Stress dependence of creep in Ni bombarded with 17-MeV deuterons

A linear stress dependence of irradiation creep was observed in pure, heavily cold-worked Ni and the creep behavior was modeled using a climb-glide creep mechanism. The Ni foils were bombarded with 17 MeV deuterons at 473 K with a damage rate of 0.0000006 dpa/s. The applied tensile stress ranged from 135 MPa to 250 MPa. Transmission electron microscopy revealed that up to 50% of the material had recrystallized during the pre-irradiation thermal creep test. A high number density of interstitial loops were observed throughout the material. Small voids were observed primarily in the recrystallized regions. The creep rate magnitude and stress dependence was rationalized using models of loop hardening of rate theory predictions of point defect annihilation at sinks.