层流冷却辊激光熔覆铁基中熵合金涂层研制

Development of Iron-Based Medium-Entropy Alloy Coatings on Laminar Cooling Rolls by Laser Cladding

  • 摘要: 本研究采用激光熔覆技术制备了Fe50Cr22(MnNiCuAlTi)20C8新型中熵合金涂层,借助SEM、XRD、显微硬度计及高温摩擦磨损试验机等实验设备,系统探究了该中熵合金涂层的微观组织与耐高温磨损性能,并与层流冷却辊广泛使用的 Rocket431SR激光熔覆涂层进行对比分析。研究结果显示,所制备的中熵合金涂层无气孔、夹渣等常见缺陷,与基体形成了稳固的冶金结合,整体熔覆质量优良。XRD检测结果表明,该中熵合金涂层主要由体心立方(BCC)相构成;SEM分析可知,涂层组织以等轴晶为主,在晶界处分布有少量TiC 颗粒析出相,同时存在连续分布的Cr23C6析出相,这种独特的微观组织结构为涂层具备高硬度和优异耐磨性能提供了重要基础。硬度测试与高温磨损性能测试结果显示,该中熵合金涂层的硬度高达790Hv0.5,明显高于Rocket431SR涂层;在600℃的高温条件下,其比磨损率仅为赫格纳斯Rocket431SR 涂层的45.4%,表现出更为优异的耐高温磨损性能,完全能够满足层流冷却辊的实际使用要求。

     

    Abstract: A new medium-entropy alloy coating of Fe50Cr22(MnNiCuAlTi)20C8 was fabricated by laser cladding technology. The microstructure and high-temperature wear resistance of the medium-entropy alloy coating were systematically investigated using experimental equipment such as SEM, XRD, microhardness tester, and high-temperature friction and wear testing machine, and a comparative analysis was conducted with the widely used Rocket431SR laser cladding coating for laminar cooling rolls. The research results showed that the prepared medium-entropy alloy coating was free of common defects such as pores and slag inclusions, formed a stable metallurgical bond with the substrate, and exhibited excellent overall cladding quality. XRD detection results indicated that the medium-entropy alloy coating was mainly composed of body-centered cubic (BCC) phase; SEM analysis revealed that the coating structure was dominated by equiaxed grains, with a small amount of TiC particle precipitates distributed at the grain boundaries, and continuous distribution of Cr23C6 precipitates. This unique microstructure provided an important basis for the coating to possess high hardness and excellent wear resistance. The results of hardness tests and high-temperature wear performance tests showed that the hardness of the medium-entropy alloy coating was as high as 790Hv0.5, which was significantly higher than that of the Rocket431SR coating; under the high-temperature condition of 600°C, its specific wear rate was only 45.4% of that of the Hoganas Rocket431SR coating, showing more excellent high-temperature wear resistance and fully meeting the actual service requirements of laminar cooling rolls.​

     

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