The temperature dependence of the yield stress for neutron-irradiated molybdenum

Molybdenum was neutron-irradiated near 80 °C at doses of 7.2 × 10−5, 7.2 × 10−4, 7.2 × 10−3, 0.072 and 0.28 dpa. Irradiated Mo was tensile tested over a temperature range of −50 to 100 °C at a strain rate of 1 × 10−3 s−1. It was found that the yield stress of irradiated Mo decreased at lower temperatures and increased at higher temperatures, resulting in reduced temperature dependence of yielding at lower doses (<0.001 dpa); the yield stress was increased, and the temperature dependence of yielding was nearly unchanged upon further irradiation at higher doses (>0.001 dpa). The temperature dependence of the yield stress for unirradiated and irradiated Mo is consistent with the theoretical expression of the Fleischer model for interactions of dislocations with tetragonal strain fields.