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Tuesday, June 19, 2007, Brüssel 11:40 AM Grundlagen und industrielle Anwendungen des Lötens Fundamentals and industrial application of brazing |
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Infrared Vacuum Brazing of Ti-6Al-4V and Nb Using the Ti-15Cu-15Ni Foil |
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Ren-Kae Shiue / National Taiwan University, TAIWAN C.S. Chang* / Engineered Materials Solutions, USA D.W. Liaw/ Department of Materials Science and Engineering, National Dong Hwa University, Taiwan Z.Y. Wu/ Department of Materials Science and Engineering, National Taiwan University, Taiwan R.K. Shiue/ Department of Materials Science and Engineering, National Taiwan University, Taiwan |
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The microstructural evolution of infrared brazed joint is primarily depended upon redistribution of alloying elements such as Cu, Ni and Nb across the joint. For the specimen infrared brazed at 970oC for 180s, the joint primarily consists of coarse eutectic Ti2Cu, Ti2Ni intermetallics and transformed beta-Ti. Increasing the brazing time to 600s results in a fine eutectoid microstructure dominating the entire joint due to the depletion of Cu and Ni from the braze alloy into Ti-6Al-4V substrate. Ti2Cu, Ti2Ni and transformed beta phases are almost absent from the specimen infrared brazed for 3600s, and the beta-Ti is stabilized by alloying high concentration of Nb. Based on the shear test result, all cracks propagate along the Nb substrate with typical ductile dimple rupture appearance. Consequently, Ti-6Al-4V and Nb can be vacuum brazed by Ti-15Cu-15Ni foil with good joint strength. |