Staff scientist, Pacific Northwest Laboratory, Richland, WA
Pages: 17 Published: Jan 1990
A broad composition range of ferritic alloys exists which satisfy the low activation requirement for fusion reactor materials five hundred years after decommissioning. Low activation bainitic alloys in the Fe-2Cr composition range, martensitic alloys in the Fe-7-to-9Cr range and stabilized martensitic alloys in the Fe-12Cr range have been successfully fabricated and are undergoing testing as demonstrated by efforts in Europe, Japan, and the United States. However, irradiation significantly degrades the properties of bainitic and stabilized martensitic alloys. Bainitic alloys containing vanadium develop severe hardening due to irradiation-induced precipitation at temperatures below 450°C and extreme softening due to carbide coarsening at temperatures above 500°C. Stabilized martensitic alloys which rely on manganese additions to provide a fully martensitic microstructure are embrittled at grain boundaries following irradiation leading to severe degradation of impact properties. The most promising composition regime appears to be the Fe-7-to-9Cr range with tungsten additions in the 2% range where high-temperature mechanical properties and microstructural stability are retained and impact properties are relatively unaffected by irradiation.
bainitic, Charpy tests, ferritic, impact properties, martensitic, microstructure, neutron irradiation, phase stability, steels, swelling, tensile properties
Paper ID: STP24953S