Mateusz Kopeć, M.Sc., Eng.

Department of Experimental Mechanics (ZMD)
Division of Strength of Materials (PWM)
position: programmer
telephone: (+48) 22 826 12 81 ext.: 408
room: 037
e-mail: mkopec

Recent publications
1.Kopeć M., Wang K., Politis D.J., Wang Y., Wang L., Lin J., Formability and microstructure evolution mechanisms of Ti6Al4V alloy during a novel hot stamping process, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2018.02.038, pp.1-20, 2018
Abstract:

A novel hot stamping process for Ti6Al4V alloy using cold forming tools and a hot blank was presented in this paper. The formability of the material was studied through uniaxial tensile tests at temperatures ranging from 600 to 900 °C and strain rates ranging from 0.1 to 5 s-1. An elongation ranging from 30% to 60% could be achieved at temperatures ranging from 750 to 900°C respectively. The main microstructure evolution mechanisms varied with the deformation temperature, including recovery, phase transformation and recrystallization. The hardness of the material after deformation first decreased with the temperature due to recovery, and subsequently increased mainly due to the phase transformation. During the hot stamping tests, qualified parts could be formed successfully at heating temperatures ranging from 750 to 850°C. The forming failed at lower temperatures due to the limited ductility of the material. At temperatures higher than 900°C, extensive phase transformation of α to β occurred during the heating. During the transfer and forming, the temperature dropped significantly which led to the formation of transformed β, reduction of the formability and subsequent failure. The post-form hardness distribution demonstrated the same tendency as that after uniaxial tensile tests.

Keywords:

titanium alloys, Ti6Al4V, hot stamping, microstructure

Affiliations:
Kopeć M.-IPPT PAN
Wang K.-Imperial College London (GB)
Politis D.J.-Imperial College London (GB)
Wang Y.-Beijing Aeronautical Manufacturing Technology Research Institute (CN)
Wang L.-Imperial College London (GB)
Lin J.-Imperial College London (GB)
2.Kopeć M., Wang K., Wang Y., Wang L., Lin J., Feasibility study of a novel hot stamping process for Ti6Al4V alloy, MATEC Web of Conferences, ISSN: 2261-236X, DOI: 10.1051/matecconf/201819008001, Vol.190, pp.1-5, 2018
Abstract:

To investigate the feasibility of a novel hot stamping process for the Ti6Al4V titanium alloy using low temperature forming tools, mechanical properties of the material were studied using hot tensile tests at a temperature range of 600 - 900°C with a constant strain rate of 1s-1. Hot stamping tests were carried out to verify the feasibility of this technology and identify the forming window for the material. Results show that when the deformation temperature was lower than 700°C, the amount of elongation was less than 20%, and it also had little change with the temperature. However, when the temperature was higher than 700°C, a good ductility of the material can be achieved. During the forming tests, parts failed at lower temperatures (600°C) due to the limited formability and also failed at higher temperatures (950°C) due to the phase transformation. The post-form hardness firstly decreased with the temperature increasing due to recovery and then increased due to the phase transformation. Qualified parts were formed successfully between temperatures of 750 - 850°C, which indicates that this new technology has a great potential in forming titanium alloys sheet components.

Keywords:

titanium, hot stamping, metal forming

Affiliations:
Kopeć M.-IPPT PAN
Wang K.-Imperial College London (GB)
Wang Y.-Beijing Aeronautical Manufacturing Technology Research Institute (CN)
Wang L.-Imperial College London (GB)
Lin J.-Imperial College London (GB)
3.Kukla D., Grzywna P., Kopeć M., Kowalewski Z.L., Assessment of hardened layer thickness for 40HNMA steel using eddy current method, INŻYNIERIA MATERIAŁOWA, ISSN: 0208-6247, DOI: 10.15199/28.2016.5.10, Vol.213, No.5, pp.263-266, 2016
Abstract:

Materials and semi-manufactured products for aviation equipment are usually subjected to increasingly rigorous demands for the quality control. In many cases, like hardened or carburized wheels or rollers assembled in the gear motors, the control procedures enforce necessity of the selective testing of details coming from production lines using destructive techniques. The main aim of diagnostic investigations carrying out on series of final products is to assess qualitatively and quantitatively the layers obtained due to carburizing and induction hardening. Unfortunately, such processes increase the fabrication costs significantly, especially in the case of complex manufacturing technology applied and small-lot production as well. In order to reduce them the attempts for application of non-destructive testing methods are taken for evaluation of either the layers quality or the products subjected to surface treatments. This paper presents the eddy currents method used for the thickness evaluation of the carburized and induction-hardened layers on the basis of the impedance signal variation. The signal was obtained as a result of the so-called ‘lift off’ effect. A methodology for the quantitative thickness evaluation of the carburized and induction-hardened layers has been elaborated under a range of technological parameters. The measurements ranges were defined in the framework of which an identification of the hardened layer was possible using the commercial defectoscope and reference specimens of the fixed thickness. Tests were carried out on specimens made of the ASM6414 steel and subjected subsequently to carburization and induction hardening. The impedance parameters were measured for selected values of frequency. The results were verified on the basis of metallographic investigations as well as the microhardness measurements captured in the form of profiles taken from specimens’ cross-sections of different layer thickness.

Keywords:

eddy current, hardening, carburizing, layers, non-destructive technique

Affiliations:
Kukla D.-IPPT PAN
Grzywna P.-IPPT PAN
Kopeć M.-IPPT PAN
Kowalewski Z.L.-IPPT PAN
4.Kopeć M., Grzywna P., Kukla D., Kowalewski Z.L., Evaluation of the fatigue damage development using ESPI method, INŻYNIERIA MATERIAŁOWA, ISSN: 0208-6247, DOI: 10.15199/28.2016.4.9, Vol.212, No.4, pp.201-205, 2016
Abstract:

Fatigue damage process developing in structural materials under long-term cyclic loading is still an unsolved problem of modern engineering. Attempts to assess a degree of materials degradation under fatigue conditions on the basis of changes in the areas of local strain concentration determined by optical methods can be treated as the promising contemporary research direction of majority of scientific centres in the world. In most cases, fatigue damage has a local character and it is based on damage development leading to generation of cracks appearing around structural defects or geometrical notches. An identification of these areas and their subsequent monitoring requires a full-field displacement measurements performed on the objects surfaces. It seems that modern contemporary optical methods for displacement components measuring on the surfaces of structural elements or tested specimens are suitable for such purpose. Digital Image Correlation (DIC) and Electronic Speckle Pattern Interferometry (ESPI) are nowadays the most widely used testing methods in this area. Both of them enable capturing of displacement and strain components distributions. This paper presents an attempt to use the ESPI method for fatigue damage evaluation and its monitoring on specimens made of the aluminide coated nickel super-alloys. Flat specimens were subjected to cyclic loading. The fatigue tests were interrupted several times in order to perform a static loading during which the optical measurements were carried out. An analysis of the results captured by the ESPI system allowed indication of places of the greatest stress concentration and demonstration of the damage development process as a function of the increasing number of cycles.

Keywords:

fatigue, damage, super-alloy, Electronic Speckle Pattern Interferometry

Affiliations:
Kopeć M.-IPPT PAN
Grzywna P.-IPPT PAN
Kukla D.-IPPT PAN
Kowalewski Z.L.-IPPT PAN

Conference papers
1.Grzywna P., Kukla D., Kowalewski Z.L., Kopeć M., Wyszkowski M., Zastosowanie elektronicznej interferometrii plamkowej do lokalizacji uszkodzeń zmęczeniowych, XXIII Seminarium NIENISZCZĄCE BADANIA MATERIAŁÓW, 2017-03-15/03-17, Zakopane (PL), pp.171-188, 2017
2.Kowalewski Z.L., Dietrich L., Kopeć M., Szymczak T., Grzywna P., Nowoczesne systemy optyczne w badaniach mechanicznych – budowa, działanie, zastosowania, XXII Seminarium NIENISZCZĄCE BADANIA MATERIAŁÓW, 2016-03-16/03-18, Zakopane (PL), pp.5-36, 2016

Conference abstracts
1.Wang K., Kopeć M., Qu H., Wang Y., Wang L., Lin J., Li Z., A unified constitutive model for two-phase titanium alloys under hot stamping condition, ICNFT 2018, 5th International Conference on New Forming Technology, 2018-08-18/08-21, Bremen (DE), pp.1-1, 2018
2.Grzywna P., Kukla D., Kowalewski Z.L., Kopeć M., Wyszkowski M., Assessment of fatigue damage development using the espi system, 27EMS, Experimental Mechanics of Solids - 27th Symposium, 2016-10-19/10-22, Jachranka (PL), pp.27, 2016
3.Kukla D., Grzywna P., Kopeć M., Kowalewski Z.L., Eddy Current method for thickness assessment of carburized layers, AMT 2016, XXI Physical Metallurgy and Materials Science Conference - Advanced Materials and Technologies, 2016-06-05/06-08, Rawa Mazowiecka (PL), pp.BP7-1-3, 2016
Keywords:

eddy current, hardening, carburizing, layers, non - destructive technique

Affiliations:
Kukla D.-IPPT PAN
Grzywna P.-IPPT PAN
Kopeć M.-IPPT PAN
Kowalewski Z.L.-IPPT PAN
4.Kopeć M., Grzywna P., Kukla D., Kowalewski Z.L., Evaluation of the fatigue damage development using ESPI method, AMT 2016, XXI Physical Metallurgy and Materials Science Conference - Advanced Materials and Technologies, 2016-06-05/06-08, Rawa Mazowiecka (PL), pp.E05-1-4, 2016
Abstract:

Fatigue damage process developing in structural materials under long-term cyclic loading is still an unsolved problem of modern engineering. Attempts to assess a degree of materials degradation under fatigue conditions on the basis of changes in the areas of local strain concentration determined by optical methods can be treated as the promising contemporary research direction of majority of scientific centers in the world. In most cases, fatigue damage has a local character and it is based on damage development leading to generation of cracks appearing around structural defects or geometrical notches. An identification of these areas and their subsequent monitoring requires a full-field displacement measurements performed on the objects surfaces. It seems that modern contemporary optical methods for displacement components measuring on the surfaces of structural elements or tested specimens are suitable for such purpose. Digital Image Correlation (DIC) and Electronic Speckle Pattern Interferometry (ESPI) are nowadays the most widely used testing methods in this area. Both of them enable capturing of displacement and strain components distributions. This paper presents an attempt to use the ESPI method for fatigue damage evaluation and its monitoring on specimens ma de of the aluminide coated nickel super-alloys. Flat specimens were subjected to cyclic loading . The fatigue tests were interrupted several times in order to perform a static loading during which the optical measurements were carried out. An analysis of the results captured by the ESPI system allowed indication of places of the greatest stress concentration and demonstration of the damage development process as a function of the increasing number of cycles.

Keywords:

fatigue, damage, super - alloy, Electronic Speckle Pattern Interferometry

Affiliations:
Kopeć M.-IPPT PAN
Grzywna P.-IPPT PAN
Kukla D.-IPPT PAN
Kowalewski Z.L.-IPPT PAN