Machinability of Titanium Metal Matrix Composites by meansof Tool Wear Evaluation

Metal matrix composites (MMCs) are composed of non-metallic reinforcements (i.e. ceramic) in metal matrices which feature high toughness, wear and fatigue resistant and relatively light weight. One of the metallic composite with remarkable mechanical properties is titanium metal matrixcomposite (Ti-MMC) that is considered as an alternative to nickel based alloys within a vast number of products and industrial sectors, including automotive and aerospace industries. Despite of excellent mechanical and physical features, due to presence of hard and abrasive ceramicparticles in metal matrices of Ti-MMCs, various issues have been emerged in the area of machining and machinability of Ti-MMCs. One of the principal machinability attribute is tool/insert wear that requires further studies. Knowing that limited studies are available on adequate machining of Ti- MMCs, this work intends to report the tool wear when turning Ti-MMCs with carbide, PCD and CBN inserts under various cutting conditions. The tool wear was evaluated based on flank wear. The main wear modes observed on the flank side of the tested inserts were adhesion, abrasion and diffusion. Presence of other phenomenon including chipping were also noted under various levels of cutting conditions, particularly with PCD tools. Except few cutting tests, other experimental tests on PCD inserts led to rapid insert failure, despite of using coolant. According to experimental results, the flank wear rate observed on the carbide and CBN inserts can be statistically controlled by the cutting parameters used, in principle cutting speed

Keywords:

Tool wear , Ti-MMC , Composite , Machinability , Turning