Effect of Neutron Irradiation on the Dynamic Fracture Toughness Behaviour of the 12% Chromium Steel MANET-I Investigated Using Subsize V-Notch Specimens

• Published in: Journal of nuclear materials 1991-11, Vol.191-194, p.850-854
• Main Authors: Wassilew, C, Ehrlich, K
• Format: Article
• Language: English
• ISSN: 0022-3115

The effect of neutron irradiation on the dynamic fracture toughness behavior of the 12% chromium steel MANET-I was investigated using DIN 50115-KLST, subsize, V-notch impact bend specimens (3 x 4 x 27 mm exp 3 ). The microstructure of the steel was varied by employing different quenching and austenitizing conditions. The specimens were irradiated in the HFR Petten at 300, 400, and 475 deg C to displacement damage levels as high as 5 dpa sub NRT . Experimental results are reported from an on going program aimed at determining the influence of irradiation-induced microstructural changes on the impact properties of MANET-I: the ductile-to-brittle transition temperature (DBTT), the relative fracture toughness, and the dynamic plane strain fracture toughness. Following irradiation a large increase in the DBTT and a remarkable decrease in the upper-shelf energy (USE) were observed. The changes in the properties depend strongly on the irradiation temperature. The DBTT and USE of the irradiated specimens also depend clearly on the initial microstructure of the material. The increase in DBTT and the decrease in USE are in general greater at 300 than at 400 and 475 deg C. Under proper conditions the instrumented impact test can be used to determine the dynamic plane strain fracture toughness K sub 1d and the J-integral of unirradiated and irradiated materials.