Nanoscale residual stress and microstructure gradients across the cutting edge area of a TiN coating on WC-Co

The lifetime of coated cutting tools is decisively influenced by residual stress gradients across cutting edges. Here, cross-sectional X-ray nanodiffraction with a beam size of 35 x 25 nm(2) was used to retrieve gradient properties of a similar to 2 mu m thick TiN coating on WC-Co substrate. The planar regions next to the edge exhibit gradual and constant stress profiles with anisotropic defect build-ups on the flank and rake faces, respectively. Directly at the edge, nonlinear lateral and cross-sectional compressive residual stress gradients up to about -3 GPa were observed. The coating's (111) fibre texture orientation correlates with the orientation of principal stress components. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.