Enhancement of Hardness, Wear, and Corrosion Resistance in Ti-6Al-4V Alloy through Multi-Layer Laser Cladding of TiZrNbCrCo High Entropy Alloy Coatings AITranslate

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Basic Information:

DOI：10.13373/j.cnki.cjrm.XY24020010

Chinese Library Classification Number:TG174.4

Citation Information:

Given the challenges posed by the low hardness and inadequate wear resistance of Ti-6Al-4V alloy, this research aimed to explore an innovative solution by employing the laser cladding technique to develop high-entropy alloy（HEA）coatings composed of TiZrNbCrCo on the alloy's surface. The primary objectives were to investigate the effects of varying the number of cladding layers on the elemental composition and to assess how these variations influenced the phase constitution, microstructure, microhardness, wear, and electrochemical properties of HEA coatings. To predict the phase composition of the solid solution phases in HEA coatings with different layer numbers, empirical thermophysical parameters were utilized. The methodology encompassed a detailed experimental setup where the laser cladding process was meticulously optimized to fabricate coatings with varying numbers of layers. This approach enabled the controlled manipulation of the dilution rate and elemental distribution within the coatings, thereby allowing for a comprehensive analysis of the resulting phase and microstructural characteristics. The coatings were systematically analyzed using X-ray diffraction（XRD）to identify their phase compositions and scanning electron microscopy to elucidate their microstructures. Microhardness measurements were conducted to evaluate the mechanical enhancements, while wear tests were performed to assess the wear resistance of the coatings. Furthermore, electrochemical tests in a 3.5%NaCl solution were carried out to determine the coatings' corrosion resistance. The results revealed that all coatings, exhibited a consistent phase composition, predominantly featuring a body-centered cubic （bcc） structured solid solution phase. This phase was characterized by dendrites rich in Nb and inter-dendrites rich in Co. It was observed that an increase in the number of cladding layers led to a decrease in the dilution rate, which in turn facilitated the formation of petal-like Laves phases enriched in Co and Zr, along with α-Ti precipitates enriched in Zr. Remarkably, the average microhardness of the coatings reached HV_0.1747.7, approximately 2.33 times that of the substrate. This significant enhancement in microhardness translated to a reduction in wear volume by 68.6% compared to the substrate. The optimal corrosion resistance was achieved with a two-layer configuration, which exhibited the lowest self-corrosion current （6.46×10⁻⁶ A·cm⁻²） a larger self-corrosion potential （-0.286 V）, and the lowest corrosion rate, indicating a substantial improvement in corrosion resistance. The conclusion drawn from this study highlighted the critical role of laser cladding parameters in influencing the microstructural and compositional characteristics of HEA coatings. The enhancement in mechanical and chemical properties could be attributed to the strategic manipulation of the number of cladding layers, which optimized the microstructural features such as the distribution of Laves phases and α-Ti precipitates. Moreover, this research contributed to the broader academic discourse by elucidating the relationship between laser cladding parameters, microstructural evolution, and the resulting properties of HEA coatings. In summary, this comprehensive investigation into the development and characterization of TiZrNbCrCo high-entropy alloy coatings on Ti-6Al-4V alloy surfaces provided a promising approach for addressing the limitations of conventional titanium alloys. The research outcomes not only demonstrated the feasibility of significantly enhancing the hardness, wear, and corrosion resistance of Ti-6Al-4V alloys through laser cladded HEA coatings but also opened up opportunities for using high-entropy alloys in surface engineering to meet the needs of modern industries.