Low Strain-Rate Microstructural Deformation Behavior in 316 Stainless Steel Irradiated in EBR-II

In order to better understand the influence of the radiation-induced defect microstructures on changes in stainless steel deformation behavior, the microstructures of irradiated 12 % cold-worked 316 stainless steel were examined following slow-strain-rate tensile testing. Tensile samples were fabricated from two hexagonal ducts that were irradiated in the outer rows of the Experimental Breeder Reactor. The samples were irradiated at temperatures ranging from approximately 383 to 443 C and doses up to approximately 41 displacements per atom. The tensile tests were conducted at a strain rate of 1 x 10{sup -7}s{sup -1} and test temperature of {approx}430 C . Transmission electron microscopy was employed to quantify the defect microstructures of three pairs of samples, each pair having been exposed to similar irradiation conditions. One sample of each pair was taken from the gauge section of a tested tensile sample, and the other was untested. The influence of the defect microstructure on the deformation and fracture behavior is evaluated and results are discussed in light of current theories of deformation behavior in irradiated metals.