Fabricación de aleaciones ligeras de Titanio y Aluminio por metalurgia de polvos

La UC3M desarrolla aleaciones ligeras de Titanio y Aluminio mediante técnicas pulvimetalúrgicas permitiendo adaptar las composiciones y propiedades a aplicaciones específicas. Sectores como la automoción requieren el empleo de materiales con propiedades mejoradas que aúnen resistencia mecánica, buen comportamiento al desgaste y corrosión disminuyendo el peso de los componentes fabricados a partir de los metales tradicionalmente empleados. Para su implantación es clave la colaboración de empresa

Manufacturing of Titanium and Aluminium Light alloys by powder metallurgy

The Group of Powder Technology (GTP) of the University Carlos III has a wide experience in the development and processing of new materials by Powder Metallurgy (PM). The mechanical alloying (MA) process, or high energy milling, allows the attainment of powders with compositions impossible to produce by other techniques, with improved properties for structural applications, where mechanical properties are the main requirement, and for applications where other specific properties are needed. The identification of the specific needs of interested industrial sectors is a critical point in this development

Development of new materials by high energy milling

The Group of Powder Technology (GTP) of the University Carlos III has a wide experience in the development and processing of new materials by Powder Metallurgy (PM). The mechanical alloying (MA) process, or high energy milling, allows the attainment of powders with compositions impossible to produce by other techniques, with improved properties for structural applications, where mechanical properties are the main requirement, and for applications where other specific properties are needed. The identification of the specific needs of interested industrial sectors is a critical point in this developmen

Low-Cost α+β PM Ti Alloys by Fe/Ni Addition to Pure Ti

Ti and its alloys can deliver a very interesting combination of properties such as low density, high strength, corrosion resistance and biocompatibility and, therefore, are very flexible materials which can be adapted to various applications. Nonetheless, Ti and Ti alloys are only employed in critical applications (i.e. aeronautical and aerospace, nautical, medical, etc.) or in products for leisure. In both of these cases the higher fabrication costs of Ti in comparison to its competitors (i.e. steel and aluminium) is not the limiting factor as it is for many structural applications, especially for mass production (i.e. automotive sector). The use of creative techniques and the decrement of the starting price of Ti have been identified as the two main routes to follow to decrease the fabrication costs. In this study, the production of low-cost α+β Ti alloys has been assessed by combining the addition of cheap alloying elements (in particular a Fe/Ni powder) with the classical powder metallurgy route (pressing and sintering). Physical and mechanical properties as well as microstructural analysis of these low-cost alloys were measured and correlated to the processing parameters used to sinter them. It is found that the low-cost Ti alloys show similar behaviour to conventional α+β Ti alloys and, thus, have the potential to be used for non-critical applications

Investigation of the factors influencing the tensile behaviour of PM Ti-3Al-2.5V alloy

Titanium, a relatively new engineering metal, has been employed principally in high demanding industries due to its high final cost and it is well known for its biocompatibility. Powder metallurgy (PM) techniques could offer the possibility to reduce the production cost without paying it in terms of mechanical properties, thanks to their intrinsic advantages. In this study the Ti-3Al-2.5V titanium alloy was produced considering two powder production routes and sintered under different temperatures in order to address their feasibility as alternative to the wrought alloy. The results indicate that PM Ti-3Al-2.5V alloys studied have comparable mechanical behaviour as their counterpart obtained by conventional metallurgy and, therefore, are potential candidates to fabricate cheaper titanium products for structural applications as well as biomedical devices. © 2014 Elsevier B.V.The authors want to acknowledge the financial support from the Spanish Ministry of Science through the R&D Projects MAT2009-14448-C02-02 and MAT2009-14547-C02-02, and from Regional Government of Madrid through the ESTRUMAT (S2009/ MAT-1585) projectPublicad

Negative ternary set-sharing

The Set-Sharing domain has been widely used to infer at compiletime interesting properties of logic programs such as occurs-check reduction, automatic parallelization, and flnite-tree analysis. However, performing abstract uniflcation in this domain requires a closure operation that increases the number of sharing groups exponentially. Much attention has been given to mitigating this key inefflciency in this otherwise very useful domain. In this paper we present a novel approach to Set-Sharing: we define a new representation that leverages the complement (or negative) sharing relationships of the original sharing set, without loss of accuracy. Intuitively, given an abstract state sh\> over the finite set of variables of interest V, its negative representation is p(V) \ shy. Using this encoding during analysis dramatically reduces the number of elements that need to be represented in the abstract states and during abstract uniflcation as the cardinality of the original set grows toward 2 . To further compress the number of elements, we express the set-sharing relationships through a set of ternary strings that compacts the representation by eliminating redundancies among the sharing sets. Our experiments show that our approach can compress the number of relationships, reducing signiflcantly the memory usage and running time of all abstract operations, including abstract uniflcation

Flexural Properties, Thermal Conductivity and Electrical Resistivity of Prealloyed and Master Alloy Addition Powder Metallurgy Ti-6Al-4V

A comparison between the properties achievable by processing the Ti&-6Al&-4V alloys by means of two powder metallurgy approaches, precisely prealloyed and master alloy addition, was carried out. Prealloyed and master alloy addition hydride&-dehydride powders characterised by an irregular morphology were shaped by means of cold uniaxial pressing and high vacuum sintered considering the effect of the variation of the sintering temperature and of the dwell time. Generally, the higher the temperature and the longer the dwell time, the higher the relative density and, consequently, the better the mechanical performances. Nevertheless, a higher processing temperature or a longer time leads also to some interstitials pick-up, especially oxygen, which affects the mechanical behaviour and, in particular, lowers the ductility. Although some residual porosity is left by the pressing and sintering route, mechanical properties, thermal conductivity and electrical resistivity values comparable to those of the wrought alloy are obtained.The authors want to acknowledge the financial support from Regional Government of Madrid through the ESTRUMAT (S2009/ MAT-1585) project and from the Spanish Ministry of Science through the R&D Projects MAT2009-14547-C02-02 and MAT2009-14448-C02-02. The authors want also to thanks the Fraunhofer IFAM-Dresden Institute for the measurements of the thermal conductivity and electrical resistivityPublicad

Influence of vacuum hot-pressing temperature on the microstructure and mechanical properties of Ti—2.5V alloy obtained by blended elemental and master alloy addition powders

This study addresses the processing of near-net-shape, chemically homogeneous and fine-grained Ti–3Al–2.5V components using vacuum hot-pressing. Two Ti–3Al–2.5V starting powders were considered. On one side, hydride-dehydride (HDH) elemental titanium was blended with an HDH Ti–6Al–4V prealloyed powder. On the other side, an Al:V master alloy was added to the HDH elemental titanium powder. The powders were processed applying a uniaxial pressure of 30 MPa. The sintering temperatures studied varied between 900 degrees C and 1300 degrees C. The relative density of the samples increased with processing temperature and almost fully dense materials were obtained. The increase of the sintering temperature led also to a strong reaction between the titanium powders and the processing tools. This phenomenon occurred particularly with boron nitride (BN) coating, which was used to prevent the direct contact between titanium and graphite tools. The flexural properties of the Ti–3Al–2.5V samples increased with vacuum hot-pressing temperature and are comparable to those specified for wrought titanium medical devices. Therefore, the produced materials are promising candidates for load bearing applications as implant materials.Financial support from Comunidad de Madrid through the ESTRUMAT (S-2009/MAT-1585) project and from the Spanish Ministry of Education through the R&D MAT2009-14448-C02-02 and MAT2009-14547-C02-02 Projects