MECHANICAL-PROPERTIES AND DAMAGE BEHAVIOR OF NONMAGNETIC HIGH MANGANESE AUSTENITIC STEELS

Fe-Cr-Mn steels have been considered as materials of structural compon ents for fusion reactor because of their low induced-radio-activity co mpared with SUS316 stainless steels. It has been expected to develop a non-magnetic steel with a high stability of the austenitic phase and a strong resistance to irradiation environments. For these objectives, a series of the Fe-Cr-Mn steels have been examined by tensile tests a nd simulation irradiation by electrons. The main alloying compositions of the steels developed are; C:0.02-0.2 wt%, Mn:15 wt%, Cr:15-16 wt%, N:0.2 wt%. These steels were heat-treated at 1323 K for 1 h. The stru cture of the steels after the heat-treatment was austenite single phas e. The yield stress of the steels was 350-450 MPa and the elongation w ere 55-60%. When the steels of high C and N was electron-irradiated at below 673 K, no voids were nucleated and only small dislocation loops were formed with high density. The austenite phase was also stable du ring irradiation below 673 K. Thus, newly developed high manganese ste els have excellent mechanical proprieties and high irradiation resista nce at relatively low temperature. (C) 1998 Elsevier Science B.V. All rights reserved.