Creep strength in polycrystalline Ni-based superalloys is influenced by the formation of a rich v... more Creep strength in polycrystalline Ni-based superalloys is influenced by the formation of a rich variety of planar faults forming within the strengthening $$\gamma '$$ γ ′ phase. The lengthening and thickening rate of these faults – and therefore the creep rate – depends on an intriguing combination of dislocation interactions at the $$\gamma $$ γ -$$\gamma '$$ γ ′ interface and diffusional processes of the alloying elements at the core of the fault tip. The effect of alloy composition on this process is not fully understood. In this work we use correlative high resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy to study the deformation faults in two different Ni-based superalloys with carefully designed ratios of disordering-to-ordering-promoting elements (Co-Cr against Nb-Ta-Ti). The results show that the additions of ordering-promoting elements reduce the diffusional processes required for the faults to lengthen and thicken thus reducing t...
Proceedings of the YIC 2021 - VI ECCOMAS Young Investigators Conference
3D printed metamaterials are a human-designed class of material capable of providing uncommon pro... more 3D printed metamaterials are a human-designed class of material capable of providing uncommon properties unseen in nature. However the freedom power of design provided by additive manufacturing in metamaterials is useless if reliable and efficient modelling design tools are not available. The objective of this work is to evaluate, validate and study the different options for finite element simulation of bio-inspired metamaterials to provide the best solutions in terms of material properties accuracy and computational efficiency. Based on this study we have developed a new hybrid material agnostic modelling method to compute the mechanical response of beam based bioinspired metamaterials with similar precision of 3D explicit meshed models. Different variables in the latticed models were investigated, these included different element sizes and element types (volumetric and beam elements). The effects of these variables on the elastic modulus and yield strength of a lattice structure w...
Aerospace components in jet engines need to outstand extreme conditions of high-temperatures and ... more Aerospace components in jet engines need to outstand extreme conditions of high-temperatures and loads. Moreover, these components can sometimes undergo dynamic conditions if impact occurs during the flight. It is critical to understand the behaviour of aerospace alloys under these combined extreme conditions of high-temperature and dynamics loads. One of the most extended alloys used in the compressor and fan stages of commercial jet engines is Ti-6Al4V. The dynamic properties of Ti-6Al-4V are strongly dependent on the microstructure state and the temperature conditions. However, these dependencies are yet not fully understood. Moreover, this alloy can present a wide variety of microstructures depending on the component and manufacturing methods. In this work, we compare the response of five typical Ti-6Al-4V microstructures tested under static and dynamic conditions and different temperatures. The macroscopic response of the alloy is rationalised on the basis of its microstructura...
Semi-crystalline polymers often present a complex non-linear behaviour that combines thermo-visco... more Semi-crystalline polymers often present a complex non-linear behaviour that combines thermo-viscoelastic and thermo-viscoplastic contributions associated to different deformation mechanisms. During the initial deformation stages, the process is influenced by the rupture and reorientation of crystalline phases while, during the final deformation stages, the process is mainly governed by the mobility and orientation of the amorphous molecular chains. Moreover, the level of reorientation of crystalline and amorphous phases is strongly affected by variables such as temperature and strain rate. This work focusses on the role of such mechanisms in the mechanical behaviour of poly-ether-ether-ketone (PEEK) within its different thermal-behaviour regions: initial glassy region, glass transition and final rubbery region. To this end, samples of PEEK are subjected to large deformations under uniaxial tension at temperatures from 20 to 240 $^\circ$C, and strain rates from 0.0001 to 0.1 s$^{-1}$...
In text mining we often have to handle large document collections. The labeling of such large cor... more In text mining we often have to handle large document collections. The labeling of such large corpuses of documents is too expensive and impractical. Thus, there is a need to develop (unsupervised) clustering techniques for text data, where the distributions of words can ...
The control of materials at the microstructural level is critical for the aerospace sector: the p... more The control of materials at the microstructural level is critical for the aerospace sector: the properties of their components are governed by microstructural features usually design with great precision. This is especially the case for Ni-based superalloy, a class of materials used in high-temperature aerospace components. In this work we present an image analysis framework based on open-source software to quantify precisely and efficiently the different microstructural properties of a set of commercial Nibased superalloys (Inconel-718, HasteloyX, Rene77 and Inconel-738). The framework is then used to investigate the failure cause of an aerospace component: an auxiliary power unit.
Most existing implants are inherently limited by the mismatch between the performance of metals a... more Most existing implants are inherently limited by the mismatch between the performance of metals and biological bone tissues. Moreover, most common biomedical alloys raise toxicological concerns. In this paper, alloy design is used to find optimal metallic titanium compositions which are bio-compatible and which offer inherent lower modulus of elasticity for optimal bone compliance. The alloys were also optimised for additive manufacturing: alloys with low cracking susceptibility and tendency to form fine microstructures were isolated. An optimal alloy composition was then produced and manufactured by 3D printing. Mechanical experiments on manufactured material under tension reveal the stiffness and strength of the alloy. This work confirms the suitability of the titanium alloy to lower the stiffness of traditional biomedical alloys while being additively manufacturable and strong.
La localización de activos en el interior de edificios es un problema con aplicaciones en diferen... more La localización de activos en el interior de edificios es un problema con aplicaciones en diferentes campos y actividades, como la sanidad, prevención de riesgos laborales o diferentes actividades comerciales. En estos lugares, donde la localización mediante GPS no está disponible, es necesario ofrecer una nueva solución que permita resolver el problema ofreciendo una precisión adecuada y manteniendo la viabilidad económica del proyecto. En este paper presentamos Xtremeloc, un sistema de posicionamiento indoor basado en tecnología Bluetooth de Baja Energía. Además, compararemos nuestra propuesta con las diferentes alternativas disponibles, describiendo sus ventajas e inconvenientes.
Creep strength in polycrystalline Ni-based superalloys is influenced by the formation of a rich v... more Creep strength in polycrystalline Ni-based superalloys is influenced by the formation of a rich variety of planar faults forming within the strengthening $$\gamma '$$ γ ′ phase. The lengthening and thickening rate of these faults – and therefore the creep rate – depends on an intriguing combination of dislocation interactions at the $$\gamma $$ γ -$$\gamma '$$ γ ′ interface and diffusional processes of the alloying elements at the core of the fault tip. The effect of alloy composition on this process is not fully understood. In this work we use correlative high resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy to study the deformation faults in two different Ni-based superalloys with carefully designed ratios of disordering-to-ordering-promoting elements (Co-Cr against Nb-Ta-Ti). The results show that the additions of ordering-promoting elements reduce the diffusional processes required for the faults to lengthen and thicken thus reducing t...
Proceedings of the YIC 2021 - VI ECCOMAS Young Investigators Conference
3D printed metamaterials are a human-designed class of material capable of providing uncommon pro... more 3D printed metamaterials are a human-designed class of material capable of providing uncommon properties unseen in nature. However the freedom power of design provided by additive manufacturing in metamaterials is useless if reliable and efficient modelling design tools are not available. The objective of this work is to evaluate, validate and study the different options for finite element simulation of bio-inspired metamaterials to provide the best solutions in terms of material properties accuracy and computational efficiency. Based on this study we have developed a new hybrid material agnostic modelling method to compute the mechanical response of beam based bioinspired metamaterials with similar precision of 3D explicit meshed models. Different variables in the latticed models were investigated, these included different element sizes and element types (volumetric and beam elements). The effects of these variables on the elastic modulus and yield strength of a lattice structure w...
Aerospace components in jet engines need to outstand extreme conditions of high-temperatures and ... more Aerospace components in jet engines need to outstand extreme conditions of high-temperatures and loads. Moreover, these components can sometimes undergo dynamic conditions if impact occurs during the flight. It is critical to understand the behaviour of aerospace alloys under these combined extreme conditions of high-temperature and dynamics loads. One of the most extended alloys used in the compressor and fan stages of commercial jet engines is Ti-6Al4V. The dynamic properties of Ti-6Al-4V are strongly dependent on the microstructure state and the temperature conditions. However, these dependencies are yet not fully understood. Moreover, this alloy can present a wide variety of microstructures depending on the component and manufacturing methods. In this work, we compare the response of five typical Ti-6Al-4V microstructures tested under static and dynamic conditions and different temperatures. The macroscopic response of the alloy is rationalised on the basis of its microstructura...
Semi-crystalline polymers often present a complex non-linear behaviour that combines thermo-visco... more Semi-crystalline polymers often present a complex non-linear behaviour that combines thermo-viscoelastic and thermo-viscoplastic contributions associated to different deformation mechanisms. During the initial deformation stages, the process is influenced by the rupture and reorientation of crystalline phases while, during the final deformation stages, the process is mainly governed by the mobility and orientation of the amorphous molecular chains. Moreover, the level of reorientation of crystalline and amorphous phases is strongly affected by variables such as temperature and strain rate. This work focusses on the role of such mechanisms in the mechanical behaviour of poly-ether-ether-ketone (PEEK) within its different thermal-behaviour regions: initial glassy region, glass transition and final rubbery region. To this end, samples of PEEK are subjected to large deformations under uniaxial tension at temperatures from 20 to 240 $^\circ$C, and strain rates from 0.0001 to 0.1 s$^{-1}$...
In text mining we often have to handle large document collections. The labeling of such large cor... more In text mining we often have to handle large document collections. The labeling of such large corpuses of documents is too expensive and impractical. Thus, there is a need to develop (unsupervised) clustering techniques for text data, where the distributions of words can ...
The control of materials at the microstructural level is critical for the aerospace sector: the p... more The control of materials at the microstructural level is critical for the aerospace sector: the properties of their components are governed by microstructural features usually design with great precision. This is especially the case for Ni-based superalloy, a class of materials used in high-temperature aerospace components. In this work we present an image analysis framework based on open-source software to quantify precisely and efficiently the different microstructural properties of a set of commercial Nibased superalloys (Inconel-718, HasteloyX, Rene77 and Inconel-738). The framework is then used to investigate the failure cause of an aerospace component: an auxiliary power unit.
Most existing implants are inherently limited by the mismatch between the performance of metals a... more Most existing implants are inherently limited by the mismatch between the performance of metals and biological bone tissues. Moreover, most common biomedical alloys raise toxicological concerns. In this paper, alloy design is used to find optimal metallic titanium compositions which are bio-compatible and which offer inherent lower modulus of elasticity for optimal bone compliance. The alloys were also optimised for additive manufacturing: alloys with low cracking susceptibility and tendency to form fine microstructures were isolated. An optimal alloy composition was then produced and manufactured by 3D printing. Mechanical experiments on manufactured material under tension reveal the stiffness and strength of the alloy. This work confirms the suitability of the titanium alloy to lower the stiffness of traditional biomedical alloys while being additively manufacturable and strong.
La localización de activos en el interior de edificios es un problema con aplicaciones en diferen... more La localización de activos en el interior de edificios es un problema con aplicaciones en diferentes campos y actividades, como la sanidad, prevención de riesgos laborales o diferentes actividades comerciales. En estos lugares, donde la localización mediante GPS no está disponible, es necesario ofrecer una nueva solución que permita resolver el problema ofreciendo una precisión adecuada y manteniendo la viabilidad económica del proyecto. En este paper presentamos Xtremeloc, un sistema de posicionamiento indoor basado en tecnología Bluetooth de Baja Energía. Además, compararemos nuestra propuesta con las diferentes alternativas disponibles, describiendo sus ventajas e inconvenientes.
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