Purpose: The goal of this paper is to investigate the influence of thicknesses of Cr and CrN layers in Cr/CrN module of multi-module coatings, on their mechanical properties. Design/methodology/approach: The objects of research are systems composed of steel substrate and Cr/CrN multi-module coatings, deposited using PVD (Physical Vapour Deposition) method, via CAE (Cathodic Arc Evaporation) technique. Mechanical properties of the substrate/coating systems were determined using scratch test, Vickers indentation, while wear of the systems was investigated via ball on disk method. Internal strain and stress states in substrate/coating systems, arising during indentation, were calculated using FEM (Finite Element Method) computer model. Findings: For two different geometries of Cr/CrN multi-module coatings mechanical properties (hardness, fracture toughness, wear and adhesion forces) were examined. Additionally, in Rockwell indentation test, the states of first principal stress and effective plastic strain states were calculated. Research limitations/implications: The coatings were deposited using CAE, which results in occurrence of various defects (eg. droplets) inside coatings. This fact has its consequences, ie. perturbations in layers structure, resulting in stochastic, spatial changes of physico-chemical properties of the coatings. This defects may be reduced by special modifications of CAE (eg. active filters) techniques, but the overall mechanical properties of the coatings will not be highly improved. Practical implications: Investigations of the influence of architecture and geometry of multi-module Cr/CrN coatings on their mechanical properties is crucial, because of their wide range of industry applications. Originality/value: The main value of the paper is an experimental case study of mechanical properties of Cr/CrN multi-module coatings referenced to CrN/CrCN coatings. Moreover, using FEM model of the indentation, the differences between residual stresses and strains were discussed.
A numerical model was developed in order to predict the hardness for casting the magnesium alloys MCMgAl6Zn1. Computer simulation of hardness was carried out with the help of finite element method in ANSYS environment, and the experimental values of hardness were determined basing on the Rockwell method. The presented model meets the initial criteria, which gives ground to the assumption about its usability for determining the hardness in casting the magnesium alloys MCMgAl6Zn1, employing the finite element method using the ANSYS program. The computer simulation results correlate with the experimental results. Presently the computer simulation is very popular and it is based on the finite element method, which allows to better understand the interdependence between parameters of process and choosing optimal solution. The possibility of application faster and faster calculation machines and coming into being many software make possible the creation of more precise models and more adequate ones to reality.
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