Hydrogen Transport Microstructure And Hydrogen Induced Cracking In Austenitic Stainless Steels PDF Download

High-energy-rate-forged (HERF) austenitic stainless steels are used for the containment of hydrogen and its isotopes. Embrittlement of these materials by hydrogen has been a source of concern for some time. The nature and the degree of embrittlement by hydrogen varies considerably and, among other factors, is a complicated function of material composition and processing variations. Helium, the radioactive decay product of tritium, will also embrittle stainless steels. Precipitation of microscopic helium bubbles tends to increase the material's flow stress, through dislocation pinning, as well as weaken interfaces like grain and twin boundaries. Since fracture toughness tends to decrease with increasing yield strength, at least part of the helium-embrittlement problem may be due to strength effects. The relationship between a material's yield strength and toughness and, the incremental strength increase and corresponding toughness decrease imparted by helium is not known. The purpose of this study was to measure the combined effects of strength, hydrogen isotopes, and helium on the room temperature mechanical and fracture toughness properties of HERF 21-6-9 stainless steel.