Influences of scanning strategy on the quality, accuracy, microstructure and performance of Inconel 625 parts by LAM

Abstract

In order to obtain the influence law of scanning strategy on the quality, accuracy, microstructure and performance of parts by Laser Additive Manufacturing (LAM), three scanning strategies, namely long-edge, short-edge and cross-layer, were used for additive manufacturing of Inconel 625 parts. Optical Microscope (OM) experiments indicate that the microstructures of samples with different scanning strategies are different. The results of Scanning Electron Microscopy (SEM) suggest that the size and distribution of Laves phase of samples with the different scanning strategies are distinctive, and Energy Dispersive Spectroscopy (EDS) tests indicate that the degree of composition segregation varies according to the scanning strategy. The results of X-ray Diffraction (XRD) show that the main phase of the samples with different scanning strategies is γ-Ni solid solution. The diffraction peak positions are basically the same, but the peak intensities are diverse, indicating that the scanning strategy has a significant impact on the orientation of grains and the intensity of texture. The mechanical properties tests prove that the cross-layer scanning strategy synthesizes the advantages of the other two scanning strategies. The microhardness test shows that the hardness of samples with different scanning strategies is determined by the size, distribution and morphology of Laves phase, as well as the size of grains. As a result, it can be proved that the scanning strategy has a great influence on the quality, accuracy, microstructure and properties of the as-formed samples. The cross-layer orthogonal scanning strategy achieves the best processing results by combining the advantages of long-edge and short-edge scanning strategies.