Laser cladding of Al alloy with MoS ₂ and Ti ₃ SiC ₂ powder for enhanced tribological performance

Solid-lubricant coatings based on molybdenum disulfide (MoS2) are attractive for aluminum alloys because their layered structure can reduce friction and wear under dry sliding conditions. However, MoS2 coatings may suffer from limited durability and weak load-bearing capacity under severe contact. In this study, MoS2–Ti3SiC2 composite coatings were fabricated on Al6061 substrates by laser cladding to improve wear resistance while retaining the solid-lubricating function of MoS2. First, MoS2 coatings were processed using one, two, and three laser-cladding cycles to examine the effect of repeated laser exposure on morphology, particle dispersion, coefficient of friction, and functional coating lifetime. SEM analysis showed that increasing the number of laser-cladding cycles refined the surface particle distribution, reducing the mean particle diameter from 28.84 ± 10.96 μm after one cycle to 19.08 ± 6.69 μm after two cycles and 14.64 ± 4.39 μm after three cycles. The three-cycle MoS2 coating showed the longest functional lifetime and was therefore selected for composite coating fabrication. MoS2–Ti3SiC2 coatings containing 5 wt.% and 10 wt.% Ti3SiC2 were then compared with the MoS2-only coating using SEM, EDS, optical wear-track analysis, nanoindentation, nanoscratch testing, and reciprocating tribological testing. Although nanoindentation showed reduced measured hardness and modulus after 5 wt.% Ti3SiC2 addition, the 10 wt.% Ti3SiC2 coating exhibited improved tribological durability, reduced substrate exposure, and a more stable sliding response. These results demonstrate that laser-cladded MoS2–Ti3SiC2 coatings can improve the wear durability of Al6061 while maintaining MoS2-based friction reduction.