Surface Integrity of Pure AW-1370 and TiC-Reinforced Aluminum WAAM Wires Under Unidirectional Sliding Contact

Wire arc additive manufacturing (WAAM) demands aluminum feedstock with tightly controlled diameter and high surface integrity. Adding hard TiC nanoparticles is a viable route to enhance the mechanical response of Al wires, yet the associated increase in contact severity can accelerate the wear of wire processing tools, particularly cemented carbide dies. This study elucidates the unidirectional sliding interaction between a TiC reinforced Al WAAM wire, and a WC/Co die material containing 5 wt% Co, using a modified scratch testing configuration under dry and lubricated conditions. Two dominant mechanisms are identified: (i) aluminum adhesion on the die surface and (ii) third body abrasion arising from WC particle pull out, promoted by preferential degradation of the cobalt binder. The presence of TiC nanoparticles reduces both the extent of Al transfer and the intensity of third body abrasion, an effect that is further amplified by lubrication. Consistently, lubrication also diminishes surface defects on the wire after sliding. The results provide a mechanistic basis to balance wire strengthening with tool life and highlight practical levers-nanoparticle reinforcement and lubrication strategies-for mitigating die damage while preserving WAAM wire surface quality.