Achieving optimal Ti content via interfacial reaction layer characteristics of diamond/Cu-Sn-Ti composites

Diamond/Cu-Sn-Ti composites as potential super-hard abrasive products were prepared in this work by spark plasma sintering at 1223 K. The effects of Ti content on the wettability, interfacial reaction layer thickness, and wear resistance of the bulk composite changes were systematically studied. The results revealed that when the Ti content was below 5 wt.%, completely uncoated and partially coated diamond grains were still observed, indicating insufficient wettability, and the interfacial reaction layer appeared to be thin. When the Ti content was 5 wt.%, all diamond grains were completely coated, and a continuous and stable interfacial reaction layer composed of TiC has been generated, in which the thickness reached a peak value of 1.72 μm. However, when the Ti content exceeded 5 wt.%, the formation of brittle Cu41Sn11 phases was observed, which led to inferior wear resistance. The minimum weight loss was obtained at 5 wt.% Ti content. Meanwhile, through FIB-TEM, confirmed that the interfacial reaction layer was mainly composed of continuous TiC layer adjacent to diamond and discontinuous TiC layer in the filler metal, and constitute the formation of a high strength metallurgical interfacial bonding layer.