Radiation-induced creep of aluminum and copper

Results of experimental and theoretical investigations of in-reactor creep of metals are presented in this paper. Experiments have been made in the WWR-K reactor at a neutron flux density of 1.4 x 10/sup 16/ n/m/sup 2/ . s (2.5 x 10/sup 15/ n/m/sup 2/ x s, E > 0.1 MeV). Polycrystalline aluminum (99.99%) and copper (99.99%) have been investigated. Aluminum specimens have been examined at temperature levels of 333 to 473 K and stresses of 9.8 to 24.5 MPa, and copper specimens at 423 to 773 K and 20 to 69 MPa, respectively. Experiments indicate the steady state creep rate depends on stress as ε/sup ./ -- σ/sup n/ (n ≅ 3 for aluminum and n ≅ 5 for copper) and increases with increasing test temperature. Three regions with different slopes are observed on the temperature versus creep rate ε/sup ./(1/T) curve. Theoretical calculations of the creep rate of irradiated metal as a function of the temperature have been carried out within the framework of the model based on the dislocation climb and glide. Calculation of the temperature dependence of the creep rate established that three temperature regions were recognized as in the case of experiments on copper