Effect of dynamic properties of materials on serrated chip formation during Ti6Al4V alloy drilling process

Titanium alloy is widely used in aerospace field because of its high specific strength, low modulus of elasticity and corrosion resistance. However, in its drilling process, the generation of serrated chips is easy to induce the fluctuation of cutting force, which has a serious impact on the machining quality and tool wear, and the dynamic properties of the material are the main factors affecting the formation of serrated chips. In order to study the influence of the dynamic properties of titanium alloys on the formation of serrated chips in drilling, the forming mechanism of serrated chips in drilling Ti6Al4V alloy is investigated by using a combination of theoretical analysis and finite element simulation; the mechanism of cyclic change of strain and cutting force in the process of serrated element formation is elucidated. Using the parameters of chip serrated degree sensitivity and serrated frequency sensitivity as evaluation indexes, the influence laws of different Johnson-Cook (J-C) constitutive model parameters and J-C damage model parameters on the chip morphology were revealed, and the J-C constitutive model parameters were optimized for the workpiece materials. The results further reveal the forming mechanism of serrated chips in the drilling process of titanium alloy and provide guidance for the optimization of process parameters and surface quality control.