The effects of rare earth on the fracture properties of different metal–diamond composites

The present study was carried out to compare the effects of rare earth (RE) in diamond composites bonded by three different metal matrices. The composites were fabricated by hot-pressing and RE was added to the base bond metals in a form of misch-metal. The transverse rupture strength (TRS) of the composites was evaluated by a three-point bending test. SEM and EDS were used to analyze the resulting fracture surfaces from the bending test. For the copper–tin based bond matrix, both hardness and TRS of the composites with RE were greater than those without RE. For other two bond matrices with high content of iron, hardness increased slightly but TRS decreased while the matrix contained RE.