articles+ search results

Volta catalana, Bóveda tabicada, Thin-tile vault, Fulles de rajola, Hojas de rasilla, Thin-tile masonry, Comportament tensió-deformació, Comportamiento tensión-deformación, Stress-strain behaviour, Mode de falla, Modo de falla, Failure mode, Propietats mecàniques, Propiedades mecánicas, Mechanical properties, Imatges digitals, Imágenes digitales, and Digital images

The thin-tile vault is a structural system widely used in the Mediterranean area. The most spectacular development took place through modernist-style buildings designed by architects such as Antonio Gaudí o Luís Domènech and Muntaner among the others. Thin-tile vault, from a morphological standpoint, is made up of one or more leaf of thin-tile lay flat, and joined with plaster or mortar. As a particularity of this arrangement, the load is applied parallel to the face of the thin-tile as opposed to the load-bearing walls masonry, where the load is applied perpendicularly to it. Deepening the knowledge of this type of masonry is the main objective of this thesis. In masonry, normally the compressive strength of the constituent materials is used to analytically establish the compressive strength of the masonry. This thesis, and based on the experimental results on one-, two- , and three-leaf thin-tile specimens, analyse stress-strain law, failure modes, and mechanical properties and compared with those corresponding to different masonries presented in the literature

Poly(lactic acid), Chitin nanocrystals, Cellulose nanocrystals, Crystallization, Nanocomposites, Mechanical properties, and Àrees temàtiques de la UPC::Enginyeria dels materials

Plastic based materials are widely used for packaging applications. However, disposal of such petroleum-based materials e.g. polyethylene (PE) and polypropylene (PP) has become a huge threat to the environment due to its non-biodegradable behavior and complexity for waste management. For a sustainable industrial and economic development, it is indeed an urgency to develop packaging materials, which are environmentally benign, easy for waste treatment and recycling, and less/non-toxic. However, developing suitable and efficient plastic-substituents needs multiple requirements to be fulfilled viz., logistics and cost-effectiveness, good mechanical, thermal, optical and barrier properties, structural integrity of the constituents and morphological properties of the films. In this regard, utilizing bio-based polymers such as poly(lactic acid) (PLA), which originates from the natural resources, can be a viable and practical option due to its low toxicity, biodegradability, and eco-friendly behavior. Moreover, PLA has good optical and mechanical properties, which are similar or comparable to the some of the petroleum-based materials. However, pristine PLA possess few challenges such as slow crystallization rate, low crystallinity, poor toughness, and poor barrier properties, which need to be modified and fine-tuned. Utilizing nano-reinforcements, such as nanocellulose and nanochitin, is a promising approach for modifying PLA because of raw materials abundancy; easily obtainable from forest-based and bio-waste, hence, utilizing such materials also help the sustainable bioeconomy. Chitin nanocrystals (ChNCs) and cellulose nanocrystals (CNCs) possess unique properties, such as, low density, biodegradability, low toxicity, good mechanical, and barrier properties; therefore, can act as suitable nano-reinforcements for PLA. First segment of the research was aimed to understand and gain an insight about the role of ChNCs on the crystallization behavior of PLA and optimize the isothermal crystallization conditions. ChNCs, due to large surface area, acted as better nucleating agent and improved the overall crystallization rate of PLA by reducing the crystallization time and size of the spherulites. In second part of the research, knowledge gained about crystallization behavior was further explored to produce isothermally crystallized films at larger scale. The effect of crystallinity on the thermal, optical, barrier, and hydrolytic degradation properties of the nanocomposites were investigated. Noticeably, at 110ºC, the highest rate of crystallization achieved within 5 min. Furthermore, homogenous crystallization and smaller spherulite size (7 nm) of PLA achieved with ChNCs, significantly improved the crystallinity, thermal, barrier, and hydrolytic degradation properties. Third part of the research involved the study of mechanical properties of oriented films (PLA/ChNCs) achieved by a combination of solid-state and melt-state drawings. These oriented PLA nanocomposites films exhibited excellent mechanical properties. For example, a tensile strength with 360%, elongation at break with 2400%, and the toughness with 9500% increment achieved as compared to un-oriented nanocomposite films. The degree of crystallinity of highly oriented nanocomposite films increased from 8% to 53% with respect to the un-oriented nanocomposite films and smaller crystallites sizes were observed. Finally, in the fourth part, mechanical properties of the surface modified PLA/CNCs nanocomposites were investigated by a conventional tensile test and compared with the small punch test. Surface modification of CNC facilitated the dispersion of CNC into PLA matrix and increased the elastic modulus of the PLA/CNC nanocomposites. Knowledge and results gained in this thesis demonstrate the potential path for the development of the PLA nanocomposites with higher properties for packaging applications.

Nanopartícules, Nanopartículas, Nanoparticles, Materials magnètics, Materiales magnéticos, Magnetic materials, Síntesi orgànica, Síntesis orgánica, Organic synthesis, Propietats mecàniques, Propiedades mecánicas, Mechanical properties, Propietats magnètiques, Propiedades magnèticas, Magnetic properties, and Ciències Experimentals i Matemàtiques

This doctoral Thesis has been focused on the preparation of magnetic materials by different methods, the characterization of their structural characteristics, and the understanding of their mechanical and magnetic properties. Furthermore, a big effort has been paid to investigate the frequency-dependent functional properties of different materials, which are increasingly demanded in novel technological applications. Moreover, this work presents this characterization in a wide range of frequencies, from the kHz to the THz. In the first chapter, the reader will find an introduction to the topic and the state of the art of those materials that have been synthesized and developed in this Thesis. Then, the general goals of our research are described. Chapter II provides all the needed fundamental theory to accomplish with the previously stated goals. The concepts exposed here will be used later in the following chapters where the results will be shown and discussed. Moreover, this chapter does not only pretend to give the essential notions used in the following chapter, but we also aim to provide a useful guide to anyone who starts working on this field. All the materials, devices, software, and experimental conditions used in this Thesis are described in Chapter III. Here, we describe these aspects in detail in order to allow an agile discussion in the following chapters. The first experimental chapter is Chapter IV, where the synthesis of copper ferrite nanoparticles by mean of sol-gel and co-precipitation is described. The sol-gel process is optimized through of design of experiments (DoE) approach. The results of the mechanical and magnetic characterization of solid pellets fabricated with the previously synthesized nanoparticles are also shown in this chapter. Finally, by using statistical methods a direct experimental correlation between the mechanical and magnetic properties is found in this material. Another material, a carbon nanotube–based nanocomposite, is studied in Chapter V. This novel material is first structurally characterized in order to understand its magnetic properties. A big effort is paid on the study of the magnetic relaxation of this material, which has not been previously reported as far as we know. The investigation of soft magnetic materials (SMM) and composites (SMC) can be found in Chapter VI. The actual SMCs are first structurally and magnetically characterized. Their magnetic properties in the kHz and MHz frequency range are also investigated, showing the better performance of the SMC at high frequencies. In the second part of the chapter, the development on new SMC’s formulations is described. The developed materials are potentially useful for applications in the kHz and MHz frequency range. The frequency is raised in Chapter VII. Terahertz time-domain spectroscopy (THz-TDS) is used to investigate the optical and dielectric properties of two different semiconductor oxides from 180 GHz to 3 THz. The signal processing and the interpretation of the effect that different characteristics of the sample may have on the observed properties are discussed. In this chapter, magnetic materials are not investigated because the Fresnel model – which is the base of this technique - assumes a non-magnetic response of the material. The work described in Chapter VIII is completely different from the previous ones. In this case, we investigate the manipulation of the magnetic moments by using surface acoustic waves (SAWs). The experiments done in this chapter lead to interesting observation about the potentiality of the use of SAWs to accelerate the magnetic moment reversal in magnetic nanoparticles.

Microelectrònica, Microelectrónica, Microelectronics, Circuits impresos, Circuitos impresos, Printed circuits, Impressores (Ordinadors), Impresoras (Ordenadores), Computer printers, Mesuraments elèctrics, Medidas eléctricas, Electric measurements, Propietats mecàniques, Propiedades mecánicas, Mechanical properties, and Ciències Experimentals i Matemàtiques

The main goal of this doctoral thesis is the development and optimization of inkjet- based technologies for hybrid electronic circuits manufacturing, as well contribute on the development of the incoming low cost electronics. Regarding that, a novel solution for connecting regular SMDs and standard silicon SMD packages by inkjet printing is proposed. The novel connecting method allows the assembling at very low temperatures, and thus assures the compatibility with the incoming substrates. Electrical contact resistance and shear strength measurements performed by silver nanoparticle- based ink are comparable to benchmark connecting materials. In sum up, flexible hybrid circuit is successfully manufactured by silver nanoparticle-based ink on paper, where different SMDs size-shaped are assembled demonstrating the reliability and feasibility of the proposed method. Another objective of the work is to apply and adapt the print-on-slope technique to assemble directly the silicon dies on PCB, proposing a novel strategy to overcome the drawbacks of the wire bonding in the Conductive AFM measurements. Then, a novel setup for conductive AFM mode 2D materials characterization was manufactured. The 2D connection on ramp-shape terminations gives a better functionality than current wire bonding connections. The AFM tip moves over the silicon die without physical obstruction, giving a unique solution at this novel method to characterize the material degradation. In the field of multilayer hybrid PCB manufacturing, the goal is to prove the potentiality of different metal-insulator-metal structures inkjet-printed and evaluate their reliability and the electrical performance for low cost multilayer circuit based on paper substrate. In the light of the results, heterogeneous structures combining inorganic and organic dielectric material, where PVP fills the inorganic cracks and voids, possess a similar and outstanding feasibility in both paper and glass substrate without short-circuits. The greatest achievement of this work is the development and optimization of a novel capillarity-assisted SMD assembling method for the manufacturing of hybrid circuits inkjet-printed. In addition, taking advantage of print-on-slope technique, direct assembling of silicon die integrated circuits to PCB is successfully applied. Moreover, heterogeneous structures inkjet-printed open new solutions for multilayer hybrid circuits.

Composite materials, Materials compòsits, Materiales compuestos, Materials testing, Assaig de materials, Ensayo de materiales, Mechanical properties, Propietats mecàniques, Propiedades mecánicas, Structural engineering, Enginyeria estructural, and Ingeniería estructural

Adhesives have been shown to be an excellent solution for joining fibre reinforced polymer (FRP) components thanks to their capacity to redistribute loads, reduces stress concentrations and contribute to overall weight saving in the structure. The most relevant mechanical property in adhesive bonded joints design is the shear (mode II) fracture toughness of the adhesive. The application of the existing mode II delamination standards to adhesive joints entails some major limitations that result in severe under/over estimations of the adhesive properties and, in many cases, can even prevent results from being obtained from tests. The main objective of the present thesis is to develop robust tools for the determination of shear (mode II) facture toughness in adhesive joints. This includes studying data reduction methods as well as the test geometries

Flexoelectricitat, Flexoelectricidad, Flexoelectricity, Propietats-mecàniques, Propiedades mecánicas, Mechanical properties, Ferroelèctrica, Ferroelectricos, Ferroelectrics, and Ciències Experimentals

Los materiales ferroeléctricos pueden tener diferentes respuestas electromecánicas, por ejemplo la piezoelectricidad, polarización inducida cuando hay deformación homogénea, y la flexoelectricidad, polarización inducida cuando hay deformación inhomogénea. Dado que la flexoelectricidad está relacionada con los gradientes de deformación, a la nanoescala su efecto es tan o más grande que la piezoelectricidad. La investigación desarrollada en ésta tesis se enfoca en estudiar la interacción entre estas dos propiedades cuando compiten y/o cuando colaboran entre ellas, y de cómo ésta interacción afecta las propiedades mecánicas de los ferroeléctricos. Hasta ahora se ha creído que las propiedades mecánicas son invariantes con respecto a al espacio de inversión, es decir que medirlas en una cara o en la opuesta no debería cambiar su valor. Sin embargo, ésta tesis demuestra que, en presencia de gradientes de deformación, ésta simetría se rompe, ya que tanto las propiedades mecánicas como la respuesta mecánica de los ferroeléctricos depende del signo de su polarización. Éste resultado representa un cambio en la teoría establecida hasta ahora y ofrece un nuevo camino para explorar en la física de fractura de sólidos. Esta tesis está distribuida de la siguiente manera: El capítulo 1 es una introducción a la física de las propiedades mecánicas, la piezoelectricidad y la flexoelectricidad, mientras que el capítulo 2 describe las técnicas experimentales utilizadas para realizar las medidas de las propiedades mecánicas y las respuestas mecánicas requeridas para el proyecto. En el capítulo 3, se midió y analizó las propiedades mecánicas de cristales ferroeléctricos de LiNbO3 con la polarización perpendicular a la superficie y en direcciones opuesta, empleando la técnica de nanoindentación. La inversión de la polarización fue realizada de dos maneras distintas (1) manualmente, es decir, girando el cristal 180º para acceder a la cara opuesta del mismo, y (2) utilizando un cristal periódicamente polarizado, de ésta manera se tuvo acceso a polarizaciones opuestas desde una misma cara. Se observó que, independientemente del método de inversión, todas las propiedades mecánicas son asimétricas con respecto al espacio de inversión. En el capítulo 4, a partir de la ecuación libre de los ferroeléctricos, se desarrolló un modelo para determinar el coeficiente de flexoacoplamiento empleando únicamente las propiedades mecánicas del material. A partir de éste modelo y los datos obtenidos en el capítulo 3, se obtuvo que el valor de dicho coeficiente para LiNbO3 ~ 40 V, un valor más realista que el medido por el método estándar e incluso más cercano al predicho por Kogan y Tagantsev. En el capítulo 5, el objetivo era estudiar el efecto de la flexoelectricidad en la propagación de grietas y la tenacidad de factura en cristales ferroeléctricos de RKTP con la polarización alineada en el plano. Se realizaron grietas paralelas, antiparalelas y perpendiculares a la polarización y Se demostró que la propagación de la grietas esta intrínsecamente relacionado con la dirección de polarización en la que se propaga, ya que la flexoelectricidad disminuye la tenacidad de fractura cuando es paralela a la polarización ferroeléctrica, y por ende las grietas son mas largas. En el capítulo 6, se plantea una posible aplicación como consecuencia de la asimetría en las propiedades mecánicas del capítulo 3: leer la polarización solamente por medios mecánicos. Para probar éste nuevo concepto, se utilizó CRF en el cristal periódicamente polarizado, obteniendo una lectura en concordancia con los resultados del capítulo 3. Además se mostró que al disminuir el volumen ferroeléctrico, es decir con películas delgadas, la resolución de lectura se ve incrementada considerablemente. Finalmente en el capítulo 7 se concluye ésta tesis y plantean las posibles líneas de trabajos futuros.

Polipropileno, Polipropilè, Polypropylene, Materiales compuestos, Materials compostos, Composite materials, Fibras celulósicas, Fibres de cel·lulosa, Cellulose fibers, Leucaena collinsii, Propiedades mecánicas, Propietats mecàniques, Mechanical properties, Propiedades térmicas, Propietats tèrmiques, and Thermal properties

This thesis studies the effect produced by the reinforcement of polypropylene with a semichemical fibre of Leucaena collinsii in the mechanical, thermal and water uptake properties. Samples with different reinforcement content are obtained and stabilized in a climatic chamber for 48 hours before being tested to tensile, flexural and the termal properties are studied by TGA, DSC, TMA, DMA and thermal conductivity test. Finally, the water uptake maximum capacity was determined. The addition of increasing quantities of reinforcement increases the maximum resistance and stiffne of the material, but a diminution of the deformation capacity was observed. None of the thermal transitions were affected by the addition of reinforcement. However, the crystallinity increased when increasing the fiber content

Memòria de forma, Polímers, Propietats mecàniques, Polímeros, Propiedades mecánicas, Shape-memory, Polymers, Mechanical properties, and Enginyeria i arquitectura

En aquesta tesi s’ha dut a terme la caracterització experimental de polímers amb memòria de forma de naturalesa termoplàstica i termostable. En concret, s’ha estudiat l’efecte que tenen diferents condicions termo-mecàniques de funcionament i l’estructura química en les propietats mecàniques i de memòria de forma. Per a l’estudi de les condicions de funcionament, s’han realitzat cicles de memòria de forma consecutius amb distintes combinacions de paràmetres termo-mecànics. Per a l’estudi de l’efecte de l’estructura química s’han utilitzat dues xarxes termostables. La primera consisteix en resines epoxi modificades amb polímers hiperramificats. En aquest cas, l’efecte del contingut i del pes molecular del polímer hiperramificat en les propietats visco-elàstiques, termo-mecàniques i de memòria de forma ha sigut estudiada en detall. La segona consisteix en xarxes de tipus acrilat sintetitzades a partir d’agent de reticulació basats en bisfenol A, els quals milloren les propietats mecàniques i de memòria de forma d’aquesta classe de materials. Per a l’estudi d’aquestes xarxes amb memòria de forma s’han dut a terme anàlisis dinamo-mecànics, assajos de caracterització mecànica i cicles de memòria de forma.

Statically undetermined structures, Two span continuous beams, Steel corrosion, Bond-slip, Mechanical properties, 3D scan, and Numerical simulation

Many reinforced concrete structures suffer damage due to aging and due to the environmental agressivity, thus affecting their serviceability performance and safety. Structural evaluation of a deteriorated structure is necessary to assess the actual structure state, to determine whether the structure should be strengthened or demolished and to optimize the interventions required to guarantee its serviceability and safety. In the case of statically indeterminate structures, as many of the existing bridges and buildings, the damage produced by local or general deterioration processes may affect the whole structure state of forces, stresses and cracks. However, even though the difficulties to adequately assess such type of structures very scarce resarch works have been done, up to now, in this field. The present research aims to contribute to those goals presenting an extensive experimental campaign, at the material and at the structural levels. Furthermore, theoretical and numerical studies based on mechanical non-linear models were performed in order to reproduce the observed experimental behaviour and to contribute to the modelling of the performance of deteriorated structures. The global effects of the structural damage were addressed by means of an experimental study, which encompassed twelve continuous two span large-scale beams. The cast beams divided in four groups of three beams each were submitted to different corrosion levels; one group was left uncorroded. Each beam was loaded with different sustained loads to assess its effect when corrosion phenomena took place. Thereafter, the beams were unloaded and loaded again up to failure. On the other hand, the local effects of steel corrosion were analysed by means of two different experimental studies. The first study encompassed more than 192 corroded steel bars. The specimens were cleaned, and after, characterized under cyclic and monotonic loads. The second study encompassed 48 cubic concrete specimens with embedded steel reinforcement bars. Different concrete types were used, including recycled aggregate concretes. The steel was submitted to accelerated corrosion and thereafter the effect of corrosion on the bond behaviour was assessed. Finally, modelling of the mechanical properties of corroded steel bars and bond in concrete was done. A model to evaluate the corroded steel reinforcement mechanical properties, s-e and fatigue life, was developed. In addition, the 3D scan novel technique was used to characterise the outer surface of corroded steel bars, by which the study of the corrosion pitting distribution and the critical cross-section was possible. Corrosion of steel reinforcement produced a substantial increment of the deflections as well as the stresses at the steel, both in the corroded and the uncorroded regions, due to the redistributions that took place in the continuous beams as a consequence of the loss of steel section. Furthermore, the redundancy of the structure provided them an extra load capacity with respect to a statically determinate beam. On the other hand, the ultimate load capacity was severely reduced. A non-linear reduction of the corroded steel mechanical properties was found. Yielding and ultimate stresses described a good correlation with respect to the corrosion level. However, the results for modulus and ultimate strain presented more dispersion. Bond capacity of recycled concrete aggregates was showed to be similar to natural aggregate concretes. Nevertheless, in corroded specimens, recycled aggregate concretes showed better performance describing lower ultimate bond reduction with respect to those of conventional concrete. The presented mechanical model defined with an excellent reliability yielding and ultimate stresses for corroded bars up to 60% of corrosion levels. The statistical model presented for the pitting depth allowed to define the upper and lower bounds of the pitting depth regarding to corrosion level.

SLM, Selective laser melting, Fundición selectiva por láser, Fusió selectiva per làser, Mechanical properties, Propiedades mecánicas, Propietats mecàniques, Dimensional analysis, Análisis dimensional, and Anàlisi dimensional

Selective laser melting process is an additive manufacturing technique that allows obtaining, from a 3D model, a physical model through a layer-by-layer manufacturing strategy. Several machines are commercially available, known as 3D printers. Recently, technology improvements have allowed the use of metallic materials; however, the amount of materials available is low due to the difficulty to find adequate manufacturing parameters. The thesis proposes a methodology, using an inclined plane, to set the minimum energy density to melt a continuous track, the first step of the melting process. Different process parameters from several commercials machines have been used to evaluate dimensional and mechanical properties. Replicas of traditional products have been fabricated using additive process and they have been compared. Finally, a protocol to use a selective laser melting process to reconstruct a personalized jaw prosthesis has been shown

Biofísica, Biophysics, Propietats mecàniques, Propiedades mecánicas, Mechanical properties, and Ciències Experimentals i Matemàtiques

Cell membranes are 2-D heterogeneous fluid systems that show nanoscale structures of great interest because of its importance in membrane functions. Due to the inherent complexity of natural membranes, the study of model membranes is essential to obtain important information about membranes. The small lateral size and tiny variation of the height of the lipid structures require the use of nanoscale characterization techniques. However, the requirement of liquid environment to preserve the integrity of the membrane limits the number of techniques that can be applied in the study of the physical and chemical properties of biomembranes. The objective of the present thesis was to develop a procedure to prepare model lipid bilayers stable in air environment and showing physicochemical properties as close as possible to their equivalent in liquid media. For the first experiments DOPC was selected as model to adapt the existing protocols for hydrated spin-coated samples to the new protocol for dried samples. In the structural study it was demonstrated that the dewetting pattern described by previous authors not only depends on the proximity of the layer to the substrate because also depends on the lipid concentration on the coating solution. Apart from that the presence of a continuous monolayer in contact with the mica substrate was demonstrated contrary to previous results with other lipids. The force spectroscopy measurements represented the first study on single bilayers in air and surprisingly demonstrated that the lipid layers in air presented similar mechanical properties than hydrated samples. Secondly the preparation protocol was adapted for phospholipids with different characteristics, the saturated phosphocholines. Contrary to unsaturated lipids, which present in general a high fluidity at ambient temperature, this is not always true for saturated lipids. For phosphocholines with short hidrocarbonated chains the melting temperature is low and then they are fluid, but for long hidrocarbonated chains the melting temperature is high and they can present a non-fluid behavior. For this reason different saturated lipids with different chain lengths were studied (DLPC, DMPC, DPPC and DSPC). The results with these lipids demonstrate that the conventional protocol of spin-coating induces the interdigitation of certain areas of the samples for the cases of DPPC and DSPC. The effect of the presence of alcohols and lateral tension were studied, being the rotation speed determined as causative of this phenomenon. Finally, we studied the more important case of multicomponent samples. In this study, ternary samples made of DOPC, Sphingomyelin and Cholesterol, relevant for lipid raft models, were selected. The corresponding binary samples with Cholesterol were also studied to determine separately the effect of Cholesterol in each of the components (DOPC and SM). Results unambiguously showed that air stable multicomponent lipid bilayers can be prepared by the spin coating technique with structural and mechanical properties remarkably resembling those of the equivalent systems in liquid media, specially on what concerns phase segregation phenomena. In particular, and more importantly, we showed that the ternary mixtures of DOPC/Chol/SM under dry conditions showed also the presence of lipid rafts. In summary, the present thesis has showed that it is possible to prepare lipid bilayer model systems morphologically stable in dry air conditions that present similar topography and mechanical properties than hydrated samples. Therefore it opens the possibility to characterize these systems with nanoscale techniques that until now have not been applied to them, thus offering the possibility to clarify physicochemical properties of lipid bilayer model systems that still today remain unexplored in spite of the vast literature of lipid bilayer model systems.

martensitic transformation, Ni-Fe-Ga, Ferromagnetic shape memory alloys, efecto doble memoria, fase gamma, deformación inducida por campo magnético, propiedades mecánicas, transformación martensítica, Aleaciones con memoria de forma ferromagnéticas, efecte doble mamòria, deformació induïda per camp magnètic, propietats mecàniques, transformació martensítica, Aliatges amb memòria de forma ferromagnètics, mechanical properties, magnetic-field induced strain, gamma phase, two-way shape memory effect., and Física Aplicada

L'interès dels aliatges amb memòria de forma ferromagnètics (FSMA), atesa la seva capacitat de poder donar lloc a grans deformacions per aplicació d'un camp magnètic. Els aliatges amb memòria de forma tenen unes propietats mecàniques molt singulars que s'associen a una transformació de fase, coneguda com a transformació martensítica.Els aliatges Ni-Mn-Ga són els que primer es varen desenvolupar dins del camp dels FSMA, però a causa la seva elevada fragilitat, s'està treballant en altres composicions, entre d'altres el Ni-Fe-Ga, etcEn el present treball s'ha dut a terme una caracterització de tipus mecànica d'aliatges poli- i monocristal·lins, en la que, a part d'una caracterització més fonamental, s'ha aprofundit en l'efecte dels precipitats en la tenacitat del material.En la darrera part de la tesi es va aconseguir induir la deformació per camp magnètic d'un aliatge Ni-Fe-Ga-Co, assistint amb una tensió mecànica perpendicular al camp, en una martensita no modulada.