Achieving cryogenic wear resistance of MoS₂ beyond conventional lubricity: An atomistic simulation study

Molybdenum disulfide MoS₂ is an attractive solid lubricant because weak interlayer interactions enable easy shear, yet its wear resistance deteriorates at low temperatures. Ti doping serves as a microstructural design strategy to strengthen MoS₂ for cryogenic service. Experiments and simulations show that dispersed Ti modifies local bonding, induces Ti-S coordinated configurations, and builds an interlayer network of Ti, S, and Ti-S clusters. This nanoscale architecture raises hardness to 1.93 GPa and elastic modulus to 45.30 GPa through lattice distortion and strong pinning that hinder interlayer shear. Although the strengthened interface increases the friction coefficient, it markedly lowers wear at 223 K. Atomistic simulations reveal a transition from progressive interlayer sliding and local delamination in pristine MoS₂ to coherent block-like deformation of pinned layers, which promotes more uniform stress accommodation. The associated increase in bending stiffness also suppresses wrinkling, offering a clear design route for durable solid-lubricant coatings in low-temperature environments.