Microstructure and mechanical properties of joints in sintered SiC fiber-bonded ceramics brazed with Ag Cu Ti alloy

Journal Article · Sat Dec 31 23:00:00 EST 2011 · Materials Science and Engineering A

DOI:https://doi.org/10.1016/j.msea.2012.05.110· OSTI ID:1093097

Singh, Mrityunjay ^[1]; Asthana, Rajiv ^[2]; Ishikawa, Toshihiro ^[3]; Matsunaga, Tadashi ^[3]; Lin, Hua-Tay ^[4]

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1. NASA-Glenn Research Center, Cleveland
2. University of Wisconsin-Stout, Menomonie
3. Ube Industries, Ltd.
4. ORNL

Active metal brazing of a new high thermal conductivity sintered SiC-polycrystalline fiber-bonded ceramic (SA-Tyrannohexs) has been carried out using a Ti-containing Ag Cu active braze alloy (Cusil-ABAs). The brazed composite joints were characterized using scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM EDS). The results show that this material can be successfully joined using judiciously selected off-the shelf active braze alloys to yield metallurgically sound joints possessing high integrity. Uniform and continuous joints were obtained irrespective of differences in the fiber orientation in the substrate material. Detailed interfacial microanalysis showed that the titanium reacts with C and Si to form TiC layer and a Ti Si compound, respectively. Furthermore, the evaluation of shear strength of the joints was also conducted at ambient and elevated temperatures in air using the single-lap offset (SLO) shear test. The perpendicular-type SA-Tyrannohex joints exhibited apparent shear strengths of about 42 MPa and 25 MPa at 650 1C and 750 1C, respectively. The fracture at the higher temperature occurred at the interface between the reactionformed TiC layer and braze. This might be caused by generation of stress intensity when a shear stress was applied, according to m-FEA simulation results.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: ORNL work for others
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1093097
• Journal Information: Materials Science and Engineering A, Journal Name: Materials Science and Engineering A Journal Issue: 11 Vol. 557; ISSN 0921-5093
• Country of Publication: United States
• Language: English