Enhancing tribological performance of 40Cr substrates through laser-cladded TiC-graded composite coatings

Le résumé fourni par la source

To address wear degradation in 40Cr alloy steel, this study employs laser additive manufacturing to fabricate TiC-reinforced coatings on 40Cr surfaces. Using 12CrNi2 alloy steel powder as the metal matrix, both gradient-reinforced and uniformly reinforced coatings are produced and systematically compared. The influence of TiC on wear resistance is evaluated through detailed analyses of phase composition and microstructure using X-ray diffraction, optical microscopy, and scanning electron microscopy. Microhardness and wear performance under varying loads are assessed using a micro-Vickers hardness tester and friction-and-wear tester, respectively. Results indicate a strong metallurgical bond between coating and substrate, with TiC and ferrite as the dominant phases. TiC nanoparticles are uniformly distributed within the coatings, showing enhanced concentration in gradient-reinforced coating, which exhibits dendritic and equiaxed crystal structures. The average microhardness of the gradient-reinforced coating reaches 861 HV, exceeding the 803 HV of the uniformly reinforced coating. Wear tests under 50 N and 100 N loads demonstrate that the gradient-reinforced coating experiences significantly lower material loss compared to uniformly reinforced coating and 40Cr substrate. Overall, the gradient-reinforced coating displays superior wear resistance, roughly double that of the bare 40Cr alloy steel, highlighting the effectiveness of TiC reinforcement and gradient distribution in enhancing tribological performance.

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