a b s t r a c tThe chip formation mechanism of the Ti-6Al-4V remains a challenging problem in the machining process as well as its modeling and simulation. Starting from experimental observation on the titanium alloys Ti-6Al-4V machining shows that the ductile fracture in the chip formation is dominated by the shear phenomenon under high strain rate and temperature, the present work develops a new coupled behavior and damage model for better representation and understanding of the chip formation process. The behavior and damage of Ti-6Al-4V have been studied via hat-shaped specimen under temperature up to 900 °C and strain rate up to 1000 s − 1 . An inverse identification method based on Finite Element (FE) is established in order to determine the constitutive law's parameters. The prediction of the segmented chip was analyzed through 3D finite element orthogonal cutting model which was validated by an in-situ and post-mortem orthogonal cutting machining observations. Finally, a particular attention is focused on the chip formation genesis which is described by three steps: Growth, Germination and Extraction.