Obtaining composite 93 W – 4.9 Ni – 2.1 Fe powder with a spherical particle and investigating the possibility of its use in selective laser melting

The powder of 93 W – 4.9 Ni – 2.1 Fe (VNZh-93) pseudo-alloy with a spherical particle shape in the size range of 15 – 50 μm with a grain size of 0.5 – 3 μm was obtained using plasma chemical synthesis, granulation and spheroidization technologies. The possibility of using spheroidized powder VNZh-93 in additive 3D-printing is demonstrated. Studies of the physical and mechanical characteristics and microstructure of VNZh-93 test samples made using the selective laser melting technology (SLM) have been carried out. It is shown that the parameters of the SLM significantly affect the formation of the microstructure of test samples. It is possible to form a homogeneous equiaxed microstructure with an average grain size of about 1 micron using optimal SLM modes. It is shown that maximum density and Vickers hardness of VNZh-93 obtained in optimal SLM modes are 16.8 g/cm3 and 480 HV, respectively. These values are not inferior to the values for VNZh-93 samples obtained using traditional liquid-phase sintering technology. At the same time, the main problem of selective laser melting of VNZh-93 powder is the heterogeneity of the bulk samples microstructure and the formation of microcracks and micropores in their structure.