宏观颗粒增强铁基复合材料的制备与性能

Fabrication and properties of Fe matrix composites reinforced by macro-particles

  • 摘要: 颗粒与基体之间难以均匀稳定的混合以及二者的界面结合强度较差是限制颗粒增强金属基复合材料制备以及推广应用的共性关键问题,而目前的主要解决措施"预制体法"以及"润湿化预处理技术"又存在生产效率较低、制备成本较高等问题.基于此,在液态模锻的基础上,提出了不做预制体、也不进行润湿化预处理的制备颗粒增强金属基复合材料的新技术——"随流混合+高压复合"技术,并采用此方法成功制备了复合效果良好的ZTA/KmTBCr26抗磨复合材料.研究了ZTA/KmTBCr26复合材料的微观组织、硬度以及冲击性能,发现复合材料内部颗粒分布比较均匀,颗粒与KmTBCr26基体的结合紧密,属于微机械啮合.冲击试验结果表明,复合材料的冲击韧性与单一金属基体相比显著降低,冲击断口形貌显示材料的断裂是沿颗粒内部扩展的,没有出现颗粒的整体脱落,说明陶瓷颗粒与金属基体具有比较高的结合强度.考察了ZTA/KmTBCr26复合材料与单一KmTBCr26的干摩擦磨损性能,结果表明,低载荷条件下ZTA/KmTBCr26复合材料的磨损性能是KmTBCr26的1.82倍,而高载荷条件下复合材料的磨损性能则是KmTBCr26的3.3倍.

     

    Abstract: The basic challenges in the preparation and application of particle-reinforced metal matrix composites are the difficulty in achieving a uniform and stable mixing and the weak bonds between the particles and matrix. At present, these challenges are mainly tackled by making the particles into precursor beforehand and adopting the wetting treatment technologies, respectively. However, these measures can result in lower production efficiency and higher preparation costs. Based on the molten metal die forging process, an innovation technology termed "mixing by the molten metal and cohering by high pressures" was proposed to prepare the metal matrix composites reinforced with ceramic particles without a precursor or wetting them beforehand. Using this technique, a kind of ZTA particles-reinforced KmTBCr26 cast iron wear resistant composite with a good compound effect had been prepared, and the microstructure, hardness, and impact property of the ZTA/KmTBCr26 composite was studied. The study reveals that the particle distribution in the ZTA/KmTBCr26 composite is generally uniform, and the interfacial bonding between ceramic particle and KmTBCr26 matrix is of micromechanical interlocking. The results of impact tests show that the impact toughness of the composites is significantly lower than that of the single metal, and the fracture morphology indicates that the fracture of the composites extends through the ceramic particle instead of the matrix. No particle detachment is observed, which indicates a high bonding strength between the particles and matrix. Furthermore, the dry friction and wear properties of the ZTA/KmTBCr26 composite and KmTBCr26 cast iron were investigated. The results show that the wear resistance of the composite is 1.82 times that of the KmTBCr26 cast iron when the load is lower, while the wear resistance of the composite increased by 3.3 times under the higher load.

     

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