Effect of composition of titanium in silver-copper-titanium braze alloy on dissimilar laser brazing of binder-less cubic boron nitride and tungsten carbide

Dissimilar vacuum brazing of WC-Co and cold work steel utilizing a new near-eutectic silver-copper filler alloy

“…Incomplete bonding had only appeared on the surface between filler and tungsten carbide, as the filler needs much higher temperature to activate the surface by the means of titanium content in the filler metal. 42,43 However, in the other surface between the filler and steel, the bonding was much better, as the silver-copper-based filler has sufficiently good wetting properties against iron base metal. 41 This explain the previous observation in Figures 9 and 10, where all the brazing joints at 800 °C with different cobalt contents showed low shear strength values and failed on the surface between tungsten carbide and filler metal.…”

“…Adding titanium (Ag 70 Cu 28 Ti 2 ) (BAg-8T) as an active element in silver-copper alloy improves the wettability of the braze joint at short melting range (778 °C/800 °C). 40–43…”

“…Adding titanium (Ag 70 Cu 28 Ti 2 ) (BAg-8T) as an active element in silvercopper alloy improves the wettability of the braze joint at short melting range (778°C/800°C). [40][41][42][43] In addition to BAg-8T filler material, a porous copper sheet, coated by active titanium hydride TiH 2 (used to enhance the wettability) on both sides, is used as an internal stress eliminator, as it contains small voids and the pores are filled with gas. The selection of this type of porous sheet is based on its tendency to buffer stress generated, due to differing coefficient of expansion.…”

“…Stainless steel was selected as the material for clamping, as it has high melting temperature and high resistance to bending on elevated temperatures and inert properties. 41,42 Figure 5 Apparatus and method. Figure 6 shows the vacuum furnace used as the heating source of brazing.…”