Machinability analysis in high speed turning of Ti–6Al–4V alloy and investigation of wear mechanism in AlTiN PVD coated tungsten carbide tool

Abstract

Titanium alloys are one of the most critical and prominently used materials in automotive, aerospace, and biomedical application due to their superior strength to weight ratio. The very property that makes it a suitable material for such applications also makes it challenging to machine. In this study, an attempt has been made to understand the machinability of Ti–6Al–4V titanium alloy at high cutting speeds in turning. A full factorial method and Analysis of Variance (ANOVA) technique were used to conduct 18 different experimental runs and determine the significance of variables that are responsible for the variation in average surface roughness (R_a) and forces. The results show that feed rate is the single most significant factor for R_a, whereas the contribution of feed and depth of cut are more for the forces, followed by cutting speed. Tool life tests were conducted with AlTiN PVD coated tools at three different cutting speeds, and SEM analysis to evaluate the wear mechanism revealed that abrasive wear, notching, and diffusion were predominant which accelerated the wear rate. Although machining studies on Ti6Al4V at low cutting speeds are well established, the novelty of the study is to perform a comprehensive analysis to evaluate the machinability and study wear mechanism using AlTiN coated tungsten carbide tool at high cutting speeds.