Finite element simulation for Ti-6Al-4V alloy deformation near the exit of orthogonal cutting

Ti-6Al-4V alloy is known as a typical difficult-to-machine hard material due to its inherent properties such as low thermal conductivity, low elastic modulus, and high reactivity with cutting tool materials. This paper proposes a two-dimensional coupled thermo-mechanical model of plane strain orthogonal cutting for Ti-6Al-4V alloy deformation near the exit edge. Johnson–Cook material constitutive model and Cockroft–Latham damage criterion are utilized in the model for better understanding the plastic behavior and chips formation during the cutting process. The machining parameters such as cutting speed, tool edge radius, rake angle, and cutting depth are taken into account in the simulation. The results show that an edge defect generates at the exit edge after machining. The edge defect consists of two fracture surfaces, namely, the first fracture surface of opening-mode crack and the second fracture surface of sliding-mode crack. Besides, the edge defect sizes are greatly sensitive to machining parameters. This study provides a better understanding of burr/breakout formation mechanism near the exit surface and optimization of machining parameters in cutting Ti-6Al-4V alloy.

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