| Abstract: |
Precision brazing of molybdenum preforms can expand the range of potential engineering applications in the development of advanced functional components, when unique physical and mechanical properties in combination with electrical, thermal, and chemical properties are all specified as critical to ensure accurate and prolonged performance reliability without compromising the design requirements and stringent standard rules for compact, lightweight and robust construction.
In this study, high temperature vacuum furnace brazing technique was successfully performed to ensure precision brazing of high-aspect ratio (HAR) molybdenum pin/disc preforms using silver-based active brazing filler alloy. Efforts were also exerted to develop a basic understanding of the run-out phenomenon observed on the surface of thin moly-discs after brazing as it is principally driven by geometric factors and metallurgical driving forces. Elemental and structural analyses were performed to inspect and characterize the brazed moly-joints by means of Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDX), and X-ray Radiographic Imaging techniques. Brazed moly-pairs were joint by a subsequent vacuum brazing process in the structure of hermetically sealed vacuum tubes to test the tightness of the pre-brazed moly-joints by means of helium leak detection system.
Keywords: Vacuum furnace brazing, silver-based active brazing filler metal, molybdenum preforms.
|
|
