Influence of Gradient Residual Stress and Tip Shape on Stress Fields Inside Indented TiN Hard Coating

Nanoindentation of treated surfaces, thin films, and coatings is often used as a simple method to measure their hardness stiffness. These quantities are technologically highly relevant allow qualitatively compare different material surface treatments but fail capture the entire extent complex mechanical interaction between indenter tip tested surface. Many studies have addressed this question by analytical or numerical modeling, they must rely on verification recalculating indentation curves ex situ microscopy deformation postexperiment. Herein, results from in measurements multiaxial stress distributions forming beneath an while sample still under load presented. A 9 μm‐thick TiN hard coating 1) as‐deposited state 2) shot‐peened Al 2 O 3 particles, using two diamond wedges tips, with 60° 143° opening angle, respectively. The reveal strong influence shape behavior main component developing inside load. In addition, crack‐closing effect can be attributed exponentially declining near‐surface compressive residual gradient that present sample.