Laser alloying with Fe–B4C–Ti on AA6061 for improved wear resistance

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.