High-strength and wear-resistant Co-Cr-Mo/diamond composites fabricated by selective laser melting

In this study, selective laser melting (SLM), an additive manufacturing technology, is used to fabricate Co-Cr-Mo/diamond (10 vol%) composite samples for application in the field of diamond tools. To obtain suitable SLM processing parameters, the samples were optimized in terms of the three-dimensional roughness, microhardness, relative density, and bending strength. The results indicated that the optimal SLM processing parameters were a laser power of 220 W, scanning speed of 750 mm/s, and layer thickness of 0.05 mm, and the bending strength of the samples reached 1000 MPa. Furthermore, the influence of the laser energy on the melting of the mixed powder, expansion of the melt pool, and bonding of Co-Cr-Mo/diamond composites during the SLM process was determined simultaneously. In addition, the abrasion resistances of the Co-Cr-Mo and Co-Cr-Mo/diamond-composite samples were compared using frictional wear tests. The results showed that the mass-loss of the Co-Cr-Mo samples equalled 2.1%, and the friction coefficient increased continuously from 0.13 to 0.75 before stabilizing. The mass-loss of the Co-Cr-Mo/diamond-composite sample equalled 0.3%, and the coefficient of friction maintained a dynamic equilibrium of approximately 0.3, which indicated that the Co-Cr-Mo/diamond-composite sample had better abrasion resistance. This study provides a new method for fabricating complex diamond tools with a high concentration of diamond in a refractory metal matrix.