Deformation mechanism and thermal conductivity of WS2/Ni heterostructure

Abstract

This study employs molecular dynamics (MD) simulations to construct WS₂-coated nickel (Ni) substrates and investigate their tribological and thermal conductivity properties. The effects of varying scratching depths, speeds, and temperatures on the tribological performance were explored, alongside analyses of temperature differences, overall temperature, and model size on thermal conductivity using non-equilibrium MD (NEMD). Results reveal that WS₂/Ni heterostructures exhibit self-repair mechanisms that mitigate surface damage during scratching, reducing friction coefficients compared to bare Ni substrates. The friction coefficient increased with deeper scratching due to atomic accumulation and extrusion, while higher scratching speeds maintained low friction levels, indicating robust lubrication. Furthermore, higher ambient temperatures reduced the friction coefficient. However, thermal conductivity was unaffected by temperature variation between hot and cold zones. Thermal conductivity increased with model size and decreased at elevated temperatures, exhibiting minimal anisotropy overall. These findings highlight the potential of WS₂/Ni heterostructures for applications requiring high-performance lubrication and thermal management in sectors such as precision machinery and aerospace.