Selective Laser Melting of TiC Solid Solution Strengthened Tungsten Matrix Composites

The nanocrystalline TiC solid solution strengthened tungsten matrix composites were prepared by selective laser melting (SLM). The influence of applied laser linear energy density (eta) on densification level, microstructure, microhardness, and wear resistance of SLM-processed composite parts was studied. Results show that a low laser linear energy density leads to the formation of micropores. In contrast, a high laser linear energy density produces the microcracks, caused by the thermal stress. These two situations generally lower the SLM densification. However, at a reasonable eta of 2.1 kJ/m, the SLM-processed composites part has a near-full 94.7 % theoretical density and a significantly increased microhardness (HV0.2) of 8062 MPa. The dry sliding wear tests reveal that a considerably low friction coefficient of 0.583 without any apparent fluctuation and a reduced wear rate of 0.69x10(-15) m(3)/Nm are achieved. A uniform distribution of columnar crystals is obtained in SLM-processed tungsten matrix composites, with an average diameter of crystals of 0.73 mu m.