3D finite element simulation of scratch testing to quantify experimental failure mechanisms of a thin film

Abstract

In this work, an exhaustive finite element (FE) simulation was developed to closely reproduce experimental parameters such as normal force, tangential force, and penetration depth along the whole scratch test. We used an 800 nm thick Ti–Al–N thin film deposited by sputtering as the reference sample to carry out scratch tests identifying the appearance of failure mechanisms at different longitudinal displacements and critical loads. The hardening models of thin film and substrate allowed us to quantify the maximum principal stresses responsible for thin film spallation, about 14.5 GPa for the tensile mode and −1.49 GPa for the compression mode. These parameters provided an improved perspective to characterize the failure mechanisms on the sample during the scratching. The present enhanced 3D FE simulation can be a crucial tool for designing film-substrate systems with more precise mechanical strength calculations.