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This work involves the preparation of WC/Co/Ni blends using different mixing ratios to form Co/Ni/WC composite-based coatings by laser cladding. The effect of each component and their mixtures on the mechanical properties was evaluated using a mixture design approach. The morphologies and microstructures of the laser clads were characterized using a scanning electron microscope and X-ray diffraction techniques. Cracking behavior and fracture based on residual stresses are explored. In addition, the mathematical models between the three-component mixtures and the mechanical properties of the laser clad were established. The results showed that the welds containing 50 % WC-50 % Ni alloys were successfully deposited by laser cladding with favorable mechanical properties. These welds reduced the remarkable fracture crack activities and did not cause delamination in the laser clads. An increase in WC content significantly enhances wear resistance and microhardness, except for the crack susceptibilities in all mixtures. Additionally, when increased Co/Ni on WC, the reduction of adhesive wear is more significant than that of abrasive wear. Wear resistance is improved by the high content of WC particles in the laser-clad joints. Based on the mixture models, better mixed ratios for the blends that were developed using a multi-objective superimposed optimization technique make these blended materials promising candidates and can ensure the quality of laser clads. The findings from this study will greatly contribute to optimizing the blend ratio of the three-ingredient mixture based on mixture design to enhance structural evolution and mechanical properties, and also obtain better quality laser-clad coatings.

Based on genetic algorithm (GA) and fuzzy neural network, a new method for the study of sputtering process is proposed in this paper. Diamond-like carbon (DLC) coatings were deposited on SKD11 steel by magnetron sputtering. An orthogonal array design is implemented and the effects of control factors on surface properties of the coatings were systematically analyzed. The coating properties were investigated by scanning electron microscopy and Raman spectroscopy, and wear volume surface performance of the Zr-doped DLC coatings was evaluated by a wear tests pin-on-disk tribometer. The Raman analyses showed that, at lower ID/IG ratio, a lower wear volume of the Zr-doped DLC coatings can be obtained. Scratch tests as well as Rockwell indentation tests revealed that the graded Zr-doped DLC structures efficiently provide better adhesive strength of DLC coatings. The results show that the wear behaviors of the DLC coatings can be improved by Zr-doping, which the Zr-doped DLC coatings exhibited promising tribological properties. Also, the predictive ability of the GA-ANFIS computations for the tribological behaviors of the Zr-DLC coatings within the experimental domains proved to be reliably obtained, where the forecasted values and experimental results are close.

A comprehensive experimental study on the high-velocity oxygen-fuel (HVOF) sprayed tungsten carbide/cobalt (WC/Co) deposits using laser cladding was conducted. A response surface methodology based on a central composite design was used to analyze, predict and optimize the WC/Co deposits of the laser-based HVOF sprayed coatings. The morphologies and microstructures of the laser clads were characterized using optical microscope, scanning electron microscope and X-ray diffraction techniques. The crack behavior and residual stress-based fractures were explored. In addition, the relationships between the residual stress of the laser clad and three factors: laser power, scanning speed and stand-off distance were examined. Further, optimization of the control factors: laser power, scanning speed and stand-off distance to minimize the residual stress was attained using a response surface methodology. The resulting lower residual stress has decreased the fracture crack activities and did not easily induce delamination in the laser clads. Findings from this study would greatly contribute to optimizing the experiments and achieve an enhanced structural evolution in the protective coating of traditional handicraft products by laser cladding.