Method of W-Ni-Fe Composite Spherical Powder Production and the Possibility of Its Application in Selective Laser Melting Technology

Abstract

For the first time, a powder of W-5Ni-2Fe composition with spherical particles from 15 to 50 microns and a tungsten grain size from 0.5 to 3 microns was obtained using a new technological approach, developed by the authors, based on plasma spheroidization of powder granules made from nanoparticles synthesized in a plasma chemical process. The possibility of using the obtained spheroidized powder W-5Ni-2Fe in the process of selective laser melting (SLM) has been proved. The microstructure, physical, and mechanical characteristics of experimental samples made using SLM technology from the produced W-5Ni-2Fe powder have been studied. The results of the performed studies have shown that the microstructure of experimental samples is extremely dependent on the parameters of the SLM process. The precise choice of the SLM process mode made it possible to obtain a homogeneous structure of experimental samples of tungsten heavy alloy (WHA), with a tungsten grain size of about 1–2 microns, which is much smaller than the tungsten grain size in traditional heavy alloys. This creates prerequisites for increasing the strength characteristics of parts of complex shapes made by the SLM method from such powders. The maximum values of density and hardness of experimental samples obtained in the conducted studies are not worse than the values of samples obtained using traditional liquid-phase sintering technology. It is determined that the main problem of SLM powder W-5Ni-2Fe during investigation is the heterogeneity of the microstructure of massive samples and the formation of micropores and microcracks.