Disk-Bend Ductility Tests for Irradiated Materials

Because irradiation is known to cause a decrease in the ductility of numerous structural alloys, a simple test to determine the ductility of small irradiated specimens would be extremely useful. A mechanical test designed for this purpose was developed by Hanford Engineering Development Laboratory (HEDL). Changes in the ductility of an alloy are determined by bending a transmission electron microscopy disk (3 mm diameter by 0.25 mm thick) in a hemispherical punch and die. We modified the HEDL test machine and are using it to qualitatively screen alloys that are susceptible to embrittlement caused by irradiation. Tests designed to understand the disk-bend test in relation to a uniaxial tensile test are discussed. Selected results of tests after neutron irradiation are also presented.