铝基TiC–TiB2自蔓延高温合成复合涂层的组织性能研究

以Ti粉、石墨粉、B₄C粉、聚四氟乙烯粉(polytetrafluoroethylene, PTFE)为原料, 采用反应熔覆技术, 结合自蔓延高温合成与真空消失模鋳造法, 在ZL205A铝合金表面制备出TiC-TiB₂复合涂层, 研究了固溶温度对基体和TiC-TiB₂涂层显微组织、硬度和热稳定性的影响, 为制备高耐磨性铝合金提供新的研究方向。结果表明: Ti-C-B₄C-PTFE体系的绝热温度的远大于1800 K, 自蔓延高温合成反应可自发进行; 通过真空消失模铸造ZL205A铝合金, 引发自蔓延高温合成反应, 在基体表面可形成TiC-TiB 2复合涂层。固溶热处理后TiC-TiB₂复合涂层表现出良好的热稳定性, 硬度为HB 285, 20 N载荷作用下的质量损失量为49.7 mg, 相对减少了90%, 大大提高了ZL205A铝合金表面的耐磨性。

Study on microstructure and mechanical properties of TiC-TiB 2 composite coatings on Al matrix by self-propagating high-temperature synthesis

The powders of Ti, C, B₄C, and polytetrafluoroethylene (PTFE) were used as the raw materials in this paper. The TiC-TiB₂ composite coatings were in-situ synthesized on the surface of ZL205A alloys by reactive cladding technology, combining with self-propagating high-temperature synthesis (SHS) and vacuum-expendable pattern casting technology. The effect of solution temperature on the microstructure, hardness, and thermal stability of Al matrix and TiC-TiB₂ coatings were investigated. The results show that, the adiabatic temperature of Ti-C-B₄C-PTFE system is much higher than 1800 K, the SHS reaction can be ignited by the vacuum-expendable pattern casting technology of molten ZL205A alloys, resulting in the formation of TiC-TiB₂ composite coatings on the surface of Al matrix. The TiC-TiB₂ composite coatings after solution heat treatment show the excellent thermal stability, the hardness of the composite coatings is HB 285, and the mass loss of composite coatings is 49.7 mg at 20 N loading, decreasing by 90%, which indicates that the wear resistance of ZL205A alloys is significantly improved.