Magnetic-ultrasonic dual-field assisted slow tool servo cutting technology: formation mechanism of high-precision freeform surfaces on FeCoNiCrMn high-entropy alloys

High-entropy alloys (HEAs) represent a groundbreaking class of high-performance materials whose unique physical and chemical properties make them indispensable in extreme environments. However, these exceptional properties also pose significant challenges for manufacturing, as traditional field-assisted machining techniques encounter substantial limitations when processing HEAs. To address these challenges and enable low-damage fabrication of complex surfaces, a novel hybrid processing method, magnetic-ultrasonic dual-field assisted slow tool servo (MU-STS) cutting technology, is proposed. This approach enables the creation of nanoscale precision freeform surfaces on FeCoNiCrMn HEA workpieces. This study primarily investigates the macroscopic machining mechanisms and microscopic evolution characteristics of HEA freeform surfaces during the MU-STS cutting process, encompassing both high-precision surface formation and atomic-scale distribution regularity. The results demonstrate that the machined surface roughness can reach as low as 2 nm, while the subsurface deformation layer is limited to a depth of only 129 nm, effectively achieving near damage-free ultra-precision manufacturing. This research aims to advance the understanding of multi-physics field-assisted machining, combining magnetic, ultrasonic, and mechanical effects, for novel high-performance materials, and to foster new research paradigms in materials science and processing technology.