US EPA

4836767 

Journal Article 

Brazing Molybdenum and Graphite with a Titanium-Based Powder Filler Metal 

Fedotov, IV; Richman, CE; Sevryukov, ON; Suchkov, AN; Li, J; Kalin, BA; Fedotov, VT; Ivannikov, AA 

2016 

1 

Welding Journal
ISSN: 0043-2296 

95 

9 

357S-361S 

WOS:000382898400023 

A new method of brazing Mo-C joints for mechanical performance up to 1650 degrees C was found. A Ti-40 Zr-8.5 Nb-1.5 Be powder filler metal was created for this brazing application, and its melting range and phase composition were found. The effects of different filler metal powder application amounts per brazed area and the texture of the graphite side of the brazed joint were studied. EDS microanalysis of the brazed joint was carried out and the connections were analyzed for shear strength and porosity. EDS analysis revealed Ti, Zr, and Nb carbides were present in the brazed joint. When the graphite surface was smooth, the most high-quality joints were obtained with a powder application of 0.5 g/cm(2). It was found that texturing the graphite surface with concentric notches increased the shear strength of the joints by 2.5x. The strongest brazed connection, in which the graphite surface was notched, was subjected to a remelting test. The braze was maintained when heated to a temperature of 1650 degrees C, though the composition of the brazed joint changed, exhibiting a higher concentration of carbides near the tips of the notches. 

Brazing; Joining; Molybdenum; Graphite; Microstructure