Parafusos corticais são uns dos implantes mais utilizados na prática cirúrgica e são normalmente compostos por ligas metálicas como o aço inoxidável F-138 e a liga de titânio 6Al-4V e, quando inseridos no organismo humano, são submetidos a diversos esforços mecânicos. Assim, é necessário avaliar as propriedades mecânicas desses implantes. Portanto, o objetivo deste estudo foi analisar o comportamento mecânico de parafusos corticais de aço inoxidável e de liga de titânio, de fabricação nacional, em ensaio de torção. Vinte parafusos de aço inoxidável foram divididos em quatro grupos (1,2,3,4) e o mesmo foi feito com os parafusos de liga de titânio. Primeiramente, suas medidas-padrão foram analisadas de acordo com a Norma Brasileira NBR ISO 5835:1996. Nos dois grupos 1 (de aço inoxidável e de liga de titânio), o ângulo de rotação foi mensurado por um goniômetro e o ensaio de torção foi manual. Já os parafusos dos dois grupos 2 foram ensaiados em uma máquina de torção. Os parafusos dos grupos 3, primeiramente, foram inseridos em cortical óssea suína e, posteriormente submetidos à torção. Nos dois grupos 4, os parafusos foram submetidos à torção sucessiva e, posteriormente submetidos à torção na máquina. Na análise estatística das propriedades mecânicas, os resultados apresentaram diferença significativa no torque no limite de proporcionalidade entre o grupo 1 e os demais grupos de aço inoxidável e entre o grupo 1 e os demais grupos de liga de titânio, sugerindo um possível erro metodológico no ensaio de torção manual. No torque no limite máximo houve diferença significativa entre o grupo 4 de liga de titânio e os grupos 2 e 3, mostrando que a torção sucessiva pode comprometer esta propriedade. Na rigidez torcional, foi demonstrada diferença estatística significativa entre os grupos 1 e 3 de liga de titânio. Na tenacidade torcional, houve diferença significativa entre o grupo 1 e os demais grupos de liga de titânio, entre o grupo 2 e os grupos 3 e 4 de aço inoxidável e entre todos os grupos de aço inoxidável e todos os grupos de liga de titânio. Conclui-se que, em geral, os parafusos de aço inoxidável apresentaram tenacidade torcional superior aos parafusos de liga de titânio, mas nas demais propriedades estes dois biomateriais apresentaram resultados semelhantes / Cortical bone screws are one of the most used implants in the surgical practice and the stainless steel (ASTM F-138) and titanic (6Al-4V) are the most common alloys used to manufacture them. When inserted into the bone such implants undergo several types of mechanical stress and, therefore, it is very useful to know their mechanical behavior. The purpose of the present study was to compare the mechanical properties of cortical bone screws made up of stainless steel and titanic alloy as tested in torsion. Twenty stainless steel screws were divided into four groups (1,2,3,4) and the same was made for the titanic alloy screws. First, the screw dimension were checked in accordance to the brazilian standard regulations. In groups 1 (either stainless steel or titanic alloy) the angle of rotation was measured with a goniometer and the torsion test was manual. For groups 2 the screws were tested in torsion in a testing machine. In groups 3, firstly, the screws were inserted into suine bone and, later, removed and submitted to torsion. In groups 4 the screws were tested in successive loading and unloading cycles in torsion and, later, submitted to torsion. The results showed statistically significant difference for the yield torque among the group 1 and the other groups of stainless steel and among the group 1 and the other groups of titanic alloy, which suggest a possible methodological error in manual torsion. For the ultimate torque there was difference among titanic groups 4, 2 and 3, showing that repeated torsion can affect such property. For the torsional stiffness there was statistical difference between titanic groups 1 and 3. The torsional tenacity was different among the 1 and the other titanic groups, also there was difference among stainless steel groups 2, 3 and 4. Finally, there was statistical difference among all stainless steel and titanic alloy groups, that, in general, the stainless steel screws showed greater torsional tenacity in comparison with the titanic alloy screws, but for the other torsional properties they displayed a similar behavior

Parafusos corticais são uns dos implantes mais utilizados na prática cirúrgica e são normalmente compostos por ligas metálicas como o aço inoxidável F-138 e a liga de titânio 6Al-4V e, quando inseridos no organismo humano, são submetidos a diversos esforços mecânicos. Assim, é necessário avaliar as propriedades mecânicas desses implantes. Portanto, o objetivo deste estudo foi analisar o comportamento mecânico de parafusos corticais de aço inoxidável e de liga de titânio, de fabricação nacional, em ensaio de torção. Vinte parafusos de aço inoxidável foram divididos em quatro grupos (1,2,3,4) e o mesmo foi feito com os parafusos de liga de titânio. Primeiramente, suas medidas-padrão foram analisadas de acordo com a Norma Brasileira NBR ISO 5835:1996. Nos dois grupos 1 (de aço inoxidável e de liga de titânio), o ângulo de rotação foi mensurado por um goniômetro e o ensaio de torção foi manual. Já os parafusos dos dois grupos 2 foram ensaiados em uma máquina de torção. Os parafusos dos grupos 3, primeiramente, foram inseridos em cortical óssea suína e, posteriormente submetidos à torção. Nos dois grupos 4, os parafusos foram submetidos à torção sucessiva e, posteriormente submetidos à torção na máquina. Na análise estatística das propriedades mecânicas, os resultados apresentaram diferença significativa no torque no limite de proporcionalidade entre o grupo 1 e os demais grupos de aço inoxidável e entre o grupo 1 e os demais grupos de liga de titânio, sugerindo um possível erro metodológico no ensaio de torção manual. No torque no limite máximo houve diferença significativa entre o grupo 4 de liga de titânio e os grupos 2 e 3, mostrando que a torção sucessiva pode comprometer esta propriedade. Na rigidez torcional, foi demonstrada diferença estatística significativa entre os grupos 1 e 3 de liga de titânio. Na tenacidade torcional, houve diferença significativa entre o grupo 1 e os demais grupos de liga de titânio, entre o grupo 2 e os grupos 3 e 4 de aço inoxidável e entre todos os grupos de aço inoxidável e todos os grupos de liga de titânio. Conclui-se que, em geral, os parafusos de aço inoxidável apresentaram tenacidade torcional superior aos parafusos de liga de titânio, mas nas demais propriedades estes dois biomateriais apresentaram resultados semelhantes / Cortical bone screws are one of the most used implants in the surgical practice and the stainless steel (ASTM F-138) and titanic (6Al-4V) are the most common alloys used to manufacture them. When inserted into the bone such implants undergo several types of mechanical stress and, therefore, it is very useful to know their mechanical behavior. The purpose of the present study was to compare the mechanical properties of cortical bone screws made up of stainless steel and titanic alloy as tested in torsion. Twenty stainless steel screws were divided into four groups (1,2,3,4) and the same was made for the titanic alloy screws. First, the screw dimension were checked in accordance to the brazilian standard regulations. In groups 1 (either stainless steel or titanic alloy) the angle of rotation was measured with a goniometer and the torsion test was manual. For groups 2 the screws were tested in torsion in a testing machine. In groups 3, firstly, the screws were inserted into suine bone and, later, removed and submitted to torsion. In groups 4 the screws were tested in successive loading and unloading cycles in torsion and, later, submitted to torsion. The results showed statistically significant difference for the yield torque among the group 1 and the other groups of stainless steel and among the group 1 and the other groups of titanic alloy, which suggest a possible methodological error in manual torsion. For the ultimate torque there was difference among titanic groups 4, 2 and 3, showing that repeated torsion can affect such property. For the torsional stiffness there was statistical difference between titanic groups 1 and 3. The torsional tenacity was different among the 1 and the other titanic groups, also there was difference among stainless steel groups 2, 3 and 4. Finally, there was statistical difference among all stainless steel and titanic alloy groups, that, in general, the stainless steel screws showed greater torsional tenacity in comparison with the titanic alloy screws, but for the other torsional properties they displayed a similar behavior

This master's thesis deals with the selection and evaluation of the appropriate welding technology for stainless steel and titanium alloys. Describes advantages and disadvantages of selected technologies. The experiment compares the mechanical properties, the heat input and the resulting surface structure of the welded samples. In conclusion, the thesis deals with the technical - economic evaluation of selected welding technologies.

This diploma thesis is focused on dental materials used in prosthetic medicine. In the introduction, the most important characteristic of dental materials is summarised, which is biocompatibility. Further it contains distribution of nowadays used dental materials, which are oxidic ceramics and titanium alloys. It describes pitfalls of machining of those materials. Final part is devoted to process of the production of the new dental crown, from the first arrival of the patient to the machining of final product. The thesis also compares the economics of dental crown production using milling and 3D printing.

Machining technology is a multi disciplinary field, and together with the economy are playing always more important role in the success of the enterprise market products and services. Recent studies show that it requires very close link between technology, management and information technology such as the integration process and production planning, simulation of manufacturing systems, production flexibility, virtual machines, control algorithms, etc. The key changes are based on the requirements for miniaturization of products, higher production accuracy, closer tolerances, better surface quality, part of weight reduction, reduction of lot size and reducing production costs. The report is focused on machining titanium alloys. In the theoretical part are presented the properties and the distribution of titanium alloys. In the practical part is then carried out an experiment aimed to influence the composition of workpiece material on tool wear. Experiment results and recommendations are listed at the end of this report.

Tato práce popisuje části dentálních náhrad, lékařské pojmy, které se s nimi vážou a vysvětluje proces a problematiku koncepce a výroby těchto částí. Různé druhy biomateriálů jako kovy, keramika, polymery či kompozity jsou zde popsány, hlavní důraz je však kladen na titanové a chrom kobaltové slitiny a korozivzdorné oceli. Experimentální část nabízí 2 řešení zlepšení výroby součásti. První část experimentální části se zabývá zlepšením kvality styčné plochy pilíře zvýšením hustoty síťování součásti. Druhá část nabízí nahrazení operace frézování operací vrtání. Byly vybrány nástoje od 4 výrobců. Pro nalezení vhodného nástroje jsou provedeny 2 testy vrtání a vybrán nástroj vhodný pro obrábění titanové a chrom kobaltové slitiny.

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Laser-based additive manufacturing offers a high degree of thermokinetic flexibility that has implications on the structure and properties of the fabricated component. However, to exploit the flexibility of this process, it is imperative to understand the process-inherent thermokinetic evolution and its effect on the material characteristics. In view of this, the present work establishes a fundamental understanding of the spatiotemporal variation of thermokinetics during the fabrication of the non-ferrous alloys using the laser powder bed fusion process. Due to existing limitations of experimental techniques to probe such thermokinetics, a finite element method-based computational model is developed to predict the thermokinetic variations during the process. With the computational approach coupled with experimental techniques, the current work presents the solidification behavior influenced by spatially varying thermokinetics. In addition, it uniquely predicts the process-inherent multi-track multi-layer evolution of thermal cycles as well as thermal stress cycles and identifies their influence on the post-solidification microstructural evolution involving solid-state phase transformation. Lastly, the response of the material with a unique microstructure is recorded under various conditions (static and dynamic), which is again compared with the same set properties obtained for the same material processed via conventional routes.

Laser metal deposition (LMD) offers a unique combination of process flexibility, time savings, and reduced cost in producing titanium alloy components. The current challenge in processing titanium alloys using LMD methods is understanding the complex microstructure evolution as a part is fabricated layer by layer. The current work focuses on the characterization, thermal, and microstructural modeling of multilayered Ti-6Al-4V deposits. A thermal model has been developed using finite difference techniques to predict the thermal history of LMD processes. A microstructure model that predicts the alpha phase fraction and morphology evolution was constructed to quantify the effect of thermal cycling on the as-deposited microstructure evolution. Alpha dissolution and growth are modeled assuming one-dimensional plate dissolution according to a parabolic rate law, and a Johnson-Mehl-Avrami-Kolmorgorov (JMAK) nucleation and growth model, respectively. Alpha morphology (colony-alpha and basketweave-alpha) evolution is tracked using a simplistic approach. Characterization of the deposit has shown that a complex microstructure evolves consisting of a two distinct regions: a transient region of undeveloped microstructure and a characteristic layer that is periodically repeated throughout the deposit. The transient region contains a fine basketweave and colony-alpha morphology. The characteristic layer contains a two phase mixture of alpha+beta, with the alpha phase exhibits regions of colony-alpha (layer band) and basketweave-alpha morphology. The different regions of microstructural contrast in the deposit are associated with thermal cycling. The thermal model results show that a heat affected zone defined by the beta transus extends approximately 3 layers into the deposit. The phase fraction model predicts the greatest variation in microstructural evolution to occur in a layer n after the deposition of layer n+3. The results of the morphology model show that increased amounts of colony-alpha form near the top of a characteristic layer. It follows that a layer band (colony-alpha region) forms as a result of heating a region of material to a peak temperature just below the beta transus, where a large amount of primary-alpha dissolves. Upon cooling, colony-alpha forms intragranularly. The coupled thermal and microstructure models offer a way to quantitatively map microstructure during LMD processing of Ti-6Al-4V. / Ph. D.