Brazing of W-20%Cu Composite Using Sandwich Filler Materials of BAg-8 Sheets and Ti Foils

W-Cu composite materials are used as electrical and electronic industries from the viewpoints of electrical, mechanical and chemical properties.   In order to prepare more complicated products, however, joining of composite materials is one of critical issues.   At IBSC2006 Conference, we reported that Ni-plating on the composite is effective to enhance the joint strength and to reduce the data scattering.   However, the average strength is still much lower than that of the bulk composite material.

In this study, we investigated the effect of Ti addition to BAg-8 filler metal on the joint strength of W-20vol%Cu composite material.   The filler materials used are sandwich-like of BAg-8 thin sheets and Ti foils.   Ti contents were ranging between 2 and 10 mass%.   Joining temperatures were 1093-1133 K and holding time was 300 s in a vacuum of 10^-4 Pa.   Results are summarized as follows. (1) Ti addition tended to enhance the joint strength and reduce the data scattering.   Optimum joining temperature was 1093 K.   (2) Ti addition distinctively changed the fracture mode.   No poor bonding regions were observed.   Fracture occurred mostly at the interface between the bonded region and the bulk material and partly in the bulk near the interface.