FRACTURE-BEHAVIOR OF NEUTRON-IRRADIATED HIGH-MANGANESE AUSTENITIC STEELS

The instrumented Charpy impact test was applied to study the fracture behavior of high-manganese austenitic steels before and after neutron irradiations. Quarter-size specimens of a commercial high-manganese steel (18% Mn-5% Ni-16% Cr), three reference steels (21% Mn-1% Ni-9% Cr, 20% Mn-1% Ni-11% Cr, 15% Mn-1% Ni-13% Cr) and two model steels (17% Mn-4.5% Si-6.5% Cr, 22% Mn-4.5% Si-6.5% Cr-0.2% N) were used for the impact tests at temperatures between 77 and 523 K. The load-deflection curves showed typical features corresponding to characteristics of the fracture properties. The temperature dependences of fracture energy and failure deflection obtained from the curves clearly demonstrate only small effects up to 2 x 10(23) n/m2 (E > 0.1 MeV) and brittleness at room temperature in 17% Mn-Si-Cr steel at 1.6 x 10(25) n/m2 (E > 0.1 MeV), while ductility still remains in 22% Mn-Si-Cr steel.