Hisashi Suzuki1, Hideaki Matsubara1, Akira Matsuo2 and Kunio Shibuki3
1Department of Metallurgy and Materials Science, Faculty of Engineering, The University of Tokyo, Tokyo
The residual stresses produced in a titanium carbonitride (C/N~eq4/6, called Ti(C, N)) layer deposited on a WC-10%Co substrate by the PVD process were studied by using 2 θ -sin2 ψ method as a function of PVD conditions such as temperature, bias voltage of substrate and thickness of layer, as compared with those produced in titanium carbide (TiC), titanium nitride (TiN) and titanium layers. Changes in residual stresses due to annealing after PVD were also studied.
The residual stresses ( σ r), being compressive, were always detected in TiC and TiN layers as well as in Ti(C, N) layer, and the |σ r| increased with decreasing PVD temperature, bias voltage (up to -20 V) and thickness of layers. It was noted that none of residual compressive stresses were found in the titanium layer. The |σ r| produced in three sorts of hard layers had a tendency to decrease by annealing treatments. However, the thermal stability of residual stresses was the highest for Ti(C, N) layer. It was suggested that the origin of σ r was in the interstitial atoms of carbon and/or nitrogen introduced during PVD in each crystal lattice. Annealing effects on σ r would be described in view of recovery of the interstitial atoms. The excellent strength of PVD coated specimen would be understood, based on the compressive stresses in the hard layers.
cemented carbide, cutting tools, coating, physical vapor deposition (PVD), ion-plating, titanium carbonitride, titanium carbide, titanium nitride, residual stress, transverse-rupture strength
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