Influence of hot pressing temperature on the microstructure and mechanical properties of 75% Cu–25% Sn alloy

• 75% Cu–25% Sn alloy is suitable for the bond in honing stones after hot pressing.
• α(Cu) + δ eutectoid structure appears in the hot pressing.
• α(Cu) + δ eutectoid structure composes hard brittle bond for honing stones.

The alloy of 75% Cu–25% Sn was utilised and hot-pressed for 4 min at 421, 520 and 600 °C to obtain a self-sharpening bond for diamond honing stones at low sintering temperature. Densification and mechanical tests were performed, and structures were investigated by X-ray diffraction, energy dispersive spectroscopy and scanning electron microscopy. Results showed that the porous structures changed into microporous structures when the hot pressing temperature was increased from 421 °C to 600 °C. The mechanical properties improved from HRB 79.1 to HRB 105.1 in hardness and from 104.2 MPa to 201.4 MPa in transverse rupture strength. After hot pressing at 600 °C, the microstructure consisted of α(Cu) + δ eutectoid and micropores, which meets the requirements of bonds for honing stones.