Microstructure and Mechanical Behavior of Porous Metal-bonded Diamond Composites for Grinding Wheels

摘要

In this paper, the effects of porosity on the metal bonds and diamond composites have been studied by analyzing their microstructures and mechanical behaviors. The experimental results revealed that a moderate fraction of porosity(15 ～ 20%) would induce a significant decrease in the transverse rupture strength (TRS). The impact of porosity on the TRS of metal bonds was greater than that of diamond composites, and, at lower fraction of porosity, the TRS of the sintered materials were more sentitive to the porosity. With an increase in porosity fraction, the average size of pores increased, and their shape changed from spherical to irregular. Furthermore, the fracture surface morphology of metal bonds changed from more characteristic of ductile appearance to a fully brittle appearance. At high fraction of porosity, the metal matrix particles had not sintered well with their adjacent particles, and the bonding between metal matrix and diamond particles was subsequently poor.