Brittleness and fatigue effect of mono- and multi-layer PVD films on the cutting performance of coated cemented carbide inserts

The effect of brittleness and fatigue of mono- and multi-layer PVD films on coated tools cutting performance is introduced. Cemented carbide inserts were coated to the same overall film thickness with various numbers of layers. Nanoindentations were conducted to evaluate the hardness of the diverse coating structures. The film brittleness and fatigue were characterized by nano- and macro-impact tests respectively. The coated inserts' wear behaviour was investigated in milling hardened steel. The attained results revealed the coatings' brittleness and fatigue endurance enhancement by increasing the number of film's layers. This increase leads simultaneously to the coated tool life improvement. (C) 2014 CIRP.