Effect of tool parameters with V-shaped structure at the atomic scale on the cutting behavior of single-crystalline γ-TiAl alloy

Abstract

In single-point diamond turning of hard and brittle materials, the micro-grooves on the cutting edge of the tool, as an important feature of tool wear, are closely related to the structural parameters and wear behavior, having a significant impact on tool performance, lifespan, and workpiece surface integrity. Therefore, this study utilizes molecular dynamics simulations to construct diamond tools with V-shaped groove structures of varying parameters (width W and height H) and single-crystal γ-TiAl alloy cutting models, systematically analyzing the influence of the evolution of the tool's V-shaped structure on the cutting behavior of the single-crystal γ-TiAl alloy and tool wear. The results show that tool groove shape evolution affects cutting temperature/stress distribution, influencing cutting instability and tool wear. During cutting, the diamond tool bond length shortens, the bond angle distorts, the sp3 hybrid orbital damages, and crystal transforms to graphite. Micro-grooves increase cutting force fluctuation. Despite a notable rise in surface roughness with increasing groove parameters, the T2 tool (W = 1.4 nm, H = 1.4 nm) reduces workpiece surface roughness Sa by 7.66% vs traditional tools, effectively enhancing surface quality. Additionally, increasing the groove width W reduces the depth of the subsurface damage layer and inhibits the expansion of subsurface dislocations. Therefore, revealing the evolution mechanism of the tool groove shape is of great significance for achieving efficient processing of single-crystal γ-TiAl alloy and synergistically improving surface quality and tool lifespan.