Investigation of bonding mechanism and effects of brazing time on microstructure and bond strength of Ti6Al4V/Al2O3 Couple

In this study, using Ag-Cu brazing metal alloy, effects of brazing time on microstructure and strength of Al2O3 / Ti6Al4V joints were investigated. Therefore, ceramic/metal couple brazed by electrical furnace. Then, brazed specimens were examined by scanning electron microscope and x-ray diffraction tests. Several phases observed at the interface area and EDS analysis were recognized titanium, copper, silver, aluminum, vanadium and oxygen in this phases. With more study using x-ray diffraction patterns and phases diagrams some intermetallic compounds identified. This compounds were Ti-Cu intermetallices near to Ti6Al4V side and reactive layer of Cu2O ૠ┻ near to Al2O3 ceramic side. Also, microstructural surveys revealed the narrow reaction layer and a little intermetallic compounds in specimen brazed for 10 minutes. With increasing brazing time, reaction layers grossed rapidly. This chemical variation made dimensional changes at metal/ceramic interface. Therefore, some crakes observed in specimen brazed for 25 minutes. Maximum of shear strength equal 295 Mpa measured in specimen brazed for 15 minutes.