Hardening Curve Plotting and Determination of the Coating Limiting State Criterion based on the Continuous Indentation Method and Computational Modelling

Alexey Zhdanov,Alexander Ivanchenko,Valentin Morozov

doi:10.1051/matecconf/201822001001

Abstract

The article describes the method of determining the parameters of the hardening curve of homogeneous and structured coatings (modulus of elasticity, tangential modulus of elasticity and yield strength) required for the strength analysis of parts with coatings that determine their basic performance and strength characteristics. The dependence for determination of tangential (tangential) modulus of elasticity using the results of nanoindentation is proposed. An algorithm for determining the yield strength of the coating material is developed based on solving the problem of elastic-plastic deformation of the coating during the introduction of the indenter by the finite element method. According to the proposed method, the parameters of the TiN/AlN in coating hardening curve were determined based on the results of indentation of the sample of tool high-speed steel with the appropriate coating.

Highlights

The hardening curve is an important characteristic of the material properties
Considering that the load increases monotonically during the simulation of the indenter penetration process, and we do not calculate the load removal process, so the required accuracy can be provided by the linear isotropic hardening model, which is applicable to isotropic materials and under considerable deformations the models with kinematic hardening are preferable
The geometric dimensions of the simulated sample were chosen so that the plastic deformation did not reach the lateral boundaries of the sample

Summary

Introduction

The hardening curve is an important characteristic of the material properties. Based on this curve, we can find the material mechanical characteristics and give an estimation of the stress-strain state during the simulation of the load application process of the components. To determine the hardness and modulus of elasticity of the surface layers, the method of continuous indentation under very small loads is increasingly being used, which has been called nanoindentation (NI) [9,11,12]. This method, based on the penetration of the indenter into the product surface, in contrast to the classical determination of the hardness number according to the impression mark, uses an indentation diagram which represents the penetration force dependence P on the penetration depth of the indenter h.

Materials and methods

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Results