Piotr Kwasniak - Academia.edu (original) (raw)

Papers by Piotr Kwasniak

Surface & Coatings Technology, Apr 1, 2019

Abstract This study concerns a detailed cross-section microstructural analysis conducted by combi... more Abstract This study concerns a detailed cross-section microstructural analysis conducted by combining complementary methods such as FIB, SEM, EDS and STEM on different scales in order to elucidate the impact of direct laser interference lithography on the microstructure and surface chemistry of a Ti substrate after laser patterning. Special attention was paid to correlate the mechanical properties determined by the nanoindentation tests with the microstructure and phase composition analysed using GI-XRD. Direct laser interference lithography surface texturing results in the formation of a thin (1–1.5 μm), continuous layer with lath-like grains. The GI-XRD analysis showed no changes in phase composition, which is in agreement with our previous results. Furthermore, laser patterning led to an increase in the nano-hardness of the surface (from 2.8 GPa to 6.6 GPa) that is mainly related to the changes that took place in the microstructure. The results presented are important to an evaluation of laser-patterned surfaces in biomedical applications, as their ultimate use depends not only on topographical changes but also mechanical properties variations as well as microstructure evolution which affects its electrochemical properties.

Materials Characterization, 2018

This paper presents a detailed characterisation of Ti surface geometries as produced by noncontac... more This paper presents a detailed characterisation of Ti surface geometries as produced by noncontact laser functionalization and its impact on the process of protein adsorption. The proposed surface modification is designed for the local treatment of implantable devices with original roughness. In this work, titanium plates were initially modified by the two most common mechano-chemical treatments, shot peening and acid etching. The material under study was next functionalized DLIL (Direct Laser Interference Lithography) in order to obtained two different surface patterns: grooves and islands. The modified surfaces were characterized in terms of their shape, roughness, wettability, surface energy and chemical composition. For this purpose, the following methods were used: scanning electron microscopy, optical profilometry, atomic force microscopy, contact angle measurements, and X-ray photoelectron spectroscopy. Protein adsorption tests were conducted to consider the potential of the proposed methodology in biomedical applications and to compare the influence of the two different surface patterns on the initial state of ossointegration. To this end, XPS and FTIR studies were conducted. The systematic analysis presented will be useful when selecting an appropriate surface geometry for the local surface functionalization of implantable devices.

Applied Surface Science, May 1, 2015

The article presents combined, chemical and physical approach to titanium surface functionalizati... more The article presents combined, chemical and physical approach to titanium surface functionalization designed for biomedical applications. The topography modification has been obtained by employing the double laser beam interference technique and chemical etching. In the outcome, clean and smooth Ti surface as well as periodic striated topography with the roughness range from nano-to micrometers were created. The obtained structures were characterized in terms of shape, roughness, chemical composition, mechanical properties and microstructures. In order to achieve all information, numerous of research methods have been used: scanning electron microscopy, atomic force microscopy, optical profilometry and microhardness measurements. Demonstrated methodology can be used as an effective tool for manufacturing controlled surface structures improving the bone-implants interactions.

Applied Surface Science, Dec 1, 2016

Highlights  Presented surface modification results in multimodal topography  Laser treatment cr... more Highlights  Presented surface modification results in multimodal topography  Laser treatment creates roughness in a range from nano-to micrometers  Multimodal topography promote protein adsorption  Hybrid surface treatment results in a texture favorable for osteogenic passes

Electrochimica Acta, Jul 1, 2019

Modern Ti-based materials such as nanocrystalline a Ti and metastable b alloy Ti-29Nb-13Ta-4.6Zr ... more Modern Ti-based materials such as nanocrystalline a Ti and metastable b alloy Ti-29Nb-13Ta-4.6Zr (TNTZ) offers unique mechanical properties which are essential in case of dental implants. However, successful permanent implantation is governed also by material's functional properties such as corrosion behaviour in body fluids. Although both of this materials demonstrated high corrosion resistance in standard physiological solutions, the effect of simulated inflammatory conditions, which are more realistic following the implantation, is still unknown. Hence, in this work the influence of simulated inflammation on the corrosion response of nanocrystalline a Ti and metastable b TNTZ alloy was investigated and compared with the widely used microcrystalline a Ti. This study provides an insight how the presence of non-toxic b phase stabilizers and grain refinement to the nanoscale affect Ti corrosion behaviour in the simulated inflammatory conditions.

Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, Jun 1, 2023

Physical Review B, Apr 11, 2014

Materials research letters, Jan 25, 2023

Materials Letters, Mar 1, 2013

ABSTRACT

arXiv (Cornell University), Dec 29, 2018

Basal slip of a screw dislocations in hexagonal closed-packed titanium is investigated with ab in... more Basal slip of a screw dislocations in hexagonal closed-packed titanium is investigated with ab initio calculations. We show that a basal dissociation is highly unstable and reconfigures to other structures dissociated in a first order pyramidal plane. The obtained mechanism for basal slip corresponds to the migration of the partial dislocations and of the associated stacking fault ribbon in a direction perpendicular to the dissociation plane. Presented results indicate that both basal and pyramidal slip will operate through the Peierls mechanism of double-kink nucleation and will be equally active at high enough temperature.

Acta Materialia, Mar 1, 2023

The present paper aims at providing a fine-scale analysis of the Ti-4.5Al-2.5Fe-0.25Si α+α'+β ret... more The present paper aims at providing a fine-scale analysis of the Ti-4.5Al-2.5Fe-0.25Si α+α'+β retained microstructures to give insight into the link between the microstructural characteristics of the alloy (phase fraction and chemistry, grain size, etc.) and the deformation mechanisms at play. These microstructures were found to exhibit outstanding work-hardening capabilities that have the great potential to be obtained simultaneously with a high yield strength when the microstructural features are carefully optimized. Ex-situ analyses coupled with TEM revealed the simultaneous occurrence of Reorientation Induced Plasticity (RIP) into the self-accommodated Feenriched α' martensite, TRansformation Induced Plasticity (TRIP) of the β retained phase and TWinning Induced Plasticity (TWIP) of the α phase that add to dislocation glide. The Fe-enriched martensite has the remarkable capability to induce reorientation through two distinctive mechanisms: by the motion upon deformation of the intervariant boundary associated to the [4 5 1 3] α ′ Type II twin, a rather classical mechanism although not often reported into α'; but more surprisingly into such a fine phase, by the creation and growth upon deformation of {1012}1011 α ′ twins. A 3-scale mechanical contrast is proposed to explain the remarkable work-hardening rates achieved. Reorientation is shown to be a key microstructural feature for the development of Ti alloys with superior mechanical properties.

Catalysis Today, Jun 1, 2013

The process of oxidation of ammonia proceeds in 800-900 • C with high reactivity hydrogen dischar... more The process of oxidation of ammonia proceeds in 800-900 • C with high reactivity hydrogen discharge. Extremely aggressive environment and temperature require using the most chemically resistant materials with catalysis properties. One of the main groups of those materials is palladium-nickel alloys. In our investigation we focused on analysis of PdNi5 degradation during catalysis process. The investigation was performed on 78 m diameter wires after long exposition to chemically aggressive environment. The samples were prepared with focused ion beam (FIB) system. The observations of surface and wire cross sections were executed using a scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS) device, which allowed defining chemical composition. The effect of a grain orientation on sensitivity to reaction with ammonia gas was tested by mapping with electron backscatter diffraction (EBSD) techniques. Significant change of wire cross section after long exposition was determined by 3D X-ray computer tomography (XCT). The obtained results can be basis of further investigation on improvement of strength of PdNi alloys in high temperature chemical application.

Research and reviews: journal of material sciences, Oct 11, 2017

Materials

The use of elemental metallic powders and in situ alloying in additive manufacturing (AM) is of i... more The use of elemental metallic powders and in situ alloying in additive manufacturing (AM) is of industrial relevance as it offers the required flexibility to tailor the batch powder composition. This solution has been applied to the AM manufacturing of nickel-titanium (NiTi) shape memory alloy components. In this work, we show that laser powder bed fusion (LPBF) can be used to create a Ni55.7Ti44.3 alloyed component, but that the chemical composition of the build has a large heterogeneity. To solve this problem three different annealing heat treatments were designed, and the resulting porosity, microstructural homogeneity, and phase formation was investigated. The heat treatments were found to improve the alloy’s chemical and phase homogeneity, but the brittle NiTi2 phase was found to be stabilized by the 0.54 wt.% of oxygen present in all fabricated samples. As a consequence, a Ni2Ti4O phase was formed and was confirmed by transmission electron microscopy (TEM) observation. This st...

Metallurgical and Materials Transactions A, 2021

The overall performance of joints fabricated using the explosive welding method depends directly ... more The overall performance of joints fabricated using the explosive welding method depends directly on the brittleness of created intermetallic phases and their cohesion with metallic substrates. In this article, we used first principles calculations to show that Sn, V, Cu, and Mg alloying elements present in Ti- and Al-based alloys have a significant influence on the elastic properties and plastic deformation ability ofγ-TiAl and Ti3Al. Selected solutes exhibit diversified preferential site occupancy in bulk phases and ordered phase/metallic substrate interface regions. The largest positive effect on ductility and cleavage energy was found for Cu addition (25 pct increase in theB/Gratio), while Sn largely deteriorates cleavage resistance (up to 8 pct). The presented results reveal that further development in the explosive welding field can be reached through the design/application of new alloys composed of elements that improve the properties of the ordered phases present in the joints.

Materials & Design, 2020

• Unfaulted crystal structure is recovered by shearing Mg crystal on π 1L plane along h1012i dire... more • Unfaulted crystal structure is recovered by shearing Mg crystal on π 1L plane along h1012i direction. • Pyramidal-I 〈c + a〉 dissociates into partial dislocations comprising shearshuffle and shuffle components. • Pyramidal-I 〈a〉 dislocation on π 1D plane dissociates and produce a two-layerthick compression twinning (CTW). • Pyramidal-I ⟨c + a⟩ slip is the favorable mechanism during loading along the caxis on π 1 plane in terms of activation energy. • CTW nucleation and growth mechanisms from pyramidal-I 〈a〉 dislocation dissociation are favorable based on activation energy.

Intermetallics, 2016

The paper discusses the effect of zirconium and chromium on the microstructure and properties of ... more The paper discusses the effect of zirconium and chromium on the microstructure and properties of the aluminide layers produced on an Inconel 713C nickel superalloy substrate. The aluminizing process was conducted using the chemical vapor deposition (CVD) method in AlCl 3 þ ZrCl 3 vapors and a hydrogen atmosphere as the carrier gas. This low-activity aluminizing process yielded a diffusive multi-component aluminide layer composed of three main zones: the outer zone, about 3 mm thick, chiefly built of AlNi 2 Zr, Ni 3 Zr and Al 3 Zr 4 , the intermediate zone, about 6 mm thick, containing the b-NiAl phase, and the inner zone, with a thickness of about 7 mm, mostly composed of the Cr 2 Al and b-NiAl grains. The substrate contained semi-coherent g 0-phases (Ni 3 Al) separated from the g-austenite matrix by a dislocation net. DFT calculations have shown that Cr added to b-NiAl markedly increases the elastic constant C11 and the isotropic shear modulus G, whereas the addition of Zr decreases the C44 component. Moreover, zirconium added to b-NiAl increases its plasticity thanks to the formation of widespread metallic ZreNi bonds. It has been found that the Zr þ Cr-modified aluminide layer formed on the Inconel 713C nickel superalloy improves its corrosion resistance (as measured in a 0.1 M Na 2 SO 4 solution).

Applied Surface Science, 2016

Abstract The most common catalysts for the ammonia oxidation process are 80 μm diameter platinum-... more Abstract The most common catalysts for the ammonia oxidation process are 80 μm diameter platinum-rhodium wires knitted or woven into the form of a gauze. In an aggressive environment and under extreme conditions (temperature 800–900 °C, intensive gas flow, high pressure) precious elements are drained from the surface of the wires. Part of this separated material quickly decomposes on the surface in the form of characteristic “cauliflower-shape protrusions”. The rest of the platinum is captured by palladium-nickel catalytic-capture gauzes located beneath. In our investigation we focused on the effects of the degradation of gauzes from one industrial catalytic system. The aim of the study was to compare the degree and the mechanism of degradation of gauzes from a different part of the reactor. The study covered PtRh7 catalytic and PdNi5 catalytic-capture gauzes. X-ray computer microtomography investigation revealed that despite strong differences in morphology, each Pt-Rh wire has a similar specific surface area. This indicates that the oxidation process and morphological changes of the wires occur in a self-regulating balance, resulting in the value of the specific surface area of the catalyst. Microtomography analysis of Pd-Ni wires revealed strong redevelopment of the wires’ surface, which is related to the platinum capture phenomenon. Scanning electron microscope observations also revealed the nanostructure in the cauliflower-shape protrusions and large grains in the wires’ preserved cores. The high temperature in the reactor and the long-term nature of the process do not favor the occurrence of the nanostructure in this type of material. Further and detailed analysis of this phenomena will provide a better understanding of the precious metals etching and deposition processes during oxidation.

Solid State Phenomena, 2015

In our investigation we focused on effects of the degradation of Pt-Rh gauzes from three differen... more In our investigation we focused on effects of the degradation of Pt-Rh gauzes from three different industrial catalytic systems. The aim of the study was to compare the degree and the mechanism of degradation under different conditions (pressure, temperature, gas flow direction). The investigation was performed on about 80μm diameter wires after long (6 months) exposition to chemically aggressive environment. Microscope observations and microtomography analysis showed that all wires surfaces were strongly developed by etching and deposition processes occurring under extreme conditions. Each wire differed in rate of degradation and morphology of the characteristic cauliflower-shape growths. Also differences in elements distribution on both, surface and cross sections, were observed. Obtained results can be basis of further investigation on improvement of endurance of PtRh alloys in high temperature chemical application.