
Vacancy cluster
Stacking fault tetrahedron
Cavity (He bubble, void)
Precipitates
Formed under irradiation of FCC metals and alloys with low stacking fault energy
High number density of SFT => contribute to radiation induced hardening
Irradiation Hardening
Loss of Ductility
Due to increase in radiation induced hardening
flat faces observed at highest exposure often referred to as channel fracture but they not cleavage faces. They are the result of intense flow localization, resulting from the first moving dislocations clearing a path of radiation produced obstacles, especially Frank loops, and thereby softening the alloy along that path.
Fatigue Property
Irradiation Creep
Creep = time dependent deformation of metal under constant load and high temperature
Radiation Induced Segregation
non-equilibrium process that occurs at point defect sinks during irradiation of an alloy at intermediate temperature (Tm = 0.3 to 0.5)
occurs when a given alloying component has a preferential association with the defect flux.
lifetimes of irradiated and uninitiated material are almost the same. Degradation due to irradiation improve hardening
strength increase usually saturates at relatively low exposure level