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利用真空熔烧工艺制备了WCP-NiCrBSi/耐热钢复合材料,棒状增强相WCP-NiCrBSi均匀分布于基体表层,实现了复合材料的“硬韧匹配”。利用SEM、EDS和显微硬度等手段,对复合材料增强相和界面的微观组织结构进行了表征。在环-盘式试验机上对复合材料的高温磨损性能进行了研究,并与基体材料进行对比。结果表明,增强相WCP分布均匀,NiCrBSi合金在凝固过程中生成了γ-Ni(Ni3Si)、Ni-B、Cr-B和多元共晶物相。复合材料的增强相与基体之间为良好冶金结合,没有裂纹、气孔等缺陷。由于界面元素的互扩散,在增强相一侧发生了等温凝固,生成了γ-Ni固溶体层;在基体一侧的扩散影响区内弥散析出了大量的Fe-Cr-B化合物。在室温至600℃温度范围内复合材料的耐磨性都优于基体材料,复合材料的耐磨性优势在室温下最大,并随着温度的升高而逐渐减小。室温下,由于WCP凸出于磨损表面阻止了金属材料之间的直接接触,复合材料的磨损机制为轻微粘着磨损。在300℃和600℃下,由于磨损表面氧化物膜的形成,WCP-NiCrBSi/耐热钢复合材料的磨损机制转变为轻微氧化磨损。
The WCP-NiCrBSi / heat-resisting steel composite was prepared by vacuum melting process. The WCP-NiCrBSi rod-like reinforcing phase was evenly distributed on the surface of the matrix, which made the “hard and tough match” of the composite material. SEM, EDS and microhardness were used to characterize the microstructure of the reinforcement phase and interface. The high temperature wear properties of the composites were investigated on a ring-and-reel test machine and compared with the matrix material. The results show that WCP distributes homogeneously and the NiCrBSi alloy forms γ-Ni (Ni3Si), Ni-B, Cr-B and multiple eutectic phases during solidification. The strengthening phase of the composite material is well metallurgical combination with the matrix, and no defects such as cracks and pores are found. Due to the interdiffusion of the interface elements, the isothermal solidification occurred on the enhanced phase side, and the γ-Ni solid solution layer was formed. A large amount of Fe-Cr-B compounds dispersedly dispersed in the diffusion-affected zone on the matrix side. The wear resistance of the composites is better than that of the matrix in the temperature range from room temperature to 600 ℃. The wear resistance of the composites is maximum at room temperature, and decreases with the increase of temperature. At room temperature, the wear mechanism of the composite is slight adhesive wear as the WCP protrudes from the wear surface and prevents direct contact between the metal materials. At 300 ° C and 600 ° C, the wear mechanism of WCP-NiCrBSi / heat-resistant steel composites translates to slight oxidative wear due to the formation of wear surface oxide films.