DCIMIQ - CIMIQ - TP - Capítulos de Monografías

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Now showing 1 - 16 of 16
  • Publication
    Ti2AlC and Ti3SiC2 MAX phase foams: processing, porosity characterization and connection between processing parameters and porosity
    (European Powder Metallurgy Association (EPMA), 2016) Velasco Núñez, Beatriz; Hutsch, T.; Weißgärber, T.; Gordo Odériz, Elena; Tsipas, Sophia Alexandra; Comunidad de Madrid
    MAX phases Ti2AlC and Ti3SiC2 foams with controlled porosity and pore size were produced using the space holder method. The foams were processed using water-leachable crystalline carbohydrate as space holder that involves: mixing, cold isostatic pressing, dissolution and sintering. Three combinations of volume percentage (20%-60%) and size distribution (250-1000 mum) of space holder were introduced during mixing. The foams were characterized and compared with the material without space holder. The characterization included: morphology (overall, open and closed porosity by Archimedes method) and gas permeability. Foams with porosity up to about 60 vol% and pore size distribution ranging from about 250 to 1000 mum were produced. Experimental porosity was compared to the theoretical expected porosity. The results show a bimodal porosity that can be customized by the sintering and the space holder. This study connects the processing parameters to the porosity created and allows control of porosity and pore size to produce tailor-made properties.
  • Publication
    Design and evaluation Of PM Ti surfaces modified by colloidal techniques and diffusion processes for biomedical applications
    (European Powder Metallurgy Association (EPMA), 2016-10) Gordo Odériz, Elena; Ureña Alcázar, Julia María; Toptan, Faith; Pinto, A.M.; Ferrari, Begoña; Tsipas, Sophia Alexandra; Jiménez Morales, Antonia; Comunidad de Madrid; Ministerio de Economía y Competitividad (España)
    The aim of this work was the modification of the composition and surface microstructure of powder metallurgy titanium to improve the wear resistance and reduce the elastic modulus while maintaining the corrosion behavior, characteristics needed for biomedical applications. For this purpose, Mo and Nb coatings were produced by colloidal techniques. Stable aqueous suspensions were prepared from micro-sized powder of Mo and Nb particles, deposited onto the powder metallurgy titanium substrates (green or sintered). After a heat treatment to promote the diffusion and the consolidation of the layers, microstructural changes were obtained. In the case of green substrates, the co-sintering process provides a diffusion depth of 85-100 micron. In the as-sintered case, a uniform depth of 40-65 microns was reached. The surfaces were characterised by micro-hardness, corrosion and tribocorrosion testing, and the results showed that hardened surfaces presented lower tendency to corrosion both under static conditions and under sliding.
  • Publication
    Micromechanical properties of a Ti(C,N)-FeNiC composite: statistical method
    (Secretaría del Grupo Español de Fractura, 2017-03) Besharatloo, H.; Roa, Joan Josep; Dios Pérez, Miguel de; Mateo, A.; Ferrari, Begoña; Gordo Odériz, Elena; Llanes Pitarch, Luis Miguel
    Durante los últimos años, se han invertido muchos esfuerzos para diseñar nuevos materiales alternativos a los metales duros (WC-Co), que exhiban respuestas mecánica y tribológica similar a la de estos. El excelente comportamiento de los compuestos WC-Co se atribuye principalmente a su ensamblaje microestructural, debido a la combinación de dos fases con propiedades muy diferentes a nivel local. En el presente trabajo se pretende evaluar la relación microestructura/propiedades micromecánicas de nuevos materiales compuestos cerámico-metal del sistema T i(C,N)- Fe,Ni. Para ello se ha utilizado un procedimiento sistemático que consta de varias etapas.
  • Publication
    Micromechanics of Ti(C,N)-Feni composites: statistical analysis and flow stress determination for the Feni Binder
    (European Powder Metallurgy Association (EPMA), 2017-10-01) Besharatloo, H.; Roa, Joan Josep; Dios Pérez, Miguel de; Mateo, A.; Ferrari Fernández, Begoña; Gordo Odériz, Elena; Llanes Pitarch, Luis Miguel
    The outstanding mechanical and tribological properties exhibited by cemented carbides results from the combination of two phases with different local properties. However, direct assessment of the small-scale response of these materials is rather limited in open literature. This is particularly true, regarding experimental analysis on the influence of phase nature, crystal orientation and interfacial adhesion strength on hardness for composites, different from plain WC-Co systems. The present work aims to conduct a systematic micro- and nanomechanical study of the mechanical integrity of two Ti(C,N)-FeNi systems with different ceramic and binder content. It is attempted by combining massive nanoindentation and statistical analysis to extract the intrinsic hardness for each constitutive phase. After that, using the intrinsic hardness for the metallic FeNi binder and the Tabor's equation, the flow stress can be determined. Experimental results are found to validate the evidence of mechanical isotropic for the Ti(C,N) phase. Moreover, they permit to identify and account the strengthening of the plastic-constrained FeNi binder; a critical input parameter for hardness and toughness modeling.
  • Publication
    Ti(C,N)-Fe/Ni/FeNi core-shell structures for cermets processing
    (European Powder Metallurgy Association (EPMA), 2016-10) Dios Pérez, Miguel de; González, Zoilo; Romero, Carlos; Gordo Odériz, Elena; Ferrari, Begoña
    This work proposes an alternative bottom-up approach to build cermet microstructures through the synthesis of metal hydroxide nanoparticles (NPs) on the surface of Ti(C,N) micrometric particles, creating core-shell Ti(C,N)-Ni(OH)2 and Ti(C,N)-FeO(OH) and their subsequent calcination cycle. This calcination cycle will help us to obtain Ti(C,N)- based cermets with fine microstructure and low amount of metal binder avoiding mechanical milling, the risks of handling nanoparticles, as well as overcoming the lack of availability and the high prices of those metal nanoparticles. The obtained structures were characterized by differential thermal analysis (DTA), thermogravimetry (TG), X-Ray Diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) and energy-dispersive X-Ray spectroscopy (EDX).
  • Publication
    Nuevos avances en el diseño de nanomateriales para la consolidación del patrimonio pétreo: evaluación de su efectividad en la dolomía de Laspra
    (TechnoHeritage, 2015) Sierra Fernández, Aránzazu; Gómez Villalba, Luz Stella; Muñoz, L.; Rabanal Jiménez, María Eugenia; Fort, R.
    La piedra constituye el principal representante del patrimonio arquitectónico, estando la caliza yla dolomía entre los materiales más empleados a lo largo de la historia. El deterioro que sufren estosmateriales genera una importante pérdida de cohesión interna que hace necesaria la aplicación deproductos consolidantes. No obstante, en muchos de los casos estos productos son inadecuados yprovocan importantes procesos de deterioro, constituyendo uno de los principales factores de degradacióndel patrimonio. En este contexto, el desarrollo de los nanomateriales constituye una importante vía deactuación en la conservación del patrimonio cultural. La manipulación de los materiales a escalananométrica permite el menor trastorno posible a la obra original, mientras que de manera eficiente luchacontra los efectos del tiempo y el medio ambiente. Así, la aplicación de la nanotecnología a la ciencia dela conservación del patrimonio supone un importante avance que puede resolver muchos de los problemasencontrados en las intervenciones tradicionales de consolidación. Uno de los requisitos más importantespara el uso de estos productos en el patrimonio pétreo es la compatibilidad física y química con el sustratopétreo a tratar. Por esta razón, la presente investigación se basa en el diseño y el estudio de estabilidad deun nuevo producto consolidante, basado en nanopartículas de hidróxido de magnesio (brucita) con el finde consolidar y proteger los sustratos de carbonato de calcio-magnesio.
  • Publication
    Core-shell Ni-Ti(C,N) structures fabricated by precipitation of based-Ni nanoparticles on TiCN suspensions
    (European Powder Metallurgy Association (EPMA), 2015) Dios Pérez, Miguel de; González Granados, Zoilo; Gordo Odériz, Elena; Ferrari Fernández, Begoña
    Ti(C,N)-based cermets are currently used in high-speed cutting tools industry due to their high thermal stability. In previous works, Fe was proposed as metal matrix, however the use of iron as continuous matrix strongly affects the processing due to the low wetting capability of molten Fe with the reinforcement phase, Ti(C,N). To solve this problem the use of alloys such as FeNi has been proposed, where Ni improves the wettability between the ceramic and the metal phases. This work proposes a bottom-up approach to build the cermet microstructure through the synthesis of metal nanoparticles on the surface of Ti(C,N) micrometric particles, creating core-shell Ti(C,N)-Ni structures. For that purpose, synthesis parameters to obtain Ni nanoparticles were optimized and then, a one-pot synthesis procedure was tested to obtain core-shell Ti(C,N)-Ni particles by the chemical precipitation of Ni nanoparticles onto the surface of micronic Ti(C,N) particles previously stabilized in an aqueous suspension. Nickel nanoparticles and subsequent core-shell were characterized by measuring the particle size by Dynamic Light Scattering (DLS), X-Ray Diffraction (XRD), field emission scanning electron microscopy (FE-SEM).
  • Publication
    Interface study for the design of alternative matrixes in cermets
    (European Powder Metallurgy Association (EPMA), 2015) Alvaredo Olmos, Paula; Dios Pérez, Miguel de; Ferrari Fernández, Begoña; Gordo Odériz, Elena
    Liquid Phase Sintering (LPS) is used in the fabrication of hard materials and cermets which are difficult to densify by other approaches. During this process the melting point of the metal matrix is reached and the solid reinforcement is soluble in it. Thereby, via rearrangement and solucion-reprecipitation mechanism, these composite materials are sintered obtaining hihg density, hardness and wear resistance.For this sintering mechanism it is very important to know the solubility and wetting behaviour at high temperature of the metallic matrix and the reinforcement. In recent years one of the research topics in the field of hard materials is the search for new metallic matrixes so it becomes mandatory to study its interaction with the reinforcement from the viewpoint of solibility and wettability. This work shows a study combination of simulation tools and experimental testing of contacta angle mesurement at high temperature of the system Ni/TiCN because Ni is the conventional metallic matrix used in cermets and it is compared with the systems Fe/TiCN and Fe-15Ni/TiCN because the Fe is the main candidate for an alternative metallic matrix.
  • Publication
    Modificación superficial de titanio pulvimetalúrgico mediante recubrimientos aplicados por técnicas coloidales y difusión
    (AIMEN Centro Tecnológico, 2015-09) Ureña Alcázar, Julia María; Mendoza, Carlos; Ferrari, Begoña; Castro, Yolanda; Tsipas, Sophia Alexandra; Morales, Alfredo José; Gordo Odériz, Elena
    El titanio y sus aleaciones son materiales conocidos por su atractiva combinación de propiedades. A pesar de ser los metales preferidos para aplicaciones biomédicas tales como prótesis o implantes para sustitución de tejido óseo, aún presentan aspectos mejorables para estas aplicaciones, como la baja resistencia al desgaste o el elevado módulo elástico. Otras potenciales aplicaciones como en automoción también requieren la mejora de la resistencia al desgaste de estas aleaciones. En este trabajo se aborda la modificación superficial de las aleaciones de titanio para mejorar estos aspectos, manteniendo la resistencia a corrosión y la biocompatibilidad. Los sustratos se han producido mediante prensado uniaxial y sinterización en vacío de polvos de titanio. Como materiales de recubrimiento se han seleccionado TiN, por sus conocidas propiedades frente al desgaste, y Mo, por ser un elemento de aleación betágeno del titanio, que reduce el módulo de elasticidad mediante la formación de fase beta, al tiempo que mejora la resistencia al desgaste. Tanto el TiN como el Mo son biocompatibles. Se han utilizado nanopartículas de TiN y partículas micrométricas de Mo para crear suspensiones acuosas estables que posteriormente se depositan sobre la superficie de los sustratos (en verde o sinterizados) bien mediante deposición electroforética (EPD) o bien mediante pulverización. Las estructuras superficiales finales se forman durante un tratamiento térmico posterior a la deposición de las partículas sobre los sustratos, gracias a la activación de fenómenos de difusión. Las superficies se han caracterizado mediante medida de dureza, difracción de rayos X (DRX) y microestructura mediante microscopía electrónica de barrido.
  • Publication
    Estudio de la intercara en materiales compuestos tipo cermet para el diseño de matrices metálicas alternativas
    (Asociacion Española de Materiales Compuestos, 2015-07) Alvaredo Olmos, Paula; Macía Rodríguez, Eric; Gordo Odériz, Elena
    Uno de los grandes temas de investigación actual en el campo de los materiales compuestos tipo cermet base TiCN es la búsqueda de matrices metálicas alternativas a las convencionales las cuales cuentan en su composición Ni y/o Co de manera mayoritaria. El objetivo principal que debe cumplir el cermet con una matriz metálica alternativa es alcanzar propiedades similares e incluso superiores a las obtenidas con matrices convencionales utilizando materiales más económicos e inocuos. Además, siendo un material compuesto, a la hora de diseñar la composición de una nueva matriz metálica se debe tener en cuenta cómo es su interacción con el refuerzo cerámico. Este concepto cobra una mayor importancia en este tipo de materiales debido a que su fabricación se lleva a cabo mediante sinterización en fase líquida y las propiedades finales del material compuesto dependerán de la mojabilidad y solubilidad entre ambas fases. Algunas investigaciones sobre cermets reforzados con partículas de TiCN y matriz convencional han concluido que carburos como WC ó Mo2C tienen una gran influencia en la sinterabilidad de estos materiales compuestos porque mejoran la mojabilidad de la matriz metálica sobre el refuerzo cerámico. El objetivo principal de este trabajo es el estudio sistemático de la influencia de estos carburos en la sinterabilidad de un cermet base TiCN con Fe como matriz metálica. Para ello se ha estudiado la solubilidad entre ambas fases estudiando su intercara tanto de forma experimental como mediante herramientas de simulación termodinámica y cinética utilizando el software Dictra. Gracias a los resultados obtenidos se crea una metodología de trabajo que permite conocer la influencia de la composición en la solubilidad entre las dos fases siendo una herramienta útil en el diseño de nuevas matrices metálicas alternativas en cermets.
  • Publication
    Estudio de fatiga térmica de cermets base hierro
    (Asociacion Española de Materiales Compuestos, 2015-07) Alonso, M.; Jiménez Suárez, Alberto; Alvaredo Olmos, Paula; Gordo Odériz, Elena; Comunidad de Madrid; Ministerio de Economía y Competitividad (España)
    En el presente trabajo se analiza el comportamiento a fatiga térmica de materiales compuestos de matriz férrea y refuerzo de TiCN desde dos puntos de vista: la influencia de la temperatura máxima alcanzada durante la fatiga térmica y la influencia del número de ciclos de calentamiento y enfriamiento. Además, se compara el comportamiento de estos materiales con el de un acero de herramientas de uso convencional. Este estudio del comportamiento frente a cambios cíclicos de temperatura para ambos materiales se realiza en base a su resistencia a la oxidación y se compara con la oxidación estática que se produce a temperatura elevada constante. Para ello las probetas se han sometido a diferentes ciclos de fatiga térmica, alcanzando temperaturas máximas de 1000 ºC durante un máximo de 100 ciclos; posteriormente se ha caracterizado tanto su superficie como su sección transversal utilizando diferentes técnicas: medida de cambio de masa, DRX, SEM, EDX y microdureza.
  • Publication
    Aplicación de las técnicas coloidales al procesamiento de cermets Acero/Ti(C,N) en agua
    (Asociacion Española de Materiales Compuestos, 2015-07) Escribano Quintana, Juan Antonio; Gordo Odériz, Elena; Sánchez Herencia, Antonio Javier; Ferrari, Begoña
    Las técnicas de procesamiento coloidal han demostrado en numerosas ocasiones su efectividad para la obtención materiales compuestos con elevado grado de homogeneidad estructural y reproducibilidad a bajo coste. A pesar de sus grandes virtudes, estas técnicas de procesamiento han recibido escasa atención en el procesamiento de materiales metálicos, debido principalmente a la tendencia a la oxidación de los metales en agua y a su elevada densidad, lo que dificulta la preparación de suspensiones estables. Sin embargo, en trabajos anteriores se ha reportado la obtención de materiales compuestos con matrices basadas en Fe reforzados con Ti(C,N), que presentaban características superiores a las de materiales de similar composición obtenidos mediante pulvimetalurgia convencional. Estos cermet de acero/Ti(C,N) son materiales que presentan bajas densidades y excelentes propiedades mecánicas, lo que les hace idóneos para su utilización como herramientas de corte a altas temperaturas
  • Publication
    Optimization of Ti suspensions for the reinforcement of Ti scaffolds via direct foaming of a polycarbosilane
    (Asociacion Española de Materiales Compuestos, 2015-07) Molero Romero, Esther; Sánchez Herencia, Antonio Javier; Ferrari, Begoña; Gordo Odériz, Elena; Colombo, Paolo
    In bio-applications, the mechanical properties of macroporous structures are of great relevance as they are subjected to significant structural stresses and satisfy specific surface requirements such as high wear resistance, which prevents wear debris proliferation. The MAX phases, as Ti3SiC2, draw a great interest because of their combination of interesting structural properties such as low density and high elastic modulus. This compound also has a crystalline structure resembling that of lamellar graphite, which makes it interesting as material for wear resistance and high toughness applications. The objective of the proposed research work is the optimization of Ti micro-powder suspensions in order to use them as filler that could react with the siliconrich residue of a polymer as a polycarbosilane, leading to a well dispersed secondary phase Ti3SiC2 in a Ti matrix after a thermal treatment in an inert/controlled atmosphere. This route has been followed for the manufacture of macro-cellular porous SiC foams by direct foaming of polycarbosilane, but in our case the no-oxide ceramic phase will appear dispersed in a Ti porous structure
  • Publication
    Comparison of Microstructure and Properties of Ti-6Al-7Nb Alloy Processed by Different Powder Metallurgy Routes
    (Trans Tech Publications, 2013) Bolzoni, Leandro; Hari Babu, N.; Ruiz Navas, Elisa María; Gordo Odériz, Elena
    The Ti-6Al-7Nb alloy was specially developed to replace the well-known Ti-6Al-4V alloy in biomedical applications due to supposed cytotoxicity of vanadium in the human body. This alloy is normally fabricated by conventional ingot metallurgy by forging bulk material. Nevertheless, powder metallurgy techniques could be used to obtain this alloy with specific properties. This is because by changing the processing parameters, such as the sintering temperature, it is possible to vary the porosity level and to tailor the final properties. This work deals with the production of the Ti-6Al-7Nb alloy by means of the master alloy addition variant of the blending elemental approach. The powder is processed by means of different powder metallurgy routes considering diverse processing conditions for each method. The materials are characterised in terms of microstructural features, relative density and hardness. Homogeneous microstructures as well as properties comparable to those of the wrought alloy are generally obtained.
  • Publication
    From Sintered Iron to High Performance PM Steels
    (Trans Tech Publications, 2011) Torralba Castelló, José Manuel; Oro, Raquel; Campos Gómez, Mónica
    Since low alloyed sintered steels were introduced in the market of the structural parts, we have followed the evolution of a material with poor mechanical properties and any uniformity (in the sense of reproducibility) to materials that today are produced with high reliability and performance. The working efficiency could be equivalent in many cases with the best wrought steel, and maintaining a good margin in terms of cost and competitively. In this paper a complete review of the topic is accomplished, from the early times when the first parts were made by plain iron or iron-carbon, going through the different alloying systems: Fe-Cu, Fe-P, Fe-Cu-Ni-Mo, and more recently Fe-Cr-Mo and Fe-Mn. The development in processing routes has been considered too. The main milestones in the field of new alloying systems have been: 1) the introduction of Cu in 60- 70‟s, 2) the new complex systems with Cu-Ni-Mo in the 80‟s and 3) the introduction of alloying elements with high oxygen affinity (in the late 90‟s). Regarding the milestones in processing could be considered: 1) the development of new mixing procedures, 2) the warm compaction and high velocity compaction, 3) the improvements in sintering control and high temperature sintering. Several decades of research and innovation, acting on the processing system (mixing, pressing, sintering, post-sintering operations,...) and on the alloying system (from the earliest times with plain iron to complex systems used today), has allowed us to have a highly competitive materials, in terms of performance, and processes in terms of cost. The future is still open to new developments.
  • Publication
    Modification of Sintered Titanium alloys by Hot Isostatic Pressing
    (Trans Tech Publications, 2012) Bolzoni, Leandro; Ruiz Navas, Elisa María; Zhang, D.; Gordo Odériz, Elena
    Powder metallurgy (PM) permits to obtain titanium alloys with properties and microstructures close to ingot metallurgy products. However, residual porosity is normally present in the products produced by the PM route of powder pressing and sintering (P&S)\, and this needs to be reduced by using post-sintering process step such as hot isostatic pressing (HIP) and forging. In this study, the microstructural and mechanical property changes caused by HIP of samples of two alloys, near-alfa Ti-3Al-2.5V alloy and alfa+beta Ti-6Al-4V, produced by P&S route were investigated. Two types of powders were utilised: prealloyed powders and blend of elemental titanium powder and master alloy powder. Four conditions defined by HIP temperature, pressure and time were used to HIP the sintered samples with two geometries. The results show that, independent of the HIP conditions used, HIP increased the relative density of the samples to approximately 97.5% and their hardness by 30-50 HV depending on the HIP condition. However, HIP at 1000ºC changes the fracture mode of the sintered samples from ductile to brittle.