STRESS-STRAIN PROPERTIES OF IRRADIATED URANIUM-10 w/o MOLYBDENUM

The stress-strain properties of the APDA reference alloy of uranium- 10 wt.% molybdenum at various burnups up to 2.1 total at. % are described. Data were ob tained on both irradiated and unirradiated specimens of the alloy by the use of a remotely operated bend-testing machine. Tensile properties of unirradiated material are also reported for comparison with data obtained from the bend tests. The mathematical procedure used in obtainirg equivalent uniaxial stress-strain properties from the bend-test data is described in the Appendix. The results of the bend tests indicate that the physical properties of the reference alloy were severely affected by irradiation to burnups as high as 2.1 total at.%. At a test temperature of 500 deg C, the modulus of elasticity, ultimate strength, and strain at fracture decreased rapidly up to a burnup of about 0.5 to 1.0 total at.% with the rate of change decreasing thereafter. No important differences were noted between coextruded and hot-rolled material. An indication was obtained that the ultimate strength of the alloy was improved with increasing irradiation temperatures up to about 500 deg C. Data obainined on unirradiated material indicated that ductility of the reference alloy was lower at 500 deg C thanmore » at room temperature. Stress-strain curves for the irradiated specimens are included. The value of these data is limited because of the large number of variables encountered in the specimen histories and the small number of tests involved in this program. (auth)« less