Parametric Optimization of Laser Additive Manufacturing ofInconel 625 Using Taguchi Method and Grey Relational Analysis

In order to improve the forming quality of the Inconel 625 cladding layer and make it to be more widely used. This paper addressesan experimental investigation on the influence of major process parameters like laser power, scanning speed, powder feed rate, andoverlapping rate along with their interactions on surface roughness and width error of laser additive manufacturing process forforming Inconel 625 samples. Taguchi method and grey relational analysis were used to optimize the selected parameters, andthe verification tests were carried out. The change of microhardness and microstructure in the overlapping zone andnonoverlapping zone of the cladding layer were studied by microhardness tester and scanning electron microscopy (SEM). Theresults show that the most significant effect in processing parameters on surface roughness and width error are both overlappingrate, and the optimal levels of laser power, scanning speed, powder feeder rate, and overlapping rate are 1800 W, 8 mm/s,10 g/min, and 30%, respectively. Analysis of microstructure and composition showed that the content of Cr was high both in theLaves phase and matrix, the content of Nb in the Laves phase increased significantly and reached up to 24.48 wt%, and the Lavesin the nonoverlapping zone was more compact than the overlapping zone.