Laser sintering of Cu-Sn-C system P/M alloys.

The Cu-Sn-C system P/M alloys were sintered by laser. The influence of laser sintering on the properties of the laser-sintered materials was investigated. The properties, such as the density, impact toughness, hardness and wear resistance of the laser-sintered materials are desirable. A maximum impact toughness of 11.7 J/cm² was achieved and the wear resistance of the laser-sintered materials was tremendously increased compared with conventional sintering. The green compact made from Cu-Sn-C powders, with a thickness of 10 mm, can be penetratively sintered by using a suitable processing condition. The laser sintering was characterised by a thermal cycle which was accomplished in a relatively short time, resulting in a relatively high temperature (950 °C). The curves showing temperature profiles for the top surface and bottom of the laser-sintered specimen were recorded by thermocouples. Differences in temperatures between the top surface and bottom were very small, less than 60 °C. Some intermetallics/phases such as α-Cu, Cu₃₁Sn₈(δ), Cu₄Sn(ε) and Cu₆Sn₅(η) were most readily produced in the laser-sintered materials and their distributions were more homogeneous than conventional sintering, owing to the better flow ability of the melt caused by a relatively high sintering temperature. The behaviour of diffusion between Cu and Sn was also studied by means of simulation diffusion couple. [ABSTRACT FROM AUTHOR]