Effect of addition on microstructures and mechanical properties of cBN/Cu-Zn-Ti composites via the pulse electric current sintering

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In order to improve the performance of metal-bonded grinding wheels, the cBN/Cu-Zn-Ti composites were fabricated by pulse current sintering with several different Co contents (i.e., 5, 10, and 15 wt%) were added. The specimen microstructure, interfacial analysis and fracture morphology of pulse current sintering cBN grain were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The mechanical properties of hardness, wear resistance, and three-point bending strength of the fabricated specimens were tested. The electrochemical properties was also tested. The specimen shape fabricated by pulse current sintering using the composite Cu-Zn-Ti alloy doped by Co was better than pure Cu-Zn-Ti alloy. The microscopic analysis revealed that TiB2 and TiN were maintained between the Cu-Zn-Ti composites and cBN. With the addition of Co, the hardness, flexural strength and wear resistance of the specimens are improved. The new phase CoTi3 enhancing strength of the metal composite via the Orowan mechanism. The S5 specimen containing 15 wt% Co particles has the highest flexural strength, which is 485.83 MPa and satisfies the requirements of high speed grinding. Meanwhile, when the Co content reaches 10 %, the lowest friction coefficient (0.217) and lowest wear rate (0.81 mg) are achieved for the sample. With the addition of Co, the corrosion resistance of the material is significantly improved.