Multi-Response Optimization of Laser-based Powder Deposition of Multi-track Single Layer Hastelloy C-276

The objective of the current work is to develop an empirical relationship between the input variables and quality characteristics in a laser-based powder deposition of Hastelloy C-276 on steel. The influence of laser power, scanning speed, powder flow rate, and percentage overlap on uniformity index, dilution, and microhardness is studied. A central composite design at five levels allowed us to obtain a second-order model to predict the optimal layer characteristics with the terms of interaction between the four chosen influential input variables. A fine equiaxed microstructure with uniform layer thickness is achieved for the laser power of 285 W, scanning speed of 11.3 mm/s, powder flow rate of 0.176 g/s, and a percentage overlap of 34.1%. The developed experimentally based statistical model can be used to predict the important prerequisites of the qualified deposit such as uniform layer thickness, minimal dilution, and homogenous metallurgical bond. The results demonstrated the existence of a critical range for the powder flow rate and overlap percentage below which the scanning speed and dilution (%) holds direct relationship.