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Finite Element Prediction for the Internal Stresses of (Ti,Al)N Coatings

Żukowska L. W., Śliwa A., Mikuła J., Bonek M., Kwaśny W., Sroka M., Pakuła D.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 1

149--152

EN

The general topic of this paper is the computer simulation with use of finite element method (FEM) for determining the internal stresses of selected gradient and single-layer PVD coatings deposited on the sintered tool materials, including cemented carbides, cermets and Al2O3+TiC type oxide tool ceramics by cathodic arc evaporation CAE-PVD method. Developing an appropriate model allows the prediction of properties of PVD coatings, which are also the criterion of their selection for specific items, based on the parameters of technological processes. In addition, developed model can to a large extent eliminate the need for expensive and time-consuming experimental studies for the computer simulation. Developed models of internal stresses were performed with use of finite element method in ANSYS environment. The experimental values of stresses were calculated using the X-ray sin2ψ technique. The computer simulation results were compared with the experimental results. Microhardness and adhesion as well as wear range were measured to investigate the influence of stress distribution on the mechanical and functional properties of coatings. It was stated that occurrence of compressive stresses on the surface of gradient coating has advantageous influence on their mechanical properties, especially on microhardness. Absolute value reduction of internal stresses in the connection zone in case of the gradient coatings takes profitably effects on improvement the adhesion of coatings. It can be one of the most important reasons of increase the wear resistance of gradient coatings in comparison to single-layer coatings.

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Structure and properties of gradient PVD coatings deposited on the sintered tool materials

Dobrzański L.A., Żukowska L. W.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 44, nr 2

115--139

EN

Purpose Investigate the structure and properties of sintered tool materials, including cemented carbides, cermets and oxide ceramics deposited with single-layer and gradient coatings (Ti,Al)N and Ti(C,N), and to determine the dependence between the substrate type, coating material or linear variation of chemical composition and the structure and properties of the obtained tool material. Design/methodology/approach: Analysis of the structure (SEM, TEM), analysis of the mechanical and functional properties: surface roughness, microhardness tests, scratch tests, cutting tests. The Ti(C,N) and (Ti,Al)N gradient coating was investigated by XPS and AES method. X-ray qualitative phase analysis and the grazing incidence X-ray diffraction method (GIXRD) was employed to collect the detailed information about phase composition of investigated material’s surface layer. Computer simulation of stresses was carried out in ANSYS environment, using the FEM method and the experimental values of stresses were determined basing on the X-ray diffraction patterns. Findings Results of the investigation the influence of PVD coatings structure (single-layer or gradient) and kind on properties of coated tool materials. Coatings are characterized by dense, compact structure. The coatings were deposited uniformly onto the investigated substrate materials and show a characteristic columnar, fine-graded structure. The coatings deposited onto the investigated substrates are characterised by good adhesion and causes increasing of wear resistance. Gradient coatings are characterized by a linear change of chemical composition in the direction from the substrate to the coating surface. A more advantageous distribution of stresses in gradient coatings than in respective single-layer coatings yields better mechanical properties, and, in particular, the distribution of stresses on the coating surface has the influence on microhardness, and the distribution of stresses in the contact area between the coating and substrate has the influence on the adhesion of coatings. Practical implications: Deposition of hard, thin, gradient coatings on materials surface by PVD method features one of the most intensely developed directions of improvement of the working properties of materials. Originality/value: The grazing incidence X-ray diffraction method (GIXRD) and using the XPS and AES method in the investigated coatings were used to describe the gradient character of the coatings. The computer simulation is based on the finite element method, which allows to better understand the interdependence between parameters of process and choosing optimal solution.

3

FEM modelling of internal stresses in advanced PVD coatings

Dobrzański L. A., Żukowska L. W., Śliwa A., Mikuła J.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 49, nr 2

259--268

EN

Purpose: The general topic of this paper is the computer simulation with use of finite element method (FEM) for determining the internal stresses of gradient and single -layer coatings (Ti,Al)N and Ti(C,N) deposited on the sintered tool materials, including cemented carbides, cermets and Al2O3+TiC type oxide tool ceramics by cathodic arc evaporation CAE-PVD method. Design/methodology/approach: Internal stresses’ models were performed with use of finite element method in ANSYS environment. The experimental values of stresses were were calculated using the X-ray sin2^ technique. The computer simulation results were compared with the experimental results. Microhardness and adhesion as well as wear range were measured to investigate the influence of stress distribution on the mechanical and functional properties of coatings. Findings: A more advantageous distribution of stresses in gradient coatings than in respective single-layer coatings yields better mechanical properties, and, in particular, the distribution of stresses on the coating surface has the influence on microhardness, and the distribution of stresses in the contact area between the coating and substrate has the influence on the adhesion of coatings. Practical implications: Deposition of hard, thin, gradient coatings on materials surface by PVD method features one of the most intensely developed directions of improvement of the working properties of materials. 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. Originality/value: Nowadays 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. Influence of gradient structure of coatings on the mechanical and functional properties were investigated with use of finite element method.

4

Structure and mechanical properties of PVD coatings for tool materials

Dobrzański L. A., Śliwa A., Żukowska L. W., Mikuła J., Gołombek K.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 42, nr 1-2

33-41

EN

Purpose: The goal of this work is to investigate and compare the properties of (Ti,Al)N, Ti(C,N) and (Ti,Al,Si)N coatings, deposited on cemented carbide and cermet substrates. Design/methodology/approach: Coatings deposition were carried out using the PVD method by the cathodic arc evaporation (CAE) process. Investigations of surfaces and structures of the deposited coatings were carried out with use of SEM and TEM methods. Roughness parameter measurements, adhesion evaluation of the coatings on the investigated inserts, the Vickers microhardness measurements and detailed cutting tests were carried out to compare the properties of the investigated materials. Findings: The results of the investigations carried out confirm the advantages of PVD coatings deposited onto both: cemented carbides and cermets, especially in case of (Ti,Al)N and (Ti,Al,Si)N coatings. Coatings deposited onto the investigated substrates are characterised by good adhesion, high microhardness, taking effect in very high increasing of wear resistance. Practical implications: Deposition of hard, thin, multicomponent coatings on materials surface by PVD method features one of the most intensely developed directions of improvement of the working properties of materials. Employment of introduced combinations of substrates and coatings make it possible to transit of machining of semi-products from roughing to semi-finishing or finishing in one setting. Originality/value: Coatings based on (Ti,Al)N, (Ti,Al,Si)N as well as Ti(C,N) were developed to provide better performance over titanium nitride since the incorporation of aluminum or carbon in TiN increased hardness, decreased coefficient of friction of the coatings. Tools with such coatings reveal a significant life extension in service compared to the uncoated tools or coated with simple coatings based on monolayers of nitrides or carbonitrides, improvement of the tribological contact conditions in the tool-chip-machined material contact zone, and protection of the tool edge from oxidation and extensive overheating.

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Functional properties of the sintered tool materials with (Ti,Al)N coating

Dobrzański L. A., Żukowska L. W., Mikuła J., Gołombek K., Podstawski P.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 36, nr 2

134-141

EN

Purpose: The paper presents investigation results of functional properties of the sintered tool materials: high-speed steel matrix composites (HSSMC), cemented carbides, cermets and Al2O3 type oxide tool ceramics with (Ti,Al)N coating deposited in the cathodic arc evaporation CAE-PVD method and comparing them with the uncoated tool materials. Design/methodology/approach: Analysis of the mechanical and functional properties: surface roughness, microhardness tests, scratch tests, cutting tests. X-ray qualitative microanalysis of elements. Findings: Deposition of (Ti,Al)N coating onto high-speed steel matrix composites (HSSMC), cemented carbides, cermet and Al2O3 type oxide tool ceramics substrate causes increase of wear resistance as well as reduces the exceeding of steady stresses critical levels. It causes multiple (up to 800%) increase of tool life. As a result of metallographic observations it was stated that linear and uniform character of wear was achieved in case of all deposited samples. Practical implications: Employment of the hard coatings deposited onto sintered tool materials is reckoned as one of the most important achievements last year in the area of improvement of functional properties of cutting tools. Originality/value: Combination of substrates (especially coatings deposited on high-speed steel matrix composite) is unique and very interesting in respect of achieved functional properties.

6

Sintered tool materials with multi-component PVD gradient coatings

Gołombek K., Mikuła J., Pakuła D., Żukowska L. W., Dobrzański L. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 31, nr 1

15-22

EN

Purpose: The main aim of researches was investigation of structure and properties of the (Ti, Al, Si)N gradient wear resistant coatings. Design/methodology/approach: The structural investigations include the metallographic analysis on the transmission and scanning electron microscope. Examinations of the chemical compositions of the deposited coatings were carried out using the X-ray energy dispersive spectrograph EDS, glow-discharge optical emission spectroscope GDOES, auger electron spectroscope (AES) and using the X-ray diffractometer. The investigations include also analysis of the mechanical and functional properties of the materials: substrate hardness tests and microhardness tests of the deposited coatings, surface roughness tests, evaluation of the adhesion of the deposited coatings as well as cutting properties. Findings: Deposition of the multicomponent gradient coatings with the PVD method, based on the Al and Si solid secondary solution in the TiN titanium nitride, isomorphous with the alternating pure titanium nitride TiN, on tools made from oxide, nitride ceramics and tool cermets, results in the increase of mechanical properties in comparison with uncoated tool materials, deciding thus the improvement of their working properties. Practical implications: Deposition of (Ti, Al, Si)N nanocrystalline coatings by the use of PVD method causes the increase of cutting properties of tools made of cermets for ca. 300% and of Al2O3+ZrO2 for ca. 100% comparing to adequately uncoated tools. Originality/value: Comparison of the wide range of modern sintered tool materials with wide unique set of PVD coatings.

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Properties of the multicomponent and gradient PVD coatings

Dobrzański L. A., Żukowska L. W.

Archives of Materials Science and Engineering

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2007

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Vol. 28, nr 10

621-624

EN

Purpose: This paper presents investigation results of the properties of the multicomponent (Ti,Al)N and gradient Ti(C,N) wear resistant coatings, deposited with the PVD process onto the substrate from the cemented carbides, cermets and Al2O3 + TiC type oxide tool ceramics. Design/methodology/approach: The methodology includes analysis of the mechanical and functional properties. The Ra parameter was assumed to be the value describing surface roughness. The microhardness tests using the Vickers method were made with use of dynamic ultra microhardness tester. The measurements were made in the "load-unload" mode. Tests of the coatings adhesion to the substrate material was made with use of the scratch test. Surface roughness tests were done both before depositing the coatings and after completing the PVD process. Cutting properties of the investigated materials were determined based on the technological continuous cutting tests of the EN-GJL-250 grey cast iron. Findings: Main properties of the investigated materials were introduced. It has been stated, that properties of the cemented carbides, cermets and oxide tool ceramics with deposited multicomponent (Ti,Al)N and gradient Ti(C,N) PVD coatings increase in comparison with uncoated material. Multiple increase of tool life result among other things from almost double increase of microhardness of PVD coated materials in comparison with uncoated cemented carbides, cermets and oxide tool ceramics, increasing of thermal and chemical wear resistance and improving of chip formation and removing process' conditions. Practical implications: Pro-ecological dry cutting processes without the use of the cutting fluids and in the „Near-Net-Shape” technology. Originality/value: Application of multicomponent (Ti,Al)N and gradient Ti(C,N) types of coatings onto sintered tool materials in order to improve cutting properties of tools.