Hydrogen susceptibility of nano-sized oxide dispersed austenitic steel for fusion reactor

Effects of hydrogen on the mechanical properties and fracture patterns of nano-sized yttria (Y2O3) dispersed 316L austenitic steel usually mentioned as oxide dispersed strengthened (ODS) steel was studied from in situ tensile test using small specimens under high-pressure hydrogen gas, and the steel's hydrogen desorption properties were quantified using thermal desorption spectra analysis. The steel samples were prepared using powder metallurgy from precursor powders with 5 mu m and 150 mu m particle size, then processed by mechanical alloying and hot isostatic press. The original powder size affected mechanical properties and hydrogen embrittlement. Type-316L ODS steel with fine grain size showed the robust tensile property under gaseous hydrogen and less hydrogen susceptibility. Yttria-doped 316L steel is a candidate for use as a structural component exposed to hydrogen in nuclear fusion reactors, so these results will be useful to material and component design criteria. (C) 2017 Elsevier B.V. All rights reserved.