Study on the nano-cutting behavior of γ-TiAl alloy by the zero-clearance-angle diamond tools with micro-structured flank

Accumulated cutting forces and thermal loads generated during γ-TiAl alloy machining degrade machined surface integrity and exacerbate tool wear. This paper proposes a novel zero-clearance-angle diamond tool with micro-structured flank. The nano-cutting behavior of γ-TiAl alloy was investigated by molecular dynamics simulation and scratch experiment. The objective is to explore the influence of diamond flank microstructure on the material removal mechanism, temperature field, stress-strain distribution, subsurface damage, and tool wear. The simulation results show that the tangential cutting force can be reduced by 31.8% and the average coefficient of friction can be reduced from 0.17127 to 0.11639 compared with unstructured diamond tools. Micro-groove structure suppresses heat accumulation by increasing the heat dissipation area. The greater the aspect ratio of microstructure, the smaller the temperature peak in the contact area between alloy matrix and tool. The micro-structured design of diamond flank can effectively inhibit dislocation initiation and propagation, reduce subsurface damage, and reduce tool wear rate by 25% by alleviating diffusion and adhesion of Ti atoms. The experimental results also show that the microstructure of flank can improve the quality of the machined surface by removing the plastic domain on the alloy surface. EDS element distribution shows that micro-structured tools can effectively reduce the proportion of Ti element on the surface of γ-TiAl alloy, and then inhibit the diffusion effect during cutting process. This study establishes theoretical support for the low-damage and high-efficiency precision processing of polycrystalline γ-TiAl alloy.