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Columbus, OH, United States

Eckardt T.,Ohio State University | Hanhold B.,Ohio State University | Petrasek D.,Ohio State University | Sattler S.,Ohio State University | And 2 more authors.
Welding Journal

The results of wetting, shear strength, and metallurgical testing for aluminum and silver-based filler metals for brazing titanium are reported. Five different aluminum-based filler metals were evaluated to find out which exhibits the best properties in brazing titanium. These five filler metals were tested on both Grade 2 and Grade 5 titanium stock. Brazing was performed in a vacuum furnace and in air by heating with a propane torch. The flux used during brazing in air was the fluoride-chloride flux RL3A16A. After analyzing wetting, shear strength, and microstructure results, TiBrazeAl-635 and TiBrazeAl-700 were determined to yield the best results. The composite TiBrazeAl-700 filler metal exhibited good shear strength values when brazed with the controlled heating and cooling rate of a vacuum furnace. TiBrazeAl-635 also yielded the highest shear strength of all alloys tested when brazed in the vacuum furnace. Source

Shapiro A.E.,Titanium Brazing Inc. | Fischer G.,Ion Vacuum Technologies Corporation | Markovich M.,Ion Vacuum Technologies Corporation
IBSC 2012 - Proceedings of the 5th International Brazing and Soldering Conference

A new method was developed and successfully implemented for vacuum brazing CP titanium, Ti-6Al-4V alloy and sintered chromium using transition metal ion bombardment in arc plasma, with application of silver-based BAg-7, titanium-based TiBraze375, and aluminum-based BAlSi-4 filler metals. The method is characterized by simple surface preparation and process control, for brazing both small and relatively massive parts. The brazing parameters can be easily optimized to the mass and shape of parts to be joined. There is rapid cooling upon completion of the brazing due to processing in a cold chamber, resulting in the formation of uniform, fine-grained microstructure in the joint metal. There is only insignificant formation of brittle intermetallics at the interface with titanium, and absence of intermetallics at the interface with chromium. The new method is applicable to manufacturing of parts for electronic devices, compressor blades, PVD cathodes, and structures in a broad range of industrial applications. Copyright 2012 ASM International® All rights reserved. Source

Shapiro A.E.,Titanium Brazing Inc. | Flom Y.A.,NASA
IBSC 2012 - Proceedings of the 5th International Brazing and Soldering Conference

Conventional Ti-based brazing filler metals (BFM) have brazing temperatures in the range of 860-1000°C which is above α-β transus of industrial titanium alloys. The limitation of brazing temperatures by the α-β transus temperature is especially important for thin-wall structures usually used in the Aerospace applications, e.g., fin-plate heat exchangers, honeycombs, and pipes. Aluminum brazing filler metals can be used to resolve the problem of low-temperature brazing titanium structural components in applications which do not experience high mechanical loads. Despite of well-known application of aluminum-based filler metals for brazing titanium, they are still out of everyday industrial practice due to low strength of joints brazed with pure aluminum or standard AWS BAl-4 (Al-12Si) filler metal, and problems in the manufacture of foils or wires from brittle alloys of Al-Cu-Si or Al-Ag-Cu systems. New cold-rolled brazing foils of Al-Mg and Al-Cu-Mg, as well as composite foils of the Al-Ni-Cu-Si and Al-Cu-Ag alloy systems modified with Mg, Fe, and Sn were studied by testing wetting of CP titanium and Ti-6Al-4V substrates in vacuum at the temperature range of 600-710°C, measuring shear strength of brazed joints, and investigating the microstructure to find out formation of intermetallics in the joints. Some of new brazing alloys demonstrated the shear strength of titanium brazed joints, which is significantly higher than that of traditional Al-12Si eutectic filler metal. Copyright 2012 ASM International® All rights reserved. Source

Duffey M.J.,Ohio State University | Marchal J.T.,Ohio State University | Loney M.R.,Ohio State University | Alexandrov B.T.,Ohio State University | Shapiro A.E.,Titanium Brazing Inc.
Welding Journal

The results of wetting and shear strength testing, and metallurgical characterization of silver-free filler metals designated for brazing low-carbon steel, stainless steel, and Ni-plated carbon steel are reported. Silver-based brazing filler metal have been utilized for hundreds of years. They offer excellent, strong joints with legacy as their advantage, and are easy to braze. Complications in terms of base metal-filler metal compatibility arise by several different mechanisms. One possible detrimental effect when introducing a braze filler metal is the formation f potentially brittle inter-metallics at the interface of the base metal. Alloying occurs in a thin layer along the joint interface, with more profound mixing, as time spent at elevated temperature increases. Source

Marchal J.T.,Ohio State University | Duffey M.J.,Ohio State University | Loney M.R.,Ohio State University | Alexandrov B.T.,Titanium Brazing Inc. | Shapiro A.E.,Titanium Brazing Inc.
Welding Journal

The results of wetting and shear strength testing along with metallurgical characterization of Cu-4Sn-6P and Cu-40Zn-1Sn-0.3Si silver-free filler metals designated for brazing copper and brass are detailed. The filler metals with low spreading area have difficulty spreading through the joint and creating fillets, thus decreasing the overall strength of the joint. Silver-free LOK59-03 exhibited better spreading on copper than a standard silver-based alloy Bag-1. The load displacement shows low ductility of the LOK59-03 brazed joint, while the copper brazed joint made with P14 has mechanical behavior with some ductility of the joint metal. When used for joining copper or brass tubes with connectors, adapters, and faucets, both tested silver free filler metals provided formation of quality, dense brazed joints with smooth fillets. Source

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