Electron-beam welding of thorium-doped iridium alloy sheets. [Ir--0. 3% W 200 ppM Th-50 ppM Al]

Technical Report · Sun Apr 01 04:00:00 EST 1979

DOI:https://doi.org/10.2172/6320475· OSTI ID:6320475

David, S. A.; Liu, C. T.; Hudson, J. D.

Modified iridium alloys containing 100 ppM Th were found to be very susceptible to hot-cracking during gas tungsten-arc and electron-beam welding. However, the electron-beam welding process showed greater promise of success in welding these alloys, in particular Ir--0.3% W doped with 200 ppM Th and 50 ppM Al. The weldability of this particular alloy was extremely sensitive to the welding parameters, such as beam focus condition and welding speed, and the resulting fusion zone structure. At low speed successful electron-beam welds were made over a narrow range of beam focus conditions. However, at high speeds successful welds can be made over an extended range of focus conditions. The fusion zone grain structure is a strong function of welding speed and focus condition, as well. In the welds that showed hot-cracking, a region of positive segregation of thorium was identified at the fusion boundary. This highly thorium-segregated region seems to act as a potential source for the nucleation of a liquation crack, which later grows as a centerline crack.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6320475
• Report Number(s): ORNL/TM-6711
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101* -- Metals & Alloys-- Preparation & Fabrication
ACTINIDE ALLOYS
ACTINIDES
ALLOYS
ALUMINIUM ADDITIONS
ALUMINIUM ALLOYS
ARC WELDING
BEAM OPTICS
CRACKS
CRYSTAL STRUCTURE
ELECTRON BEAM WELDING
ELEMENTS
FABRICATION
GAS METAL-ARC WELDING
IRIDIUM ALLOYS
IRIDIUM BASE ALLOYS
JOINING
JOINTS
METALLURGICAL EFFECTS
METALS
NUCLEATION
PLATINUM METAL ALLOYS
SEGREGATION
THORIUM
THORIUM ADDITIONS
THORIUM ALLOYS
TUNGSTEN ADDITIONS
TUNGSTEN ALLOYS
WELDABILITY
WELDED JOINTS
WELDING