Microstructure and mechanical properties of pre-brazed diamond abrasive grains using Cu–Sn–Ti alloy

• A new way was put forward to fabricate metalized diamonds with brazing alloy.
• The diamonds are called pre-brazed diamonds.
• The interfacial resultant containing TiC was formed at joining interface of pre-brazed diamonds during the brazing process.
• The diamond segments consisting of pre-brazed diamonds and metal matrix were fabricated.
• Good interfacial bonding strength between pre-brazed diamonds and metal matrix was obtained.

A new method of surface metallization of diamond abrasive grains was developed using Cu–Sn–Ti brazing alloy. The diamond grains metalized by brazing are called pre-brazed diamond grains. Brazing equipment was vacuum resistance furnace and high-frequency induction furnace separately. Diamond segments consisting of the pre-brazed diamonds and metal matrix were sintered. The static compressive strength of the diamonds and the bending strength of the segments were measured. The interfacial microstructures of the diamonds and the segment fracture surface were characterized. The surface micrograph of the diamonds brazing in vacuum resistance furnace was better. When the mean weight gain rate of the diamonds was 6.4%, the mean strength value of the diamonds was 2533.4 MPa. Elemental distribution showed that Ti mainly concentrated at the joining interface of diamond/Cu–Sn–Ti alloy. The interfacial resultant containing TiC was formed at diamond/Cu–Sn–Ti alloy interface. Good interfacial bonding strength was formed at the joining interface of pre-brazed diamonds/metal matrix.