Tool wear induced modifications of plastic flow and deformed material depth in new generated surfaces during turning Ti-6Al-4V

Abstract

The thermo-mechanical loads induced by tribological interfaces complicate the descriptions of the local plastic deformation behaviours in high-speed machining. This study utilized finite element simulation technique and microstructural observation to investigate the local plastic deformation behaviours of new generated chips and machined surface in turning Ti-6Al-4 V. The plastic deformation behaviours modifications of plastic flow and deformed material depth under different tool wear states were discussed. On one hand, the Arbitrary-Lagrangian-Eulerian (ALE) modelling based on hybrid sticking-sliding friction model was proposed with dependence of tool wear geometrical changes. The multi-physics variables distributions such as cutting temperature, strain, and strain rate were acquired to provide the basic analysis of thermo-mechanical loads induced by tribological effects. On other hand, the experimental evidences of local plastic deformation behaviours including intensive microstructural changes in primary/secondary/tertiary deformation zones were analysed in details. Both simulated and experimental results indicated that thermo-mechanical loads due to tool wear effects were the critical driving factor for local plastic behaviours evolution. The deformation strength of primary/secondary/tertiary zones increased because of the gradual increasing contact areas and heat generation. This study can help to control the microstructural evolutions by limiting tool wear and enhance the surface quality.

Keywords

• Ti-6Al-4V
• ALE
• Plastic behaviours
• Tribological interfaces
• High-speed machining