RADIATION SOFTENING AND HARDENING IN NEUTRON IRRADIATED MOLYBDENUM.

Abstract

Molybdenum was neutron irradiated at reactor ambient temperature in the range from 6. 3 multiplied by 10**2**1 to 5. 0 multiplied by 10**2**3 n/m**2 (E//n greater than 1 MeV) and tensile tested over temperatures from 223 to 525 K and of strain rates from 2. 8 multiplied by 10** minus **6 to 2. 8 multiplied by 10** minus **2/s. Radiation softening was observed in the specimen irradiated to 6. 3 multiplied by 10**2**1 and 1. 0 multiplied by 10**2**2 n/m**2 in testing at room temperature with strain rates larger than 2. 8 multiplied by 10** minus **4/s. The athermal component of the yield stress was increased by irradiation and further increased by post-irradiation annealing up to 780 K.