Effect of Strain Rate on the Tensile Mechanical Properties of Electron Beam Welded OFE Copper and High-Purity Niobium for SRF Applications

Abstract An investigation of the tensile mechanical properties electron beam welded OFE copper and high-purity niobium sheets is presented. Specimens were deformed in tension at strain rates ranging from 10 −3 to ~ 1600 s −1 . The 0.2% yield stress ultimate strength (UTS) specimens are similar those unwelded lower or equal 20 At higher rates, these for specimens. consistently than over range studied, while UTS comparable all rates. elongation failure remains unchanged ductility reduces greater reaches a minimum 400 effects weld on non-standardized short specimen geometry, developed this study obtain order 3 , more pronounced due large grain sizes (up 1200 μm) fusion region. However, trends, with respect standard specimen, measured low conservation relatively high sheets, especially copper, suggest that bent tubes could be used fabrication seamless superconducting radiofrequency (SRF) cavities. These results promising use high-speed forming techniques, like electro-hydraulic forming, manufacturing parts using sheets.