Microstructure-Mechanics Interactions in Modeling Chip Segmentation during Titanium Machining

Chip segmentation in machining of titanium alloys is strongly influenced by the microstructural state of the material. A numerical model is presented that incorporates material changes into the phenomenological behavior of the chip. It is calibrated by comparing results with experimental measurements at different cutting speeds and feeds. It predicts that at lower cutting speeds fracture propagates in the α-β phase towards the cutting tool face resulting in a discontinuous chip. At higher cutting speeds, temperature in the secondary shear zone reaches β transus increasing material ductility; the fracture propagates towards the outer surface resulting in a continuous but segmented chip.