Performance investigation of surface modified cutting tools in dry machining of titanium alloy

Abstract

The need for cutting tools with improved tool life to dry machine hard materials such as Titanium alloy has been of huge research interest over a long period of time. Various surface modifications have been introduced on cutting tools to improve its performance. Surface modifications such as coatings, texturing and surface treatment have been deployed for the performance enhancement in terms of tool life. Tool coatings have evolved from monolayer hard coatings to multilayer soft lubricant based nanocomposites over the years. Surface textures have also gathered huge interest in the recent times. The present research attempts to investigate upon the performance of surface modified cutting tools to improve the machinability of Titanium Grade V alloy. Solid lubricant based TiN-WS2 nanocomposites were developed through reactive co-sputtering technique and its nano-mechanical and tribological characteristics have been evaluated and this facilitated the choice of process parameters for coating on cutting tools. The TiN-WS2 coated tools were subjected to machining analysis and its performance evaluated. Surface textures were developed on cutting tool and the influence of surface texture in machining Titanium Grade V alloy was evaluated. A combination of surface modifications such as coating the textured tool was investigated and its performance evaluated. newlineThe TiN-WS2 coatings possessed a characteristic feature of uniform deposition across the substrates being investigated. The hardness of the nanocomposite was 36 GPa, on par with that of pristine TiN. The nanocomposite coatings possessed excellent adhesion characteristics with a critical load of 235 mN. The friction coefficient of TiN-WS2 nanocomposites was found to be as low as 0.11, nearer to that of WS2, 0.08. The wear rate of TiN-WS2 nanocomposites was found to 3.7 × 10-9 mm3/mN.mm. newline