Abstract
<jats:p>Understanding the coupled roles of chemical potential, microstructure, thermomechanical loading, and compositional gradients is essential for controlling tool–material interactions and mitigating wear in precision machining. This study investigates interfacial phenomena occurring during diamond turning, where material removal at micrometer length scales leads to the formation of a strongly adhered built-up edge (BUE). Tribochemically driven interactions between single-crystal diamond tools and plastically deformed chips promote atomic inter-diffusion, which accelerates tool degradation upon BUE fracture. These effects were examined for diamond in contact with transition metals, including titanium, niobium, and zirconium. Tribochemical activity was observed even under quasistatic deformation conditions (< mm/s), indicating that mechanically driven processes dominate in the absence of significant thermal contributions and intensify with increasing deformation rates. Carbon transport at the tool–chip interface during plane strain machining was characterized using electron microscopy, revealing pronounced microstructural and phase transformations within the BUE and interaction zone. Elemental redistribution and phase evolution were found to depend on deformation load, rate, and temperature. The findings provide mechanistic insight into diffusion-assisted wear in diamond machining and inform the design of wear-resistant diamond tooling for d-shell–rich metals.</jats:p>