ISSN   1004-0595

CN  62-1224/O4

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原位合成M23C6-WC双相碳化物协同增强激光熔覆层摩擦磨损行为的研究

Friction and Wear Behavior of In-Situ Synthesized M23C6-WC Dual-Carbides Synergistically Reinforced Laser Cladding Coatings

  • 摘要: 选用W-Fe60-C合金粉末作为原材料,利用激光熔覆技术以最佳工艺参数(激光功率1.5 kW、扫描速度4 mm/s和送粉率10 g/min)在16Mn钢表面制备M23C6-WC (M: Cr, W, Fe)双相碳化物增强铁基熔覆层,并对其微观结构与物相进行表征,以及在商用铁基合金数据库的基础上,使用Thermo-Calc软件进行热力学计算来研究熔覆层的凝固过程. 此外,还对比研究了纯Fe60合金熔覆层、WC增强铁基熔覆层和M23C6-WC双相碳化物增强铁基熔覆层的显微硬度和摩擦磨损行为. 结果显示:M23C6-WC双相碳化物增强铁基熔覆层主要以α-Fe枝晶为基体、W、WC和M23C6复合碳化物为增强相. M23C6碳化物以连续网状结构分布在α-Fe枝晶间,WC颗粒以残留W为形核核心生长成块状分布在熔覆层中. 微观结构结合热力学计算结果表明:激光熔覆过程中M23C6-WC双相碳化物增强铁基熔覆层的凝固过程为液态+W→液态+W+WC→液态+W+WC+γ-(Fe,Ni)枝晶→W+WC+γ-(Fe, Ni)枝晶+M23C6→W+WC+α-Fe枝晶+M23C6. 根据显微硬度和磨损率测试可知:M23C6-WC双相碳化物增强铁基熔覆层的平均显微硬度为835.3 HV0.5,比纯Fe60合金涂层(604.6 HV0.5)和WC增强铁基熔覆层(658.9 HV0.5)分别增加了约230 HV0.5和180 HV0.5. M23C6-WC双相碳化物增强铁基熔覆层的磨损率为3.44×10−6 mm3/(N·m),比纯Fe60合金熔覆层8.51×10−5 mm3/(N·m)和WC增强铁基熔覆层7.98×10−6 mm3/(N·m)分别减少了约24.7倍和2.3倍.

     

    Abstract: Abstract: M23C6-WC (M: Cr, W, Fe) dual-carbide reinforced Fe-based coating was fabricated on the surface of a 16Mn steel by laser cladding W-Fe60-C alloy powders under the optimized parameters of laser power 1.5 kW, scanning velocity 4 mm/s and powder feeding rate 10 g/min, and microstructure and phase composition of coating were further characterized. Thermodynamic calculation was also performed with Thermo-Calc software on the basis of a commercially available Fe-based Alloys' database to explore the solidification process of the coating. In addition, a comparative study on the microhardness and wear behavior of pure Fe60 alloy coating, WC reinforced Fe-based coating and M23C6-WC dual-carbide reinforced Fe-based coating was conducted. Experimental results showed that M23C6-WC dual-carbide reinforced Fe-based coating was mainly composed of dendritic matrix α-Fe, reinforcing phases W, WC and M23C6. M23C6 carbide was distributed in the inter-dendritic region with a continuous network structure, and block-shaped WC particles grew with the residual W as a nucleation core and distributed in the coating. Combined to the microstructure and thermodynamic calculation results, the solidification process in the M23C6-WC dual-carbides reinforced Fe-based coating during laser cladding process was liquid+W→liquid+W+WC→liquid+W+WC+γ-(Fe, Ni) dendrite→WC+W+γ-(Fe, Ni) dendrite+M23C6→WC+W+α-Fe dendrite+M23C6. The average microhardness of M23C6-WC dual-carbide reinforced Fe-based coating was about 835.3 HV0.5, which was 230 HV0.5 and 180 HV0.5 higher than that of pure Fe60 alloy coating (604.6 HV0.5) and WC-reinforced Fe-based coating (658.9 HV0.5), respectively. Furthermore, the wear rate of M23C6-WC dual-carbide reinforced Fe-based coating was about 3.44×10−6mm3/mN, which was about 24.7 and 2.3 times lower than that of pure Fe60 alloy cladding 8.51×10−5 mm3/(N·m) and WC reinforced Fe-based coating 7.98×10−6 mm3/(N·m), respectively.

     

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