Brazing of C/C composites and titanium alloys with inserting OFHC copper foil

摘要

The brazing of C/C composites (CFC) and commercially pure titanium with Ag-Cu-Ti active brazing filler was conducted. The composition of titanium in the brazing filler was determined by the spreading test of the brazing filler on the CFC plate. The brazing filler metal of Ag-36mass%Cu-1.8mass%Cu was considred suitable for the CFC/Ti brazing. By arranging the C/C composites' ply surface perpendicular to the brazing interface, the tensile strength of the brazed joint was improved as high as 62 MPa at maximum and 45 MPa in average. The microstructure of the brazing interface was examined optically and using SEM. The infiltration of the brazing filler into the C/C composites was observed, which could degrade the brazed joint strength. For long brazing time, the solidification cracking was occurred, which also could degrade the brazed joint strength and reliability. To prevent these effects, the oxygen free high conductivity copper foil was inserted in the brazing interface. This brazed joint showed the comparable joint strength with the directly brazed joint, and improved the variation in the joint strength.