Multi-criteria optimization of processing parameters in laser cladding of Al0.5CoCrFeNiNb0.5-Si0.1 high entropy alloy coating
Masoume Nozari Nezhad, M.R. Aboutalebi, S.H. Seyedein, Masoud Barekat
Abstract
In this study, an experimental investigation was conducted to successfully perform laser cladding of Al 0.5 CoCrFeNiNb 0.5 -Si 0.1 high-entropy alloy (HEA) coating on an Inconel 718 substrate using a fiber laser. Subsequently, the response surface methodology (RSM) was employed to develop a mathematical model that establishes a correlation between the laser processing parameters (laser power, scanning speed, and powder feeding rate) and the geometric characteristics of the single-track cladding, including cladding width, cladding height, penetration depth, dilution percentage, and wetting angle. Through the optimization process, it was determined that a laser power of 500 W, scanning speed of 4 mm/s, and powder feeding rate of 106 mg/s were the optimal parameters for achieving multiple objectives. To validate the effectiveness of the developed models and the chosen processing parameters, validation experiments were conducted under the optimized conditions. The results indicated a high level of agreement between the predicted values and the actual values, with a maximum relative error of 8.553%. Furthermore, the microstructure of the cladding with the optimized processing parameters was analyzed. The microstructure analysis revealed the presence of a columnar dendritic structure near the interface of the substrate and cladding when the constitution undercooling was low compared to the top of the cladding. Conversely, an equiaxed dendritic microstructure was observed at the top of the cladding, which can be attributed to the reduction in thermal gradient.