Browsing by Keyword "Mechanical properties"
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Item Additive Manufactured Scaffolds for Bone Tissue Engineering: Physical Characterization of Thermoplastic Composites with Functional Fillers: Physical Characterization of Thermoplastic Composites with Functional Fillers(2021-08-13) Sinha, Ravi; Sanchez, Alberto; Camara-Torres, Maria; Uriszar-Aldaca, Iñigo Calderon; Calore, Andrea Roberto; Harings, Jules; Gambardella, Ambra; Ciccarelli, Lucia; Vanzanella, Veronica; Sisani, Michele; Scatto, Marco; Wendelbo, Rune; Perez, Sergio; Villanueva, Sara; Matanza, Amaia; Patelli, Alessandro; Grizzuti, Nino; Mota, Carlos; Moroni, Lorenzo; ECOEFICIENCIA DE PRODUCTOS DE CONSTRUCCIÓN; Tecnalia Research & InnovationThermoplastic polymer–filler composites are excellent materials for bone tissue engineering (TE) scaffolds, combining the functionality of fillers with suitable load-bearing ability, biodegradability, and additive manufacturing (AM) compatibility of the polymer. Two key determinants of their utility are their rheological behavior in the molten state, determining AM processability and their mechanical load-bearing properties. We report here the characterization of both these physical properties for four bone TE relevant composite formulations with poly(ethylene oxide terephthalate)/poly(butylene terephthalate (PEOT/PBT) as a base polymer, which is often used to fabricate TE scaffolds. The fillers used were reduced graphene oxide (rGO), hydroxyapatite (HA), gentamicin intercalated in zirconium phosphate (ZrP-GTM) and ciprofloxacin intercalated in MgAl layered double hydroxide (MgAl-CFX). The rheological assessment showed that generally the viscous behavior dominated the elastic behavior (G″ > G′) for the studied composites, at empirically determined extrusion temperatures. Coupled rheological–thermal characterization of ZrP-GTM and HA composites showed that the fillers increased the solidification temperatures of the polymer melts during cooling. Both these findings have implications for the required extrusion temperatures and bonding between layers. Mechanical tests showed that the fillers generally not only made the polymer stiffer but more brittle in proportion to the filler fractions. Furthermore, the elastic moduli of scaffolds did not directly correlate with the corresponding bulk material properties, implying composite-specific AM processing effects on the mechanical properties. Finally, we show computational models to predict multimaterial scaffold elastic moduli using measured single material scaffold and bulk moduli. The reported characterizations are essential for assessing the AM processability and ultimately the suitability of the manufactured scaffolds for the envisioned bone regeneration application.Item Design, Microstructure and Mechanical Properties of Cast Medium Entropy Aluminium Alloys(2019-12-01) Sanchez, Jon Mikel; Vicario, Iban; Albizuri, Joseba; Guraya, Teresa; Acuña, Eva Maria; CIRMETAL; PROMETALIn this work, the design, microstructures and mechanical properties of five novel non-equiatomic lightweight medium entropy alloys were studied. The manufactured alloys were based on the Al65Cu5Mg5Si15Zn5X5 and Al70Cu5Mg5Si10Zn5X5 systems. The formation and presence of phases and microstructures were studied by introducing Fe, Ni, Cr, Mn and Zr. The feasibility of CALPHAD method for the design of new alloys was studied, demonstrating to be a good approach in the design of medium entropy alloys, due to accurate prediction of the phases, which were validated via X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy. In addition, the alloys were manufactured using an industrial-scale die-casting process to make the alloys viable as engineering materials. In terms of mechanical properties, the alloys exhibited moderate plastic deformation and very high compressive strength up to 644 MPa. Finally, the reported microhardness value was in the range of 200 HV0.1 to 264 HV0.1, which was two to three times higher than those of commercial Al alloys.Item Development of a Squeeze Semisolid High-Pressure Die Casting Process for Magnesium Structural Parts(2019-07-15) Vicario, Iban; Crespo, Iñigo; Val, D.; Weiss, U.; Cao, D.; Martinez de la pera, Ignacio; Sanchez, Jon Mikel; PROMETAL; CIRMETALHigh-pressure die casting is the most common method used to produce magnesium castings, due to the excellent balance of cost and properties for high production volumes with limitations in terms of final mechanical properties. A newly developed process based on employing low injection speeds, in a range slightly over the standard semisolid speeds with a modified die, with thick gates and high die temperatures has been developed. Despite working with speeds that are not in the lamellar flow, the obtained parts present very low porosity, allowing the use thermal treatments to increase the ductility without producing blisters. The demonstration has been performed in a AM60B magnesium body joint produced by the squeeze casting process. Finally, the microstructure and the mechanical properties of as-cast and T4 heat-treated samples were studied. The results indicate the improvement of the mechanical properties in T4 heat-treated parts; specifically, a 40% improved deformation-to-failure, 40-60% improved penetration force and 90% of energy absorption were possible to obtain employing the newly developed SC + T4 process.Item Electrical Connectors for Underwater Applications(wiley, 2020-01-01) Remouit, Flore; Engström, Jens; Ruiz-Minguela, Pablo; Ruiz‐Minguela, Pablo; RENOVABLES OFFSHORENowadays, numerous companies offer a large choice of underwater connectors and assemblies, and it can be complex to distinguish the different technologies employed for each of them. This chapter provides an overview of the types of connectors that exist for underwater and subsea electrical connections. It presents different types of commercial-off-the-shelf electrical connectors, and lists their performances and defaults, as well as typical failure modes and their known causes. Although each manufacturer has its own designs and technologies, underwater connectors can be grouped into five main categories: rubber-molded, rigid-shell or bulkhead assemblies, fluid-filled underwater mateable, inductive coupling, and assemblies (non-unmateable). The chapter contains the theory on sealing and on connectors’ thermal, electrical, and mechanical properties. It provides information on connection procedures and other details about connecting subsea cables with a focus on the connection of offshore renewable energy farms.Item Experimental Investigation of the Influence of Wire Arc Additive Manufacturing on the Machinability of Titanium Parts(2020-01) Alonso, Unai; Veiga, Fernando; Suárez, Alfredo; Artaza, Teresa; Tecnalia Research & Innovation; FABRIC_INTELThe manufacturing of titanium airframe parts involves significant machining and low buy-to-fly ratios. Production costs could be greatly reduced by the combination of an additive manufacturing (AM) process followed by a finishing machining operation. Among the different AM alternatives, wire arc additive manufacturing (WAAM) offers deposition rates of kg/h and could be the key for the production of parts of several meters economically. In this study, the influence of the manufacturing process of Ti6Al4V alloy on both its material properties and machinability is investigated. First, the mechanical properties of a workpiece obtained by WAAM were compared to those in a conventional laminated plate. Then, drilling tests were carried out in both materials. The results showed that WAAM leads to a higher hardness than laminated Ti6Al4V and satisfies the requirements of the standard in terms of mechanical properties. As a consequence, higher cutting forces, shorter chips, and lower burr height were observed for the workpieces produced by AM. Furthermore, a metallographic analysis of the chip cross-sectional area also showed that a serrated chip formation is also present during drilling of Ti6Al4V produced by WAAM. The gathered information can be used to improve the competitiveness of the manufacturing of aircraft structures in terms of production time and cost.Item Fabrication and characterisation of Titanium Matrix Composites obtained using a combination of Self propagating High temperature Synthesis and Spark Plasma Sintering(2016-02-08) Lagos, M. A.; Agote, I.; Atxaga, G.; Adarraga, O.; Pambaguian, L.; EXTREMAT; PRINTEXThis work presents a novel processing method for the fabrication of particle reinforced Titanium Matrix Composites (TMCs). TMCs are a promising alternative to improve the mechanical properties of titanium alloys. In the processing method, the reinforcement (TiC-Ti) was obtained by Self-propagating High-temperature Synthesis (SHS). The composition of the reinforcement was Ti1.3C. An excess of titanium compared to the equiatomic TiC was introduced in the reaction in order to control the size of the reinforcement and to improve the compatibility between reinforcement and matrix. This reinforcement was mixed with Ti-6Al-4V powder and the final consolidation of the TMC was performed by Spark Plasma Sintering (SPS). The microstructure and mechanical characterisation of the TMCs are presented. Comparing tensile properties with conventional Ti-6Al-4V alloys, the materials developed in this work present higher young modulus and tensile strength. In addition, in order to study the possible scale up of SPS process for the production of TMCs, the manufacturing of large samples was studied.Item High-Temperature Mechanical Properties of IN718 Alloy: Comparison of Additive Manufactured and Wrought Samples(Multidisciplinary Digital Publishing Institute (MDPI), 2020-08-09) Bhujangrao, Trunal; Veiga, Fernando; Suárez, Alfredo; Iriondo, Edurne; Mata, Franck GirotWire Arc Additive Manufacturing (WAAM) is one of the most appropriate additive manufacturing techniques for producing large-scale metal components with a high deposition rate and low cost. Recently, the manufacture of nickel-based alloy (IN718) using WAAM technology has received increased attention due to its wide application in industry. However, insufficient information is available on the mechanical properties of WAAM IN718 alloy, for example in high-temperature testing. In this paper, the mechanical properties of IN718 specimens manufactured by the WAAM technique have been investigated by tensile tests and hardness measurements. The specific comparison is also made with the wrought IN718 alloy, while the microstructure was assessed by scanning electron microscopy and X-ray diffraction analysis. Fractographic studies were carried out on the specimens to understand the fracture behaviour. It was shown that the yield strength and hardness of WAAM IN718 alloy is higher than that of the wrought alloy IN718, while the ultimate tensile strength of the WAAM alloys is difficult to assess at lower temperatures. The microstructure analysis shows the presence of precipitates (laves phase) in WAAM IN718 alloy. Finally, the effect of precipitation on the mechanical properties of the WAAM IN718 alloy was discussed in detail.Item MECHANICAL IMPROVEMENT OF HARDENING AND TEMPERING STEEL WITH THE ADDITION OF SiC AND TiCN NANOPARTICLES IN THE STEEL MELT(2022-07) Callejo, Lorena M.; Pérez, Iñaki; Callejo-Piedra, Lorena M.; Pérez-Bilbao, Iñaki; CIRMETAL; Tecnalia Research & InnovationNovel processing technologies have allowed the reinforcement of several steel grades and alloys through the fine dispersion of different types of particles. However, the addition of ceramic particles in the steel melt causes agglomeration and coarsening phenomena. For this reason, little research has been carried out to add ceramic particles in steel in the traditional steelmaking process. Here we report a hardened and tempered steel grade that is reinforced for the first time through the addition of ceramic nanoparticles, such as TiCN and SiC, into the steel melt at laboratory scale. The results obtained from the tensile tests and hardness measurements reveal the mechanical behaviour of the steel grade is enhanced after the addition of the nanoparticles.Item Mechanical Properties Assessments for Materials of High Porosity and Light Alloys with Predominant Embedded Phases(Springer Science and Business Media Deutschland GmbH, 2021) Parashkevova, Ludmila; Drenchev, Ludmil; Egizabal, Pedro; Georgiev, Ivan; Kostadinov, Hristo; Lilkova, Elena; Tecnalia Research & InnovationIn the present contribution, upgrading the findings of previous works, [11], new models are proposed for evaluation of effective mechanical properties of light alloys regarded as multiphase composites. This study concerns three - phase composites with high volume fraction of non-matrix phases. The elastic properties assessments of such materials are calculated by analytical approach based on the variant of Differential Effective Medium (DEM) method. Here in the methodology from [10, 11] is further developed for two cases: composite type A and composite type B. The composite A consists of matrix and two inclusion phases. The matrix material is much softer than the inclusions material of the first kind and at it is much harder than the inclusions of second kind. The composite B is a closed cell porous material. It is assumed that the high porosity is induced by spherical pores of two sets very different by size: Di≫ di. At high volume fraction of pore space the average diameter of small pores is comparable to the inter-pores distance (cell’s wall). For assessment of the elastic moduli of both composites A an B a two-step homogenization procedures are applied. New yield conditions for the composites A and B are derived to define the initial plastic state of composites. Hill’s strain energy equivalent condition and leading role of matrix are taken into account describing the transition point from elastic to plastic state.Item Microstructure and Phase Formation of Novel Al80Mg5Sn5Zn5X5 Light-Weight Complex Concentrated Aluminum Alloys(2021-12-01) Sanchez, Jon Mikel; Pascual, Alejandro; Vicario, Iban; Albizuri, Joseba; Guraya, Teresa; Galarraga, Haize; CIRMETAL; PROMETALIn this work, three novel complex concentrated aluminum alloys were developed. To investigate the unexplored region of the multicomponent phase diagrams, thermo-physical parameters and the CALPHAD method were used to understand the phase formation of the Al80Mg5Sn5Zn5Ni5 , Al80Mg5Sn5Zn5Mn5 , and Al80Mg5Sn5Zn5Ti5 alloys. The ingots of the alloys were manufactured by a gravity permanent mold casting process, avoiding the use of expensive, dangerous, or scarce alloying elements. The microstructural evolution as a function of the variable element (Ni, Mn, or Ti) was studied by means of different microstructural characterization techniques. The hardness and compressive strength of the as-cast alloys at room temperature were studied and correlated with the previously characterized microstructures. All the alloys showed multiphase microstructures with major α-Al dendritic matrix reinforced with secondary phases. In terms of mechanical properties, the developed alloys exhibited a high compression yield strength up to 420 MPa, high compression fracture strength up to 563 MPa, and elongation greater than 12%.Item Numerical Modeling of the Influence of Nanometric Ceramic Particles on the Nucleation of AlSi10MnMg Alloy(2022-05-17) Jimenez, Ane; Sanchez, Jon Mikel; Girot, Franck; Renderos, Mario; Egizabal, Pedro; CIRMETAL; Tecnalia Research & InnovationIn recent years, many researchers have attempted to model the solidification process of nano-reinforced materials. In the present document, the effect on the heterogeneous solidification regime of the different sizes, shapes, and chemical compositions of nanometric ceramic particles in an AlSi10MnMg alloy is studied. This article develops a mathematical model to predict the solidification behavior of a general nano-reinforced alloy, then validates the results using experimental techniques. The main objective of the model is to minimize the costly and time-consuming experimental process of fabricating nano-reinforced alloys. The proposed model predicts the critical Gibbs energy and the critical radius required for nucleation in the heterogeneous solidification regime. Conversely, the experimental part focuses on understanding the solidification process from the differential thermal analysis (DTA) of the solidification curves. It was concluded that if subcooling is involved, cubic and pyramidal particles work better as nucleating particles in the studied alloy.Item The performance of steel-making slag concretes in the hardened state(2014-08) San-Jose, Jose Tomas; Vegas, Iñigo; Arribas, Idoia; Marcos, Ignacio; GENERAL; TRAZABILIDAD CIRCULARThe use of oxidizing slag from electric-arc furnaces as an aggregate is a sustainable option in the manufacture of concrete, the performance of which is similar to an ordinary aggregate concrete. This study examines the reuse of two different types of oxidizing slag in concretes designed for use in structural components and compares their performance against relevant specifications contained in current working standards. Fundamental aspects are discussed, among which density and workability that are related to the proportioning of the concrete and its mechanical and physical properties. The results show that overall concrete quality is maintained and that its performance is acceptable for the proposed applicationItem PM Based Titanium Matrix Composites for Aerospace Applications: Processing, Mechanical Properties and Scale Up: Processing, mechanical properties and scale up(2017) Lagos, M.A.; Agote, Iñigo; Atxaga, G.; Pambaguian, L.; EXTREMATThe reinforcement of titanium with a hard phase is an efficient way to increase the stiffness and strength of conventional titanium alloys. The high reactivity of titanium is a critical challenge in the processing of Titanium Matrix Composites (TMCs). For this reason, Powder Metallurgy is considered a very promising route for the manufacturing of TMCs. In this work, a master alloy (Ti-TiC) was developed by combustion synthesis. This alloy was further blended with conventional titanium alloy and the final consolidation was performed by Spark Plasma Sintering. In addition to the processing details, microstructural and thermomechanical characterization is presented. Materials obtained present higher Young Modulus and strength than conventional Ti-6Al-4V, with higher thermal conductivity and maintaining similar thermal expansion coefficient (CTE). The good corrosion resistance of the material makes it a candidate for possible applications in aerospace. This work presents also the scale up of the process to obtain aerospace demonstrators.Item Ti3SiC2-Cf composites by spark plasma sintering:: Processing, microstructure and thermo-mechanical properties(2019-08) Lagos, M.A.; Pellegrini, C.; Agote, I.; Azurmendi, N.; Barcena, J.; Parco, M.; Silvestroni, L.; Zoli, L.; Sciti, D.; EXTREMATMAX phases, and particularly Ti3SiC2, are interesting for high temperature applications. The addition of carbon fibers can be used to reduce the density and to modify the properties of the matrix. This work presents the densification and characterization of Ti3SiC2 based composites with short carbon fibers using a fast and simple fabrication approach: dry mixing and densification by Spark Plasma Sintering. Good densification level was obtained below 1400 °C even with a high amount of fibers. The reaction of the fibers with the matrix is limited thanks to the fast processing time and depends on the amount of fibers in the composite. Bending strength at room temperature, between 437 and 120 MPa, is in the range of conventional CMCs with short fibers and according to the resistance of the matrix and the presence of residual porosity. Thermo-mechanical properties of the composites up to 1500 °C are also presented.