Machinability aspects in dry turning of Ti6Al4V alloy with HiPIMS coated carbide inserts

Abstract

Owing to their unique mechanical properties, titanium alloys have been and will be used extensively in a myriad of industries ranging from aerospace to automotive to medical field. Hence, a continuous improvement in the performance of the coated inserts with hard materials capable of enhanced tribological and wear resistive properties is necessary. The present work contributes to investigation of the influence of cutting parameters in turning operations of the alpha-beta titanium alloy- Ti-6Al-4V. Tungsten carbide inserts of K20 grade is coated with TiAlN and AlCrN monolayer coatings by high power impulse magnetron sputtering (HPPMS). Machinability of Ti6Al4V alloy is studied at different cutting speed, feed ranging from 60 to 120 m/min and 0.1 to 0.25 mm/rev with constant depth of cut of 0.5 mm to evaluate the optimum turning parameters under dry environment. The tool wear is observed initially under an optical microscope and nature of wear is observed with scanning electron microscope (SEM). It is witnessed that the AlCrN coated inserts have an upper edge over the TiAlN coated inserts due to better adhesion and thermal stability of the coating. Tool wear and surface finish is found to be optimum at cutting speed of 100 m/min, feed of 0.1mm/rev and depth of cut 0.5 mm. The present will provide useful and economic machining solutions for the high speed machining of titanium alloys by effective utilization of coated tungsten carbide inserts.