EFFECTS OF HYDROGEN ATMOSPHERE ON MECHANICAL-PROPERTIES AND SURFACE CONDITIONS OF A REDUCED-ACTIVATION FERRITIC STEEL F82H

Effects of hydrogen atmosphere on mechanical properties and surface co nditions have been studied for a reduced activation ferritic steel F82 H (Fe-8Cr-2W-V-Ta). Test specimens of F82H were exposed to hydrogen ga s atmosphere simulating the operating conditions of a fusion reactor. Surface analyses were performed by Auger electron spectroscopy in orde r to evaluate the depth profiles of surface atomic compositions of F82 H, and surface oxidation layers with a thickness of up to 56 nm were o bserved on the surface, mainly due to the high diffusion rate of oxyge n in F82H matrix. A quantitative analyses of the specimens exposed to hydrogen atmosphere were performed by a gaschromatograph, and absorbed hydrogen in F82H was found negligibly small, less than 5 ppm. Tensile and Charpy impact tests were carried out on these specimens, and mech anical properties were found comparable to those of as-received materi als. (C) 1998 Elsevier Science B.V. All rights reserved.