Brazing of tungsten-copper composites using Ag-Cu alloys

摘要

Brazing of W-19vol%Cu composite was carried out using Ag-Cu alloy foils with thickness of 20, 50 and 100μm. Ag-Cu alloy was used as the brazing material, considering both its lower melting point than pure copper and its good wettability for copper. Microstructure of the brazed layer and its vicinity was observed using SEM. Yield and maximum strengths of the brazement were evaluated using three-point bend tests at room temperature. After tests, all the fracture surfaces were examined using SEM. Results are summarized as follows. (1) Thickness of the brazed layer was ranging between 15 and 40μm, depending on the initial thickness of Ag-Cu alloy. (2) Brazement using Ag-Cu alloy of 50μm thick demonstrated yield and maximum strengths comparable with those of bulk composite. (3) Fracture site was basically along the boundary between the brazed layer and the composite.