Selective Laser Melting of Multi-component Ni-based powder mixture for Building Metallic Parts

摘要

Selective laser melting (SLM) is an advanced manufacturing technology, which is flexible in building three-dimensional (3D) metallic parts. In this work, SLM experiment of a multi-component Ni-based composite powder, which consisted of Ni, Cr, Fe, and Al powders, was conducted with favorable forming ability. The SEM, EDX, and XRD analysis were used to characterize the surface morphology, microstructure, and phase structure of as-formed Ni-based alloy. The XRD analysis showed that the as-received phase structure was Ni based solid solution. The SEM analysis of surface morphology revealed that metal agglomerates or balls were very easily formed in SLM surface, between which some pore channels existed. The surface condition and porosity could be improved by increasing laser energy input, because of a higher molten temperature and accordingly better flowing and flatting characteristics. The SEM analysis of microstructure showed that the crystalline grains were in cellular and columnar shape. Moreover, the grains were very fine with average dimensions about 5um, due to the rapid cooling rate with rapid laser beam moving. The EDX analysis illustrated that the element contents of starting powder were uniformly distributed in as-prepared sample. A case investigation into SLM of this composite powder to form an impeller was also performed.