Cr3C2/Ni3Al复合材料耐磨性提高的机制分析

Wear mechanism of Cr3C2/Ni3Al composites showing excellent wear resistance

  • 摘要: 为了探讨Cr3C2强化相提高Cr3C2/Ni3Al复合材料耐磨性的机制, 本文采用热等静压技术制备了Ni3Al合金和Cr3C2/Ni3Al复合材料, 借助纳米压痕仪对Ni3Al合金和Cr3C2/Ni3Al复合材料中各组成相的力学性能进行了表征, 利用销-盘式摩擦磨损试验机研究了热等静压Ni3Al合金和Cr3C2/Ni3Al复合材料的耐磨性能, 并结合扫描电子显微镜和纳米压痕仪分析了材料磨损表面形貌和磨损次表面层硬度变化.结果表明, Cr3C2的添加提高了复合材料基体的硬度, Cr3C2/Ni3Al复合材料中各组成相的纳米硬度和弹性模量由基体相、扩散相到硬芯相是逐渐增大的, 呈现出梯度变化, 有利于提高Cr3C2/Ni3Al复合材料的耐磨性.在本研究实验条件下, Ni3Al合金和Cr3C2/Ni3Al复合材料表面的磨损形式主要为磨粒磨损, Cr3C2/Ni3Al复合材料表现出更加优异的耐磨性能.Cr3C2/Ni3Al复合材料耐磨性能的提高主要跟碳化物强化相阻断磨粒切削、减弱摩擦副间相互作用、减小加工硬化层厚度、磨粒尺寸等因素有关.

     

    Abstract: The Ni3Al intermetallic compound is considered an excellent wear-resistant material. The addition of Cr3C2 particles can further improve the wear resistance of Ni3Al-based alloys. In order to elucidate the wear mechanism of Cr3C2/Ni3Al composites improved by the Cr3C2 strengthening phase, Ni3Al-alloy and Cr3C2/Ni3Al composites were prepared by the hot isostatic pressing process in this study. The mechanical properties and wear resistance of each phase in the Ni3Al-alloy and Cr3C2/Ni3Al composites were investigated using a nano-indentation instrument and a pin-on-disk friction and wear tester, respectively. The worn surface morphologies and the hardness of the subsurface layer under the worn surfaces of the Ni3Al-alloy and Cr3C2/Ni3Al composites were determined by a scanning electron microscopy (SEM) and a nano-indentation instrument. The results indicate that the hardness of the matrix phase in the Cr3C2/Ni3Al composites is significantly improved by the addition of Cr3C2 particles. The nano-hardness and the elastic modulus of each phase in the Cr3C2/Ni3Al composites gradually increase from matrix phase through diffusion phase to hard core phase. The mechanical properties between the matrix, diffusion, and hard core phases in the Cr3C2/Ni3Al composites present a gradient transition. This kind of structure distribution is good for enhancing the wear resistance of Cr3C2/Ni3Al composite materials. As for friction and wear conditions in this study, abrasive wear was the dominant wear mechanism, which occurred on the surfaces of the Ni3Al-alloy and Cr3C2/Ni3Al composites. The Cr3C2/Ni3Al composites showed a good wear resistant property. The carbide-strengthening phase can block up the cutting action of the wear debris, reduce the interaction between the wear materials, and decrease the thickness of the subsurface layer and the size of the wear debris, resulting in improved wear resistance of Cr3C2/Ni3Al composites.

     

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