Prediction of Bilinear Stress-Strain Curve of Thin Hard Coating by Nanoindentation Test and Finite Element Method

This study applies the finite element method (FEM) in conjunction with an nanoindentation test to predict bilinear stress-strain curve of thin hard coatings. To verify the prediction of FEM simulation for loading and unloading process, the experimental data are compared with the results of current simulation. Loading curve is investigated for different material parameters, such as elastic modulus E, yield stress Y-0 and tangent modulus ET of nanoindentation process, by finite element analysis. The effects of material properties of thin film on the stress distribution for loading and unloading in the nanoindentation are also investigated. Finally, the bilinear stress-strain curve of thin hard coatings is directly extracted by comparing of loading curves between FEM simulation results and nanoindentation test results.