β Recrystallisation characteristics of α + β titanium alloys for aerospace applications

To investigate the recrystallisation characteristics of Ti-6Al-4V and the novel alloy Timetal 575 (Ti575), twelve 100mm diameter double cone samples were forged, sectioned then heat treated in the beta phase field. The double cone geometry chosen provided a gradient of strain in each sample with a strain profile provided by output from a finite element modelling package. The matrix of tests covered three forging temperatures and two deformation rates and was followed by heat treatments to two temperatures for two different times at temperature generating a recrystallised microstructure as a function of these parameters. The extent of microstructural refinement for both alloys was analysed using optical microscopy of the as-received and recrystallised micro-structure

Electron beam structuring of Ti6Al4V: New insights on the metal surface properties influencing the bacterial adhesion

Soft tissue adhesion and infection prevention are currently challenging for dental transmucosal or percutaneous orthopedic implants. It has previously been shown that aligned micro-grooves obtained by Electron Beam (EB) can drive fibroblast alignment for improved soft tissue adhesion. In this work, evidence is presented that the same technique can also be effective for a reduction of the infection risk. Grooves 10-30 \u3bcm wide and around 0.2 \u3bcm deep were obtained on Ti6Al4V by EB. EB treatment changes the crystalline structure and microstructure in a surface layer that is thicker than the groove depth. Unexpectedly, a significant bacterial reduction was observed. The surfaces were characterized by field emission scanning electron microscopy, X-ray diffraction, confocal microscopy, contact profilometry, wettability and bacterial adhesion tests. The influence of surface topography, microstructure and crystallography on bacterial adhesion was systematically investigated: it was evidenced that the bacterial reduction after EB surface treatment is not correlated with the grooves, but with the microstructure induced by the EB treatment, with a significant bacterial reduction when the surface microstructure has a high density of grain boundaries. This correlation between microstructure and bacterial adhesion was reported for the first time for Ti alloys

Combination of Electron Beam Surface Structuring and Plasma Electrolytic Oxidation for Advanced Surface Modification of Ti6Al4V Alloy

The objective of this work is to study for the first time the combination of electron beam (EB) surface structuring and plasma electrolytic oxidation (PEO) with the aim of providing a multiscale topography and bioactive surface to the Ti6Al4V alloy for biomedical applications. Ca and P-containing coatings were produced via 45 s PEO treatments over multi-scale EB surface topographies. The coatings morphology and composition were characterized by a means of scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The effect on the previous EB topography was evaluated by means of a 3D optical profilometry and electrochemical response via potentiodynamic polarization tests. In general, the PEO process, morphology, composition and growth rate of the coatings were almost identical, irrespective of the topography treated. Minimal local differences were found in terms of morphology, and the growth rate were related to specific topographical features. Nevertheless, all the PEO-coated substrates presented essentially the same corrosion resistance. Electrochemical tests revealed a localized crevice corrosion susceptibility of all the bare EB topographies, which was successfully prevented after the PEO treatment.Depto. de Ingeniería Química y de MaterialesFac. de Ciencias QuímicasTRUEMICINN/AEI/ FEDER, UEComunidad de MadridComunidad de MadridUCMChristian Doppler Forschungsgesellschaftpu

In Situ Analysis of the Phase Transformation Kinetics in the β-Water-Quenched Ti-5Al-5Mo-5V-3Cr-1Zr Alloy during Ageing after Fast Heating

Thermal treatments are the main route to achieve improvements in mechanical properties of β-metastable titanium alloys developed for structural applications in automotive and aerospace industries. Therefore, it is of vital importance to determine phase transformation kinetics and mechanisms of nucleation and precipitation during heat treatment of these alloys. In this context, the present paper focuses on the assessment of solid-state transformations in a β-water-quenched Ti-5Al-5Mo-5V-3Cr-1Zr alloy during the early stages of ageing treatment at 500 ◦C. In situ tracking of transformations was performed using high-energy synchrotron X-ray diffraction. The transformation sequence β + ω → α + α”iso + β is proposed to take place during this stage. Results show that isothermal α” phase precipitates from ω and from spinodal decomposition domains of the β phase, whereas α nucleates from ω, β and also from α” with different morphologies. Isothermal α” is considered to be the regulator of transformation kinetics. Hardness measurements confirm the presence of ω, although this phase was not detected by X-ray diffraction during the in situ treatment

Influences of Surface, Heat Treatment, and Print Orientation on the Anisotropy of the Mechanical Properties and the Impact Strength of Ti 6Al 4V Processed by Laser Powder Bed Fusion

The scope of this work is to provide an overview of the influences of process parameters, print orientation, and post-process treatments of Ti6AlV4 processed by laser powder bed fusion on its microstructure and physical and mechanical properties and their anisotropic behavior. To avoid the influence of changes in powder quality and ensure comparability, experiments were carried out using a single batch of virgin powder. First, characterization of the density and surface roughness was performed to optimize the process parameters utilizing design of experiment. Tensile, notched bar impact and compression test specimens were built in three different orientations: vertically, horizontally, and inclined at 45° to the build plate. Later, the influence of the staircase effect and the possible course of anisotropy from vertical to horizontal were investigated. Subsequently, heat treatments for stress relief, furnace annealing, and hot isostatic pressing were performed. In addition to as-built samples, mechanical machining and a two-step electrochemical polishing surface treatment were applied to investigate the influence of the surface roughness. With parameter optimization, a relative density of 99.8% was achieved, and surface roughness was improved over default parameters, reducing Ra by up to 7 µm. Electrochemical polishing is a viable way to decrease the surface roughness. An Ra value of 1 µm and an Rz value of 4 µm can be achieved for 45° downskin surfaces with as-built surface roughness values of Ra 24 µm and Rz 117 µm. As-built and stress-relieved conditions show little anisotropy in their yield and tensile strength (max 2.7%), but there is a strong influence of the build orientation on necking, and brittle fracture behavior is shown due to the martensitic microstructure (up to 70%). Heat treatment can increase the ductility and further decrease the strength anisotropy with both furnace annealing and hot isostatic pressing delivering similar results for tensile properties, while angled samples exhibit behavior that is closer to vertical than horizontal, indicating a non-linear change in break behavior. Electrochemical polishing increases fracture necking, and its isotropy drastically increases from 4% to over 30% compared with as-built parts, which is close to the level of the machined specimen

Mapa eólico de la provincia del Neuquén

El Ente Provincial de Energía del Neuquén (EPEN) con la asistencia técnica del Centro Regional de Energía Eólica de Chubut y la colaboración de la Universidad Nacional del Comahue ha iniciado el desarrollo del mapa eólico de la Provincia del Neuquén. Este proyecto tiene por finalidad identificar áreas potencialmente aptas para el desarrollo de proyectos y el diseño de estudios o programas de evaluación del recurso en sitios específicos (micrositing). En esta comunicación se detallan los fundamentos del proyecto, la metodología seguida y el estado actual de los trabajos.EPEN (Entre Provincial de Energía del Neuquén) with the technical assistance of CREE (Centro regional de Energía Eólica de Chubut) and the co-operation of Comahue University has initiated the development of Neuquen’s province wind map. The objective of this project is to identify areas of interest for the development of wind plants and the design of wind resource evaluation studies in specific sites (micrositing). In this paper are detailed the basis of the project, the methodology and the present status.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Mapa eólico de la provincia del Neuquén

El Ente Provincial de Energía del Neuquén (EPEN) con la asistencia técnica del Centro Regional de Energía Eólica de Chubut y la colaboración de la Universidad Nacional del Comahue ha iniciado el desarrollo del mapa eólico de la Provincia del Neuquén. Este proyecto tiene por finalidad identificar áreas potencialmente aptas para el desarrollo de proyectos y el diseño de estudios o programas de evaluación del recurso en sitios específicos (micrositing). En esta comunicación se detallan los fundamentos del proyecto, la metodología seguida y el estado actual de los trabajos.EPEN (Entre Provincial de Energía del Neuquén) with the technical assistance of CREE (Centro regional de Energía Eólica de Chubut) and the co-operation of Comahue University has initiated the development of Neuquen’s province wind map. The objective of this project is to identify areas of interest for the development of wind plants and the design of wind resource evaluation studies in specific sites (micrositing). In this paper are detailed the basis of the project, the methodology and the present status.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Evaluación del recurso eólico del departamento Confluencia de la provincia del Neuquén

Se realizó el mapa de potencial eólico del Departamento Confluencia de la provincia del Neuquén para evaluar la energía eléctrica posible de extraer. El objetivo fue detectar los sitios más propicios para la ubicación de futuros parques eólicos. La zona de estudio se caracteriza por tener varias líneas de transmisión de alta tensión facilitando una conexión al Sistema Interconectado Nacional/Provincial en caso de instalarse un parque eólico. Para este trabajo se contó con herramientas modernas de procesamiento de datos, como un SIG que tiene incluido un modelo atmosférico numérico, llamado WindMap. Se determinaron las características geofísicas de la zona a través de sensores remotos, como los datos topográficos provistos por la NASA y el análisis y procesamiento de imágenes satelitales SAC-C. Con estas herramientas se logró la evaluación del recurso eólico obteniendo los mapas del campo de viento y de potencia eólica disponible a 50 metros de altura.The wind energy map of the Confluence Department of the Neuquén province was carried out to evaluate the possible electric power of to extract. The objective was to determinate the most favourable places for the location of future wind farms. The study zone has several high-voltage transmission lines facilitating a connection with the National/Provincial System Interconnected in case of being installed wind farm. This work integrated modern tools of processing data, as a SIG that has included a numerical atmospheric model, WindMap. The geophysical characteristics of the zone were determined through remote sensors, as the topography data, provided by NASA, or the analysis and prosecution of SAC-C satellite images. With these tools the evaluation of the wind power resource was achieved obtaining the maps of the wind field and of available wind power at 50 meters.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Recurso eólico de la provincia del Neuquén

Se realizó el mapa de la distribución de vientos y de la potencia eólica disponible de la provincia del Neuquén para evaluar la energía eólica posible de extraer. El objetivo fue detectar los sitios más propicios para la ubicación de futuros parques eólicos. La provincia se caracteriza por tener varias líneas de transmisión de alta tensión facilitando una conexión al Sistema Interconectado Nacional/Provincial en caso de instalarse parques eólicos. En este trabajo se utilizó un sistema de información geográfica que tiene incluido un modelo atmosférico numérico, llamado ArgentinaMap. Se determinaron las características geofísicas (topografía y rugosidad superficial del suelo) de la provincia a través de sensores remotos (datos SRTM y MMRS). Se utilizaron datos de dirección e intensidad del viento en superficie y de altura de varios lugares. Con estos materiales se logró la evaluación del recurso eólico obteniendo los mapas del campo de viento y de densidad de potencia eólica a 50 m y 70 m de altura, que muestran que la provincia tiene un recurso eólico muy significativo.The maps of the wind field and wind power of the Neuquén province was carried out to evaluate the possible wind power of extract. The objective was to detect the most favorable places for the location of future wind farms. The province has several high-voltage transmission lines facilitating a connection with the National/Provincial System Interconnected in case of being installed wind farms. In this work a geographical information system was utilized that it has included a numerical atmospheric model (ArgentinaMap). The province geophysical characteristics (topography and aerodynamic roughness) were determined through remote sensors (SRTM and MMRS data). Surface wind and upper air data, of various places, were utilized. With these tools the evaluation of the wind power resource was achieved obtaining the maps of the wind field and wind power at 50 m and 70 m above ground level, that show that the province has a very good win power resource.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Evaluación del recurso eólico del departamento Confluencia de la provincia del Neuquén

Se realizó el mapa de potencial eólico del Departamento Confluencia de la provincia del Neuquén para evaluar la energía eléctrica posible de extraer. El objetivo fue detectar los sitios más propicios para la ubicación de futuros parques eólicos. La zona de estudio se caracteriza por tener varias líneas de transmisión de alta tensión facilitando una conexión al Sistema Interconectado Nacional/Provincial en caso de instalarse un parque eólico. Para este trabajo se contó con herramientas modernas de procesamiento de datos, como un SIG que tiene incluido un modelo atmosférico numérico, llamado WindMap. Se determinaron las características geofísicas de la zona a través de sensores remotos, como los datos topográficos provistos por la NASA y el análisis y procesamiento de imágenes satelitales SAC-C. Con estas herramientas se logró la evaluación del recurso eólico obteniendo los mapas del campo de viento y de potencia eólica disponible a 50 metros de altura.The wind energy map of the Confluence Department of the Neuquén province was carried out to evaluate the possible electric power of to extract. The objective was to determinate the most favourable places for the location of future wind farms. The study zone has several high-voltage transmission lines facilitating a connection with the National/Provincial System Interconnected in case of being installed wind farm. This work integrated modern tools of processing data, as a SIG that has included a numerical atmospheric model, WindMap. The geophysical characteristics of the zone were determined through remote sensors, as the topography data, provided by NASA, or the analysis and prosecution of SAC-C satellite images. With these tools the evaluation of the wind power resource was achieved obtaining the maps of the wind field and of available wind power at 50 meters.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES