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EN
The titanium alloys are materials susceptible to tribological wear and the laser treatment can be applied in surface treatment processes to obtain for example higher hardness level. From the other side, it is important to take into consideration, that hardness increase that can be connected with cracks . The aim of this research was to investigate the effects of different lasers and the process parameters on the form and level of residual stresses in the Ti6Al4V alloy, which determine the initiation and propagation of cracking. Two lasers were used, the CO2 and Nd:YAG lasers. The specimens were remelted in liquid nitrogen, water or calm air at different pre-heating temperature. The different laser power and scan rates were applied. The increase in energy density increased the number of cracks, the change of an environment and pre-heating affected alo the surface cracking. The cracks observed after remelting with Nd:YAG laser were longer than those observed after treatment with CO2 laser. The compressive stresses after the CO2 laser treatment, and tensile stresses after treatment with the Nd:YAG laser, were found. The appearance of cracks was attributed to an excessive energy density. The different distribution of heat energy inside and around the laser tracks was discussed as the origin of presence either tensile or compressive stresses in the alloy treated with different lasers.
PL
Stop tytanu z aluminium i wanadem jest jednym z najczęściej używanych stopów tytanu w implantologii. Ti6Al4V charakteryzuje się dobrymi właściwościami i jest względnie tani. Na stopie wytworzono warstwy metodą anodowania, przy zastosowaniu trzech różnych elektrolitów i różnych parametrów procesu. Na wszystkich próbkach otrzymano nanorurki.
EN
Titanium alloy with aluminum and vanadium is one of the most commonly used titanium alloy in implantology. Ti6Al4V has good properties and is relatively cheap. Oxide layers on the alloy were made by anodising process using three different electrolytes and different process parameters. Nanotubes were obtained on all samples.
3
Content available remote Hydroxyapatite deposition on the laser modified Ti13Nb13Zr alloy
EN
The Ti13Nb13Zr alloy was subjected to laser modification with the Nd:YAG laser provided that such treatment would increase the surface roughness followed improved adhesion of hydroxyapatite (HAp) coatings The hydroxyapatite was deposited by electrophoretic method in suspension of 0.5 g HA powder and 100 ml ethyl alcohol. The deposition was carried out for 10 min at 10 V voltage followed by drying at room temperature for 24 h and heating at 800°C for 1 h in vacuum. The thickness of the HAp coatings was found as of about 4.06 μm to 9.05 μm. The examinations of surfaces were carried out at each stage of the experiment with the ultra-high resolution scanning electron microscope. The measurements of surface roughness after laser treatment and after HAp deposition were performed with the Hommel Etamic Waveline profilograph.
PL
Dotychczasowe badania powierzchni wszczepów tytanowych dla chirurgii kostnej wykazały, że osteointegracja na powierzchniach rozwiniętych jest znacznie szybsza niż na powierzchniach gładkich, co za tym idzie chropowatość powierzchni implantu ma bardzo duży wpływ na adhezję składników środowiska biologicznego. W artykule przedstawiono wstępne wyniki badań dotyczące wpływu chropowatości powierzchni stopu Ti13Nb13Zr o bardzo małym module Younga na budowę wytworzonej powłoki hydroksyapatytowej. Próbki z biostopu tytanu poddano obróbce laserowej za pomocą lasera Nd:YAG firmy Trumph o średniej mocy 150 W w celu zmiany geometrii powierzchni. Na tak przygotowanym podłożu wytwarzano powłoki hydroksyapatytowe metodą elektroforezy, stosując 0,5 i 1,0 g stężenie proszku HAp na 100 ml alkoholu etylowego. Osadzanie katodowe prowadzono przy napięciu 10 i 50 V przez 5 i 10 min. Po przeprowadzonej obróbce laserowej i wytworzeniu powłok HAp mierzono profil chropowatości powierzchni i prowadzono obserwacje za pomocą skaningowego mikroskopu elektronowego.
EN
So far research of the surfaces of titanium implants in bone surgery demonstrate that osteointegration on rough surface is much faster than on smooth ones. The roughness of implant surface influences then the adhesion of components of biological environment. In this paper the preliminary research results made on the Ti13Nb13Zr alloy treated with pulse laser and coated with hydroxyapatite are presented. The aim of the research was to determine the influence of effect of laser treatment and HAp deposition parameters on structure of the hydroxyapatite coating. The laser treatment was carried with the pulse Nd:YAG laser (Trumph) of the 150 W average power in order to change the surface geometry. Next the HAp coatings were deposited by electrophoretic method using the suspension of 0.5 or 1.0 g of HAp powder in 100 ml ethanol. The deposition was made at 10 V and 50 V for 5 and 10 min. The surface roughness profiles and microscopic examinations were performed after laser treatment and HAp deposition.
EN
The purpose of this paper is to show results of laser treatment at cryogenic conditions of the Ti6Al4V alloy used for orthopedic applications. That modification process ought to bring beneficial changes of microstructure and residual stresses in the surface layer. The paper presents the abrasive wear of the base and laser remelted material in association with ceramics Al2O3. Despite the surface cracking after laser treatment the tribological properties in simulated body fluid have been substantially improved.
PL
Celem artykułu jest pokazanie rezultatów obróbki laserowej w warunkach kriogenicznych stopu Ti6Al4V używanego w aplikacjach ortopedycznych. Tego rodzaju proces modyfikacji powinien przynieść korzystne zmiany w mikrostrukturze i naprężeniach własnych warstwy wierzchniej. Artykuł prezentuje badania odporności na zużycie ścierne materiału podstawowego i nadtopionego laserowo w skojarzeniu z ceramiką Al2O3. Pomimo pęknięć na powierzchni materiału po obróbce laserowej własności tribologiczne badane w roztworze symulującym płyn ustrojowy zostały znacznie ulepszone.
EN
The paper reports the study of the complexation processes in aqueous solution of α-CD and DMSO. Cyclodextrins (CDs) (sometimes called cycloamyloses) are cyclic oligosaccharides formed by glucose units interconnected by α-(1,4) linkages; α-CD is one of three the most common CDs. It consists of six glucopyranose units. The speed of ultrasonic waves has been measured by the resonance method on ResoscanTM System apparatus. Some collateral data, such as density and heat capacity of the system, have also been measured. On the basis of the experimental data the excess adiabatic compressibility was determined. The extremes of the excess adiabatic compressibility function for different mixture compositions allowed us to establish the composition of molecular complexes formed in the solution. The obtained results suggest the formation of the α-CD with DMSO inclusion complexes with chemical stoichiometric ratio value of 1:1.
PL
Najczęściej stosowanym biomateriałem tytanowym na elementy endoprotez stawu kolanowego jest stop Ti6Al4V. Ze względu na zawartość wanadu, zaliczanego do pierwiastków o dużej toksyczności, są podejmowane działania w kierunku zastąpienia tego stopu stopami bezwanadowymi. Jednym z najbardziej obiecujących jest stop Ti13Nb13Zr zawierający w swoim składzie jedynie pierwiastki witalne, niewywołujące stanów zapalnych i odczynów alergicznych. W artykule zaprezentowano wyniki badań odporności na zużycie ścierne stopów tytanu: Ti6Al4V (powszechnie stosowanego) i Til3Nbl3Zr (stopu nowej generacji) w skojarzeniu z polietylenem (PE-UHMW) predysponowanych na elementy pary trącej w endoprotezie kolanowej. Otrzymane wyniki przeanalizowano pod kątem możliwości zastosowania stopu tytanu nowej generacji na komponenty tej endoprotezy. Próby odporności na zużycie ścierne wybranych par ciernych przeprowadzono z wykorzystaniem tribometru PT-3 w środowisku cieczy symulującej płyn ustrojowy - roztworu Ringera. Zastosowano obciążenie rzędu 2 kN przy prędkości obrotowej próbek tytanowych 30 obr/min przez 1 lub 2 godziny. Zużycie ścierne w parze trącej Ti13Nb13Zr-PE-UHMW jest mniej sze niż w przypadku pary Ti6Al4V-PE-UHMW i to zarówno globalnie w odniesieniu do całego skojarzenia, jak i w odniesieniu do pojedynczych próbek. Udział produktów zużycia w strefie tarcia także jest większy w przypadku skojarzenia Ti6Al4V-PE-UHMW. Produkty te, przemieszczając się pomiędzy współpracującymi materiałami, działają jak ścierniwo, intensyfikując procesy zużycia ściernego. Średni ubytek masy określany na podstawie metody wagowej próbki Z Ti6Al4V wyniósł 0,00177 g, a Ti13Nb13Zr 0,00062 g. W przypadku próbek UHMW-PE współpracujących Z Ti6Al4V ubytek wynosił 0,0043 g, a dla skojarzonych Z Ti13Nb13Zr 0,00234 g. Badania struktury geometrycznej powierzchni próbek roboczych z rejestracją zmian chropowatości Ra wykazały większe zużycie po stronie próbek ze stopu Ti6Al4V, dla których mimo mniej szych, początkowych wartości Ra, końcowa, uśredniona wartość była równa 0,53 um. Dla próbek Ti13Nb13Zr wyniosła ona 0,43 um. W przypadku próbek UHMW-PE współpracujących z Ti6Al4V to 0,85 um, a dla skojarzonych Z Ti13Nb13Zr 0,61 um.
EN
The Ti6Al4V alloy is commonly used titanium biomaterial in elements of knee joint endoprosthesis. Taking into consideration the content of vanadium, which is ranked as the element ofhigh toxicity, there are taken efforts to substitute this alloy with non-vanadium alloys. One of the most promising is Ti13Nb13Zr alloy. It contains only vital elements which do not cause infiammations or allergic reactions. The paper presents research results of resistance to abrasive wear of titanium alloys: Ti6Al4V (commonly used) and Ti13Nb13Zr (alloy of new generation) in association with polyethylene (PE-UHMW) predisposed for elements on pair ofthe knee endoprosthesis. Results were analyzed considering the possibility of use new generation titanium alloys for components for these endoprosthesis. Tests of resistance to abrasive Wear of selected friction pair were conducted in PT-3 tribometer in Ringer”s solution environment under constant load 2.0 kN, rotational speed of the moving specimens (Til3Nbl3Zr and Ti6Al4V): 30 rpm, test duration: 1 or 2 hours. Resistance to abrasive wear of selected pair of friction Til3Nb13Zr-PE- UHMW is lower than fon Ti6Al4V-PE-UHMW pair, not only globally - in reference to whole join - but also in reference to individual samples. Contribution of wear products is also higher in Ti6Al4V-PE-UHMW pair. These products move between mating materials, they act as grindings, thus intensifying the process of abrasive Wear. average mass losses determined by weight method for Ti6Al4V and Ti13Nb13Zr sample were 0.00177 g and 0.00062 g, respectively. In case of PE-UHMW samples associated with Ti6Al4V it Was 0.0043 g, whereas for Til3Nbl3Zr it Was 0.00234 g. Geometric structure analysis of sample surfaces, from registration Ra roughness changes, revealed higher wear on Ti6Al4V alloy samples, despite lower initial value of Ra, their final average value was 0.53 um while for Ti13Nb13Zr sample was 0.43 um. In case of UHMW-PE samples associated with Ti6Al4V this value equaled to 0.85 um, while in case ofTi13Nb13Zr it was 0.61 um.
EN
The laser remelting of the Ti6Al4V alloy was made on specimens pre-heated at elevated temperatures. The laser treatment effected in change of microstructures of surface layers and an appearance of blisters and numerous cracks. The corrosion tests demonstrated the decrease in corrosion resistance for each preheating temperature. The observed effects were attributed to negative influence of excessive compressive stresses with no substantial relation of cracking phenomenon on pre-heating and its temperature.
PL
Wykonano nadtapianie stopu Ti-6Al-4V laserem CO2 przy zanurzeniu stopu w ciekłym azocie. Stwierdzono powstanie twardej warstwy o zmiennej głębokości, do kilkuset mikrometrów, chropowatej i ujawniającej pęknięcia równoległe do przesuwu wiązki lasera. Badania zużycia ściernego w warunkach tarcia posuwisto-zwrotnego w płynie Ringera wykazały wyraźny wzrost odporności na zużycie ścierne. Wzrost odporności na tribokorozję tłumaczyć można znaczną twardością warstwy przy równoczesnym spadku znaczenia istnienia pęknięć, w których gromadzą się produkty zużycia.
EN
The laser remelting of the Ti-6Al-4V alloy immersed in liquid nitrogen has been performed. The hard rough layer deep up to a few hundred micrometers, disclosing the cracks parallel to the laser beam direction has been obtained. The investigations of wear at sliding motion in Ringer`s solution have shown a substantial increase in wear resistance. The increasing tribocorrosion resistance can be explained by a great layer hardness at simultaneous low impor-tance of cracks` presence in which wear debris may be accumulated.
EN
The main reason for laser remelting of the components made of aluminium, copper and titanium alloys is to obtain high hardness and corrosion resistance at the surface for longer lifetime as result of the rapid solidification. The final microstructure, phase composition and properties of aluminium, copper and titanium alloys depend on the laser process parameters and obviously on the nature of the equilibrium system. The effect of laser surface remelting at cryogenic conditions on the microstructure and corrosion characteristics of the AlSi13Mg1CuNi, SUPERSTON and Ti-6Al-4V alloys are presented. The beneficial effects of laser treatment on the microstructure and corrosion behaviour of those alloys used for different products are observed.
11
Content available remote Surface cracking of laser melted Ti-6Al-4V alloy
EN
The characteristic features of surface cracking observed after laser melting with CO2 and Nd:YAG laser were described. The cracks were always present, their length approaching some part of melted zone and scarcely dependent on laser melting conditions. The appearance of cracks was attributed mainly to martensitic transformation within the surface layer. The possible contribution of developed thermal stresses cannot be also excluded. The existence of cracks may be utilized for the enhancement of bonęe-implant strength.
12
EN
Purpose: The research work has been to determine whether surface melting of the Ti6Al4V bioalloy with the high power laser, when immersed in liquid nitrogen, would result in an appearance of hard and thick surface layer, containing new structural constituents. Design/methodology/approach: The laser melting of the Ti6Al4V alloy has been made by the CO2 laser at different laser beam energy and scan rate. The specimens have been immersed in liquid nitrogen bath during laser treatment. The Vickers microhardness of cross-sections of the surface layer has been measured, and the microscopic examinations have been performed with the SEM. Findings: The laser melting at cryogenic conditions has resulted in creation of the modified surface layer, up to 1.5 mm thick with HAZ, of properties and structures different from those of the base metal. The layer has been well adjacent to base metal, its microhardness being significantly higher. The numerous zones have been observed within the surface layer, with nitrogen-containing martensite and titanium nitride structures. The negative effect has been an initiation of surface cracks. The laser beam energy has influenced the presence of different zones, their thickness, and number of cracks. Research limitations/implications: So far research has shown that proposed technique can create thick and hard surface layer, containing new structural important components. The new research is necessary in order to establish the laser treatment parameters which permit to avoid cracking and determine the phase constituents and crystallinity within the surface layer. Practical implications: The elaborated technique may be useful in order to improve the surface properties of the Ti alloys for biomedical applications. Originality/value: The paper shows original in the world-scale results of laser treatment of the Ti bioalloy at cryogenic conditions.
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