Many uranium rich alloys are susceptible to stress corrosion cracking (SCC)1-6 The alloy U-5wt% Nb, for example, is susceptible to SCC in a wide range of environments. The study presented here shows that the incubation time and the fracture mode are pronounced functions of thermal history for this particular alloy.
The data was obtained from 40 mil wires, cold swaged and drawn at Los Alamos Scientific Laboratories. As received, the wires possessed an ultimate tensile strength (UTS) of 230 ksi with 4 to 5% elongation.(1)
The as-received wires were vacuum annealed for one hour at 800 C (1472 F), 7-quenched in a quartz capsule filled with helium, aged, and then tensile stressed to 40 ksi, by dead weight loading, in 10-4N KC1 solution. Each specimen was processed prior to test, by wiping with hexane, followed by ultrasonic cleaning in benzene, ethanol and water.
At temperatures between...
