Cast Titanium Research Articles

The use of platinum metals to increase the corrosion and strength characteristics of industrial titanium casting

The materials used for technological equipment manufacture should have high mechanical strength, chemical and thermal resistance. Technical titanium is widely used for these purposes. The article studies the effect of small palladium additives on titanium chemical and mechanical properties. It was revealed that the introduction of 0.23% palladium during titanium smelting has little effect on the mechanical properties of doped titanium, but it increases its resistance to sulfuric and hydrochloric acids.

Formation of Alpha-Case Layer During Investment Casting of Pure Ti and Ti-6Al-4V Using Comparative XRD and EXAFS Investigation

In titanium casting, a reaction byproduct known as alpha-case is a hard and brittle phase layer that exists on the surface of cast objects. This reaction layer may be detrimental to the mechanical properties of cast objects and may complicate the finishing processes. To investigate the formation of the alpha-case layer during the casting of commercially pure titanium (CP-Ti) and Ti-6Al-4V alloy, both metal ingots were cast in spinel-based investments in a controlled environment. The cast samples were metallographically prepared and analyzed for the thicknesses of alpha-case layer depth and the metal matrix. The samples were characterized using light microscopy, Vickers microhardness testing, X-ray diffractometry, and extended X-ray absorption fine structure spectrometry. The alpha-case layer on the CP-Ti cast sample was thicker than that of the Ti-6Al-4V cast sample due to the ability of the α-titanium matrix to uptake oxygen faster, which in turn is attributed to the higher diffusion coefficient of the α-titanium phase. A metastable Ti3O phase was observed as an intermediate reaction product which could be transformed into the alpha-case layer and the α-titanium phase.

Design and Evaluate A Model of Vehicle Suspension System by Using Fem

The suspension system assists the vehicle's braking system in terms of safety, driving pleasure and passenger comfort when driving without road noise, bumps or vibrations. If the roads were perfectly smooth, a vehicle suspension system would not be necessary. As a result, the wheel of the machine undergoes a sudden vertical movement as it moves over the bumps. To improve the stability of the suspension system design multiple spring in vehicle suspension system and the design multiple spring in vehicle suspension system for different materials to enhance the results. Final conclusion of the analysis the Titanium Ti-6Al-4V is the much batter material than other two materials Cast iron and titanium Ti-13V-11Cr-3Al. Because the yield stress of Titanium Ti-6Al-4V is higher the titanium Ti-13V-11Cr-3Al. And the density of the Titanium Ti-6Al-4V was lower than cast iron and titanium Ti-13V-11Cr-3Al.

Preliminary Study on the Application of Concentrated Solar Power in Metallurgy of Titanium

The applicability of concentrated solar power for metallurgy of titanium is discussed based on preliminary experimental works performed at Plataforma Solar de Almeria Spain, using solar furnace SF40 under protective argon atmosphere. As a starting material, titanium powder was used. The possibility of melting titanium compacts on yttria stabilized zirconia mat was investigated, and the effect of density and size of different green compacts was studied. It was observed that the time to achieve melting point is very short when concentrated solar power is used. The obtained results are expected to be similar for titanium sponge from which titanium powder is processed. After optimization of processing parameters, this will probably lead to a significant decrease of carbon footprint in the titanium ingots and castings production.

The chemical composition of the surface of the sand molds based on magnesium oxide used in titanium castings

The XPS method has been used to study the chemical composition of the surface of sand forms based on magnesium oxide. The original and modified forms were investigated. Modification of the form was carried out by plasma deposition of a titanium coating on the inner surface. The surface of the initial form consists of the initial oxides and intermetallic compounds based on the elements of the form. In the surface layers of the modified form, TiO2 is the main titanium-containing compound, silicon titanates and intermetallic compounds based on the elements of the form and titanium are present.

The composition of alpha case of the titanium casting obtained in a ceramic mold based on MgO

The X-ray photoelectron spectroscopy method has been used to study the alpha case formed on the surface of a titanium alloy during its casting into ceramic molds, based on a mixture of oxides of magnesium, silicon, calcium, and water glass, as a binder. It is established that the alpha case consists of mold metal oxides, titanium oxides and complex intermetallic compounds based on titanium and mold elements.

The Antimicrobial Activity and Characterization of the Cast Titanium Copper Alloys with Variations of Copper Content

The effect of Cu addition on antimicrobial activity of Cast Ti-Cu Alloys against Staphylococcus aureus were studied. The Ti-Cu alloys were prepared with a variation of 0.5, 1, 2, 3, 4, 8 and 10 wt% of copper. Pure Ti metal was also prepared and tested as a comparison. The antibacterial was performed by killing activity test of colony forming unit (CFU) method with variation of contact time. Optical microscope observation, XRD, and the Vickers hardness test were carried out to characterize the investigated alloys. The results showed that Ti-Cu alloys were able to decrease the amount of bacteria by time. However, the activity of killing of bacteria in the varied range of Cu content did not show significantly different result. The highest bacterial kill ability in the alloy was observed in addition of 3 wt% Cu.

Mechanisms of TiAl alloys isomorphic inoculation from cryo-milled Ti-Al-Nb powders

Isomorphic inoculation has recently been introduced by the authors as a successful method to grain refine cast titanium aluminides [1]. Analyses of the cast grain size together with introduced particle size distributions revealed anomalously high grain refinement efficiency which was attributed to the particles breaking up during the holding stage prior to solidification [2]. In the present work, the microstructure of the inoculant powders is investigated in both the cryo-milled state as well as after simulated thermal cycles to reproduce their heating and holding in the melt. Results show that milling time does not impact the grain size in the particles, only their size distributions. Heat treatments between 1500 and 1600°C for short periods of time allowed the activation energy for grain growth and evaluation of the grain size evolution in the particles during the isomorphic inoculation process to be determined. Assuming that grain boundary melting is the predominant break up mechanism, a model to estimate dissolution of the powders is presented which includes diffusion and fluid flow. Despite its relative simplicity, the predicted number of particles remaining after heating and holding, which lead to grains in the as-cast structure, are in good agreement with the measured grain size. Finally, the paper summarizes the main features and mechanism making isomorphic inoculation a promising route for grain refining as-cast alloys.

Low-cost beta titanium cast alloys with good tensile properties developed with addition of commercial material

The low-cost β-titanium alloys, Ti-Cr-Al-Si, have been designed by the addition of a commercial Al-based die-cast alloy (ADC12, Al87.38Cu0.95Si10.65Mg0.27Zn0.30Fe0.32Mn0.11Cr0.02 in at.%) containing Si content. The microstructural investigation on Ti84-xCr16(ADC12)x (x = 6, 16 at.%) alloys exhibited that the addition of 6 at.%ADC12 completely dissolved in the β-Ti phase, and exhibited reasonable yield strength by solid solution hardening of the β-Ti phase with large plasticity. The addition of 16 at.%ADC12 effectively reduces the cost of the β-titanium alloys and induces microstructural evolution with formation of Ti-silicide. The β-Ti phase containing high content of solutes and the very fine Ti5Si3 phase that segregated in the interdendritic regions, due to Si solute partitioning during dendritic solidification, mediates outstanding tensile mechanical properties (1015 MPa in yield strength and 17.5% in elongation). These results reveal that the alloy designs using the commercial materials containing various solute elements can facilitate the development of the competitive low-cost β-titanium alloys with excellent mechanical properties.

Investment casting of titanium alloys with calcium zirconate moulds and crucibles

Titanium alloys are very difficult to process via investment casting due to their high melting temperature and reactivity. The objective of the present work was to evaluate new shell mould materials for the suitability for titanium casting in comparison to conventional materials. A new corrosion-resistant material for crucibles and shell moulds based on calcium zirconate (CaZrO3) is proposed with the aim of improving the casting quality of titanium alloys. Tilt casting trials into CaZrO3 shell moulds using three different crucible materials were conducted. The results were compared to a commercial shell system containing silica. The reactivity with the titanium melt was extensively studied as a function of melt temperature, part dimensions and shell mould temperature by hardness profiles and oxygen measurements. The reaction of the CaZrO3 shell was very low, indicated by small oxygen contents and thereby low surface hardness. The formation of an α-case was avoided by choosing appropriate casting parameters.

An In-Vitro Study on the Influence of Ceramic Thickness in the Color of Titanium Ceramic Restoration

Background: Various factors such as metal alloy, thickness of the opaque porcelain, different methods of condensation of ceramic, thickness of the dentine ceramic, different ceramic firing condition affect the color of final ceramic restoration. It is not considered significant while taking single variable into account but several subtle changes in these factors lead to discernible color change.
 Purpose: The aim of this study was to evaluate the influence of ceramic thickness over color of ceramic layered on the titanium casting.
 Methods: Ultra low fusing ceramics of different thickness (0.5mm, 1mm, 1.5mm and 2mm) was veneered over a metal substrate of pure titanium and spectrophotometric analysis of 20 such discs was done to determine parameters (CIELAB system). One-way ANOVA and multiple comparison results of ANOVA were performed for statistical analysis.
 Results: The different thickness of ceramic significantly influences the ΔE value. There was significant change in the L* value (P<0.05) with different thickness of titanium metal ceramic tabs. There was also significant difference in C*ab values with different thickness of ceramic.
 Conclusions: The thickness of the ceramic has significant effect in the L* value of the titanium ceramic restoration. The thicker restoration appeared darker than the thinner one. There was also significant effect in the color saturation or chroma with different thickness of ceramic. Chroma decreased with increased thickness. Color difference between groups were significant. Overall thickness had effect on the final color of the titanium ceramic restoration.

Dimensional accuracy of microcomputed tomography-scanned half-arch impressions

Statement of problemAccuracy in impression making may be enhanced by digitizing the physical impression directly and thereby be unhampered by errors introduced by gypsum casts. PurposeThe purpose of this in vitro study was to compare the dimensional accuracy of microcomputed tomography (micro-CT) scans of impressions with that of optical scans of impressions and gypsum casts. Material and methodsA titanium maxillary cast with 3 metrology-grade ruby spheres in place of 3 teeth was used as a reference. Sphere 1 (S1) to sphere 2 (S2) distance (S1-S2) was 25.036 mm, and sphere 1 (S1) to sphere 3 (S3) distance (S1-S3) was 41.846 mm. Half-arch impressions were made of the titanium cast using polyvinyl siloxane impression material with a 1-step 2-phase technique. The polyvinyl siloxane impressions were then micro-CT scanned and optically scanned, and the resulting stone casts were also optically scanned. Scans from the 3 groups—CT scanning of impressions (CT), optical scanning of impressions (OP), and optical scanning of stone casts (SC)—were used to measure the distances between the 3 ruby spheres and were compared with the reference titanium model. The Wilcoxon signed-rank test for matched pairs was used to compare the groups (α=.01). ResultsFor the distance of 25.036 mm, S1-S2 distance, CT scans of impressions (CT) showed an error of 20 ±20 μm, whereas optical scans of stone casts (SC) showed an error of 0 ±20 μm. At a distance of 41.846 mm, S1-S3 distance, CT showed an error of 0 ±40 μm, whereas SC showed an error of −40 ±40 μm. The difference in error between measurements at both distances was statistically significant (P<.01). The group of optical scans of impressions (OP) had to be excluded because of missing data and deformed features on the scan. ConclusionsAlthough optically scanned stone models are more dimensionally accurate than micro-CT scanned impressions at a 25.036-mm distance, at a distance of 41.846 mm, micro-CT scanned impressions showed less error than optically scanned stone models. Micro-CT scanning of half-arch impressions is a viable method of digitizing a physical impression of dental structures and capturing data about the patient's oral structures. A digital image obtained by micro-CT scanning is more accurate than that obtained by optical scans of stone casts for long-span restorations.

Investigation of the interactions between titanium and calcium zirconium oxide (CaZrO3) ceramics modified with alumina

Powdered mixtures of CaO, ZrO2 and Al2O3 in various ratios were hot pressed. The mixtures reacted with titanium at 1600?C for 30min in argon to evaluate the suitable ceramic crucibles for casting of titanium. The interfacial microstructures between titanium and ceramic composites were characterized using X-ray diffractometer, scanning and transmission electron microscope. The produced hot pressed mixtures that were chemically bonded together, contained calcium aluminate (CaAl2O4), calcium dialuminate (CaAl4O7), cubic zirconia (c-ZrO2), and calcium zirconium oxide (CaZrO3). The increase in Al2O3 amount led to the decrease in CaZrO3 amount and an increase in the amount of CaAl2O4, CaAl4O7 and c-ZrO2 due to the reaction of CaO and Al2O3. At the end of the reaction of the ceramic mixtures with Ti at 1600?C for 30min, the acicular ?-Ti and ??-Ti were formed at the interface of Ti and the composites containing up to 10 vol.% Al2O3. In composites containing more than 20 vol.% Al2O3, Ti3Al5 was found at the interface instead of ?-Ti and ??-Ti. Furthermore, CaZrO3, ZrO2 and Ca3Al2O6 existed on the sides of the ceramic far away from the interface. CaZrO3/Al2O3 composites with less than 20 vol.% Al2O3 could be a potential crucible or mould material for productive applications in titanium casting.

In vitro marginal and internal adaptation of metal-ceramic crowns with cobalt-chrome and titanium framework fabricated with CAD/CAM and casting technique.

The purpose of this study was to compare the marginal and internal fit of Co-Cr and titanium ceramic crowns fabricated with 2 different techniques: CAD/CAM milling and traditional casting (TC). Ten traditional casting of Co-Cr (TCC), 10 CAD/CAM milling of Co-Cr (MC), 10 traditional casting of titanium (TCT), 10 CAD/CAM milling of titanium ceramic crowns (MT) were fabricated. Silicone replicas were obtained to measure internal gap volume, marginal gap and internal adaptation that was evaluated at 3 regions: axial wall, axio-occlusal angle, and occlusal surface. Measurements were made with a X-ray micro computerized tomography (micro-CT) and analyzed with Bonferroni and Dunnet T3 post-hoc tests (α = 0.05). One-way ANOVA revealed no statistically significant differences among the groups for measurements at the marginal gap (P > 0.05). At axial wall region the mean values of TCT group were higher than those of groups but only statistically not significant for TCC group (P < 0.05). TCC group statistically gives better results than MC group in axio-occlusal and occlusal regions (P < 0.05). The mean measurement of internal gap volume were 20.59 ± 0.83 mm3 for TCC, 22.73 ± 0.82 mm3 for MC, 22.83 ± 1.11 mm3 for TCT and 20.51 ± 1.16 mm3 for MT. Mean internal gap volume values MT group were smaller than those of groups but only statistically not significant for TCC group (P > 0.05). All groups performed similar marginal adaptation. The cement film thickness at axio-occlusal angle point and occlusal region were higher for MC crowns.

Investigating the morphological effects of solute on the β-phase in as-cast titanium alloys

An outstanding challenge in titanium solidification processes is controlling the primary β-phase morphology. Consequently, this paper investigates the efficacy of chromium additions to reduce anisotropic growth morphologies of the primary β-phase in titanium castings. By characterising the size, morphology and positions of β-grains in the cross-sections of each alloy, it is determined that, in contrast to established theory, chromium-containing castings yielded increased β-grain anisotropy, both in terms of size and morphology. It is proposed that these experimental results may still be consistent with established theory if certain theoretical assumptions are reconsidered.

Scanning electron beam treatment of Ti-6Al-4V titanium alloy produced by casting and EBM processes

The results obtained by studying the surface morphology, microstructure and microhardness of Ti-6Al-4V titanium alloy subjected to scanning electron beam treatment are discussed. It is shown that the surface of titanium parts produced by electron beam melting followed by scanning electron beam post-treatment becomes smoother as compared with the surface of the as-build parts. The occurrence of the martensite α’-phase in the structure of melted surface layer of both Ti-6Al-4V titanium cast alloy and EBM-printed Ti-6Al-4V parts subjected to scanning electron beam treatment is discussed. The latter results in increase the microhardness of the samples under study.

アコースティックエミッション解析によるチタンの変形・破壊機構に関する研究 : 第2報 シリカ-アルミナ-リン酸塩埋没材の鋳型に鋳造したチタン表層の多層構造組織の役割

アコースティックエミッション解析によるチタンの変形・破壊機構に関する研究 : 第2報 シリカ-アルミナ-リン酸塩埋没材の鋳型に鋳造したチタン表層の多層構造組織の役割

Research of boundary layers of molds, used in titanium casting

Boundary layers of the mold used for castings from titanium have been investigated by the method of electron microscopy with a system of probe microanalysis. Migration both components of mold and additives of titanium alloy is established to the surface layers of the form.

Surface modification of molds for titanium casting, and its influence on the allocation of chemical elements in boundary layers of molds

Influence of titanium sputtering on the inner surface of the casting mold on the chemical elements’ allocating in the boundary layers of the mold is considered. It is established that the sputtering of titanium does not exclude the migration of mold’s chemical elements through the titanium to the casting surface.

A low-cost and high-strength Ti-Al-Fe-based cast titanium alloy for structural applications

A cost-effective α-β titanium casting alloy, Ti-6Al-5Fe-0.05B-0.05C,11All compositions in wt% except otherwise stated. has been designed using Calculation of Phase Diagrams (CALPHAD) method and the workhorse alloy Ti-6Al-4 V as a baseline. The substitution of iron for vanadium significantly reduces the raw material cost and improves the castability compared to the Ti-6Al-4 V alloy. The very fine α phase in the microstructure of the new alloy, likely due to Fe partitioning, provides exceptionally high strength (1023 MPa yield strength and 1136 MPa ultimate tensile strength) and reasonable ductility (3.71% elongation) for structural applications.