K. J. Kurzydlowski

Sahand University of Technology, Tebriz, East Azarbaijan, Iran

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Publications (189)216.89 Total impact

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    ABSTRACT: The structure and corrosion resistance of Grade 2 titanium subjected to the hydroextrusion processes were examined. The microstructure was characterized using optical microscopy and transmission electron microscopy. The corrosion resistance was determined using the impedance and potentiodynamic methods, in 0.1 M H2SO4 solutions and an acidified 0.1 M NaCl solution with a pH of 4.2, at ambient temperature. Nanohardness tests were performed under a load of 100 mN. It has been demonstrated that the hydroextrusion method makes it possible to obtain relatively homogeneous nanocrystalline titanium Grade 2 with an increased hardness, the elastic modulus almost unchanged with respect to that of the initial structure and a lower corrosion resistance.
    Journal of Nanoscience and Nanotechnology 07/2015; 15(7):4992-4998. DOI:10.1166/jnn.2015.10027 · 1.34 Impact Factor
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    P. Kwasniak, M. Muzyk, H. Garbacz, K. J. Kurzydlowski
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    ABSTRACT: The interactions of prime interstitial and alloying elements in hexagonal Ti were investigated using a density functional theory calculations. The binding energies of oxygen with all substitution elements whose solubility limit in α-Ti is greater than 3 at% were calculated. The investigations performed reveal no attraction between Zn, Zr, Ag and O, and strong O–Sc and O–Sn binding. It was found that the O–X clustering mechanism is based on a direct and long-range O–X interaction, both controlled by valence structure and electronegativity of substitational elements. The single crystal and isotropic elastic constants together with Pugh's plasticity criterion were calculated for Ti with multiple point defects to evaluate their impact on mechanical properties. The results obtained reveal that a low concentration of O improves ductility in Ti + Sc solid solutions and increases the brittleness of Ti + Sn alloys. The diverse effect on ductility is due to different chemical bond types in the vicinity of O. The results show that the interstitial-substitational elements clustering effect may be used to optimize mechanical properties of α-Ti alloys.
    Materials Chemistry and Physics 03/2015; 154. DOI:10.1016/j.matchemphys.2015.01.056 · 2.13 Impact Factor
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    ABSTRACT: Corrosion behavior of a metallic biomaterial is an important characteristic because the biocompatibility of a biomedical grade metallic implant is primarily related to corrosion behavior. The aim of this research was to study the effect of Equal Channel Angular Pressing (ECAP) process on corrosion behavior of the AISI 316L type austenitic stainless steel. ECAP was conducted on an AISI 316L stainless steel up to eight passes. Scanning transmission electron microscopy (STEM) technique was utilized to study the microstructure of the as-received material and the samples subjected to ECAP. Electrochemical corrosion polarization and electrochemical impedance spectroscopy tests were performed in Ringer solution in order to determine and compare the corrosion behavior of initial coarse-grained and ECAP-ed specimens as an indication of biocompatibility. The results showed that an ultrafine-grained/ nanocrystalline 316L stainless steel with a mean grain size of about 78 nm was obtained after performing the eight passes of ECAP. The corrosion resistance of 316L stainless steel was improved considerably by increasing of the number of ECAP passes. After performing the eight passes of ECAP process, the corrosion rate of 316L stainless steel measured to be 0.42 μA.cm2 which is significantly lower than that of initial coarse-grained material (3.12 μA.cm2).
    Corrosion -Houston Tx- 03/2015; DOI:10.5006/1359 · 2.91 Impact Factor
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    ABSTRACT: Biodegradable polymeric fibers with nano and submicron diameters, produced by electrospinning can be used as scaffolds in tissue engineering. However is necessary to characterize their mechanical properties especially at the nanoscale. The PeakForce Quantitative NanoMechanics (PF-QNM) is recently developed AFM mode, which allows to probe mechanical properties of the material, such as: reduced Youngs modulus, deformation, adhesion, and dissipation, simultaneously with topographical imaging. In this paper we are presenting results of PF-QNM characterization of two kinds of electrospun fibers: PCL and PCL/HAp. The average calculated from DMT theory Young modulus was 3 ± 1 MPa for PCL mesh and 17 ± 3 MPa for PCL+HAp mesh. 1. Introduction Biodegradable polymeric fibers, produced by electrospinning method, with nano and submicron diameters can be used as scaffolds in tissue engineering. It is possible due to their interfibrous pore size, high surface area to volume ratio, immunogenicity, biodegradability and structural similarity to the extracellular matrix (ECM) 1). In physiological conditions fibers are subjected to stresses and strains from the surrounding biological environment. Such stresses can cause permanent deformation or even failure to scaffold structure. Therefore, there is a growing need to characterize their mechanical properties, especially at the nanoscale. Atomic force microscopy (AFM) has emerged as a powerful tool in the imaging of cells and biomaterials and probing selected mechanical properties under physiological conditions 2,3,4). The PeakForce Quantitative NanoMechanics (PF-QNM) is recently developed AFM mode, which allows to measure mechanical properties of the material, such as: reduced Youngs modulus, deformation, adhesion, and dissipation, simultaneously with topographical imaging 5) .
    IAPS2015, Hawaii, Honolulu, Waikiki; 03/2015
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    R. Sitek, J. Mizera, K. J. Kurzydlowski
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    ABSTRACT: Electrospun polymeric submicron and nanofibers can be used as tissue engineering scaffolds in regenerative medicine. In physiological conditions fibers are subjected to stresses and strains from the surrounding biological environment. Such stresses can cause permanent deformation or even failure to their structure. Therefore, there is a growing necessity to characterize their mechanical properties, especially at the nanoscale. Atomic force microscopy is a powerful tool for the visualization and probing of selected mechanical properties of materials in biomedical sciences. Image resolution of atomic force microscopy techniques depends on the equipment quality and shape of the scanning probe. The probe radius and aspect ratio has huge impact on the quality of measurement. In the presented work the nanomechanical properties of four different polymer based electrospun fibers were tested using PeakForce Quantitative NanoMechanics atomic force microscopy, with standard and modified scanning probes. Standard, commercially available probes have been modified by etching using focused ion beam (FIB). Results have shown that modified probes can be used for mechanical properties mapping of biomaterial in the nanoscale, and generate nanomechanical information where conventional tips fail. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Micron 02/2015; 72C. DOI:10.1016/j.micron.2015.01.005 · 2.06 Impact Factor
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    P. Maj, J. Zdunek, M. Gizynski, J. Mizera, K.J. Kurzydlowski
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    ABSTRACT: The Portevin–Le Chatelier effect manifests itself as an unstable plastic flow which occurs during tensile tests of some dilute materials in a certain range of temperatures and strain rates. This phenomenon is also exceptionally intense in nickel based superalloys used in the aerospace industry. The aim of this research was to investigate the Portevin–Le Chatelier effect in Inconel 718 solution strengthened superalloy. The tested material was subjected to tensile tests carried out within the temperature range 250–600 °C with three different strain rates 2×10−3 s−1, 10−2 s−1 and 5×10−2 s−1. The strain curves were analyzed in terms of intensity and statistical behavior. A quantitative method to describe the phenomenon was used in the study. The results indicate the presence of clear trends with temperature and strain rates. Additional optical observations were carried out to assess the changes of the microstructure.
    Materials Science and Engineering A 12/2014; 619:158–164. DOI:10.1016/j.msea.2014.09.075 · 2.41 Impact Factor
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    ABSTRACT: This study concerns imaging of the structure of materials using AFM tapping (TM) and phase imaging (PI) mode, using probes modified with Focused Ion Beam (FIB). Three kinds of modifications were applied–thinning of the cantilever, sharpening of the tip and combination of these two modifications. Probes shaped in that way were used for AFM investigations with Bruker AFM Nanoscope 8. As a testing material, titanium roughness standard supplied by Bruker was used. The results show that performed modifications influence the oscillation of the probes. In particular thinning of the cantilever enables one to acquire higher self-resonant frequencies, which can be advantageous for improving the quality of imaging in PI mode. It was found that sharpening the tip improves imaging resolution in tapping mode, which is consistent with existing knowledge, but lowered the quality of high frequency topography images. In this paper the Finite Element Method (FEM) was used to explain the results obtained experimentally.
    Micron 11/2014; 66. DOI:10.1016/j.micron.2014.05.001 · 2.06 Impact Factor
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    ABSTRACT: The melting of aluminum thin film was studied by a molecular dynamics (MD) simulation technique. The effect of the grain size and type of confinement was investigated for aluminum film with a constant thickness of 4 nm. The results show that coherent intercrystalline interface suppress the transition of solid aluminum into liquid, while free-surface gives melting point depression. The mechanism of melting of polycrystalline aluminum thin film was investigated. It was found that melting starts at grain boundaries and propagates to grain interiors. The melting point was calculated from the Lindemann index criterion, taking into account only atoms near to grain boundaries. This made it possible to extend melting point calculations to bigger grains, which require a long time (in the MD scale) to be fully molten. The results show that 4 nm thick film of aluminum melts at a temperature lower than the melting point of bulk aluminum (933 K) only when the grain size is reduced to 6 nm. (C) 2014 AIP Publishing LLC.
    Journal of Applied Physics 10/2014; 116(16). DOI:10.1063/1.4899240 · 2.19 Impact Factor
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    P. Maj, J. Zdunek, J. Mizera, K. J. Kurzydlowski
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    ABSTRACT: The aim of this research was to investigate the influence of a geometrical notch on the Portevin–Le Chatelier effect. This phenomenon manifests itself as the serrated stress–strain curve obtained for certain materials when they undergo plastic deformation during tensile tests. The Portevin–Le Chatelier effect can often be observed in aluminum alloys especially those with an addition of magnesium. The material examined in the present experiments was a model Al–3Mg alloy. Samples were prepared with notches cut in the specimens with different depths and shapes. The results clearly indicate that the notch has a significant influence on the Portevin–Le Chatelier effect. With increasing notch depth, the stress amplitude of the serrations increases together with their frequency and the course of the serrations changes.
    Materials Characterization 10/2014; 96:46–53. DOI:10.1016/j.matchar.2014.07.007 · 1.93 Impact Factor
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    ABSTRACT: Fabrication of scaffolds for tissue engineering (TE) applications becomes a very important research topic in present days. The aim of the study was to create and evaluate a hybrid polymeric 3D scaffold consisted of nano and microfibers, which could be used for bone tissue engineering. Hybrid structures were fabricated using rapid prototyping (RP) and electrospinning (ES) methods. Electrospun nanofibrous mats were incorporated between the microfibrous layers produced by RP technology. The nanofibers were made of poly(L-lactid) and polycaprolactone was used to fabricate microfibers. The micro- and nanostructures of the hybrid scaffolds were examined using scanning electron microscopy (SEM). X-ray microtomographical (μCT) analysis and the mechanical testing of the porous hybrid structures were performed using SkyScan 1172 machine, equipped with a material testing stage. The scanning electron microscopy and micro-tomography analyses showed that obtained scaffolds are hybrid nanofibers/microfibers structures with high porosity and interconnected pores ranging from 10 to 500um. Although, connection between microfibrous layers and electrospun mats remained consistent under compression tests, addition of the nanofibrous mats affected the mechanical properties of the scaffold, particularly its elastic modulus. The results of the biocompatibility tests did not show any cytotoxic effects and no fibroblast after contact with the scaffold showed any damage of the cell body, the cells had proper morphologies and showed good proliferation. Summarizing, using RP technology and electrospinning method it is possible to fabricate biocompatible scaffolds with controllable geometrical parameters and good mechanical properties.
    09/2014; 62(3):551-556. DOI:10.2478/bpasts-2014-0059
  • W. Chrominski, M. Kulczyk, M. Lewandowska, K.J. Kurzydlowski
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    ABSTRACT: Precipitation strengthening of an ultrafine-grained Al-Mg-Si alloy has been studied using samples obtained by hydrostatic extrusion. It has been demonstrated that the microstructure after hydrostatic extrusion consists of two types of grains: (1) nano-sized free of dislocations and surrounded with high angle grain boundaries and (2) micron-sized with dislocation substructure. After ageing at 160 °C, small needle-like precipitates appear in grain interiors of both nano- and micron-sized grains, bringing about a significant strength improvement. However, the precipitates are smaller than those in their coarse grained counterparts. As a consequence, they constitute weaker barriers for dislocations and induce a lower strengthening effect. In addition, one may observe intensive precipitation at nano-grains boundaries, which further reduces the strengthening effect. It was also shown that peak ageing and overageing take place for much shorter time than in the case of coarse grained samples and are caused by the grain growth rather than a change in the precipitation state.
    Materials Science and Engineering A 07/2014; 609:80–87. DOI:10.1016/j.msea.2014.04.092 · 2.41 Impact Factor
  • Marcin K. Heljak, Wojciech Swieszkowski, Krzysztof Jan Kurzydlowski
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    ABSTRACT: The rate of hydrolytic degradation of tissue-engineered scaffolds made from bioresorbable polyesters is dependent on several factors. Some are related to the properties of the degrading polymeric material, but others are related to the geometry of the porous structure and the operating environment. It is well known that the rate of hydrolytic degradation of a given object, porous or nonporous, is lower when it is exposed to dynamic conditions, a flowing medium, than when it operates in static conditions. The most likely reason is the more efficient removal of the acidic degradation products from the vicinity of the polymeric material when it is operating in a flowing medium. In this article, we present a new phenomenological reaction–diffusion model of aliphatic polymer degradation. The model can be used to predict the significance of various factors in in vitro degradation tests, with particular reference to the flow of the degradation medium, and the frequency of medium replacement in the case of static conditions. The developed model was used to simulate the degradation of poly(dl-lactide-co-glycolide) scaffolds with different porosities subjected to static and dynamic testing conditions. The results confirm that the porosity of the scaffold had a significant influence on the degradation rate. It was shown that the combination of dynamic conditions and high porosity effectively reduced the mass loss and molecular weight loss of the degrading polymer. However, the effect of changes in the velocity of the flowing medium had a negligible effect on the rate of degradation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40280.
    Journal of Applied Polymer Science 06/2014; 131(11). DOI:10.1002/app.40280 · 1.64 Impact Factor
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    ABSTRACT: In this paper the effect of production method and heat treatment of magnesium alloys to their corrosion resistance is presented. The study was carried out on the AZ91D alloy obtained by permanent mould casting, pressure die casting and pressure die casting with the subsequent heat treatment. Studies of the microstructure were carried out using a light microscope. The corrosion resistance was examined using the Potentiodynamic Test. The surface observations after corrosion tests were carried out using the Scanning Electron Microscope (SEM). It was stated that the best corrosion resistance is typical for AZ91D alloy produced by pressure die casting method with heat treatment. The alloy after permanent mould casting has got the worst corrosive properties.
    06/2014; 983:110-115. DOI:10.4028/www.scientific.net/AMR.983.110
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    ABSTRACT: The precipitation phenomena in 7475 nanograined aluminium alloy was analysed by means of microhardness measurements, small angle X-ray scattering and electron microscopy. The nanograined samples were obtained by the hydrostatic extrusion of solution annealed and water quenched samples. It has been established that low temperature ageing causes precipitation processes to occur. However, the precipitation phenomena in nanograined materials proceed differently to those in micrograined materials. Moreover, the particle strengthening is limited by enhanced grain boundary precipitation which does not contribute to an increase in strength (when dislocation slip is the dominant deformation mechanism) and by the smaller size of precipitates.
    Advanced Engineering Materials 05/2014; 16(5). DOI:10.1002/adem.201400018 · 1.51 Impact Factor
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    Ida Dulińska-Molak, Jakub Jaroszewicz, Krzysztof J. Kurzydlowski
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    ABSTRACT: Bone tissue has a composite nature given by a highly complex and well-harmonized structure of organic and inorganic components on the microscale, macroscale and nanoscale. Thus, biodegradable composite scaffolds made of poly (ε-caprolactone) urethane (PCL_PUR) porous matrix and calcium carbonate (CaCO3) were developed and studied for bone tissue engineering. The aim of this work was to examine the structure of new polyurethane/calcite composites. Micro-computer tomography (μ-CT) and image analysis enabled 3D visualization and quantification of the porosity, wall thickness and internal pore size distribution. The fabricated porous polyurethane composites exhibited porosity >70% with a pore size not exceeding 450 μm and wall thickness about of 50 μm in size. The mechanical properties of the foams were evaluated using Dynamic Mechanical Analysis (DMA). In-vitro bioactivity tests in simulated body fluid (SBF) were carried out and the marker of bioactivity, e.g. formation of surface bone-like apatite layers upon immersion in SBF, was investigated. Our results indicated that PUR/calcite scaffolds were more activity then PUR scaffolds and possessed the function to enhance cell proliferation and differentiation, and might be used as bone tissue engineering materials.
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    ABSTRACT: This work presents results of the characterization of dust collected in ASDEX Upgrade, with special emphasis on the size, morphology, structure and composition of the dust particles. The dust particles were collected after the 2009 campaign using the filtered vacuum technique. The structure and composition of the particles were examined by scanning electron microscopy combined with energy-dispersive x-ray spectroscopy, focused ion beam and scanning transmission electron microscopy with special interest in the tungsten particles.
    Physica Scripta 04/2014; T159:014066. DOI:10.1088/0031-8949/2014/T159/014066 · 1.30 Impact Factor
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    ABSTRACT: Equal channel angular pressing (ECAP) CP-Ti Ultrafine-grained materials Corrosion resistance Cell behavior The electrochemical and cellular behavior of commercially pure titanium (CP-Ti) with both ultrafine-grained (UFG) and coarse-grained (CG) microstructure was evaluated in this study. Equal channel angular pressing was used to produce the UFG structure titanium. Polarization and electrochemical impedance tests were carried out in a simulated body fluid (SBF) at 37 °C. Cellular behaviors of samples were assessed using fibroblast cells. Results of the investigations illustrate the improvement of both corrosion and biological behavior of UFG CP-Ti in comparison with the CG counterpart.
    Materials Science and Engineering C 03/2014; DOI:10.1016/j.msec.2014.03.001 · 3.09 Impact Factor
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    ABSTRACT: In the current work we propose a software tool for thermal analysis and design of various composite material structures, represented by a unit volume a form of cuboid. The software operates with three most popular composite structures.
    ECS Meeting Abstracts 2014 MA2014-03(6): 585 (Recent ECEE Posters - Mar 14 2014 5:20PM), Print ISSN: 2151-2041, Shanghai, China; 03/2014
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    ABSTRACT: Nerve tissue engineering (TE) is a rapidly expanding area of research advancing towards the repair and regeneration of non-union peripheral nerve defects caused by injuries. The current challenge for researchers is to develop a biomimetic scaffold that is capable of stimulating the re-growth of the native tissue, thus structurally mimicking the extracellular matrix (ECM), providing chemical guidance cues and mechanical support for re-enervation of the damaged region. Laminin is a glycoprotein naturally occurring in nerves and it plays a significant role towards the migration of nerve cells and axonal outgrowth. In this study, laminin incorporated scaffolds were produced by co-axial electrospinning and blend electrospinning techniques, in order to develop suitable biomaterial constructs for peripheral nerve tissue regeneration. Core–shell and blend nanofibers of laminin incorporated poly(L-lactic acid)-co-poly(ε-caprolactone) (PLCL) with diameters of 316 ± 110 nm and 350 ± 112 nm were respectively, fabricated and the morphology, surface hydrophilicity, chemical and mechanical properties were investigated. The ability of attachment and proliferation of Schwann cells on the electrospun nanofibrous scaffolds was investigated by cell proliferation assay and their phenotype was evaluated by immunocytochemical staining using specific S100 antibody. The cells were found to attach and proliferate on core–shell PLCL–laminin scaffolds, expressing bi- and tri-polar elongations retaining their typical phenotype. Results of 7 days of in vitro culture of Schwann cells, showed 78% increase in cell proliferation on core–shell structured nanofibers compared to blend PLCL–laminin scaffolds, which confirmed the potential application of these constructs as substrates for peripheral nerve regeneration.
    European Polymer Journal 01/2014; 50:30–38. DOI:10.1016/j.eurpolymj.2013.10.021 · 3.24 Impact Factor

Publication Stats

851 Citations
216.89 Total Impact Points

Institutions

  • 2015
    • Sahand University of Technology
      Tebriz, East Azarbaijan, Iran
  • 1985–2015
    • Warsaw University of Technology
      • • Faculty of Materials Science and Engineering
      • • Division of Materials Design
      Warszawa, Masovian Voivodeship, Poland
  • 1993–1994
    • Brunel University London
      अक्सब्रिज, England, United Kingdom
  • 1986–1992
    • University of Manitoba
      • • Department of Mechanical and Manufacturing Engineering
      • • Faculty of Engineering
      Winnipeg, Manitoba, Canada
  • 1988
    • The University of Winnipeg
      Winnipeg, Manitoba, Canada