In this paper, the performance and the wear mechanisms of coated carbide to
ols have been investigated when face milling titanium alloy, Ti-6Al-4V. The
two tools used were PVD-TiN and CVD-TiCN + Al2O3 coated. Tool life, tool f
ailure modes and wear mechanisms were examined for various cutting conditio
ns. Both tools experienced long tool life at the low cutting speed of 55 m/
min and feed of 0.1 mm per tooth. When considering the volume of material r
emoved and tool lives, the CVD coated tools gave a better performance than
the PVD coated tools. Excessive chipping at the cutting edge and chipping a
nd/or flaking on the rake face were the dominant failure modes under most c
utting conditions. Analysis carried out with the SEM suggests that coating
delamination, adhesion of work material, attrition, diffusion, plastic defo
rmation and thermal cracks were the operating wear mechanisms of the coated
tools. (C) 2000 Published by Elsevier Science S.A. All rights reserved.