Evaluation of bonding properties by flat indentation method for an EBW joint of RAFM steel for fusion application

Abstract Welding is essential to construction and safe operation of fusion reactors. Besides fusion materials themselves, small specimen test technologies (SSTT) are also essential to evaluate bonding properties of the joints for fusion application. In the present study, flat indentation method based on energy–density equivalent principle was utilized for bonding properties evaluation for an electron beam welded (EBW) joint of a reduced-activation ferritic/martensitic (RAFM) steel, CLF-1. The energy–density equivalent principle describes relationships among the material parameters of Hollomon’s power law, indenter diameter, energy, and indentation displacement. The flat indentation method can determine the Hollomon’s power law parameters of materials directly. For the base metal (BM), the true strain–stress data from flat indentation tests are almost consistent with the results obtained via uniaxial tensile tests and are proved to be reliable. When the indentation tests executed on the weld metal (WM), the bonding properties can be reliably obtained by this method. The WM shows larger yield strength, ultimate tensile strength, and uniform elongation, but a little smaller strain hardening index than the BM.