Machining performance of TiSiN(Ag) coated tools during dry turning of TiAl6V4 aerospace alloy

Abstract

One of the main opportunities to increase the tool life during the dry machining of “hard-to-cut” aerospace alloys is the possibility of protecting the components with self-lubricant coatings. Here, self-lubricant TiSiN(Ag) coatings deposited by HiPIMS working in DOMS mode were deposited onto two types of cutting inserts to assess the influence of the solid lubricant (Ag) on the dry machining performance during turning of the TiAl6V4 aerospace alloy. First type of cutting inserts were tested in laboratorial environment using a conventional lathe, whilst, second types of inserts were tested in an industrial automated computer numerical control – CNC machine in an enterprise premises. Tests in the CNC machine were performed to assess their performance benchmarked in relation to a commercial insert coated with AlTiN coating. In both of these tests, the same behaviour was found with the addition of silver clearly displaying an improvement in the tool life of the inserts, especially for higher cutting speeds. Addition of silver also showed its solid lubricant effect by reducing either the wear or the formation of built-up edges (BUE) during the tests and, thus, contributing to an increase in the tools lifetime. Ultimately, this work shows the potential use of TiSiN(Ag) coatings for machining TiAl6V4 aerospace alloy under dry conditions.