Morphological investigation of Ti-6Al-4V chips produced by conventional turning

Abstract

The chips produced while machining titanium alloys (Ti-alloys) exhibit a distinctive behaviour. The investigation of chip morphology has been emphasised by the researchers. This paper reports the results of a scientific examination to understand the morphological phenomena of chips of titanium α-β alloy Ti-6Al-4V. The whole examination is based on the traditional turning operation, and the machining has been performed by tungsten carbide tools (coated and uncoated) using optimal machining parameters in both of the cases for Ti-6Al-4V. Applying various selected combinations of optimal cutting parameters in the turning operation for the chosen types of tools, the chips produced have been collected and examined. Both optical microscopy and scanning electron microscopy (SEM) have been used for the detailed exploration. The study included a physiognomy analysis of chips and chip segments and then a detailed morphological analysis of chip segments (using SEM), which have revealed the nature of the adiabatic shear stresses and the phase-change phenomenon in the cutting zone of the superalloy.