| HUANG Hua,YIN Cunhong,WU Jiazhu,ZHANG Dabin,LIU Xixia.Design of Three-phase AlCrNiCuSix Laser Cladding Coatingsand Their Friction-reducing and Wear-resistant Properties[J],54(9):152-163, 203 |
| Design of Three-phase AlCrNiCuSix Laser Cladding Coatingsand Their Friction-reducing and Wear-resistant Properties |
| Received:September 30, 2024 Revised:February 24, 2025 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2025.09.013 |
| KeyWord:laser cladding AlCrNiCuSix high entropy alloy coating three-phase structure intermetallic compounds friction and wear |
| Author | Institution |
| HUANG Hua |
College of Mechanical Engineering, Guizhou University, Guizhou , China |
| YIN Cunhong |
College of Mechanical Engineering, Guizhou University, Guizhou , China |
| WU Jiazhu |
College of Mechanical Engineering, Guizhou University, Guizhou , China |
| ZHANG Dabin |
College of Mechanical Engineering, Guizhou University, Guizhou , China |
| LIU Xixia |
College of Mechanical Engineering, Guizhou University, Guizhou , China |
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| Abstract: |
| This investigation examines the impact of varying silicon (Si) content on the microstructure and tribological characteristics of AlCrNiCuSix laser cladding coatings, so as to establish a theoretical foundation for improving the wear and friction performance of Ti-6Al-4V alloys. Four coatings with distinct Si content (Si0, Si0.1, Si0.3, and Si0.5) are designed based on valence electron concentration and mixing enthalpy theory, and fabricated by laser cladding technology. The microstructure and phase composition of the coatings are analyzed by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The findings reveals that the Si0 coating is primarily composed of BCC1, BCC2, and FCC phases. The increase in Si content effectively suppresses the segregation of Cr and Cu, resulting in the precipitation of the Cr3Si phase along grain boundaries. The Si0.3 coating exhibits a denser microstructure characterized by fine and uniformly dispersed Cr3Si and Cu-rich phases, which enhances its hardness and wear resistance. However, the increased solubility of Ti in the Si0.5 coating leads to an over-precipitation of the Cr3SiTi2 phase, potentially increasing brittleness and adversely affecting overall performance. Microhardness tests reveal that the Si0.3 coating exhibits the highest hardness at 683.07HV0.5, which is significantly greater than that of the Si0 coating. Tribological tests demonstrate that the Si0.3 coating has the lowest friction coefficient (0.325 3) and wear rate (6.761×10−6 mm3.N−1.m−1), indicating exceptional wear resistance. Wear analysis identifies oxidation wear and minor abrasive wear as the primary wear mechanisms for the Si0.3 coating, which displays minimal surface damage, thereby supporting its superior tribological performance. This study confirms that an optimal addition of silicon markedly enhances the mechanical properties of the coating by facilitating the formation of fine intermetallic phases that contribute to improved wear resistance. Moreover, the findings suggest that excessive silicon (Si) content, as observed in the Si0.5 coating, can lead to the over-precipitation of intermetallic phases such as Cr3SiTi2, which compromises the coating's mechanical integrity and wear performance. This phenomenon occurs due to the increased brittleness and reduced toughness associated with the excessive formation of hard but brittle phases. The tribological performance of the coatings is further examined by analyzing their wear tracks using optical microscopy and 3D profilometry. The Si0.3 coating exhibits a smooth, less worn surface, whereas coatings with higher Si content, particularly Si0.5, demonstrates increased wear and more pronounced surface degradation. The wear rate findings are consistent with the microhardness data, wherein the harder Si0.3 coating exhibits superior wear resistance. The development of a stable oxide layer on the Si0.3 coating enhances its low friction and wear resistance, whereas the Si0 and Si0.1 coatings exhibit less effective oxide formation, leading to increased friction and wear. In conclusion, the Si0.3 coating demonstrates superior performance, characterized by improved hardness, wear resistance, and tribological properties. This provides valuable insights for optimizing laser cladding coatings for industrial applications that demand high wear resistance. Additionally, the study emphasizes the significance of controlling Si content to balance the formation of intermetallic compounds, thereby ensuring optimal hardness, toughness, and wear resistance for aerospace, biomedical, and other high-performance applications. |
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