Research on Process and Microstructure Formation of W-Ni-Fe Alloy Fabricated by Selective Laser Melting

W-Ni-Fe alloys are important materials for many practical applications; however, at present, they are usually fabricated by conventional powder metallurgy techniques, which is difficult in fabrication with complex shapes. In this work, a selective laser melting (SLM) processing method was developed for fabricating W-Ni-Fe alloys parts. A process map was obtained for selection of proper laser parameters by optimizing processing conditions. Microstructures of laser fabricated samples in different laser energy inputs were investigated. There are two coexisting forming mechanisms in the SLM process: (i) liquid phase sintering (LPS) with full melting of Ni and Fe powders but non-melting of W powders and (ii) melting/solidification with full melting of W powders. Moreover, with increasing laser energy, a transition trend of forming mechanism from LPS to full melting/solidification can be observed.