Reduction of adhesive wear in shear cutting and deep drawing via tailored extreme high-speed laser material deposition tool coatings

In metal forming, thermoelectric currents, arising from differences in the Seebeck coefficient between the tool and workpiece, can critically promote adhesive wear (galling) at their interface. In this study, tailored coatings deposited via extreme high-speed laser material deposition (EHLA) were used to locally tune the Seebeck coefficient and modulate this thermoelectric behavior. Shear cutting experiments under single- and continuous-stroke conditions, with and without lubrication, showed a strong correlation between local current flow and adhesion onset. Validation via dry deep drawing in single-stroke mode confirmed the reduction in adhesion. Coatings engineered for defined thermoelectric potential gradients significantly reduced adhesion-driven material transfer in aluminum sheet metal processing. However, the approach was less effective for stainless steel due to abrasive wear and limited coating hardness. Thermal simulations indicate the required coating thickness to maintain substrate temperatures below critical thresholds even under severe thermal loads. EHLA coatings with thicknesses of 500–1000 µm were experimentally validated to achieve this. Developed analytical and machine-learning models based on chemical composition predict the Seebeck coefficient of multi-component alloys, complementing the estimation of thermoelectric behavior and guiding the experimental design of EHLA coatings. The results substantiate thermoelectric-aware coating design as an effective strategy to mitigate adhesive wear in metal forming tools.