Instytut Podstawowych Problemów Techniki
Polskiej Akademii Nauk


Krzysztof Sztwiertnia

Ostatnie publikacje
1.  Kowalczyk-Gajewska K., Sztwiertnia K., Kawałko J., Wierzbanowski K., Wroński M., Frydrych K., Stupkiewicz S., Petryk H., Texture evolution in titanium on complex deformation paths: Experiment and modelling, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2015.04.040, Vol.637, pp.251-263, 2015

Texture evolution in commercially pure titanium deformed by equal-channel angular pressing (ECAP) and extrusion with forward–backward rotating die (KoBo) is studied both experimentally and numerically. New results are provided that demonstrate the effects of distinct and complex deformation paths on the texture in the ultra-fine grained (UFG) material obtained after severe plastic deformation (SPD). The numerical simulations are based on the self-consistent viscoplastic method of grain-to-polycrystal scale transition. A recently proposed modification of the probabilistic scheme for twinning is used that provides consistent values of the twin volume fraction in grains. The basic components of the experimentally observed texture are reasonably well reproduced in the modelling. The numerical simulations provide an insight into the internal mechanisms of plastic deformation, revealing substantial activity of mechanical twinning in addition to the basal and prismatic slip in titanium processed by ECAP.

Słowa kluczowe:
Texture evolution, UFG materials, SPD processes, Crystal plasticity, Twinning

Afiliacje autorów:
Kowalczyk-Gajewska K. - IPPT PAN
Sztwiertnia K. - inna afiliacja
Kawałko J. - inna afiliacja
Wierzbanowski K. - inna afiliacja
Wroński M. - inna afiliacja
Frydrych K. - IPPT PAN
Stupkiewicz S. - IPPT PAN
Petryk H. - IPPT PAN
2.  Nalepka K.T., Sztwiertnia K., Nalepka P., Pęcherski R.B., The strength analysis of Cu/α−Al2O3 interfaces as a key for rational composite design, ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.1515/amm-2015-0332, Vol.60, No.3, pp.1953-1956, 2015

Electron back-scattered diffraction (EBSD) studies carried out for the Cu/α−Al2O3 composites manufactured by pulsed laser deposition method and by the powder metallurgy enable to uncover a set of orientation relationships characteristic for materials of this type. The identified interfaces are categorized according to the bonding strength. Additionally, their microstructure is reproduced by molecular dynamic (MD) simulations. The obtained classification of the phase boundaries constitutes key information for effective composite design.

Słowa kluczowe:
EBSD, Cu/α−Al2O3 composites, PLD, bonding strength, molecular dynamics simulation

Afiliacje autorów:
Nalepka K.T. - inna afiliacja
Sztwiertnia K. - inna afiliacja
Nalepka P. - Agriculture University in Krakow (PL)
Pęcherski R.B. - inna afiliacja

Abstrakty konferencyjne
1.  Pęcherski R.B., Nalepka K.T., Nalepka P., Sztwiertnia K., Kret S., Ustrzycka A., Assessment of the strength of nanocomposites based on interface bonding analysis, ICTAM XXIV, 24th International Congress of Theoretical and Applied Mechanics, 2016-08-21/08-26, Montréal (CA), pp.2384-2385, 2016

Recent investigations reveal that interface bonding strength is dependent on the relative orientation of crystallites of the both phases [2]. The experimental, theoretical and computational investigations confirm this observation in the case of Cu/Al2O3 system, [3], [4]. It is shown that the statistical distribution of the values of interface strength for different relative orientations of bonded phases should be included in the phenomenological model of the damage initiation in nanocomposites. The novelty of the presented study is the combination of different experimental techniques: HRTEM, EBSD and molecular dynamics simulations with phenomenological theory of damage development in nanocomposites due to debonding at the interphase boundary [5], [6], [7]. A class of new models with the yield condition determined by one of quadric surfaces, in particular paraboloid or ellipsoid one is considered and the comparison with popular Gurson approach is discussed, [8].

Słowa kluczowe:
nanocompistes, strength, interface, bonding, HRTEM, EBSD, molecular dynamics

Afiliacje autorów:
Pęcherski R.B. - IPPT PAN
Nalepka K.T. - IPPT PAN
Nalepka P. - Agriculture University in Krakow (PL)
Sztwiertnia K. - inna afiliacja
Kret S. - Institute of Physics, Polish Academy of Sciences (PL)
Ustrzycka A. - IPPT PAN

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