Analysis of factors inducing deformation instability and loss of plasticity of neutron irradiated copper

Using copper as an example one studied the irradiation effect on stretch curves and deformation stability of radiation hardened metals. Analysis is based on the equation of density evolution of dislocations with deformation in a plastically deformed material. Deformation instability at the initial stage of stretch curves results from strong localization of deformation at the microlevel due to transformation of immobile radiation defects (vacancy and interstitial loops) to mobile dislocations. Channeling of numerous dislocations along sweeping planes in stress-deformation curves results in occurrence of a tooth and yield point. One determined the critical conditions of their occurrence and the theoretical dependences of the yield point length and of the value of equilibrium deformation up to necking down on irradiation dose