A multi-objective optimization of laser cladding processing parameters of AlCoCrFeNi2.1 eutectic high-entropy alloy coating

In order to obtain the optimal processing parameters for laser cladding (LC) of AlCoCrFeNi2.1 eutectic high-entropy alloy, a multi-objective optimization method based on response surface methodology (RSM) was proposed. In this paper, a one-way pre-test was conducted by varying the processing parameters using a single control variable method. The results show that the porosity and microhardness of the coating are closely related to the processing parameters. The cross-section microhardness of the coating showed instability under certain process parameters, based on which the optimization window of RSM processing parameters was determined. In the RSM model, a mathematical prediction model was developed according to the laser power, scanning speed, powder feeding rate and microhardness, dilution rate and aspect ratio. Microhardness is inversely correlated with laser power and positively correlated with scanning speed and powder feeding rate. The optimal processing parameters (laser power: 1675 W, scanning speed: 7.8 mm/s and powder feeding rateing rate: 12.91 g/min) were determined. The model showed a good agreement with the experimental validation results. The coatings have good shape with an average microhardness of 322 HV0.2. The maximum average error between model predictions and experimental validation was 5.27 %.