Influence of brazing temperature on interfacial reaction layer characteristics of Cu-Sn-Ti/diamond composites

Cu-Sn-Ti/diamond composites have been manufactured by cold-press forming followed by high-temperature vacuum brazing. The effects of brazing temperature on Cu-Sn-Ti/diamond wetting behaviors and associated morphologies, interfacial reaction layer products and thickness variations, elemental distribution features, as well as corresponding orientation relationships, have been systematically investigated. It has been documented that as the brazing temperature increases, diamond particles are gradually coated by the active Cu-Sn-Ti filler alloy. The interfacial reaction layer products are determined to be primarily composed of TiC, the formation of which is driven by the diffusion of dissolved Ti and reaction with C. It has been revealed that the thickness of the TiC layer shows a definitive increasing trend till reaching 1.75 mu m up to 1213 K but stops afterwards. Concurrently, TiC has been confirmed to possess a semi-coherent orientation relationship ((1 1 1)TiC//(1 1 1)diamond and [1 1 0]TiC//[1 1 0]diamond) with the diamond matrix, boding well for a robust chemical bonding. It is suggested that the brazing temperature shall be limited under 1213 K for optimized bonding strength and grinding capability.