Heterogeneous structures in a Ni-based superalloy with tailoring mechanical properties produced by a twin laser powder bed fusion system

摘要

Powder bed fusion using a laser beam (PBF-LB) is a promising additive manufacturing (AM) technology, used to produce components with complex geometry and design freedom. The parts are built in a layer-by -layer fashion during PBF-LB, and changing the processing parameters within different layers can lead to the modification of microstructures and finally a great impact on the mechanical properties. Thus, PBF-LB provides the possibility for the customization of material properties by changing the microstructures of layers using different processing parameters. In this investigation, a twin PBF-LB system, i.e., with a low -power laser beam and a high-power laser beam in a machine, is used to produce fine and coarse micro-structures using the Inconel 718 (IN718) alloy, respectively. The fine and coarse microstructures are alter-nately printed to form different heterogeneous structures. Correspondingly, different mechanical properties are achieved. The microstructures are analyzed using optical microscope (OM), scanning electron micro-scope (SEM), electron backscatter diffraction (EBSD) and numerical calculation. The defects generated by these 2 laser beams are simultaneously discussed. This study facilitates the tailoring of alloy properties using the PBF-LB technology to meet the users' needs of multiple service conditions.

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