Comparative study on machining performance of TiAlSiN, AlTiN/TiAlSiN-coated cutting tools

ABSTRACT The present study investigates the microstructure of monolayer TiAlSiN and bilayer AlTiN/TiAlSiN coatings deposited on WC-Co inserts through magnetron sputtering. Further, a comparative study on the tool life and wear characteristics of uncoated, monolayer and bilayer coated inserts was performed through dry turning of tempered EN-8 steel under extreme cutting conditions. The TiAlSiN coating showed a dense fine morphology whereas the AlTiN/TiAlSiN coating showed a mixed morphology with a columnar structure for the intermediate layer of AlTiN followed by a dense nanocrystalline structure for the top layer of TiAlSiN. The dry turning experiments show that the major form of wear mechanism observed during machining was crater wear. Both monolayer and bilayer coated inserts showed promising cutting performance and the bilayer coated inserts showed better tool life than the monolayer coated inserts under most of the cutting conditions.