Effect of implanted deuterium on tensile properties of helium-doped RAFM EUROFER97

Reduced activation ferritic-martensitic (RAFM) 9%Cr steel EUROFER97 specimens were homogeneously implanted to a concentration of 300 appm helium at temperatures of 125 degrees C, 250 degrees C 01 500 degrees C. Some specimens were subsequently implanted to 3000 appm deuterium at temperatures of 125 degrees C or 250 degrees C, while others were annealed before deuterium implantation for 10 h at 750 degrees C to form helium bubbles. The specimens were tensile tested at temperatures of 25 degrees C, 125 degrees C, 250 degrees C or 500 degrees C. After tensile testing, fracture surfaces were analysed by scanning electron microscopy. Tensile strength was increased and strain reduced by low temperature (25 degrees C or 125 degrees C) He-implantation, while implantation at higher temperatures as well as annealing after He-implantation gave just the opposite effects, causing strain recovery even beyond the value of unimplanted material. Deuterium implantation reduced ductility, but significantly only when both, implantation and testing occurred at low temperatures. Helium pre-implanted as well as after subsequently annealing, had no influence on hydrogen embrittlement. (C) 2010 Elsevier B.V. All rights reserved.