ABSTRACT

To improve the wear resistance of AA6061 aluminium alloy, Fe-based composite coatings were prepared by laser surface alloying with Fe–B₄C or Fe–B₄C–Ti mixed powders. Microstructures, phase compositions and wear properties were investigated. The results indicated that the coating fabricated with Fe–B₄C was mainly composed of FeAl, Fe₃Al, Fe₄Al₁₃, CrB, Cr₂B, Cr₂₃C₆, Al₄C₃, (Fe, Cr) and α-Al phases. When adding Ti in the precursor powders, TiB₂ and TiC were also well detected. In-situ synthesised TiB₂ particles dispersed on the matrix in a hexagonal platelike structure or closely agglomerated and connected with each other to form a whole. The formation mechanism of TiB₂ in different morphologies was further discussed. Compared with the 6061 Al substrate, the micro-hardness of the alloyed coatings was improved to 5.7–6.5 times. With the addition of Ti, the wear volume loss reduced to 10% of that of the substrate, indicating a significant improvement in wear resistance.

摘要

为提高AA6061铝合金的耐磨性，采用Fe-B ₄ C或Fe-B ₄ C-Ti混合粉末激光表面合金化制备Fe基复合涂层。研究了微观结构、相组成和磨损性能。结果表明，Fe-B ₄ C制备的涂层主要由FeAl、Fe ₃ Al、Fe ₄ Al ₁₃、CrB、Cr ₂ B、Cr ₂₃ C ₆、Al ₄ C ₃、(Fe、Cr)和α -Al 相。当在前驱体粉末中加入 Ti 时，TiB ₂和 TiC 也被很好地检测到。原位合成TiB₂颗粒以六边形板状结构分散在基体上或紧密团聚并相互连接形成一个整体。进一步讨论了不同形貌下TiB ₂的形成机制。与 6061 Al 基体相比，合金涂层的显微硬度提高了 5.7-6.5 倍。随着Ti的加入，磨损量损失减少到基体的10%，表明耐磨性有显着提高。