24 research outputs found
A comparative analysis of surface modification influence on selected properties of titanium and titanium alloy
Modyfikacja powierzchni metali poprzez zastosowanie cienkich warstw ceramicznych jest jedn膮 z nowoczesnych i popularnych metod podwy偶szania w艂a艣ciwo艣ci biomateria艂贸w metalicznych. Artyku艂 prezentuje mo偶liwo艣ci osi膮gania nowych w艂a艣ciwo艣ci tytanu i jego stopu poprzez wytwarzanie z艂o偶onych warstw bioceramicznych metodami zol-偶el oraz elektroforezy. Jest to kr贸tkie podsumowanie kilkuletnich bada艅, realizowanych przy wsp贸艂pracy z zespo艂em badawczym AGH-CM UJ, nad trwa艂o艣ci膮 biomateria艂贸w tytanowych.The modification of metals surface by thin ceramic layers is one of modern and popular methods of improving properties of metallic biomaterials. The paper presents the possibility of new properties achieved through creating bioceramic composite layers on titanium and titanium alloy by the use of sol鈥揼el and electrophoresis methods. It is the short summary of few years research on durability and biocompatibility of these materials realized in cooperation with AGH - CM UJ research group
Applicattion of the SIO2-TIO2 coatings in dental prosthetics
Przeprowadzono badania przyczepno艣ci czterech kombinacji po艂膮cze艅: Ti/Triceram, Ti/SiO2-TiO2/Triceram, Remanium 2000/Vita Keramik i Remanium 2000/ SiO2-TiO2/Vita Keramik metod膮 trzypunktowego zginania (wg PN-EN ISO 9693). Pow艂oki SiO2-TiO2 nanoszone by艂y na tytanowe i kobaltowe pod艂o偶e metod膮 zol-偶el. Otrzymane wyniki bada艅 wykaza艂y wi臋ksz膮 przyczepno艣膰 po艂膮czenia Ti/SiO2-TiO2/Triceram w stosunku do uk艂adu po艂膮czenia Ti/Triceram bez warstwy przej艣ciowej zol-偶el. Zastosowanie pow艂oki przej艣ciowej zol-偶el w przypadku stopu CoCrMoW nie podwy偶sza wytrzyma艂o艣ci po艂膮czenia metal-porcelana, a otrzymane wyniki s膮 zbli偶one do rezultat贸w uzyskiwanych z zastosowaniem tradycyjnych technik przygotowania i napalania dentystycznych koron. Potwierdza to celowo艣膰 stosowania ceramicznej warstwy po艣redniej na pod艂o偶u tytanowym.The bond strength by three-point bending (according to PN-EN ISO 9693) of four combinations Ti /Triceram, Ti/SiO2-TiO2/Triceram, Remanium 2000/Vita Keramik and Remanium 2000/ SiO2-TiO2/Vita Keramik was evaluated. Coatings SiO2-TiO2 on base titanium and cobalt alloy were deposited using sol-gel method. The results showed that the bond strength of Ti/SiO2-TiO2/Triceram and Ti/SiO2/Triceram in control group was significantlyhigher than the Ti/Triceram without intermediate layers sol-gel. Application of SiO2-TiO2 intermediate sol-gel coating on CoCrMoW alloy doesn't increase bond strength of metal-porcelain, and the results obtained are similar to the commercial techniques. The purposefulness of the application of the intermediate ceramic layer on base titanium was been confirmed
Evaluation of Force-Time Changes During Impact of Hybrid Laminates Made of Titanium and Fibrous Composite
Fibre metal laminates (FML) are the modern hybrid materials with potential wide range of applications in aerospace technology due to their excellent mechanical properties (particularly fatigue strength, resistance to impacts) and also excellent corrosion resistance. The study describes the resistance to low velocity impacts in Ti/CFRP laminates. Tested laminates were produced in autoclave process. The laminates were characterized in terms of their response to impacts in specified energy range (5J, 10J, 20J). The tests were performed in accordance with ASTM D7137 standard. The laminates were subjected to impacts by means of hemispherical impactor with diameter of 12,7 mm. The following values have been determined: impact force vs. time, maximum force and the force at which the material destruction process commences (Pi). It has been found that fibre titanium laminates are characterized by high resistance to impacts. This feature is associated with elasto-plastic properties of metal and high rigidity of epoxy - fibre composite. It has been observed that Ti/CFRP laminates are characterized by more instable force during impact in stage of stabilization of impactor-laminate system and stage of force growth that glass fibre laminates. It has been observed more stable force decrease in stage of stress relaxation and withdrawal of the impactor. In energy range under test, the laminates based on titanium with glass and carbon fibres reinforcement demonstrate similar and high resistance to low-velocity impact, measured by means of failure initiation force and impact maximum force
Wp艂yw uderze艅 wielokrotnych na rozw贸j uszkodzenia kompozyt贸w polimerowych wzmacnianych w艂贸knami
The study presents the problems of the influence of repeated low velocity and low energy impacts on damage growth in carbon and glass fibre reinforced high strength polymer composite. The laminate response to impacts was analyzed, the types of damages and their interrelations were identified as well as damages mechanisms were described for tested laminates subjected to repeated impacts. The following conclusions have been drawn on the basis of completed tests: (1) composite materials with polymer matrix reinforced with continuous glass and carbon fibres demonstrate limited resistance to repeated impacts. The laminates resistance to impacts depends mainly on the properties and type of components, particularly in case of reinforcing fibres, orientation of layer under the influence of external impact; (2) tested laminates with carbon fibres are characterized by lower resistance to repeated impacts than laminates with glass fibres. This is proved by the curves of laminate response to impacts, wider damage area and tendency to laminate structure perforation as a result of repeated impacts; (3) repeated impacts lead to damage growth mainly through propagation of damage initiated in initial impacts phase. Delaminations and matrix cracks belong to the basic mechanisms of damages in composite materials; (4) composite damage propagates with increasing number of impacts in fibres orientation direction, particularly in lower composite layers. Further impacts may result in higher stress concentration and higher initiation energy causing the damage growth in various areas of the material. Further impacts increase the damage leading to gradual growth of damages initiated before.W pracy przedstawiono problematyk臋 wp艂ywu powtarzaj膮cych si臋 uderze艅 o niskiej pr臋dko艣ci i niskiej energii na rozw贸j uszkodzenia wysokowytrzyma艂ych kompozyt贸w polimerowych wzmacnianych w艂贸knem w臋glowym oraz szklanym. Dokonano analizy odpowiedzi laminatu na uderzenia, zidentyfikowano rodzaj i relacje pomi臋dzy uszkodzeniami, a tak偶e przedstawiono mechanizmy uszkodzenia w badanych laminatach poddanych wielokrotnym uderzeniom. Na podstawie przeprowadzonych bada艅 wykazano 偶e: (1) materia艂y kompozytowe o osnowie polimerowej wzmacniane ci膮g艂ymi w艂贸knami szklanymi i w臋glowymi wykazuj膮 ograniczon膮 odporno艣膰 na wielokrotne uderzenia. O odporno艣ci laminat贸w na uderzenia decyduj膮 g艂贸wnie w艂a艣ciwo艣ci i rodzaj komponent贸w, w szczeg贸lno艣ci w艂贸kien wzmacniaj膮cych, orientacja warstw pod wp艂ywem oddzia艂ywania zewn臋trznego; (2) badane laminaty z w艂贸knami w臋glowymi charakteryzuj膮 si臋 ni偶sz膮 odporno艣ci膮 na wielokrotne uderzenia w por贸wnaniu do laminat贸w z w艂贸knem szklanym. 艢wiadcz膮 o tym charakterystyki odpowiedzi laminatu na uderzenia, wi臋kszy obszar uszkodzenia oraz sk艂onno艣膰 do perforacji struktury laminatu w wyniku wielokrotnych uderze艅; (3) uderzenia wielokrotne powoduj膮 rozw贸j uszkodzenia g艂贸wnie przez propagacj臋 uszkodzenia inicjowanego w czasie pocz膮tkowych uderze艅. Do podstawowych mechanizm贸w uszkodzenia materia艂贸w kompozytowych nale偶膮 rozwarstwienia oraz p臋kni臋cia osnowy; (4) wraz ze wzrostem liczby uderze艅 uszkodzenie kompozytu propaguje w kierunku u艂o偶enia w艂贸kien, szczeg贸lnie dolnych warstw kompozytu. Kolejne uderzenia mog膮 powodowa膰 wi臋ksz膮 kumulacj臋 napr臋偶e艅 oraz energii inicjacji odpowiedzialnej za rozw贸j uszkodzenia w r贸偶nych obszarach materia艂u. Kolejne uderzenia powoduj膮 zwi臋kszanie uszkodzenia prowadz膮c do stopniowego rozwoju wcze艣niej zainicjowanych uszkodze艅
Fractography and Damage Analysis of Carbon/Epoxy Composites Under Static and Dynamic Loading at Elevated Temperatures
This paper presents the microstructural and fractographic analysis of damage in carbon/epoxy composites after static and fatigue strength (shear) tests at elevated temperature. The microstructural tests and fractographic analysis confirmed the complexity of degradation process and degradation mechanisms in composite structure. Multiple cracks, delaminations and interface degradation between fibre and matrix have been observed. The fracture analysis indicate the occurrence of characteristic failure area: matrix river lines, matrix rollers, fractures and reinforcing fibres imprints. The interface, except of the type of components and their features, is the principal factor determining the properties of composite material. The quality of the bonding between the reinforcing phase and matrix, mechanism of composite cracking as a whole as well as cracks of individual components are directly affected by the interface
Evaluation of Force-Time Changes During Impact of Hybrid Laminates Made of Titanium and Fibrous Composite
Fibre metal laminates (FML) are the modern hybrid materials with potential wide range of applications in aerospace technology due to their excellent mechanical properties (particularly fatigue strength, resistance to impacts) and also excellent corrosion resistance. The study describes the resistance to low velocity impacts in Ti/CFRP laminates. Tested laminates were produced in autoclave process. The laminates were characterized in terms of their response to impacts in specified energy range (5J, 10J, 20J). The tests were performed in accordance with ASTM D7137 standard. The laminates were subjected to impacts by means of hemispherical impactor with diameter of 12,7 mm. The following values have been determined: impact force vs. time, maximum force and the force at which the material destruction process commences (Pi). It has been found that fibre titanium laminates are characterized by high resistance to impacts. This feature is associated with elasto-plastic properties of metal and high rigidity of epoxy - fibre composite. It has been observed that Ti/CFRP laminates are characterized by more instable force during impact in stage of stabilization of impactor-laminate system and stage of force growth that glass fibre laminates. It has been observed more stable force decrease in stage of stress relaxation and withdrawal of the impactor. In energy range under test, the laminates based on titanium with glass and carbon fibres reinforcement demonstrate similar and high resistance to low-velocity impact, measured by means of failure initiation force and impact maximum force
Effect of recycling on structure and mechanical properties of dental casting cobalt alloy
P臋kanie metalowego szkieletu protez cz臋艣ciowych jest do艣膰 cz臋stym przypadkiem w protetyce stomatologicznej. G艂贸wn膮 przyczyn膮 tego typu uszkodzenia jest niew艂a艣ciwa jako艣膰 odlewu. Ze wzgl臋d贸w ekonomicznych producenci stop贸w dopuszczaj膮 stosowanie z艂omu metalowego jako cz臋艣ci wsadu. W pracy dokonano analizy wp艂ywu recyklingu na w艂a艣ciwo艣ci mechaniczne i struktur臋 odlewniczego stopu kobaltu. Zastosowano odlewanie pr贸偶niowo-ci艣nieniowe do wsad贸w zawieraj膮cych 0%, 25% oraz 50% z艂omu pochodz膮cego z kana艂贸w wlewowych i sto偶k贸w odlewniczych stopu CoCrMo. Por贸wnano w艂a艣ciwo艣ci mechaniczne i struktur臋 odlew贸w. Stwierdzono, 偶e wytrzyma艂o艣膰 mechaniczna wszystkich stop贸w jest ni偶sza ni偶 艣rednia deklarowana przez producenta. Prze艂omy maj膮 charakter kruchy, z wyra藕nie widoczn膮 struktur膮 dendrytyczn膮. Wraz ze wzrostem udzia艂u materia艂u wt贸rnie przetapianego ro艣nie niejednorodno艣膰 struktury na przekroju poprzecznym pr贸bek oraz g臋sto艣膰 mikrop臋kni臋膰 w obj臋to艣ci dendryt贸w po pr贸bie rozci膮gania.Cracking of the frame partial dentures is frequent case in dental prosthodontics. The wrong quality of cast is the main reason for this type of damage. The alloys producers allow to use the scrap metal as the part of charge on account of economy. In this paper an influence of recycling on mechanical properties and structure of Co-Cr-Mo dental alloy is carried out. The vacuum pressure casting was used. The charges consist of 0%, 25% and 50% of scrap metal from gate assembly. The mechanical properties and microstructure of precision castings was compared. It was found that all casts strength was lower than average one declared by producer. The brittle fractures and dendritic structures was observed. The structure inhomogeneity and density of microcracks inside dendrites after tension test increase along with percentage growth of scrap metal