Abstract
The premise of surface strengthening and repair of high valued components is to identify the relationship between coating formulation, structure, and properties. Based on the full factorial design, the effects of process parameters (laser power, scanning speed, gas-powder flow rate, and weight fraction of TiC) on the phase composition, microstructure, and element distribution of Ni35A/TiC cladding layer were investigated, followed by the cause identification of wear behavior. Through ANOVA, the correlation was established with good prediction accuracy (R2 = 0.9719). The most important factors affecting the wear rate of the cladding layer were recognized as laser power and particle ratio with a p-value < 0.001. The cladding layer was mainly comprised of Ni3Fe and TiC0.957. The excessive laser power would enhance the process of convection-diffusion of the melt pool, increase dilution, and improve wear volume. High laser power facilitates renucleation and growth of the hard phase, especially the complete growth of secondary axis dendrite for the top region. Increased TiC significantly changes the microstructure of the hard phase into a non-direction preferable structure, which prevents stress concentration at tips and further improves the mechanical properties. The research results are a valuable support for the manipulation of microstructure and prediction of wear behavior of composite cladding layer.
Highlights
As an advanced material processing technology, laser cladding is a novel surface modification technique
Compounding the two and performing laser cladding is expected to obtain a new type of composite coating with more excellent physical and chemical properties
The results showed that TiC had an important effect on the morphology of the composite coating
Summary
As an advanced material processing technology, laser cladding is a novel surface modification technique. TiC-reinforced ceramic composite coatings, using different raw material forms and molding methods to optimize the hardness, tensile strength, wear resistance, corrosion resistance, and other properties of the composite coatings, and they have made some progress. It was found that adding an ultrafine TiC particle could obtain a better columnar dendrite structure and could significantly improve the parts’ tensile properties and wear resistance. Sahoo et al [14] adopted a pre-coating method and obtained a wear-resistant TiC/Ni composite coating using the TIG cladding process. A lot of research has been conducted on the performance of TiC composite coatings, there are few reports on the multi-factor coupling relationship between the laser cladding process parameters and the composite coating wear rate. In this work, a full factorial experimental design (L42 ) was proposed to investigate the effects of process parameters together with the weight fraction of TiC on the wear rate and microstructure evolution of composite coating
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