Shear punch and tensile measurements of mechanical property changes induced in various austenitic alloys by high-energy mixed proton and neutron irradiation at low temperatures

Tensile and shear punch tests of Inconel 718, 316 L and 304 L specimens irradiated with very high-energy protons and spallation neutrons showed that irradiation caused significant hardening and loss of uniform elongation. The specimens were irradiated at temperatures from room temperature to 150 °C in the Los Alamos Spallation Radiation Effects Facility (LASREF) at the Los Alamos Neutron Scattering Center (LANSCE). Dose levels ranged from 0.01 to 12 dpa. Most of the observed hardening for all three alloys occurred within the first 0.1 dpa (i.e., low dose) and before significant gas accumulation, indicating that gas generation may not play a significant role in the hardening or ductility loss. The correlations between tensile and shear punch data were as expected for yield strength but were unusual for the maximum strength in comparison with previous correlations based on fission-neutron-irradiated alloys.