Copper was used as an example to analyze the effect of radiation on the stress–strain curves and deformation stability of radiation-hardened metals. The analysis was based on an equation that describes the evolution of the dislocation density with deformation in a plastically deformed material. Deformation instability in the initial stage of the stress–strain curve was caused by strong deformation localization at the microscopic level as a result of the transformation of immobile radiation defects (vacancy and interstitial loops) into mobile dislocations. The channelling of a large number of dislocations along slip planes causes the appearance of a yield drop and a yield plateau in the stress–strain curves. The critical conditions for their appearance, as well as the theoretical irradiation-dose dependences of the yield-plateau length and the uniform strain to necking, were found.

Analysis of the Factors That Cause Unstable Deformation and Loss of Plasticity in Neutron-Irradiated Copper. G.A.Malygin: Physics of the Solid State, 2005, 47[4], 656-62