Ultrasonic–electrical pulse synergistic milling technology for surface integrity of Ti/TiC composites

Titanium-based titanium carbide (Ti/TiC) composites exhibit outstanding properties, offering broad application prospects in demanding operating conditions. However, the introduction of hard TiC ceramic particles significantly reduces the material's machinability, often resulting in severe surface damage during conventional milling. Although traditional and single-assisted techniques can process these materials, unstable cutting behavior and high surface damage remain prominent issues. To address this, ultrasonic-electrical pulse synergistic milling (UECM) is employed. Comparative experiments across CM, UAM, EPAM, and UECM systematically evaluated changes in surface morphology, roughness, defects, hardness, and altered layers. Results show UECM reduces surface roughness by over 40% compared to CM. It effectively suppresses particle pull-out and matrix tearing by shifting material removal from brittle fracture to matrix-dominated viscoplastic shear. Furthermore, surface integrity exhibits a non-monotonic response to pulsed current density, reflecting a balance between electroplastic softening and Joule heating. Moderate currents improve quality and mitigate subsurface damage, whereas excessive currents deteriorate it. Notably, the optimized parameters of 5.293 A/mm 2 and 400 Hz achieve minimal defects and lowest roughness. These findings reveal the intrinsic mechanisms of surface integrity evolution, providing valuable insights for processing complex metal matrix composites.