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Sample records for aleacion al-si tipo

  1. Effect of NaCl upon an Al-Si casting alloy hipoeutec; Efecto del NaCl sobre una aleacion de Al-Si hipoeutectica vaciada

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    Martinez Delgado, E.J.; Ortega de la Rosa, R. [Istituto Tecnologico de Zacatecas, Zacatecas (Mexico)]. E-mail: enriquemartinez_1999@yahoo.com; rubin_ortega_2002@yahoo.com.mx; Cisneros Guerrero, M.A. [Instituto Tecnologico de Saltillo, Saltillo, Coahuila (Mexico)]. E-mail: cisneros@its.mx; Haro Rodriguez, S. [Universidad Autonoma de Zacatecas, Zacatecas, Zacatecas (Mexico)]. E-mail: haros907@hotmail.com

    2009-10-15

    This work, comprehends the study about the effect of NaCl kind Halite upon the morphology of eutectic Silicon and porosity in a cast hipoeutectic Al-Si alloy. The melting was carried out in two furnaces, the first to combustion of LP gas in graphite crucible to increase the content of Si in the alloy from 0.13 to 5% wt using metallic silicon with a purity of 99.35% wt, and the second of electric resistances in the same kind of crucible to control the temperature at 750 degrees Celsius. The melting material was casting into molds of sand shell. To add the salt into the metallic bath, two techniques were used; one with injection by means of Argon gas and the other on by gravity, both cases three quantities of salt were used, 0.5, 1.5 and 2.5% wt respectively, powdered and preheated at 150 degrees Celsius during 60 min. The obtained samples were analyzed metallographily evidencing the modification of the eutectic Si, presenting the best results the samples with 1.5 and 2.5% wt of salt added by gravity. Too was obtained effect of Salt upon the degassing of bath metallic, where the simples with 1.5% wt presented the best results. Finally, by means of Scanning Electron Microscopy, the precipitates present were characterized in the samples. [Spanish] Este trabajo comprende el estudio del efecto del NaCl tipo Halita sobre la morfologia del Si eutectico y la porosidad en una aleacion fundida Al-Si hipoeutectica. La fusion se llevo a cabo en dos hornos, el primero a combustion con gas LP en crisol de grafito con la finalidad de incrementar el contenido de Si en la aleacion de 0.13 a 5% en peso, utilizando silicio metalico con una pureza de 99.35%, y el segundo de resistencias electricas en el mismo tipo de crisol para controlar la temperatura a 750 grados Celsios. El material fundido fue vaciado en modelos de arena. La sal se anadio al bano metalico a 0.5, 1.5 y 2.5% en peso, respectivamente, pulverizada y precalentada a 150 grados Celsios durante 60 min, mediante dos

  2. Conformado de aleaciones en estado semisólido. Aplicación a aleaciones hipereutécticas de Al-Si

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    Valer, J.

    1996-08-01

    Full Text Available The processing of alloys in the semi-solid state, known as Rheocasting, Thixoforming, Thixoforging or Thixocasting, is within the new technologies used for the production of materials. This work describes the process as well as the phenomena implied in it. As the forming of alloys in the semisolid state requires of a previous material preparation (in order to obtain a non-dendritic structure the Osprey process or Spray-forming, used in this work, is briefly described. Finally, both the microstructural results obtained from the combination of the two technologies in hypereutectic Al-Si alloys (Al-25%Si-5%Cu, Al-25%Si-5%Cu-2%Mg and Al-30%Si-5%Cu and comparison with microstructures obtained from similar alloys processed by conventional methods are shown.

    Dentro de las nuevas tecnologías utilizadas para la producción de materiales, se encuentra el procesamiento de aleaciones en estado semisólido denominado, en sus distintas versiones, Rheocasting, Thixoforming, Thixoforging o Thixocasting. En este trabajo se describe el proceso, así como los fenómenos implicados en el mismo. Puesto que el conformado de aleaciones en estado semisólido requiere una preparación previa del material (para obtener una microestructura no dendrítica, se describe brevemente el proceso Osprey o Spray-forming, utilizado en este trabajo. Finalmente, se muestran los resultados microestructurales obtenidos mediante la combinación de estas dos tecnologías, en aleaciones hipereutécticas de Al-Si (Al-25%Si-5%Cu, Al-25%Si-5%Cu- 2%Mg y Al-30%Si-5%Cu y su comparación con las microestructuras obtenidas en aleaciones similares procesadas por métodos convencionales.

  3. Comportamiento a tracción a temperaturas ambiente y elevadas de nuevos composites basados en aleaciones hipereutécticas de Al-Si

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    Valer, J.

    1997-02-01

    Full Text Available This work shows the improvement obtained on tensile stress at room and high temperatures of hypereutectic Al-Si alloys. These alloys are produced by a combination of spray-forming, extrusión and thixoforming process, in comparison with conventional casting alloys. Al-25%Si-5%Cu, Al- 25%Si-5%Cu-2%Mg and Al-30%Si-5%Cu alloys have been studied relating their microstructural parameters with tensile stress obtained and comparing them with conventional Al-20%Si, Al-36%Si and Al-50%Si alloys. Al-25%Si-5%Cu alloy was tested before and after semi-solid forming, in order to distinguish the different behaviour of this alloy due to the different microstructure. The properties obtained with these alloys were also related to Al-SiC composites formed by similar processes.

    En este trabajo se muestra la mejora obtenida en la resistencia a la tracción a temperatura ambiente y a elevadas temperaturas de aleaciones hipereutécticas de Al-Si producidas por una combinación de un proceso de solidificación rápida y del conformado en estado semisólido, en comparación con aleaciones obtenidas por procedimientos convencionales de inyección en estado líquido. Se han estudiado las aleaciones Al-25%Si-5%Cu, Al-25%Si-5%Cu-2%Mg y Al-30%Si-5%Cu, relacionando sus parámetros microestructurales con las resistencias a tracción obtenidas, y se han comparado con las aleaciones binarias Al-20%Si, Al-36%Si y Al-50%Si. La aleación Al-25%Si-5%Cu se ha ensayado antes y después del conformado en estado semisólido, lo que ha permitido conocer la diferencia en el comportamiento de la aleación como consecuencia de la distinta microestructura. También se comparan las propiedades obtenidas en estas aleaciones con las que presentan composites de aleaciones de aluminio reforzados con partículas de SiC y procesados por métodos similares.

  4. Nuevos tratamientos T6 para aleaciones de AlSi obtenidas por conformación en estado semisólido

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    Menargues, S.

    2013-08-01

    Full Text Available In this work the microstructural changes that occurs during the solution and aging steps of heat treated of AlSi alloys, conformed in semi-solid state, were analysed. The study allowed developing a new T6 heat treatment, with solution times down to 30 min. With this new short heat treatment, the alloy showed better mechanical properties in comparison with the same alloy heat treated in standard conditions (solution times between 6 h and 8 h. This new heat treatment, carried out at 540 ºC, allowed complete magnesium dissolution and, at the same time, minimizes the grain and eutectic silicon growth. Although this experimentation was carried out with A356 and A357 aluminum alloys, conformed by Sub-Liquidus-Casting process, these results may be applicable to components produced with other semi-solid technologies and with others AlSi hardenable alloys that form coherent magnesium precipitates. The characterization of samples was carried out by micrographic analysis, by hardness and ultramicrohardnes tests.Se estudian los cambios microestructurales que tienen lugar en los tratamientos térmicos de las aleaciones AlSi, conformadas en estado semisólido, durante las etapas de puesta en solución y envejecimiento. El estudio ha permitido proponer nuevos tratamientos T6, con tiempos de puesta en solución inferiores a los 30 min, manteniendo o mejorando las propiedades mecánicas que se obtienen con los actuales procesos de tratamiento de 6 a 8 h. Estos tratamientos de corta duración, realizados a 540 ºC, permiten una completa disolución del magnesio, minimizando al mismo tiempo el crecimiento de los granos y del silicio eutéctico. Si bien la experimentación se ha realizado con componentes producidos por Sub-Liquidus Casting (SLC con aleaciones A356 y A357, se considera que los resultados obtenidos pueden ser aplicables a los componentes producidos en estado semisólido por otras tecnologías, con diferentes aleaciones AlSi que se endurecen por

  5. Comportamiento a la corrosión electroquímica de aleaciones MgAl con recubrimientos de materiales compuestos Al/SiCp mediante proyección térmica

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    Pardo, A.

    2010-04-01

    Full Text Available The corrosion protection of Mg-Al alloys by flame thermal spraying of Al/SiCp composite coatings was evaluated by electrochemical impedance spectroscopy in 3.5 wt.% NaCl solution. The volume fraction of SiC particles (SiCp varied between 5 and 30%. The as-sprayed Al/SiCp composite coatings revealed a high number of micro-channels, largely in the vicinity of the SiC particles, that facilitated the penetration of the electrolyte and the subsequent galvanic corrosion of the magnesium substrates. The application of a cold-pressing post-treatment reduced the degree of porosity of the coatings and improved the bonding at the coating/substrate and Al/SiC interfaces. This resulted in improved corrosion resistance of the coated specimens. The effectiveness of the coatings slightly decreased with the addition of 5-30 vol.% SiCp compared with the unreinforced thermal spray aluminium coatings.

    Se estudia, mediante espectroscopía de impedancia electroquímica en solución 3,5 % NaCl, la protección frente a la corrosión de aleaciones Mg-Al recubiertas por proyección térmica con materiales compuestos Al/SiCp. Se varió la fracción de volumen de las partículas de SiC (SiCp entre 5 y 30 %. Los recubrimientos efectuados por proyección térmica revelan un elevado número de microcanales, en la vecindad de las partículas de SiC, que facilitan la penetración del electrolito originando procesos de corrosión galvánica en los substratos de las aleaciones de magnesio. Un tratamiento posterior mediante la aplicación de una presión en frío reduce el grado de porosidad de los recubrimientos y mejora la unión, tanto entre el substrato y el recubrimiento como entre las partículas de aluminio y SiC, mejorando la resistencia a la corrosión de las aleaciones recubiertas. La efectividad de los recubrimientos disminuye ligeramente con la adición de SiCp cuando se comparan con los mismos recubrimientos de aluminio sin refuerzo.

  6. Electrochemical corrosion behaviour of Mg-Al alloys with thermal spray Al/SiCp composite coatings; Comportamiento a la corrosion electroquimica de aleaciones MgAl con recubrimientos de materiales compuestos Al/SiCp mediante proyeccion termica

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    Pardo, A.; Feliu Jr, S.; Merino, M. C.; Mohedano, M.; Casajus, P.; Arrabal, R.

    2010-07-01

    The corrosion protection of Mg-Al alloys by flame thermal spraying of Al/SiCp composite coatings was evaluated by electrochemical impedance spectroscopy in 3.5 wt.% NaCl solution. The volume fraction of SiC particles (SiCp) varied between 5 and 30%. The as-sprayed Al/SiCp composite coatings revealed a high number of micro-channels, largely in the vicinity of the SiC particles, that facilitated the penetration of the electrolyte and the subsequent galvanic corrosion of the magnesium substrates. The application of a cold-pressing post-treatment reduced the degree of porosity of the coatings and improved the bonding at the coating/substrate and Al/SiC interfaces. This resulted in improved corrosion resistance of the coated specimens. The effectiveness of the coatings slightly decreased with the addition of 5-30 vol.% SiCp compared with the un reinforced thermal spray aluminium coatings. (Author) 31 refs.

  7. New T6 heat treatments for AlSi alloys conformed in semi-solid state; Nuevos tratamientos T6 para aleaciones de AlSi obtenidas por conformacion en estado semisolido

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    Menargues, S.; Baile, M. T.; Forn, A.

    2013-07-01

    In this work the microstructural changes that occurs during the solution and aging steps of heat treated of AlSi alloys, conformed in semi-solid state, were analysed. The study allowed developing a new T6 heat treatment, with solution times down to 30 min. With this new short heat treatment, the alloy showed better mechanical properties in comparison with the same alloy heat treated in standard conditions (solution times between 6 h and 8 h). This new heat treatment, carried out at 540 degree centigrade, allowed complete magnesium dissolution and, at the same time, minimizes the grain and eutectic silicon growth. Although this experimentation was carried out with A356 and A357 aluminum alloys, conformed by Sub-Liquidus-Casting process, these results may be applicable to components produced with other semi-solid technologies and with others AlSi hard enable alloys that form coherent magnesium precipitates. The characterization of samples was carried out by micrographic analysis, by hardness and ultramicrohardnes tests. (Author)

  8. Colour metallography in commercial Al-Si alloys. Optimization of the microstructural characterization techniques in light optical microscopy; Metalografia a color en aleaciones Al-Si comerciales. Optimizacion de las tecnicas de caracterizacion microestructural mediante microscopia optica de reflexion

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    Suarez-Pena, B.; Asensio-Lozano, J.; Vander-Voort, G.F.

    2010-07-01

    The present demand on alloy production with improved quality requires the optimization of the metallographic procedures used on its characterization. Traditional etching techniques ommonly employed for phase identification by optical metallography in aluminium alloys are not always suitable for a detailed analysis of existing phases, nor to accurately predict the mechanisms that govern the solidification process in certain detail. This work explores the potential of colour metallography to reveal at its best as-cast microstructures in Al-Si 12 alloys. For this purpose a colour etching technique, specifically developed for aluminium alloys and based on theWeck reagent[1]. The application of such etchant has allowed the qualitative characterization of the microstructure. And it has also shown the advantages of colour metallography over black and white (B&W) etching techniques. (Author).

  9. Study of the removal mechanism of magnesium from Al-Si liquid alloys using silica base minerals injection; Estudio del mecanismo de eliminacion de magnesio de aleaciones Al-Si en estado liquido mediante inyeccion de minerales base silice

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    Munoz-Arroyo, R.; Escobedo-Bocardo, J. C.; Hernande-Garcia, H. M.; Cortes-Hernandez, D. A.; Terrones-Maldonado, M.; Rodriguez-Pulido, A.; Hernandez-Pinero, J. L.

    2010-07-01

    In order to eliminate magnesium from an A 380 Al-Si alloy at 750 degree centigrade, the submerged powder injection method, using an inert carrier gas (Ar), was applied. The injected powders in the liquid aluminum bath were zeolite, silica and mixtures of zeolite-silica minerals. For each experiment the response variables were: eliminated magnesium versus injection time and quantity of drosses produced. Chemical analysis by atomic absorption spectrometry showed that mixtures of silica-zeolite 66:34 wt% have the best results with regarding to the removal magnesium from 1 to 0.0066 wt%. During the elimination of magnesium complex stoichiometry compounds were formed due to the reactions among zeolite, water steam and liquid aluminum. These compounds were analyzed by XRD, SEM and TEM. The results obtained, along with using the FactSage 6 thermodynamic software, allowed to elucidate the reaction mechanism between the minerals used and liquid aluminum. (Author)

  10. Metalografía a color en aleaciones Al-Si comerciales. Optimización de las técnicas de caracterización microestructural mediante microscopía óptica de reflexión

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    Vander-Voort, G. F.

    2010-10-01

    Full Text Available The present demand on alloy production with improved quality requires the optimization of the metallographic procedures used on its characterization. Traditional etching techniques commonly employed for phase identification by optical metallography in aluminium alloys are not always suitable for a detailed analysis of existing phases, nor to accurately predict the mechanisms that govern the solidification process in certain detail. This work explores the potential of colour metallography to reveal at its best as-cast microstructures in Al-Si 12 alloys. For this purpose a colour etching technique, specifically developed for aluminium alloys and based on the Weck reagent. The application of such etchant has allowed the qualitative characterization of the microstructure. And it has also shown the advantages of colour metallography over black and white (B&W etching techniques.La demanda de aleaciones con calidades optimizadas conlleva la mejora continua de estas calidades, lo que viene suscitando la necesidad de mejora y optimización permanentes de las técnicas de caracterización metalográfica. Las técnicas de ataque tradicionales, utilizadas en la observación microscópica de las aleaciones de aluminio, no permiten un análisis detallado de la evolución microestructural de las fases presentes ni de parte de los mecanismos que rigen la solidificación. En el presente trabajo, se explora el potencial de la metalografía en color aplicada a las estructuras de solidificación de aleaciones Al-Si 12. Se ha utilizado un procedimiento de ataque en color, basado en un reactivo desarrollado porWeck para aleaciones de aluminio. El empleo de esta técnica ha permitido la evaluación cualitativa de la microestructura. La técnica ha permitido revelar características microestructurales que los métodos de ataque en blanco-negro no revelan.

  11. Estudio del mecanismo de eliminación demagnesio de aleaciones Al-Si en estado líquido mediante inyección de minerales base sílice

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    Muñoz-Arroyo, R.

    2010-08-01

    Full Text Available In order to eliminate magnesium from an A 380 Al-Si alloy at 750°C, the submerged powder injection method, using an inert carrier gas (Ar, was applied. The injected powders in the liquid aluminum bath were zeolite, silica and mixtures of zeolite-silica minerals. For each experiment the response variables were: eliminated magnesium versus injection time and quantity of drosses produced. Chemical analysis by atomic absorption spectrometry showed that mixtures of silica-zeolite 66:34 wt% have the best results with regarding to the removal magnesium from 1 to 0.0066 wt%. During the elimination of magnesium complex stoichiometry compounds were formed due to the reactions among zeolite, water steam and liquid aluminum. These compounds were analyzed by XRD, SEM and TEM. The results obtained, along with using the FactSage 6 thermodynamic software, allowed to elucidate the reaction mechanism between the minerals used and liquid aluminum.

    Se empleó el método de inyección sumergida de polvos por medio de un gas de arrastre inerte (Ar con el fin de eliminar el magnesio de la aleación Al-Si A380 a 750 °C. Los polvos inyectados al baño de metal fundido fueron zeolita mineral, arena sílice y mezclas de ambas. Las variables de respuesta medidas fueron el contenido de magnesio en el baño metálico respecto al tiempo de inyección y las mermas de metal al final de cada experimento. En el análisis de resultados, la mezcla sílice:zeolita 66:34 % e.p. obtuvo la mayor eficiencia, lográndose una disminución en el contenido de magnesio en el baño metálico de 1 a 0.0066 % e.p. Los productos de reacción se analizaron por difracción de rayos-X, microscopía electrónica de barrido y de transmisión. Los resultados de estos análisis y el empleo del paquete termodinámico FactSage, versión 6, permitieron justificar el mecanismo de reacción entre los minerales y el aluminio líquido.

  12. Evaluación del efecto de modificadores y refinadores en el comportamiento mecánico y magnitud del rechupe de aleaciones Al-Si-Mg. // Modifier and refiners effect evaluation in the magnitude and mechanical shrinkage behavior of Al-Si-Mg alloys.

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    V. Lavaert

    2002-05-01

    Full Text Available Se estudia la influencia del Na, Sr y Ti y sus combinaciones (Na-Ti y Sr-Na en las propiedades mecánicas y el rechupe(superior y lateral de la aleación hipoeutéctica AlSi7Mg Aunque todos estos elementos y combinaciones tienden aneutralizar la formación del rechupe substancialmente, el Sr se presenta como el más eficaz para disminuir el rechupesuperior mientras la combinación Na-Ti llevó a la menor formación de rechupe lateral.Se observó una acción modificadora excelente para 0.02% de Sr y 0.02% de Na, pero a diferencia del Sr, el efectomodificador del Na comienza a desvanecerse después de 30 min afectando el alargamiento notablemente. El estroncio, sinembargo, mostró un efecto de la modificación muy duradero (aproximadamente 3 h. Otro hallazgo interesante es laexistencia de un cierto periodo de incubación de aproximadamente 90 minutos después de agregar Sr. Contrariamente a loesperado el uso de titanio no mejoró las propiedades mecánicas a pesar de un eficaz refinamiento de grano.Palabras claves: Rechupe superior, acción modificadora, propiedades mecánicas, metalurgia no ferrosa._________________________________________________________________________AbstractThe influence of Na, Sr and Ti and their combinations (Na-Ti and Sr-Na on the mechanical properties and the shrinkage(top macro shrinkage and lateral macro shrinkage of hypoeutectic aluminium-silicon alloys (AlSi7xMg has been studied.Although all these elements and combinations tend to counteract substantially the shrinkage formation, Sr appeared to bethe most effective to decrease top macro shrinkage whereas the combination Na-Ti led to the least formation of lateralmacro shrinkage. An excellent modifying action was observed for 0.02% Sr and 0.02% Na, but unlike Sr the modifyingeffect provided by Na started fading after 30 min of holding which affected the elongation markedly. However, strontiumshowed a very lasting modification effect (about 3 h. Another interesting

  13. An electrochemical investigation of the corrosion behavior of Al-Si-Cu hypereutectic alloys in alcoholic environments

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    Traldi, S. M.

    2003-12-01

    Full Text Available Al-Si-Cu hypereutetic alloys produced by spray forming are mostly used in the automotive industry, especially for cylinder liners. They have the advantage of low weight associated with low coefficient of thermal expansion and excellent mechanical properties - mainly wear resistance at high temperatures. The corrosion resistance of these alloys in fuels, particularly alcoholic media, however is not yet known. In this investigation, electrochemical impedance spectroscopy (EIS and potentiodynamic polarisation have been used to evaluate the corrosion resistance of a hypereutectic Al-Si-Cu alloy in alcoholic environments. The EIS tests were carried out in pure ethanol, and ethanol with small additions (1 mM of acid and chloride, to investigate the effect of these contaminants on corrosion resistance. The corrosion resistance of a grey cast iron has also been evaluated in pure ethanol for comparison. The Al-Si-Cu alloy showed high corrosion resistance in pure ethanol, far superior to that of grey cast iron in the same medium.

    Aleaciones hipereutécticas producidas por conformación por spray son muy empleadas en la industria automovilística, especialmente en los revestimientos de los cilindros. Tienen la ventaja de añadir menos peso con bajo coeficiente de expansión térmica y excelentes propiedades mecánicas, sobre todo resistencia al desgaste en altas temperaturas. Todavía, la resistencia a la corrosión de estas aleaciones en combustibles no es conocida. En este estudio fueron utilizadas las técnicas de espectroscopia de impedancia electroquímica y polarización potenciodinámica, para evaluar la resistencia a la corrosión de una aleación hipereutéctica Al-Si-Cu en medio alcohólico. Las pruebas fueron conducidas en etanol puro y etanol con pequeñas adiciones (1 mM de ácido y cloruro, con la finalidad de investigar el efecto de estos contaminantes en la resistencia a la corrosión. Hierro fundido gris, también fue

  14. Estudio y caracterización de aleaciones Zn-Sb para aplicaciones termoeléctricas

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    Gonzàlez Martín, Sergio

    2011-01-01

    En este proyecto se estudian diferentes aleaciones del sistema Zn-Sb con propiedades termoeléctricas, destinadas a su empleo en la fabricación de generadores termoeléctricos (TEGs), siendo éstos dispositivos capaces de generar una corriente eléctrica al ser sometidos a un gradiente de térmico. Para ello se sintetizan dichas aleaciones mediante procesos tradicionales de fusión y colada en horno de inducción, y se preparan diferentes tipos de probetas del material obtenido par...

  15. Propiedades de aleaciones Ag-Pd para usos odontológicos

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    Basualto, J.

    1996-10-01

    Full Text Available In this search for economically alternative alloys for odontological uses, three complex Ag-Pd alloys, Ag-Pd-Au-Cu type, are studied: two experimental alloys and one commercial product. Chemical and mechanical properties were obtained for these alloys and a comparative analysis of these results was made. The cost, important factor, is established in relation to the materials cost of the commercial product. Vickers hardness values obtained from Ag-Pd alloys with different heat treatments allow to show their versatility in relation to restorative uses and to classify them according to standard practice. Electrochemical and tarnish behavior were obtained that allow to compare the trends. It is concluded that chemical properties are acceptable, when they are compared with odontological alloys of reference. Experimental alloys A1 y A2 were installed in mouth, over a year ago, with satisfactory results until now, which validate previous laboratory predictions.

    En la búsqueda de aleaciones para usos odontológicos, económicamente alternativas, se trabaja con tres aleaciones Ag-Pd complejas, del tipo Ag-Pd-Au-Cu-Otros, dos aleaciones experimentales y un producto comercial. Se determinan las propiedades mecánicas y químicas de estas aleaciones y se hace un análisis comparativo de los resultados. El costo, factor importante, se establece con relación a los materiales del producto comercial. Se determina la dureza Vickers de las aleaciones Ag-Pd con diversos tratamientos térmicos, lo que permite mostrar su versatilidad en cuanto a usos restauradores y clasificarlas según norma. Se determina su comportamiento electroquímico y la resistencia a la pigmentación, lo que permite comparar las tendencias exhibidas. Se concluye que las propiedades químicas son aceptables cuando se compara con aleaciones odontológicas de referencia. Se instalaron en boca aleaciones experimentales A1 y A2, hace más de un año, con resultados satisfactorios hasta

  16. Characteristic of Al-Si-Cu Alloy Technology%Al-Si-Cu合金工艺的特点

    Institute of Scientific and Technical Information of China (English)

    冯俊

    2002-01-01

    Al-Si-Cu合金中最典型的Al-Si9-Cu4合金为对象,比较Al-Si-Cu合金熔炼(重熔)工艺和压铸工艺诸多要素中的几个主要工艺因素对压铸试样力学性能的影响,揭示了Al-Si-Cu合金的某些工艺特点,为进一步研究和更好地应用Al-Si-Cu合金提供参考.

  17. Desarrollo y caracterización de aleaciones Ti-Nb-Sn obtenidas por vía pulvimetalúrgica.

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    Devesa Albeza, Francisco

    2013-01-01

    Las aleaciones de titanio con microestructura ß destacan sobre todo por sus buenas propiedades específicas, su resistencia a la corrosión y por su bajo módulo elástico que las hacen muy apropiadas para su utilización como biomaterial en implantología ya que reducen de forma drástica fenómenos indeseados como el apantallamiento de tensiones. Existen grandes dificultades para procesar este tipo de aleaciones pero la pulvimetalurgia convencional se muestra como una de las mejores opciones. U...

  18. Al-Si/B4C composite coatings on Al-Si substrate by plasma spray technique

    International Nuclear Information System (INIS)

    Plasma-sprayed coatings of Al-Si/B4C have been prepared on Al-Si piston alloys for diesel engine motors. The Al-Si/B4C composite powders including 5-25 wt% B4C were prepared by mixing and ball-milling processes. These powders were deposited on Al-Si substrate using an atmospheric plasma spray technique. The coatings have been characterised with respect to phase composition, microstructure, microhardness, bond strength and thermal expansion. It was found that Al, Si, B4C and Al2O3 phases were determined in the coatings with approximately 600 μm thick by using X-ray diffraction analysis. Scanning electron microscope observation revealed that boron carbide particles were uniformly distributed in composite coatings and B4C particles were fully wetted by Al-Si alloy. Also, no reaction products were observed in Al-Si/B4C composite coatings. It was found that surface roughness, porosity, bond strength and thermal expansion coefficient of composite coatings decreased with increasing fraction of the boron carbide particle. It was demonstrated that the higher the B4C content, the higher the hardness of coatings because the hardness of B4C is higher than that of Al-Si

  19. Description of hypoeutectic Al-Si-Cu alloys based on their known chemical compositions

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    Djurdjevic, M. B.

    2013-10-01

    interés durante las últimas décadas, y la cantidad de programas de simulación existentes en el mercado es un buen indicador del interés de la industria en este campo. La mayoría de los datos empleados en estos programas se basan en los diagramas de fase binarios, ternarios o incluso superiores. Desafortunadamente, excepto para los diagramas binarios, el ajuste de los datos no es lo suficiente bueno. Teniendo en cuenta que la mayoría de los sistemas binarios del aluminio están bien definidos se ha intentado convertir los sistemas multi-componentes en un pseudo binario sistema Al-Xi (en este caso el diagrama de fase Al-Si es el elegido como sistema de referencia. El nuevo algoritmo del Silicio Equivalente (SiEQ expresa la cantidad de los elementos de la aleación que son mayoritarios y minoritarios, a través de una cantidad “equivalente” de silicio. Este sistema puede emplearse para calcular varias características termo-físicas y de solidificación de sistemas multicomponentes, como las aleaciones de aluminio. Esto permite al modelo tener la capacidad de realizar predicciones de las características de la solidificación de las piezas fundidas, donde las velocidades de enfriamiento son bajas y las características del proceso de solidificación son bien conocidas, para evitar posibles problemas en la fundición. Este trabajo demuestra cómo el algoritmo del SiEQ puede ser empleado para el cálculo de las características de las temperaturas de solidificación de las aleaciones multi-componentes Al-Si, así como sus calores latentes y el factor de restricción del crecimiento del grano. El análisis estadístico de los resultados obtenidos en un amplio rango de composiciones químicas de la aleación, muestra una muy buena correlación entre los datos experimentales y los cálculos realizados con el SiEQ. La misma aproximación matemática podría ser aplicada para otros sistemas metálicos como el hierro y el magnesio, empleando el carbono equivalente en el

  20. X-Ray Videomicroscopy Studies of Eutectic Al-Si Solidification in Al-Si-Cu

    Science.gov (United States)

    Mathiesen, R. H.; Arnberg, L.; Li, Y.; Meier, V.; Schaffer, P. L.; Snigireva, I.; Snigirev, A.; Dahle, A. K.

    2011-01-01

    Al-Si eutectic growth has been studied in-situ for the first time using X-ray video microscopy during directional solidification (DS) in unmodified and Sr-modified Al-Si-Cu alloys. In the unmodified alloys, Si is found to grow predominantly with needle-like tip morphologies, leading a highly irregular progressing eutectic interface with subsequent nucleation and growth of Al from the Si surfaces. In the Sr-modified alloys, the eutectic reaction is strongly suppressed, occurring with low nucleation frequency at undercoolings in the range 10 K to 18 K. In order to transport Cu rejected at the eutectic front back into the melt, the modified eutectic colonies attain meso-scale interface perturbations that eventually evolve into equiaxed composite-structure cells. The eutectic front also attains short-range microscale interface perturbations consistent with the characteristics of a fibrous Si growth. Evidence was found in support of Si nucleation occurring on potent particles suspended in the melt. Yet, both with Sr-modified and unmodified alloys, Si precipitation alone was not sufficient to facilitate the eutectic reaction, which apparently required additional undercooling for Al to form at the Si-particle interfaces.

  1. Quality analysis of the Al-Si-Cu alloy castings

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2007-04-01

    Full Text Available The developed design methodologies both the material and technological ones will make it possible to improve shortly the quality of materials from the light alloys in the technological process, and the automatic process flow correction will make the production cost reduction possible, and - first of all - to reduce the amount of the waste products. Method was developed for analysis of the casting defects images obtained with the X-ray detector analysis of the elements made from the Al-Si-Cu alloys of the AC-AlSi7Cu3Mg type as well as the method for classification of casting defects using the artificial intelligence tools, including the neural networks; the developed method was implemented as software programs for quality control. Castings were analysed in the paper of car engine blocks and heads from the Al-Si-Cu alloys of the AC-AlSi7Cu3Mg type fabricated with the “Cosworth” technological process. The computer system, in which the artificial neural networks as well as the automatic image analysis methods were used makes automatic classification possible of defects occurring in castings from the Al-Si-Cu alloys, assisting and automating in this way the decisions about rejection of castings which do not meet the defined quality requirements, and therefore ensuring simultaneously the repeatability and objectivity of assessment of the metallurgical quality of these alloys.

  2. Prediction of hardness of the Zn-Al-Cu alloys of agreement by composition in weight; Prediccion de la dureza de la aleacion Zn-Al-Cu de acuerdo a su composicion en peso

    Energy Technology Data Exchange (ETDEWEB)

    Villegas-Cardenas, Jose David; Camarillo-Villegas, Alejandra; Juanico-Loran, Antonio [Universidad Politecnica del Valle de Mexico, Tultitlan, Estado de Mexico (Mexico)]. E-mails: jdvc76@yahoo.com.mx; v_c_a_77@hotmail.com; ajuanico@yahoo.com.mx; Espinosa-Rojas, Raul [Universidad Autonoma Metropolitana, Unidad Azcapotzalco (Mexico)]. E-mail: rer21@hotmail.com; Camacho-Olguin, Carlos [Universidad Politecnica del Valle de Mexico, Tultitlan, Estado de Mexico (Mexico)]. E-mail: ccamacho@upvm.edu.mx

    2013-07-15

    Ten alloys Zn-Al-Cu were developed in two parts, in agreement to two zones presented in the isopleth diagrams (Villas et al., 1995). The percentage of Cu and Al was systematically varied. Subsequently, hardness measurements were performed. These measurements allowed establishing two equations that predict the hardness with an error lower than 5%. With these equations, it is possible to obtain alloys that replace Al base alloys by a Zn base alloy, having the same hardness. This implicates also the elimination of the volumetric change in the presence of e phase. [Spanish] Se desarrollaron diez aleaciones Zn-Al-Cu divididas en dos partes, de acuerdo a dos zonas presentadas en los diagramas isopleticos de Hans (Villas et al., 1995). Se incremento el porcentaje de Cu y Al paulatinamente. Posteriormente se desarrollaron pruebas de macrodureza y de ese analisis se obtuvieron dos ecuaciones que permiten pronosticar y disenar aleaciones de una dureza determinada de acuerdo a su porcentaje en peso de cada elemento, con un error menor que 5%. Como se demuestra en este trabajo, con estas ecuaciones es posible desarrollar aleaciones sustitutas base aluminio por una aleacion base zinc o viceversa, teniendo la misma dureza para cada tipo de aleacion y eliminando el problema del cambio volumetrico debido a la presencia de la fase e.

  3. Mechanism of Corrosion in Al-Si-Cu

    Science.gov (United States)

    Hayasaka, Nobuo; Koga, Yuri; Shimomura, Koji; Yoshida, Yukimasa; Okano, Haruo

    1991-07-01

    An Al-Cu local cell was formed between the Cu precipitation and adjacent Al in an Al-Si-Cu alloy when Cu was added in excess to the alloy. Once an Al-Cu local cell was formed, corrosion took place simply by dipping the alloy in deionized water without any contamination. Furthermore, it was found that corrosion was enhanced at the Al-Si-Cu lines in contact with the p+-n junction of Si. The reason for this is that holes are injected into Al-Si-Cu from p+-Si due to electromotive force produced by light irradiation and an external circuit connecting the alloy and n-Si formed by the adsorption of moisture on the surface. Furthermore, it was found that the irradiation of light with a wavelength between 320 to 380 nm was most effective in enhancing the corrosion reaction.

  4. Influence of silicon concentration on linear contraction process of Al-Si binary alloy

    OpenAIRE

    J. Mutwil; Kujawa, K.; Marczewski, P.; P. Michajłow

    2008-01-01

    Investigations of shrinkage phenomena during solidification and cooling of aluminium and aluminium-silicon alloys (AlSi5, AlSi7, AlSi9, AlSi11, AlSi12.5, AlSi18, AlSi21) have been conducted. A vertical shrinkage rod casting with circular cross-section (constant or fixed: tapered) has been used as a test sample. By constant cross-section a test channel mould was parted and allowed a constrained contraction to examine. No parted test channel mould was tapered and allowed an unconstrained contra...

  5. TEMPERATURE DEPENDENCE OF VISCOSITY OF Al-Si ALLOY MELTS

    Institute of Scientific and Technical Information of China (English)

    H.R. Geng; R. Wang; Z.X. Yang; J.H. Chen; C.J. Sun; Y. Wang

    2005-01-01

    The relationship between the viscosity and temperature of Al-Si alloy melts was investigated.The viscosity of three different types of Al-Si alloy melts was measured. It was showed that the relationship between the viscosity and temperature of hypoeutectic Al-5% Si and eutectic Al12.5%Si alloy melts is approximately exponential except for some special zones, but that of the hypereutectic melt is different. The paper discussed the correlation of the viscosity and atomic density, which is thought that the viscosity corresponds to the atomic density to some extent.

  6. Laser surface treatment of cast Al-Si-Cu alloys

    OpenAIRE

    K. Labisz

    2013-01-01

    Purpose: The test results presented in this chapter concern formation of the quasi-composite MMCs structure on the surface of elements from aluminium cast alloys AC-AlSi9Cu and AC-AlSi9Cu4 by fusion of the carbide or ceramic particles WC, SiC, ZrO2 and Al2O3 in the surface of alloys. In addition, within the scope of the tests the phase transformations and precipitation processes present during laser remelting and fusion at appropriately selected parameters: laser power, the ra...

  7. Caracterización mecánica de aleaciones Ti-Nb mediante ensayos de flexión biaxial

    Directory of Open Access Journals (Sweden)

    Amigó, V.

    2010-12-01

    Full Text Available Nowadays titanium and titanium alloys are increasingly being used in the industry. Particularly β-Ti alloys that stand out for having great strength properties and low elastic modulus compared to Ti c.p. or Ti-6Al-4V. Among Ti alloys, Ti-Nb alloys with high contents of alloying elements are widely used. In this work Ti-Nb alloys have been obtained using conventional powdermetallurgy. It has been studied the evolution of properties of these alloys as a function of the percentage of niobium. It can be noted the ball on three balls test used in order to characterize the samples.

    En la actualidad, cada vez, son más importantes en la industria las aleaciones de titanio. En especial las aleaciones tipo-β, que destacan por tener buenas propiedades resistentes y bajos módulos elásticos, en comparación con el Ti c.p. o el Ti-6Al-4V. Dentro de estas aleaciones cabe destacar las Ti-Nb con altos contenidos en elementos aleantes. En este trabajo se han obtenido, mediante pulvimetalurgia convencional, una serie de aleaciones Ti-Nb, en el rango del 20-40 % de niobio. Se ha obtenido la evolución de las propiedades de dichas aleaciones en función del porcentaje de niobio, mediante la utilización del ensayo de flexión biaxial con tres apoyos (three ball test.

  8. Study of the U(Al,Si)3 vertex location in the 400°C isothermal section of the U-Al-Si phase diagram

    International Nuclear Information System (INIS)

    Ternary U-Al-Si system has been extensively investigated due to the high potential of Uranium alloyed with Silicon as low-enriched fuel. Another interest in the U-Al-Si ternary system originates from the use of Aluminum alloy, where Silicon is a major alloying element, as U-fuel cladding. Due to the high exploitation temperature, U-Al-Si interaction layer forms among the Uranium fuel and Al-Si-alloy cladding. Thus, investigation of the U-Al-Si system is of technological importance. In order to perform thermodynamic modeling (one of the options to study the ternary U-Al-SI phase diagram) the exact composition of invariant points and exact homogeneity ranges of intermetallides formed in this phase diagram have to be determined empirically. In the past, thermodynamic modeling of the U-Al-Si system was based on the isothermal section suggested by Dwight. In this work the U(Al,Si)3 ordered phase was not identified, whereas in a later research it was found to be stable in a wide range of compositions. This emphasizes the need to verify his results. U(Al,Si)3 vertex is one of the critical locations required for thermodynamic calculations . With an intention to either contradict or support previous results on the U(Al,Si)3 vertex location, two alloys with different compositions existing within the Al-Si-U(Al,Si)3 triangle were characterized. The alloys were heat treated in order to obtain equilibrium state. Phase characterization of the alloys was performed using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Rietveld method was applied on XRD data for quantitative analysis. Experimental results imply that the location of the U(Al,Si)3 vertex should be at 25at.% U-13at.% Al- 62at.%Si. This result contradicts previous results reported in

  9. Dendrite coherency of Al-Si-Cu alloys

    Science.gov (United States)

    Veldman, Natalia L. M.; Dahle, Arne K.; Stjohn, David H.; Arnberg, Lars

    2001-01-01

    The dendrite coherency point of Al-Si-Cu alloys was determined by thermal analysis and rheological measurement methods by performing parallel measurements at two cooling rates for aluminum alloys across a wide range of silicon and copper contents. Contrary to previous findings, the two methods yield significantly different values for the fraction solid at the dendrite coherency point. This disparity is greatest for alloys of low solute concentration. The results from this study also contradict previously reported trends in the effect of cooling rate on the dendritic coherency point. Consideration of the results shows that thermal analysis is not a valid technique for the measurement of coherency. Analysis of the results from rheological testing indicates that silicon concentration has a dominant effect on grain size and dendritic morphology, independent of cooling rate and copper content, and thus is the factor that determines the fraction solid at dendrite coherency for Al-Si-Cu alloys.

  10. Quantification of precipitate fraction in Al-Si-Cu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Z. [Sente Software Ltd., Surrey Technology Centre, Guildford GU2 7YG (United Kingdom); Sha, W. [Metals Research Group, School of Civil Engineering, Queen' s University of Belfast (United Kingdom)]. E-mail: w.sha@qub.ac.uk

    2005-02-15

    Quantification of precipitate fraction is difficult when the precipitates formed are of low volume fraction. A simple method is proposed in the present work to estimate the precipitate fraction of Al{sub 2}Cu phase in Al-Si-Cu alloys based on X-ray diffraction analysis. The change in the lattice parameter of the matrix due to ageing, measured from X-ray diffraction profiles, is correlated to the fraction of Al{sub 2}Cu phase formed during ageing. JMatPro, a software package for calculating the properties of metallic systems, is used to calculate the phase constitution and composition in the Al-Si-Cu alloys studied after different heat treatments. Factors that affect the lattice parameter of the matrix have been discussed and considered in the calculations.

  11. Phase diagram of the Nb-Al-Si ternary system

    International Nuclear Information System (INIS)

    A high-efficiency diffusion-multiple approach was employed to map the phase diagram of the Nb-Al-Si ternary system which is very valuable for the design of niobium silicide-based composites. These composites have high potential as a replacement for Ni-base superalloys for jet engine applications. Aluminum is an alloying element for these composites, thus the Nb-Al-Si phase diagram, especially solubility of Al in Nb5Si3, is important information for the composite design. An isothermal section at 1000 deg. C was constructed from the results obtained from a diffusion multiple using scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). A ternary phase Nb3Si5Al2 was observed. The solubility data of Al in αNb5Si3 and NbSi2 as well as Si solubility in Nb3Al, Nb2Al and NbAl3 were obtained. The new isothermal section helps to judge the reliability of the existing literature results and to add new data to the Nb-Al-Si phase equilibria

  12. Microstructure analysis of the automotive Al-Si-Cu castings

    Directory of Open Access Journals (Sweden)

    M. Krupiński

    2008-04-01

    Full Text Available The developed design methodologies both the material and technological ones will make it possible to improve shortly the quality of materials from the light alloys in the technological process, and the automatic process flow correction will make the production cost reduction possible, and - first of all - to reduce the amount of the waste products. In the metal casting industry, an improvement of component quality depends mainly on better control over the production parameters.Castings were analysed in the paper of car engine blocks and heads from the Al-Si-Cu alloys of the AC-AlSi7Cu3Mg type fabricated with the “Cosworth” technological process. In this work the AC-AlSi7Cu3Mg alloy structure was investigated, of this alloy samples were cut of for structure analysis of the cylinder part as well of crankshaft of a fuel engine. The investigation shows a difference in the (phase structure morphology as a result of cast cooling rate.

  13. Silicon determination in AlSi and AlSiCu alloys using X-ray fluorescence analysis

    International Nuclear Information System (INIS)

    A technique of sample preparation of AlSi and AlSiCu alloys was developed allowing silicon determination by X-ray fluorescence analysis. High-frequency sample remelting followed by centrifugal casting will guarantee to a sufficient extent the same rate and conditions of melt solidification for all samples, and thus also silicon crystallization in the alloys. This permits rapid and reliable X-ray spectrometric determination of silicon within 2 to 13% Si and of other elements in the alloy samples. The accuracy of silicon determination by this method matches that of chemical analysis. The relative standard deviation was found to be 1.1% for ten castings of the same sample. (J.B.). 4 figs., 2 tabs., 8 refs

  14. Fundamentals of GNF Al-Si-O Additive Fuel

    International Nuclear Information System (INIS)

    The aluminosilicate (Al-Si-O) additive fuel has been developed by GNF/NFD as a candidate of the PCI/SCC resistant material. The PCI/SCC resistance has been demonstrated by power ramp tests and all the additive fuel rods survived[1]. The prominent performance of the additive fuel originates from the microstructure, which contributes to pellet softening, lower fission gas release and immobilization of corrosive fission products such as Cd and Cs for SCC. These characteristics have been investigated by several in-pile and out-of-pile tests, and a lot of basic properties and comprehensive PIE of the additive fuel have been presented so far[2,3]. As a result, GNF Al-Si-O Additive Fuel is well accepted to be one of the key technologies for Defense in Depth concept. This paper will present two of main characteristics of the additive fuel i.e. mechanical properties and chemical effect of additive. As part of mechanical property, new data on steady state creep and yield strength of the fresh additive fuel will be presented. The creep rate of the additive fuel is higher than standard UO2 fuel. The yield strength of the additive fuel is decreased by Al-Si-O addition. These results imply 'softer pellet' which reduce stress and strain on the cladding during reactor operation. Some demonstrations are obtained on the chemical reaction between the fresh additive fuel and Cs/Cd. Firstly, thermodynamic calculations for Cs-M-O system (M = Mo, Zr, Si, Cr) are conducted. The result shows that Cs could react with Al-Si-O and exist as cesium silicate in the fuel rod environment, indicating chemical trap effect of Cs by Al-Si-O theoretically. Secondly, the microanalysis and phase identification for Al-Si- O additive phase by using focused ion beam system (FIB) and transmission electron microscopy (TEM) technique are presented. Finally, the demonstration of chemical reaction between the additive fuel and Cs/Cd is introduced. The chemical reaction of the additive phase with Cs/Cd is

  15. Thermodynamic prediction of thixoformability in alloys based on the Al-Si-Cu and Al-Si-Cu-Mg systems

    Energy Technology Data Exchange (ETDEWEB)

    Liu, D. [Department of Engineering, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Atkinson, H.V. [Department of Engineering, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Jones, H. [Department of Engineering Materials, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD (United Kingdom)

    2005-08-15

    Most commercial semi-solid processing (of which thixoforming is one type) utilises the conventional casting alloys A356 and A357. There is, however, a demand to widen the range of alloys, including those with higher performance which tend to show poor characteristics for thixoforming. Thermodynamic calculation packages, such as MTDATA, provide a tool for predicting thixoformability. Here, the effects of compositional variations, in particular the effect of added copper on the thixoformability of alloy A356 and the effect of added silicon on the thixoformability of alloy 2014, have been investigated using MTDATA thermodynamic and phase equilibrium software combined with the MTAL database. Criteria for thixoformability are identified and a range of alloy compositions based on Al-Si-Cu and Al-Si-Cu-Mg evaluated in relation to these criteria. Compositions which satisfy these criteria include: 308 (Al-5.5Si-4.5Cu); 319 (Al-6Si-3.5Cu); 238 (Al-10Cu-4Si-0.3Mg); 355 (Al-5Si-1.3Cu-0.5Mg); 2014 based alloys Al-4.4Cu-0.5Mg-(4-6)Si; and a range of alloys (7.5 Si + Cu 9 and 1.5 Si/Cu 2.33) and alloys (9 < Si + Cu 10 and Si/Cu = 1.5) based on the Al-Si-Cu-Mg system.

  16. Aluminio pulvimetalúrgico: desarrollo y mejora de sus aleaciones y materiales compuestos

    Directory of Open Access Journals (Sweden)

    Ruiz-Navas, E. M.

    2008-06-01

    Full Text Available Powder metallurgy components demand is increasing in the last few years mainly due to the necessity of products assigned to automotive and aerospace industries, which has allow an important development of aluminium alloys and composites (AMCs. Consolidation of aluminium alloys by sintering present a main problem: the oxide layer that cover aluminium particles. Several alternatives are studied in this work as solution to the oxide layer problem during the sintering of series 2xxx aluminium alloys. One of these solutions is related to the addition of tin traces, and the other is the addition of a second alloy. Moreover, aluminium metal matrix composites are characterized by excellent properties as combination of properties which comes from the matrix and from the reinforcement. The last part of this study is focused to the analysis of one aluminium matrix composite as the influence of several quantities of reinforcement.

    El auge en la demanda de componentes pulvimetalúrgicos destinados principalmente al sector automovilístico y aeroespacial ha permitido un fuerte desarrollo tanto de aleaciones como de MMCs base aluminio (AMCs. El principal problema a la hora de consolidar estos materiales vía pulvimetalúrgica es la capa de óxido que recubre a las partículas de aluminio. En este trabajo se presentan varias alternativas como solución a este problema, aplicadas a la consolidación de aleaciones de aluminio pertenecientes a la serie 2xxx, entre ellas, la adición de trazas de estaño y la adición de una aleación Al-Si. En cuanto a los materiales compuestos de matriz de aluminio, se caracterizan por presentar propiedades únicas como combinación de las propiedades individuales que caracterizan tanto a la matriz como al refuerzo. En la última parte de este trabajo se estudia la consolidación de un material compuesto así como la influencia de las distintas cantidades de refuerzo.

  17. Crystal structural refinement for NdAlSi

    Institute of Scientific and Technical Information of China (English)

    HE Wei; ZHANG Jiliang; ZENG Lingmin; ZHUANG Yinghong

    2006-01-01

    The compound NdAlSi was studied using X-ray powder diffraction technique and refined by the Rietveld method. The compound NdAlSihas tetragonal α-ThSi2-type structure, space group I41/amd (No.141), Z = 4, and the lattice parameters a = 0.41991(1) nm, c = 1.44916(3) nm. The Smith and Snyder figure of merit FN is F30= 103.1(36). The R-factors of Rietveld refinement are Rp= 0.113 and Rwp= 0.148, respectively. The X-ray powder diffraction data is presented in this article.

  18. Polythermal cutting of Al-Si-YAl2 system

    International Nuclear Information System (INIS)

    Given the out come of the research of the Al-Si-YAl2 system with studies of polythermal cutting. It was found out that the most cutting of Al-YSi2Al2, Al-YSiAl2, Al-Y5SiAl14, YSiAl2-YSi2Al2, Y5SiAl14-YSiAl2 and Y5SiAl14-YAl2, Si-YSiAl2 has the nature of quasibinary eutectics

  19. New orthorhombic phase in U-Fe-Al-Si system

    Energy Technology Data Exchange (ETDEWEB)

    Zenou, V.Y. [Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Nuclear Research Center - Negev, P.O. Box 9001, Beer-Sheva 84190 (Israel); Ezersky, V.; Meshi, L.; Fuks, D. [Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Talianker, M., E-mail: mital@bgu.ac.il [Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel)

    2011-01-12

    Research highlights: > In this paper we report on the results of structure investigation of a new quaternary phase observed in U-Fe-Al-Si system. > The composition of this phase is: U-18.6 at% Fe-29.2 at% Al-32.6 at% Si. > This phase is orthorhombic and its symmetry can be described by the Immm space group. > The unit cell parameters of the new phase are: a = 12.241 A, b = 18.362 A and c = 4.066 A. > Structural investigations were performed using electron microscopy, X-ray powder diffraction, conventional and convergent beam electron diffraction techniques. - Abstract: A new quaternary phase with the approximate composition U-18.6 at%Fe-29.2 at%Al-32.6 at%Si was observed in U-Fe-Al-Si system. The crystal structure of this phase was investigated by electron diffraction and X-ray powder diffraction techniques. It has an orthorhombic unit cell with lattice parameters a = 12.241 A, b = 18.362 A and c = 4.066 A and can be described by the Immm space group.

  20. New orthorhombic phase in U-Fe-Al-Si system

    International Nuclear Information System (INIS)

    Research highlights: → In this paper we report on the results of structure investigation of a new quaternary phase observed in U-Fe-Al-Si system. → The composition of this phase is: U-18.6 at% Fe-29.2 at% Al-32.6 at% Si. → This phase is orthorhombic and its symmetry can be described by the Immm space group. → The unit cell parameters of the new phase are: a = 12.241 A, b = 18.362 A and c = 4.066 A. → Structural investigations were performed using electron microscopy, X-ray powder diffraction, conventional and convergent beam electron diffraction techniques. - Abstract: A new quaternary phase with the approximate composition U-18.6 at%Fe-29.2 at%Al-32.6 at%Si was observed in U-Fe-Al-Si system. The crystal structure of this phase was investigated by electron diffraction and X-ray powder diffraction techniques. It has an orthorhombic unit cell with lattice parameters a = 12.241 A, b = 18.362 A and c = 4.066 A and can be described by the Immm space group.

  1. Laser surface treatment of cast Al-Si-Cu alloys

    Directory of Open Access Journals (Sweden)

    K. Labisz

    2013-12-01

    Full Text Available Purpose: The test results presented in this chapter concern formation of the quasi-composite MMCs structure on the surface of elements from aluminium cast alloys AC-AlSi9Cu and AC-AlSi9Cu4 by fusion of the carbide or ceramic particles WC, SiC, ZrO2 and Al2O3 in the surface of alloys. In addition, within the scope of the tests the phase transformations and precipitation processes present during laser remelting and fusion at appropriately selected parameters: laser power, the rate of fusion and quantity of the ceramic powder fed have been partially examined. Design/methodology/approach: In general, the laser surface processing should result in achievement of the surface layer with the most favourable physical and mechanical properties, in particular enhancement of surface hardness, improvement of abrasion resistance and resistance to corrosion is assumed in relation to the selected aluminium alloys after standard thermal processing. Findings: The presented results of the surface layer include analysis of the mechanisms responsible for formation of the layer, and particularly concern remelting of the substrate and its crystallisation at various parameters of the High Power Diode Laser (HPDL and the technological conditions of the surface processing, remelting and fusion of the particles in the surface of cast alloys ACAlSi9Cu and ACAlSi9Cu4. For the purpose of testing the structure of the obtained surface layers the test methods making use of the light microscopy method supported with computer image analysis, transmission and scanning electron microscopy, X-ray analysis, X-ray microanalysis, as well as methods for testing the mechanical and usable properties have been used. Practical implications: What is more, development of the technology of surface refinement of cast alloys Al-Si-Cu with the laser fusion methods will allow for complex solving of the problem related to enhancement of the surface layer properties, taking into account both economic

  2. Plaster mould casting process of AlSi11 alloy

    Directory of Open Access Journals (Sweden)

    R. Władysiak

    2009-07-01

    Full Text Available The paper presents the results of the crystallization and cooling process of AlSi11 silumin in the plaster mould with TDA method and describes the impact of the preparation of plaster mould and liquid silumin on received microstructure and quality of casting. The effect of the pouring temperature of silumin on porosity and filling of mould cavity was investigated. The nature and rate of change of temperature in casting and the formation of the microstructure was shown by means thermal and derivative curves. Through the use of control samples in range of a thickness of 0.5 ÷ 4 mm confirmed the possibility of obtaining thin-walled silumin castings in pre-heated before plaster moulds. It has been proved that changing the parameters of pre-treatment moulds of gypsum, the pouring temperature and modification of silumin you can control the crystallization process, obtained microstructure and properties Rm, RP02 and HB.

  3. Fatigue of an Al-Si gravity die casting alloy

    Energy Technology Data Exchange (ETDEWEB)

    Styles, C.M. [Defence Evaluation and Res. Agency, Farnborough (United Kingdom). MSS; Reed, P.A.S.

    2000-07-01

    Fatigue crack initiation, short crack and long crack growth studies were performed on a high performance cast piston type alloy (Al-Si-Cu-Ni-Mg). Crack initiation was mainly associated with large blocky Si particles although a few cracks were initiated at clusters of FeNiAl{sub 9} intermetallics. Classical short crack growth was shown with crack arrest for up to 15000 fatigue cycles at second phase particles. Long crack growth showed no evidence of stage I like facets near threshold or ductile striations in the mid {delta}K region. A large number of fractured Si particles were, however, observed on the fracture surfaces and crack profiles the incidence of which increased with {delta}K. The findings of this study suggest this alloy is brittle in nature with the Si particle content generally controlling fatigue crack initiation and growth. (orig.)

  4. Growth restriction factor in Al-Si-Mg-Cu alloys

    International Nuclear Information System (INIS)

    The Growth Restriction Factor, Q, proved to be useful to analyse and control grain refinement during solidification of alloys. It is known that in multicomponent alloys a simple summation of the Qi values of the individual constituents taken from the binary phase diagrams can lead to grossly wrong results and that the ternary or higher-level phase diagram needs to be evaluated. This work demonstrates that the actual evaluation of Q using the liquidus gradient and partition coefficients of the multicomponent phase diagram requires some precautions and may be cumbersome. More importantly, this approach entirely fails if an intermetallic phase turns out to be the primary solidifying phase even in tiny amount. A very simple and general solution of this problem is illustrated for Al-Si-Mg-Cu alloys.

  5. Influence of technological factors on eutectic silicon morphology in Al-Si alloys

    OpenAIRE

    P. Skocovský; E. Tillová; Belan, J.

    2009-01-01

    From the background about Al-Si alloys modifying from eutectic silicon morphology and mechanical properties relation point of view is at solving of chosen technological problems used structural analysis and Si morphology quantification. There were solved two concrete problems: parameters of solution annealing AlSi9Cu3 alloy and confirming of laser treatment influence on AlSi7Mg0.3 alloy structure. In both cases have material heating caused spheroidization of eutectic silicon. Optimal regime o...

  6. Novel insights into the tribology of hypereutectic AlSi cylinder bore surfaces; Neue Erkenntnisse zur Tribologie von uebereutektischen AlSi-Zylinderlaufflaechen

    Energy Technology Data Exchange (ETDEWEB)

    Dienwiebel, M.; Scherge, M. [IAVF Antriebstechnik AG, Karlsruhe (Germany)

    2007-03-15

    Aluminium alloys remain highly attractive for weight reduction measures. Yet the fundamental mechanisms on the nanometre scale which dominate friction and wear are still largely unexplored. Using state-of-the-art surface analytical tools scientists at IAVF Antriebstechnik AG have studied the cylinder bore surface of a hypereutectic AlSi crankcase. These investigations led to a new model that is able to explain a number of wear phenomena of AlSi materials. (orig.)

  7. Compositions and morphologies of TiAlSi intermetallics in different diffusion couples

    International Nuclear Information System (INIS)

    Two kinds of diffusion couples were designed to investigate the formation of ternary TiAlSi phases in Al–Si–Ti alloys. It was found that different diffusion processes result in various compositions and morphologies of TiAlSi intermetallics. The melted Al, Si and Ti atoms in the diffusion couple leads to the formation of flake-like TiAlSi phase through liquid–liquid reaction. Besides, unidirectional diffusion of Al and Si atoms into blocky TiAl3 particles or Ti powders via a liquid–solid diffusion process also results in the formation of TiAlSi, while keeping the block-like morphology. This kind of diffusion is a gradual process, driven by the concentration gradient. The reactions in the diffusion couples are helpful to understand the compositional and morphological evolutions of TiAlSi as reported in previous work. - Highlights: • Two diffusion couples were designed to investigate the formation of TiAlSi phases. • Compositions and morphologies of TiAlSi are influenced by the diffusion process. • Liquid–liquid and liquid–solid diffusions were detected. • The corresponding mechanisms were discussed

  8. Influence of silicon concentration on linear contraction process of Al-Si binary alloy

    Directory of Open Access Journals (Sweden)

    J. Mutwil

    2008-12-01

    Full Text Available Investigations of shrinkage phenomena during solidification and cooling of aluminium and aluminium-silicon alloys (AlSi5, AlSi7, AlSi9, AlSi11, AlSi12.5, AlSi18, AlSi21 have been conducted. A vertical shrinkage rod casting with circular cross-section (constant or fixed: tapered has been used as a test sample. By constant cross-section a test channel mould was parted and allowed a constrained contraction to examine. No parted test channel mould was tapered and allowed an unconstrained contraction to investigate. In the experiments the dimensions changes of solidifying test bar and the test mould have been registered, what has allowed to explain a mechanism of pre-shrinkage extension of solidifying metals and alloys. Registered time dependence of the test bar and the test mould dimension changes have shown, that so-called pre-shrinkage extension has been by mould thermal extension caused. The investigation results have also shown that time- and temperature dependences of shrinkage of Al-Si alloys have been on silicon concentration depended.

  9. Refining Effect of Boron on Hypoeutectic Al-Si Alloys

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@Several concepts of the grain refinement mechanism of B on hypoeutectic Al-Si alloys have been adopted: the refining effect of B on the α-Al and eutectic Si with the different additions of Al-B master alloys made at 850℃ was investigated; and the Al-B master alloys formed under different temperature conditions have been studied to explore the morphologies of AlB2 particles;slowly cooled sample with addition of Al-B was made to explore the refinement mechanism. AlB master alloy can refine not only α-Al, but eutectic Si. Theoretical analysis indicates that,although AlB2 does not take part directly in the nucleation process in pure Al in the presence of Si, it provides a substrate for precipitation of a small content of Si from which α-Al will grow without any undercooling. When the temperature decreases to eutectic line, AlB2 subsequently nucleates eutectic Si; AlB2 particles appear in two different morphologies, namely, hexagonal platelet and tetradehedron morphology which depend on the processing temperature conditions.

  10. Wear resistance of TiAlSiN thin coatings.

    Science.gov (United States)

    Silva, F J G; Martinho, R P; Alexandre, R J D; Baptista, A P M

    2012-12-01

    In the last decades TiAIN coatings deposited by PVD techniques have been extensively investigated but, nowadays, their potential development for tribological applications is relatively low. However, new coatings are emerging based on them, trying to improve wear behavior. TiAlSiN thin coatings are now investigated, analyzing if Si introduction increases the wear resistance of PVD films. Attending to the application, several wear test configurations has been recently used by some researchers. In this work, TiAISiN thin coatings were produced by PVD Unbalanced Magnetron Sputtering technique and they were conveniently characterized using Scanning Electron Microscopy (SEM) provided with Energy Dispersive Spectroscopy (EDS), Atomic Force Microscopy (AFM), Electron Probe Micro-Analyzer (EPMA), Micro Hardness (MH) and Scratch Test Analysis. Properties as morphology, thickness, roughness, chemical composition and structure, hardness and film adhesion to the substrate were investigated. Concerning to wear characterization, two very different ways were chosen: micro-abrasion with ball-on-flat configuration and industrial non-standardized tests based on samples inserted in a feed channel of a selected plastic injection mould working with 30% (wt.) glass fiber reinforced polypropylene. TiAISiN coatings with a small amount of about 5% (wt.) Si showed a similar wear behavior when compared with TiAIN reported performances, denoting that Si addition does not improve the wear performance of the TiAIN coatings in these wear test conditions. PMID:23447962

  11. Microstructural development of rapid solidification in Al-Si powder

    Energy Technology Data Exchange (ETDEWEB)

    Jin, F.

    1995-11-01

    The microstructure and the gradient of microstructure that forms in rapidly solidificated powder were investigated for different sized particles. High pressure gas atomization solidification process has been used to produce a series of Al-Si alloys powders between 0.2 {mu}m to 150 {mu}m diameter at the eutectic composition (12.6 wt pct Si). This processing technique provides powders of different sizes which solidify under different conditions (i.e. interface velocity and interface undercooling), and thus give different microstructures inside the powders. The large size powder shows dendritic and eutectic microstructures. As the powder size becomes smaller, the predominant morphology changes from eutectic to dendritic to cellular. Microstructures were quantitatively characterized by using optical microscope and SEM techniques. The variation in eutectic spacing within the powders were measured and compared with the theoretical model to obtain interface undercooling, and growth rate during the solidification of a given droplet. Also, nucleation temperature, which controls microstructures in rapidly solidified fine powders, was estimated. A microstructural map which correlates the microstructure with particle size and processing parameters is developed.

  12. Microstructural Development in Al-Si Powder During Rapid Solidification

    Energy Technology Data Exchange (ETDEWEB)

    Amber Lynn Genau

    2004-12-19

    Powder metallurgy has become an increasingly important form of metal processing because of its ability to produce materials with superior mechanical properties. These properties are due in part to the unique and often desirable microstructures which arise as a result of the extreme levels of undercooling achieved, especially in the finest size powder, and the subsequent rapid solidification which occurs. A better understanding of the fundamental processes of nucleation and growth is required to further exploit the potential of rapid solidification processing. Aluminum-silicon, an alloy of significant industrial importance, was chosen as a model for simple eutectic systems displaying an unfaceted/faceted interface and skewed coupled eutectic growth zone, Al-Si powder produced by high pressure gas atomization was studied to determine the relationship between microstructure and alloy composition as a function of powder size and atomization gas. Critical experimental measurements of hypereutectic (Si-rich) compositions were used to determine undercooling and interface velocity, based on the theoretical models which are available. Solidification conditions were analyzed as a function of particle diameter and distance from nucleation site. A revised microstructural map is proposed which allows the prediction of particle morphology based on temperature and composition. It is hoped that this work, by providing enhanced understanding of the processes which govern the development of the solidification morphology of gas atomized powder, will eventually allow for better control of processing conditions so that particle microstructures can be optimized for specific applications.

  13. Fabrication of Spherical AlSi10Mg Powders by Radio Frequency Plasma Spheroidization

    Science.gov (United States)

    Wang, Linzhi; Liu, Ying; Chang, Sen

    2016-05-01

    Spherical AlSi10Mg powders were prepared by radio frequency plasma spheroidization from commercial AlSi10Mg powders. The fabrication process parameters and powder characteristics were investigated. Field emission scanning electron microscope, X-ray diffraction, laser particle size analyzer, powder rheometer, and UV/visible/infrared spectrophotometer were used for analyses and measurements of micrographs, phases, granulometric parameters, flowability, and laser absorption properties of the powders, respectively. The results show that the obtained spherical powders exhibit good sphericity, smooth surfaces, favorable dispersity, and excellent fluidity under appropriate feeding rate and flow rate of carrier gas. Further, acicular microstructures of the spherical AlSi10Mg powders are composed of α-Al, Si, and a small amount of Mg2Si phase. In addition, laser absorption values of the spherical AlSi10Mg powders increase obviously compared with raw material, and different spectra have obvious absorption peaks at a wavelength of about 826 nm.

  14. Influence of technological factors on eutectic silicon morphology in Al-Si alloys

    Directory of Open Access Journals (Sweden)

    P. Skocovský

    2009-04-01

    Full Text Available From the background about Al-Si alloys modifying from eutectic silicon morphology and mechanical properties relation point of view is at solving of chosen technological problems used structural analysis and Si morphology quantification. There were solved two concrete problems: parameters of solution annealing AlSi9Cu3 alloy and confirming of laser treatment influence on AlSi7Mg0.3 alloy structure. In both cases have material heating caused spheroidization of eutectic silicon. Optimal regime of AlSi9Cu3 alloy (515 °C/4 hrs. solution annealing was confirmed based on structural analysis, which have achieved fine globular silicon particles segregation and structural changes study at AlSi7Mg0,3 alloy after laser treatment showed improving of mechanical properties, proved also with metallography analysis. Modern methods of structure analysis application enable to spread present knowledge’s in area of technological research.

  15. Optimización de tratamientos térmicos cortos para aleaciones Al-Si conformadas en estado semi-sólido

    OpenAIRE

    Turegano Marchan, Sergi

    2010-01-01

    La industria actual demanda la disminución de costes en los procesos productivos así como la obtención de componentes de formas complejas, ligeros y con buenas propiedades mecánicas. Las técnicas de conformado en estado semisólido, como la Sub-Liquidus Casting (SLC) y Semisolid Rheocasting (SSR) estudiadas en este trabajos, ofrecen la posibilidad de obtener componentes con una alta complejidad de formas característica de las piezas de colada unidas a un buen control dimensional...

  16. Corrosion of high temperature resisting alloys exposed to heavy fuel ash; Corrosion de aleaciones resistentes a altas temperaturas expuestas a ceniza de combustoleo pesado

    Energy Technology Data Exchange (ETDEWEB)

    Wong Moreno, Adriana del Carmen

    1998-03-01

    aleaciones de diferente tipo (aceros de baja y media aleacion, aceros inoxidables ferriticos y austeniticos, aleaciones base niquel y una aleacion FeCrAl del tipo ODS) expuestas a temperaturas elevadas (580 grados Celsius - 900 grados Celsius) a 15 depositos de ceniza con diferente potencial corrosivo, los cuales fueron colectados de la zona de alta temperatura de calderas de centrales termoelectricas. Los estudios posteriores a los ensayos de corrosion consistieron en el analisis por microscopia electronica de barrido apoyada con microanalisis de las probetas corroidas, con el fin de determinar el efecto de Na, V y S sobre la corrosividad de los depositos de ceniza y el efecto de los principales elementos aleantes sobre la resistencia a la corrosion de las aleaciones. Tales efectos son ampliamente documentados y discutidos para apoyar los mecanismos propuestos de degradacion que estan operando. El analisis global de los resultados generados ha permitido proponer un modelo para explicar el mecanismo global de corrosion de aleaciones expuestas a altas temperaturas de depositos de ceniza. El modelo propuesto, complementa el elaborado por Wilson, ampliamente aceptado para vanadatos fundidos, en cuanto a que por un lado, considera el efecto de la presencia de sulfato de sodio (ademas de los compuestos de vanadio) en los depositos, y por otro, lo extiende a temperaturas mas altas que el punto de fusion de los compuestos de vanadio constituyentes de los depositos. Ambos aspectos involucran el considerar el papel que el proceso de difusion de especies tiene sobre la degradacion y la capacidad de proteccion de la aleacion. La investigacion realizada permitio confirmar lo establecido por el modelo de Wilson para depositos con alto contenido de vanadio y muy bajo contenido de azufre, a las temperaturas proximas al punto de fusion de los compuestos de vanadio que los constituyen. El desarrollo de los procesos de deterioro metalico que se incluyen en el modelo propuesto fue documentado

  17. Fabrication and Properties of Thermal Sprayed AlSi-Based Coatings from Nanocomposite Powders

    Science.gov (United States)

    Limpichaipanit, A.; Banjongprasert, C.; Jaiban, P.; Jiansirisomboon, S.

    2013-02-01

    AlSi-based nanocomposite powders (where nanoparticles were TiO2, ZrO2, and Al2O3 and the amount of reinforcement was 2.5, 5, and 10 wt.%) were made by ball milling and then thermal sprayed using low velocity oxy-fuel technique. The AlSi-based nanocomposite powders had nanosized ceramic reinforcement adhered to the surface of the powders after ball milling. The AlSi-based coatings had the typical thermal spray microstructure where lamellae, oxide layers, unmelted particles, and pores could be seen. Submicron second phase in the form of agglomerates, molten splats, or unmelted particles between AlSi lamellae could be observed as well. Hardness and porosity of the coatings increased when more ceramic second phase particles (harder than AlSi) were added. Sliding wear tests were carried out in pin-on-disk geometry. The wear tracks of AlSi and AlSi-based coatings show plastic deformation as the main material removal mechanism during the sliding wear test. The sliding wear rate of the coatings decreased as more second phase ceramic particles were added. It was due to an increase in the hardness and a decrease in the friction coefficient of the coatings.

  18. Nuevas aplicaciones decorativas de aleaciones a base de aluminio-molibdeno

    OpenAIRE

    V. H. Mesa-Laguna; C. D. Hernández-Pérez; M. A. Alvarez-Pérez; J. Guzmán; M. García-Hipólito; J. A. Juárez-Islas; González, C.; O. Alvarez-Fregoso

    2005-01-01

    Las propiedades decorativas de aleaciones bimetálicas nanoestructuradas de aluminio molibdeno se han analizado en función de la composición química y los tratamientos térmicos aplicados. Sus aplicaciones decorativas se deben exclusivamente a que las aleaciones están nanoestructuradas. Las aleaciones se elaboraron a temperatura ambiente por la técnica de erosión catódica a magnetrón en atmósfera de argón, variando los tiempos de depósito para obtener diferentes grosores y composiciones elem...

  19. Nuevas aplicaciones decorativas de aleaciones a base de aluminio-molibdeno

    OpenAIRE

    V. H. Mesa-Laguna; C. D. Hernández-Pérez; M. A. Alvarez-Pérez; Guzmán, J; M. García-Hipólito; J. A. Juárez-Islas; González, C; O. Alvarez-Fregoso

    2005-01-01

    Las propiedades decorativas de aleaciones bimetálicas nanoestructuradas de aluminio molibdeno se han analizado en función de la composición química y los tratamientos térmicos aplicados. Sus aplicaciones decorativas se deben exclusivamente a que las aleaciones están nanoestructuradas. Las aleaciones se elaboraron a temperatura ambiente por la técnica de erosión catódica a magnetrón en atmósfera de argón, variando los tiempos de depósito para obtener diferentes grosores y composiciones element...

  20. Effects of water absorption of dielectric underlayers on Al-Si-Cu film properties and electromigration performance in Al-Si-Cu/Ti/TiN/Ti interconnects

    Science.gov (United States)

    Yoshida, Tomoyuki; Hashimoto, Shoji; Ohwaki, Takeshi; Mitsushima, Yasuichi; Taga, Yasunori

    1998-01-01

    The effects of underlying dielectric (phosphosilicate glass and borophosphosilicate glass) films to a humid air ambient on Al-Si-Cu film properties and electromigration (EM) performance in Al-Si-Cu/Ti/TiN/Ti layered films have been investigated as a function of the boron content and exposure time of the dielectric films. The Al(111) orientation in the layered films was found to improve drastically with increasing boron content and exposure time. The full width at half maximum value of an Al(111) x-ray rocking curve reached less than 1°. It was also found that the Al-Si-Cu surface becomes smoother and grain sizes increase as the Al(111) orientation improves. The improved Al(111) orientation was attributed to the improved Ti(002) orientation of the bottom Ti films. Further, it was demonstrate that interconnects fabricated from the improved layered film have excellent EM performance.

  1. Separation of primary solid phases from Al-Si alloy melts

    OpenAIRE

    Ki Young Kim

    2014-01-01

    The iron-rich solids formed during solidification of Al-Si alloys which are known to be detrimental to the mechanical, physical and chemical properties of the alloys should be removed. On the other hand, Al-Si hypereutectic alloys are used to extract the pure primary silicon which is suitable for photovoltaic cells in the solvent refining process. One of the important issues in iron removal and in solvent refining is the effective separation of the crystallized solids from the Al-Si alloy mel...

  2. Rapidly solidified hypereutectic Al-Si alloys prepared by powder hot extrusion

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Rapidly solidified hypereutectic Al-Si alloys were prepared by powder hot extrusion. By eliminating vacuum degassing procedure, the fabrication routine was simplified. The tensile fracture mechanisms at room temperature and elevated temperature were investigated by SEM fractography. Compared with KS282 casting material, the tensile strength of rapidly solidified Al-Si alloy is greatly improved due to silicon particles refining while its density and coefficient of thermal expansion are lower than those of KS282. The wear resistance of RS AlSi is better than that of KS282.

  3. Elaboración de aleaciones de Cu-Al-Ni con efecto memoria de forma mediante pulvimetalurgia

    Directory of Open Access Journals (Sweden)

    Pérez-Sáez, R. B.

    1998-05-01

    Full Text Available During the production of shape memory alloys, a very fine grain size should be obtained in order to obtain better mechanical properties and a good thermomechanical behaviour during cycling. The classically used grain refiners show some secondary effects on the martensitic transformations that could be at the origin of some technological problems. For this reason, a new processing method by powder metallurgy has been developed for this kind of alloys. The three proceeding stages are described: Atomization, hot isostatic pressing and hot rolling. The microstructure of the materials is characterized. The martensitic transformation and the thermomechanical properties are also studied.

    En la elaboración de aleaciones Cu-Al-Ni con efecto memoria de forma es importante conseguir un tamaño de grano fino, para mejorar las propiedades mecánicas y el comportamiento durante el ciclado termomecánico. Clásicamente, esto se ha conseguido mediante la adición de refinadores de grano; sin embargo, los efectos secundarios que éstos producen pueden ser problemáticos. Por esta razón, se ha desarrollado un nuevo método de procesado de este tipo de aleaciones mediante pulvimetalurgia. En este trabajo se presenta el proceso de elaboración consistente en tres etapas: atomización, compactación isostática en caliente y laminación en caliente. Se estudia la microestructura del material, se caracteriza la transformación martensítica y se determinan las propiedades termomecánicas.

  4. Tensile property of Al-Si closed-cell aluminum foam

    Institute of Scientific and Technical Information of China (English)

    YU Hai-jun; YAO Guang-chun; LIU Yi-han

    2006-01-01

    Al-Si closed-cell aluminum foams of different densities were prepared by molten body transitional foaming process. The tensile behavior of Al-Si closed-cell aluminum foam was studied and the influence of relative densities on the tensile strength and elastic modulus was also researched. The results show that the fracture surfaces of Al-Si closed-cell aluminum foam display quasi-cleavage fiacture consisting of brittle cleavages and ductile dimples. The tensile strength and elastic modulus are strictly affected by the relative density of Al-Si closed-cell aluminum foam. With increasing relative density, the tensile strength increases and the strain at which the peak strength is measured also increases; in addition, the elastic modulus increases with increasing relative density.

  5. Separation of primary solid phases from Al-Si alloy melts

    Institute of Scientific and Technical Information of China (English)

    Ki Young Kim

    2014-01-01

    The iron-rich solids formed during solidification of Al-Si aloys which are known to be detrimental to the mechanical, physical and chemical properties of the aloys should be removed. On the other hand, Al-Si hypereutectic alloys are used to extract the pure primary silicon which is suitable for photovoltaic cells in the solvent refining process. One of the important issues in iron removal and in solvent reifning is the effective separation of the crystalized solids from the Al-Si aloy melts. This paper describes the separation methods of the primary solids from Al-Si aloy melts such as sedimentation, draining, ifltration, electromagnetic separation and centrifugal separation, focused on the iron removal and on the separation of silicon in the solvent refining process.

  6. Separation of primary solid phases from Al-Si alloy melts

    Directory of Open Access Journals (Sweden)

    Ki Young Kim

    2014-07-01

    Full Text Available The iron-rich solids formed during solidification of Al-Si alloys which are known to be detrimental to the mechanical, physical and chemical properties of the alloys should be removed. On the other hand, Al-Si hypereutectic alloys are used to extract the pure primary silicon which is suitable for photovoltaic cells in the solvent refining process. One of the important issues in iron removal and in solvent refining is the effective separation of the crystallized solids from the Al-Si alloy melts. This paper describes the separation methods of the primary solids from Al-Si alloy melts such as sedimentation, draining, filtration, electromagnetic separation and centrifugal separation, focused on the iron removal and on the separation of silicon in the solvent refining process.

  7. Bulk Al/SiC nanocomposite prepared by ball milling and hot pressing method

    Institute of Scientific and Technical Information of China (English)

    GU Wan-li

    2006-01-01

    Nano-sized Al/SiC powders were prepared by mechanical alloying method. Two sorts of SiC particle,i.e.,nano-sized and popular micron-sized SiC were utilized. The particle size and microstructure of the milled powder were characterised. Effects of the particle size and agglomerate state of SiC,as well as the microstructure of Al/SiC nanocomposite were studied by SEM and TEM. The results show that nano-sized SiC particles is dispersed in aluminium uniformly after ball milled for only 2 h,whereas the similar process need about 10 h for popular micron-sized SiC particle. The bulk Al/SiC nanocomposite can be fabricated by hot pressing the nano-sized Al/SiC powders at temperature about 723 K under pressure of 100 MPa.

  8. Pencegahan Terjadinya Retak Panas pada Proses Pengecoran Squeeze Benda Tipis Al-Si

    Directory of Open Access Journals (Sweden)

    Elfendri Elfendri

    2009-01-01

    Full Text Available Solidification of molten metal in squeeze casting was done under high pressure condition. It will produce small grains and decrease porosity of product but have high probability of hot crack. Hot crack depend on silicon content, molding and pouring temperature of squeeze cast parameters. The aim of this research is to analize silicon content, melt temperature and mold temperature on hot crack to eliminate this defect on production of thin wall of Al-Si. Hydraulic pressure of 135 MPa is applied to forge molten metal of aluminum-silicon alloys. Mold temperature from 220 to 330 0C, pouring temperature from 665 to 885 0C and silicon content from 0.45 to 6.04 % weight were considered. Hot crack length and cracking index were used to indicate the dimension of hot crack. The increasing of silicon content decreases hot crack length and cracking index of thin wall. The increasing of pouring and mold temperature increases hot crack length and cracking index of thin wall. Combination of the higher silicon content, the lowest melt and mold temperature produced the flawless thin wall squeeze cast of hot crack. Abstract in Bahasa Indonesia: Pengecoran squeeze Al-Si adalah proses pengecoran dimana logam cair Al-Si dibekukan dibawah tekanan tinggi sehingga akan menghasilkan produk dengan butir halus dan menekan jumlah cacat porositas namun cendrung mengalami retak panas. Parameter kandungan silikon Al-Si, temperatur tuang dan cetakan mempengaruhi terjadinya retak panas pada benda cor tipis Al-Si. Penelitian ini bertujuan untuk menganalisis pengaruh kandungan silikon Al-Si, temperatur tuang dan cetakan terhadap terjadinya retak panas pada proses pengecoran squeeze benda tipis Al-Si sehingga tindakan pencegahan bisa dilakukan pada proses produksi. Pengecoran squeeze ini menggunakan penekan hidrolik bertekanan 135 MPa. Temperatur yang dipakai adalah 220, 275 dan 330 0C untuk cetakan dan 665, 775 dan 885 0C untuk logam cair. Kandungan silikon material mengunakan

  9. Examination of the stir-casting method to produce Al-SiC composites

    OpenAIRE

    Naher, Sumsun

    2004-01-01

    This work examined the influence of processing parameters on the production of Al-SiC metal matrix composites (MMC) by batch compocasting process. Processing parameters investigated includes tirring speed, stirring time, stirrer geometry, stirrer position , metal fluid temperature (viscosity). Room temperature (25°C) visual simulations, computer simulations and validation Al-SiC MMC production tests were performed. In the visual and computer simulations, water an d g ly c e ro l/water wer...

  10. Modified Mechanism of Eutectic Silicon in Al2O3/Al-Si Alloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Al2O3/Al-Si alloy composite was manufactured by squeeze casting. The morphology of the eutectic silicon in the composite was observed by scanning electronic microscope (SEM), and the modified mechanism of eutectic silicon in the composite was approached. The alumina fiber in the composite can trigger twin during the growth of Al-Si eutectic and lead to the modification of eutectic silicon near the fiber.

  11. Melt Processing and Characterization of Al-SiC Nanocomposite, Al, and Mg Foam Materials

    OpenAIRE

    Ahmed M. Nabawy; Khalil Abdelrazek Khalil; Al-Ahmari, Abdulrahman M.; Sherif, El-Sayed M.

    2016-01-01

    In the present work, metallic foams of Al, Mg and an Al-SiC nanocomposite (MMNC) have been fabricated using a new manufacturing technique by employing melt infiltration assisted with an electromagnetic force. The aim of this investigation was to study and to develop a reliable manufacturing technique consisting of different types of metallic foams. In this technique, an electromagnetic force was used to assist the infiltration of Al-SiC slurry and of pure liquid metal into a leachable pattern...

  12. The influence of electrical current on Al-Si alloys crystallization

    OpenAIRE

    A. Száraz; R. Pastirčák; A. Sládek

    2008-01-01

    This paper handles about the effect of electrical current on the cast microstructure of Al-Si alloy. By the application of direct current during the solidification there is intended the refinement of result microstructure. The change of result microstructure and mechanical properties was investigated. By the application of direct and alternating electrical current during the Al-Si alloy solidification there were observed some changes in the microstructure. The dendrites size in primary alpha ...

  13. Investigations of linear contraction and shrinkage stresses development in hypereutectic al-si binary alloys

    OpenAIRE

    J. Mutwil; Kujawa, K.; G. Bajon; P. Hajn

    2009-01-01

    Shrinkage phenomena during solidification and cooling of hypereutectic aluminium-silicon alloys (AlSi18, AlSi21) have been examined. A vertical shrinkage rod casting with circular cross-section (constant or fixed: tapered) has been used as a test sample. Two type of experiments have been conducted: 1) on development of the test sample linear dimension changes (linear expansion/contraction), 2) on development of shrinkage stresses in the test sample. By the linear contraction experiments the l...

  14. A new method to evaluate the hydraulic activity of Al-Si materials

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Slag,fly ash,gangue and 500℃ calcined gangue are analyzed by using identical coupled plasma optical emission spectroscopy (ICP),X-ray photoelectron spec-troscopy (XPS),infrared spectroscopy (IR) and magnetic angle spinning nuclear magnetic resonance (MAS NMR). Research results show that there is a negative linear relationship between the Si 2p and Al 2p binding energies of Al-Si materials and the compressive strength of aluminosilicate based cementitious materials prepared with these Al-Si materials,i.e. the lower the binding energies,the higher the compressive strength. Indeed,the Si 2p and Al 2p binding energies of Al-Si materials can be used to indicate their hydraulic activity. The binding energies of the four examined materials increase in the order of slag,fly ash,500℃ calcined gangue and untreated gangue. Moreover,the binding energies of Si 2p,Al 2p and O 1s of every Al-Si material have excellent correlation. By using the Al 2p binding energy and 27Al MAS NMR spectra,the coordination number of aluminum in slag is determined to be four,while that in gangue,is six. Based on the aforementioned discoveries,this paper presents a new effective method to evaluate the hydraulic activity of Al-Si materials by using the surface binding energies of silicon and alu-minum of Al-Si materials.

  15. Towards hard yet self-lubricious CrAlSiN coatings

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Yuexiu [Central Iron and Steel Research Institute, 76 South Xueyuanlu Rd, Haidan District, Beijing 100081 (China); Advanced Technology and Materials Co., Ltd, 76 South Xueyuanlu Rd, Haidan District, Beijing 100081 (China); Zhang, Sam [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Lee, Jyh-Wei [Department of Materials Engineering, Ming Chi University of Technology, 84 Gung Juan Road, Taishan, Taipei 24301, Taiwan (China); Center for Thin Film Technologies and Applications, Ming Chi University of Technology, 84 Gung Juan Road, Taishan, Taipei 24301, Taiwan (China); Li, Bo [Central Iron and Steel Research Institute, 76 South Xueyuanlu Rd, Haidan District, Beijing 100081 (China); Wang, Yuxi [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Zhao, Dongliang [Central Iron and Steel Research Institute, 76 South Xueyuanlu Rd, Haidan District, Beijing 100081 (China); Sun, Deen [School of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China)

    2015-01-05

    Highlights: • Hard yet self-lubricious CrAlSiVN coatings are developed. • Incorporating vanadium into CrAlSiN structure refines crystal grains. • Tribo-oxidized vanadium provides CrAlSiN coatings lubriciousness. - Abstract: CrAlSiN coatings are of high hardness, excellent wear and oxidation resistance but lack of lubriciousness. Vanadium nitride (VN) is easily oxidized to form vanadium oxides and becomes lubricious under stress. Incorporating VN into CrAlSiN to form CrAlSiVN coating renders both hardness and self-lubrication in dry machining. This study investigates the effect of vanadium content on hard yet self-lubricious coating’s mechanical and tribological properties. The coatings are deposited on cemented tungsten carbide and Si wafer (1 0 0) substrates in an in-line magnetron sputtering system. Grazing incidence X-ray diffractometer, scanning electron microscopy, transmission electron microscopy, electron probe micro-analyzer, X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy are employed to characterize the microstructures and chemistry. Nanoindentation and ball-on-disc tribo-tester are used in characterization of the mechanical and tribological properties. The coatings demonstrate lubriciousness of coefficient of friction with tungsten carbide from 0.55 down to 0.39 with acceptable loss of hardness (from ∼35 GPa down to ∼30 GPa)

  16. Towards hard yet self-lubricious CrAlSiN coatings

    International Nuclear Information System (INIS)

    Highlights: • Hard yet self-lubricious CrAlSiVN coatings are developed. • Incorporating vanadium into CrAlSiN structure refines crystal grains. • Tribo-oxidized vanadium provides CrAlSiN coatings lubriciousness. - Abstract: CrAlSiN coatings are of high hardness, excellent wear and oxidation resistance but lack of lubriciousness. Vanadium nitride (VN) is easily oxidized to form vanadium oxides and becomes lubricious under stress. Incorporating VN into CrAlSiN to form CrAlSiVN coating renders both hardness and self-lubrication in dry machining. This study investigates the effect of vanadium content on hard yet self-lubricious coating’s mechanical and tribological properties. The coatings are deposited on cemented tungsten carbide and Si wafer (1 0 0) substrates in an in-line magnetron sputtering system. Grazing incidence X-ray diffractometer, scanning electron microscopy, transmission electron microscopy, electron probe micro-analyzer, X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy are employed to characterize the microstructures and chemistry. Nanoindentation and ball-on-disc tribo-tester are used in characterization of the mechanical and tribological properties. The coatings demonstrate lubriciousness of coefficient of friction with tungsten carbide from 0.55 down to 0.39 with acceptable loss of hardness (from ∼35 GPa down to ∼30 GPa)

  17. Al/SiC界面结合机制的研究现状(续)%Present study of combination mechanism of Al/Si interface

    Institute of Scientific and Technical Information of China (English)

    陈建; 潘复生; 刘天模

    2000-01-01

    @@ 2.3 Al/SiC界面反应机理 一般认为在SiC/Al系统中,Al4C3的形核通过两个步骤进行:即SiC溶解于熔融Al中,然后与Al发生如式(1)的反应,基本上是溶解、扩散和化合的过程,Al/SiC界面属于既有溶解又有反应结合的混合型界面.SiC的溶解似乎是一个择优过程,当SiC与Al液接触时,界面能具有各向异性的特点,为了减少系统的界面能,SiC表面高能量位置发生溶解,从而产生台阶,使与基体结合的SiC晶面是低能量、低能数晶面[29],实验结果也表明SiC的溶解是不均匀的[28],但对于Al/SiC界面反应的速控步骤不同研究又存在不同说法,Lin[30]等人研究认为,SiC在Al液中的溶解动力学是Al/SiC界面反应的速控步骤.

  18. Pengaruh Modulus Cor Riser Terhadap Cacat Penyusutan Pada Produk Paduan Al-Si

    Directory of Open Access Journals (Sweden)

    Soejono Tjitro

    2002-01-01

    Full Text Available Shrinkage defect can be eliminated or reduced by controlling the casting modulus of riser. Casting modulus is ratio volume to surface area of castings. The higher casting modulus of riser, the longer solidification time of melted metal. Therefore the temperature gradient of melted metal become lower. However, the temperature gradient is also influenced by the composition of aluminum-silicon alloys. This research investigates 7% Al-Si alloy and 12.5% Al-Si alloy using two type of risers with different casting modulus. The casting process is sand casting. The research result shows that casting modulus of riser and alloys composition influence shrinkage defect. However, for the same Al-Si alloys, grain size isn't influenced by casting modulus of riser. Abstract in Bahasa Indonesia : Cacat penyusutan dapat dieliminir atau dikurangi dengan mengontrol modulus cor riser. Modulus cor merupakan perbandingan antara volume terhadap luas permukaan coran. Modulus cor besar berarti waktu pembekuan cairan logam lebih lama. Akibatnya gradien temperatur cair logam rendah. Namun demikian, gradien temperatur cair logam juga dipengaruhi oleh komposisi paduan aluminium-silikon. Penelitian ini menggunakan paduan Al-Si 7% dan Al-Si 12,5% . Riser yang digunakan dua jenis yang memiliki modulus cor yang berbeda. Proses pengecoran yang digunakan adalah pengecoran dengan cetakan pasir. Hasil penelitian menunjukkan bahwa modulus cor riser dan komposisi paduan berpengaruh terhadap terjadinya cacat penyusutan. Besar butir tidak dipengaruhi oleh modulus cor riser untuk paduan Al-Si yang sama. Kata kunci: modulus cor, cacat penyusutan, paduan Al-Si.

  19. Electronic properties and superconductivity of rapidly quenched Al-Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chevrier, J.; Pavuna, D.; Cyrot-Lackmann, F.

    1987-12-15

    We present detailed studies of electronic properties of Al-Si alloys prepared in a nonequilibrium state by means of rapid solidification. The quenched alloys exhibit an enhanced superconducting transition temperature up to 6.2 K in an Al--Si 30 at. % alloy as well as an increased thermal slope of resistivity. Using differential scanning calorimetry, a large enthalpy variation (..delta..H = 4.1 kJ/mole for Al--Si 30 at. %) has been measured during the irreversible transition from the non- equilibrium state to the equilibrium one. This is mainly attributed to the energy difference between the metallic state of silicon atoms trapped in fcc aluminum matrix during quenching and the usual covalent state of silicon precipitates in an equilibrium state. This large energy difference is presented as the origin of a lattice instability which softens the phonon spectrum and gives rise to a stronger electron-phonon coupling. This appears to be a characteristic property of nonequilibrium Al-Si solid solutions, which is associated with the metallic state of silicon atoms. An interpretation of the T/sub c/ enhancement is proposed for both Al-Si and Al-Ge alloys based on the phonon softening in these nonequilibrium crystalline alloys.

  20. Preparation and study of nanostructured TiAlSiN thin films

    Directory of Open Access Journals (Sweden)

    Jakab-Farkas L.

    2011-12-01

    Full Text Available TiAlSiN thin film coatings were deposited by DC reactive magnetron sputtering of TiAlSi target with 40 at.% Ti, 40 at.% Al and 20 at.% Si, performed in N2-Ar gas mixture. The sputtering power used in these experiments was controlled for 400 W. The bias voltage of the substrates was kept at -20 V DC and the temperature at 500 0C. All the samples were prepared with a constant flow rate of Ar and different nitrogen flow rates, which were selected from 1.25 sccm to 4.0 sccm. Nanostructured TiAlSiN coatings were developed on Si(100 and HSS substrates. Microstructure investigation of the coatings was performed by transmission electron microscopy investigation, structure investigation was performed by XRD analysis, and the mechanical properties of the coatings have been tested by ball-on-disk tribological investigation and micro-Vickers hardness measurements. In this paper will be shown that for optimized nitrogen concentration the microstructure of TiAlSiN coating evolve from a competitive columnar growth to a dendritic growth one with very fine nano-lamellae like morphology. The developed nanostructured TiAlSiN coatingshave hardness HV exceeding 40 GPa and show an increased abrasive wear resistance

  1. Modeling of the DP and TRIP microstructure in the CMnAlSi automotive steel

    Directory of Open Access Journals (Sweden)

    A.K. Lis

    2006-02-01

    Full Text Available Purpose: The CMnAlSi steel is a new grade of TRIP steels with 1wt % of Al and Si. It is important to determine the usability of the CMnAlSi for production of sheets for automotive applications.Design/methodology/approach: The effect of cooling rate and austenitization temperature on phase transformations was investigated. The dilatometric experiments of the steel were done for the full austenitization temperature 1200°C, and for (α+γ temperature ranges: 1100°C, 1000°C, 900°C and 800°C. Steel was also processed to achieve TRIP grade by continuous annealing with modeled vertical hot dip galvanizing line. The microstructures were investigated by light optical microscopy and SEM with EDX attachment. The amount of retained austenite in the obtained microstructures was investigated with X-ray diffractionFindings: There is possibility to produce “dual-phase” CMnAlSi steel grade with controlled rolling at finishing temperature below 900°C to 800°C and fast cooling. Steel CMnAlSi is well suited for production of TRIP grade via heating cycle which correspond to vertical hot dip galvanizing process.Practical implications: This steel is suitable for production of automotive applications.Originality/value: The new procedure of control rolling from the (α+γ temperature range of CMnAlSi steel was presented.

  2. A family of hexagonal and orthorhombic (Al,Si)4Cr approximants of quasicrystals

    International Nuclear Information System (INIS)

    By means of transmission electron microscopy, four crystalline phases with compositions close to (Al,Si)4Cr have been found in Al-Cr-Si alloys. The hexagonal μ'-(Al,Si)4Cr has the same space group P63/mmc as μ-(Al,Si)4Cr, but its c parameter is only one half of cμ. On the other hand, the orthorhombic ε-Al4Cr, ε' - and ε''-(Al,Si)4Cr have about the same lattice parameters but different space groups: Bbmm (or Cmcm), Pbnm and P212121, respectively. The lattice parameters of these phases are closely related: aε,ε',ε''=√3aμ,μ' ≅ 3.46nm; bε,ε',ε''=aμ,μ' ≅ 2.00nm; cε,ε',ε''=1/2cμ=cμ' ≅ 1.24nm. The symmetry of space group decreases from μ(μ'), ε, ε' to ε'' and the space groups of any two neighboring phases have the minimal supergroup and the maximal subgroup relationship. Strong diffraction spots of all these phases exhibit pseudo icosahedral symmetry. In the (001) plane, icodahedra are linked by mutual penetration along the five-fold axis forming icosahedral chains in three directions at 120 deg. apart. These four (Al,Si)4Cr phases together with the ε-Al4Cr are not only structurally close related, but also are approximants of quasicrystals

  3. CsAlSi5O12: a possible host for 137Cs immobilization

    International Nuclear Information System (INIS)

    CsAlSi5O12 exhibits more acid resistance than pollucite (CsAlSi2O6). At pH values of 1.02 and 1.40, the extraction of Cs from CsAlSi5O12 at 250C was approximately proportional to the square root of leach time. The Cs extraction at 250C varied as [H+]036 over the pH range of 1 to 6. Also, the Cs extraction in various brines at 3000C/30 MPa was comparable with that for pollucite. CsAlSi5O12 can be crystallized at about 10000C from calcines if a small amount of CaO is present, but in the absence of such sintering acids, crystallization temperatures of about 14000C are necessary. Compatibility data were also obtained with respect to several other phases with which CsAlSi5O12 might be expected to coexist in tailored ceramics designed for high-level defense waste

  4. Dry sliding friction and wear behavior of woodceramics/Al-Si composites

    International Nuclear Information System (INIS)

    Woodceramics/AlSi (WCMs/AlSi hereafter) composites were prepared by means of high-pressure vacuum infiltration of liquid alloy into woodceramics. The friction and wear behavior of WCMs/metal composites at various applied loads and sliding velocities was investigated by using a block-on-ring test at room temperature under dry conditions. Furthermore, the morphologies, phases and element valences of the worn surface and debris were observed, examined and analyzed by scanning electron microscopy (SEM), energy-dispersive X-ray microanalysis (EDAX) and X-ray photoelectron spectroscopy (XPS), respectively. In addition, load and sliding velocity dependence mechanisms of the wear and friction behavior of the composite and matrix alloy were discussed. Experimental results show that WCMs/AlSi composites have a topologically uniform interconnected network microstructure. Their tribological properties are improved dramatically, compared to those of the matrix AlSi alloy, due to the formation of wide, compacted surface carbon films. The wear mechanisms of WCMs/AlSi composites and of the matrix alloy vary with applied load from mild to severe wear

  5. After-Corrosion Suppression Using Low-Temperature Al-Si-Cu Etching

    Science.gov (United States)

    Aoki, Hidemitsu; Ikawa, Eiji; Kikkawa, Takamaro; Teraoka, Yuden; Nishiyama, Iwao

    1991-07-01

    The authors investigated the low-temperature etching effect on Al-Si-Cu after-corrosion. The after-corrosion extent was evaluated from the corrosion point density generated on the rinsed Al-Si-Cu stripes after dry etching. As the etching temperature was reduced, after-corrosion was suppressed. In order to study the low-temperature etching effect, the authors analyzed the Cl compounds remaining on the Al-Si-Cu film by thermal desorption spectroscopy (TDS). TDS revealed that the Cl concentration remaining on the Al-Si-Cu film etched at -60°C after rinsing in water was smaller than that remaining on the film etched at 30°C. Consequently, suppression of after-corrosion by low temperature etching could be attributed to the smaller number of Al-Cu bonds remaining in the Al-Si-Cu etch surface after removal of the AlClx layer by rinsing with water. This fact is due to the reduction of chemical reaction and diffusion rate by lowering the substrate temperature.

  6. The shear behaviour of partially solidified Al-Si-Cu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sumitomo, T.; Steinberg, T. [Queensland Univ., Brisbane (Australia). Dept. of Mech. Eng.; StJohn, D.H. [CRC for Cast Metals Manufacturing (CAST), Department of Mining, Minerals and Materials Engineering, The University of Queensland, 4072, Brisbane, Qld. (Australia)

    2000-09-30

    A direct shear cell was used to measure the shear behaviour of partially solidified Al-Si-Cu alloys with compositions of AlSi4Cu1, AlSi7Cu1, AlSi4Cu4 and AlSi7Cu4. Determination of rigidity and shear strength with respect to solid fraction for each alloy revealed two transition points, identified in the literature as coherency and maximum packing solid fraction, where changes in shearing mechanism occurred. Coherency occurred between 0.18 and 0.21 solid fraction for the 7%Si alloys and between 0.24 and 0.27 for the 4%Si alloys. Maximum packing occurred between 0.33 and 0.35 solid fraction for the 7%Si alloys and between 0.44 and 0.47 for the 4%Si alloys. For a given solid fraction after coherency, the shear strength increased when the silicon content was increased. This was due to the effect of silicon where the 4%Si alloys have a globular, rosette-like microstructure, while the 7%Si alloys have a larger grain size and a more irregular dendritic morphology. After the maximum packing solid fraction, an increase in copper content resulted in increased strength for a given solid fraction. This is hypothesised to be caused by a correspondingly lower temperature for the same solid fraction with increasing copper content, leading to a more rigid dendritic network. The deformation mechanisms occurring during shear are also discussed. (orig.)

  7. Al-Si-Re Alloys Cast by the Rapid Solidification Process / Stopy Al-Si-Re Odlewane Metodą Rapid Solidification

    Directory of Open Access Journals (Sweden)

    Szymanek M.

    2015-12-01

    Full Text Available The aim of the studies described in this article was to present the effect of rare earth elements on aluminium alloys produced by an unconventional casting technique. The article gives characteristics of the thin strip of Al-Si-RE alloy produced by Rapid Solidification (RS. The effect of rare earth elements on structure refinement, i.e. on the size of near-eutectic crystallites in an aluminium-silicon alloy, was discussed. To determine the size of crystallites, the Scherrer X-ray diffraction method was used. The results presented capture relationships showing the effect of variable casting parameters and chemical composition on microstructure of the examined alloys. Rapid Solidification applied to Al-Si alloys with the addition of mischmetal (Ce, La, Ne, Pr refines their structure.

  8. Al-Si-Cu合金低温力学性能的研究%Study of the Mechanical Properties of Al-Si-Cu Alloy Under Low Temperature

    Institute of Scientific and Technical Information of China (English)

    张洪坤

    2013-01-01

    主要以A1-Si-Cu合金为研究对象,研究了低温变化对锶变质后的A1-Si-Cu合金组织及性能的影响.变质处理后的A1-Si-Cu合金的抗拉强度和屈服强度随温度的降低均升高,同时伸长率和断面收缩率随温度的降低也略有上升.通过对Al-Si-Cu合金金相观察,加入Sr元素后,合金的组织得到显著细化.变质后的Al-Si-Cu合金在低温下具有更好的力学性能.

  9. Influence of Nanosized Silicon Carbide on Dimensional Stability of Al/SiC Nanocomposite

    Directory of Open Access Journals (Sweden)

    S. M. Zebarjad

    2008-01-01

    Full Text Available This study concentrated on the role of particle size of silicon carbide (SiC on dimensional stability of aluminum. Three kinds of Al/SiC composite reinforced with different SiC particle sizes (25 μm, 5 μm, and 70 nm were produced using a high-energy ball mill. The standard samples were fabricated using powder metallurgy method. The samples were heated from room temperature up to 500∘C in a dilatometer at different heating rates, that is, 10, 30, 40, and 60∘C/min. The results showed that for all materials, there was an increase in length change as temperature increased and the temperature sensitivity of aluminum decreased in the presence of both micro- and nanosized silicon carbide. At the same condition, dimensional stability of Al/SiC nanocomposite was better than conventional Al/SiC composites.

  10. Control of silicon solidification and the impurities from an Al-Si melt

    Science.gov (United States)

    Wang, Panpan; Lu, Huimin; Lai, Yuanshi

    2014-03-01

    The investigation on purification of metallurgical grade silicon by solidification of hypereutectic Al-Si melt under the temperature gradient as an intensified separation way was carried out. Based on the available thermodynamic parameters and experimental data, the thermodynamic behavior and chemical composition of metallic impurities was studied in the solidification process. The principle for the silicon growth in the Al-Si melts was investigated. The results indicated that the refined silicon grains were successfully enriched at the top of the Al-Si alloy. Then the top part refined silicon was collected by aqua regia leaching. Electrorefining of the bottom part (Al-22%Si) was investigated effectively in view of recovering pure Si and Al. Additionally, according to previous investigation, the optimized technical process for SOG-Si production was proposed.

  11. Microstructural dependence of annealing temperature in magnetron-sputtered Al-Si-Cu films

    Science.gov (United States)

    Liang, Ming-Kaan; Ling, Yong-Chien

    1993-09-01

    The effect of sputtering temperature, sputtering bias, and annealing temperature upon the sheet resistance, WO3 formation at the Al-Si-Cu/Ti-W interface, and diffraction intensity of the Al2Cu precipitates of magnetron-sputtered Al-Si-Cu films were investigated. Statistical methods and microcharacterization techniques were applied to study these effects. Statistical analysis verifies the effect of annealing temperature on the measured sheet resistance. Annealing temperature alone is the dominant factor upon the WO3 formation at the Al-Si-Cu/Ti-W interface and the Al2Cu (211) plane diffraction intensity. Annealed samples are of higher sheet resistance. Increase in sheet resistance is ascribed to the formation of interfacial WO3. Reduced electromigration is related to the formation of Al2Cu precipitates. Secondary ion mass spectrometry (SIMS) analysis of the as-deposited sample depicts the presence of an excess amount of oxygen atoms at the surface and the Al-Si-Cu/Ti-W and Ti-W/Ti interfaces. Rutherford backscattering spectrometry and SIMS analyses reveal the outdiffusion of W from the Ti-W layer toward the Al-Si-Cu layer, the presence of Si nodules at the Al-Si-Cu/Ti-W interface, and the formation of Ti silicides at the Ti/Si interface. These phenomena are confirmed by transmission electron microscopy, energy dispersive x-ray analysis, and scanning electron microscopy analyses. It is concluded that interfacial oxygen, which reacts with W to form WO3 upon annealing, warrants further reduction to yield films of better sheet resistance.

  12. Effects of lead and copper particles on corrosion and wear behaviour of Al-Si matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, S.F.; Wu, T.F.; Lee, S.L.; Kao, C.H.; Lin, J.C.; Le, Z.K.

    2005-09-15

    Matrix composites of Al-Si containing dispersed lead and copper particles were fabricated by hot pressing. The effects of the addition of 5 and 10 wt-% lead and 3 wt-% copper particles on the wear and wear corrosion properties of Al-Si composites have been evaluated. Wear testing was conducted at ambient temperature without lubricant, and wear corrosion testing was executed in 3.5 wt-%NaCl solution (pH 6.7). The results show that the dry wear loss of Al-Si/Pb and Al-Si/Cu-Pb composites decreased as the lead content increased. The hardness increased and the dry wear loss was reduced with the addition of copper particles. The corrosion potential E{sub corr} decreased with the presence of copper and with an increase of the lead content, for both pressed and heat treated conditions. The corrosion current density I{sub corr} increased with copper and lead incorporation into composites in the as pressed state, and decreased after heat treatment for Al-Si/Cu and Al-Si/Cu-Pb composites. Wear corrosion properties were improved by addition of the lead phase to Al-Si and Al-Si/Cu composites. The Al-Si/Cu-Pb composites exhibited better dry wear and wear corrosion resistance than those of other composites in the present study. The lead containing composites (Al-Si/Pb and Al-Si/Cu-Pb) possessed lower E{sub corr} values compared with other Al-Si composites. (author)

  13. Modeling of the DP and TRIP microstructure in the CMnAlSi automotive steel

    OpenAIRE

    A.K. Lis; B. Gajda

    2006-01-01

    Purpose: The CMnAlSi steel is a new grade of TRIP steels with 1wt % of Al and Si. It is important to determine the usability of the CMnAlSi for production of sheets for automotive applications.Design/methodology/approach: The effect of cooling rate and austenitization temperature on phase transformations was investigated. The dilatometric experiments of the steel were done for the full austenitization temperature 1200°C, and for (α+γ) temperature ranges: 1100°C, 1000°C, 900°C and 800°C. Steel...

  14. Analysis of intermetallic particles in AlSi1MgMn aluminium alloy

    OpenAIRE

    G. Mrówka-Nowotnik; J. Sieniawski; M. Wierzbińska

    2007-01-01

    Purpose: The main objective of this study was to analyze the morphology and composition of complexmicrostructure of the intermetallic phases in AlSi1Mg alloy.Design/methodology/approach: In this study, several methods were used such as: optical light microscopy(LM), transmission (TEM) and scanning (SEM) electron microscopy in combination with X-ray analysis (EDS)using polished sample, and X-ray diffraction (XRD) to identify intermetallics in AlSi1MgMn aluminium alloy.Findings: The results sho...

  15. The influence of chemical composition on the properties and structure Al-Si-Cu(Mg) alloys

    OpenAIRE

    M. Kaczorowski; A. Krzyńska

    2007-01-01

    The mechanical properties of different chemical composition AlSiCuMg type cast alloys after precipitation hardening are presented. The aim of the study was to find out how much the changes in chemistry of aluminum cast alloys permissible by EN-PN standards may influence the mechanical properties of these alloys. Eight AlSi5Cu3(Mg) type cast alloys of different content alloying elements were selected for the study. The specimens cut form test castings were subjected to precipitation hardening ...

  16. Surface interactions and tribochemistry in boundary lubrication of hypereutectic Al-Si alloys. Poster

    OpenAIRE

    Jiménez Ballesta, Ana Eva; Morina, Ardian; Neville, Anne; Bermúdez Olivares, María Dolores

    2008-01-01

    Al-Si alloys are characterized with 3.3.- miniSIMS DEPTH PROFILES a range of properties which make them potential materials to substitute cast iron in automotive engines. The formation of polyphosphate films on Al-Si alloys would indicate the potential use of ZDDP in lubrication of these alloys and hence facilitate their use as replacement materials for cast iron. It has been shown that the addition of MoDTC assists ZDDP to reduce friction and wear of hy...

  17. Improvement in mechanical properties of hypereutectic Al-Si-Cu alloys through sono-solidified

    OpenAIRE

    Yoshiki Tsunekawa; Shinpei Suetsugu; Masahiro Okumiya

    2014-01-01

    For the wider applications, it is necessary to improve the ductility as well as the strength and wear-resistance of hypereutectic Al-Si-Cu alloys, which are typical light-weight wear-resistant materials. An increase in the amounts of primary silicon particles causes the modified wear-resistance of hypereutectic Al-Si-Cu alloys, but leads to the poor strength and ductility. It is known that dual phase steels composed of hetero-structure have succeeded in bringing contradictory mechanical prope...

  18. Influence of antimony on the mechanical properties and gas content of alloy AlSi6Cu4

    OpenAIRE

    D. Medlen; D. Bolibruchova

    2011-01-01

    Aluminium alloys based on Al-Si are used in automotive and aerospace industries. AlSi6Cu4 alloy is used the complicated castings, whichmust comply high strength requirements. Strength characteristics can also be affected by the modifiers: Na, Sr, Sb. In the li terature ismentioned, that AlSi6Cu4 modified by sodium and strontium has negative effect - increases of the gas absorption. Modification of AlSi6Cu4 alloy by antimony, is still not mentioned in the literature. The article gives the effe...

  19. Parameter-free calculation of K alpha chemical shifts for Al, Si, and Ge oxides

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper

    2001-01-01

    The chemical shifts of the K alpha radiation line from Al, Si, and Ge ions between their elemental and oxide forms are calculated within the framework of density functional theory using ultrasoft pseudopotentials. It is demonstrated that this theoretical approach yields quantitatively accurate re...... implanted in silica are found to be in excellent agreement with experimental data, providing support for the proposed atomic geometry....

  20. A solidification model for unmodified, Na-modified and Sr-modified Al-Si alloys

    DEFF Research Database (Denmark)

    Tiedje, Niels Skat; Hattel, Jesper Henri; Taylor, J. A.;

    2012-01-01

    An addition of small amounts of Na and Sr is commonly used in the industry to modify the eutectic in Al-Si alloys. Both Na and Sr suppress nucleation of the eutectic forcing nucleation and growth to take place at higher undercooling than in the unmodified material. Thus the scale of the eutectic ...

  1. Laser cladding of Al-Si/SiC composite coatings : Microstructure and abrasive wear behavior

    NARCIS (Netherlands)

    Anandkumar, R.; Almeida, A.; Vilar, R.; Ocelik, V.; De Hosson, J.Th.M.

    2007-01-01

    Surface coatings of an Al-Si-SiC composite were produced on UNS A03560 cast Al-alloy substrates by laser cladding using a mixture of powders of Al-12 wt.% Si alloy and SiC. The microstructure of the coatings depends considerably on the processing parameters. For a specific energy of 26 MJ/m2 the mic

  2. Microstructure and abrasive wear studies of laser clad Al-Si/SiC composite coatings

    NARCIS (Netherlands)

    Anandkumar, R.; Colaco, R.; Ocelik, V.; De Hosson, J. Th. M.; Vilar, R.; Gyulai, J; Szabo, PJ

    2007-01-01

    Surface coatings of Al-Si/SiC metal-matrix composites were deposited on Al-7 wt. % Si alloy substrates by laser cladding. The microstructure of the coatings was characterized by optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The microstructure of the coating mate

  3. The annealing behaviour of hydrogen implanted into Al metal and Al-Si alloy

    International Nuclear Information System (INIS)

    In the present experiment, we have investigated how defects and elements as additive play a role as trap site by observing the annealing behaviour of hydrogen implanted into Al and Al-Si alloy. It was found that hydrogen is trapped as molecules in grain boundaries of Si in Al. (author)

  4. Effect of sol gel coating on wettability and interfacial reaction in Al-SiC MMC

    DEFF Research Database (Denmark)

    Liu, Y.L.; Breivik, T.R.; Kindl, B.

    1995-01-01

    The control of the interfacial reaction between the matrix and the SiC reinforcement in Al-SiC metal matrix composites (MMCs) is an important production parameter. The reaction causes degradation of the reinforcement, weakening of the interface and a decrease of the mechanical properties of the p...

  5. Structural and age hardening characteristics of near eutectic Al-Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Kamalpreet; Pandey, Om Prakash [Thapar Univ., Patiala (India). School of Physics and Materials Science

    2010-09-15

    In the present work structural features of near eutectic Al-Si and Al-Si-Cu alloys prepared by a normal melting and casting route are studied. It is observed that morphology of Si plays an important role in enhancing the mechanical properties of Al-Si alloys. In order to modify the Si network in the matrix of Al some immiscible elements such as Pb, Sn, Cd and Bi have been added in small quantities to the alloy. Since the structure developed after casting governs the mechanical properties, it is essential to understand the structural features before testing the mechanical properties. Taking into consideration the age hardening characteristics of the alloys, microstructural assessment and a thermal study of these alloys have been done. Thermal analysis shows that immiscible elements are homogeneously distributed in the alloys. It is observed that the addition of Pb leads to a rosette type structure, whereas in the case of Cd and Sn blunt and twisted Si needles can be seen. The structural features of the eutectic change to hypoeutectic completely on addition of Bi. The shift in the eutectic depression on addition of a ternary element causes a change in the morphology of Si. Addition of Cu to the Al-Si alloys gives precipitation hardening characteristics. (orig.)

  6. Influence of La on microstructures of hypereutectic Al-Si alloys

    Institute of Scientific and Technical Information of China (English)

    张荻; 易宏坤; 吕维洁; 范同祥

    2003-01-01

    The modification effects of La addition on the microstructural evolution of hypereutectic Al-17% Si and Al-25% Si(mass fraction) alloys were investigated. The Al-Si alloys were fabricated using conventional casting, spray atomization and deposition processing. Microstructures were examined using optical microscopy and SEM. The results show that the addition of La has strong modification effect on the conventional microstructure of as-cast Al-Si alloys, while little effect on that of spray-deposited Al-Si alloys. EDS and XRD experiments show that La reacts with Al and Si to form some intermetallics, which can be represented as AlSi2La2 consisting of LaSi2 and some unknown ternary AlSixLay phase. Spray atomization and deposition processing show significant microstructural modification in Al-17Si-xLa alloys as compared to their as-cast counterpart. Equiaxed Si particulates were observed evenly distributed in all the spray-deposited Al-17Si-xLa alloys regardless of the addition of La.

  7. Low-Cost Process for Silicon Purification with Bubble Adsorption in Al-Si Melt

    Science.gov (United States)

    Yu, Wenzhou; Ma, Wenhui; Lv, Guoqiang; Ren, Yongsheng; Dai, Yongnian; Morita, Kazuki

    2014-08-01

    The primary silicon and Al-Si alloy have been separated in hypereutectic Al-Si melt by the electromagnetic stirring and directional solidification processes. During the electromagnetic separation process, the behavior of a hydrogen bubble in Al-Si melt has been discussed. Furthermore, the bubble adsorption effect for the Si purification has been revealed. The results show that the bubble cavity formed in the lower part of the sample by pulling it up. The scanning electron microscope along with energy dispersive spectrometer (SEM-EDS) analysis indicated that a lot of impurities were adsorbed onto the surface of the bubble cavity that may be beneficial for the Si purification. By decreasing the pulling-up rates, the size of the bubble cavity in Al-Si alloy increased, which results in the decreasing of the impurity contents in primary silicon. In this work, the impurity content in primary silicon is 10.8 ppmw, which is obviously improved compared with the 777.57 ppmw in metallurgical silicon. It is a low-cost technology that will be a potential route for the Si purification.

  8. Separation Mechanism of Primary Silicon from Hypereutectic Al-Si Melts Under Alternating Electromagnetic Fields

    Science.gov (United States)

    Xue, Haiyang; Lv, Guoqiang; Ma, Wenhui; Chen, Daotong; Yu, Jie

    2015-07-01

    Solar grade silicon (SOG-Si) and hypereutectic Al-Si alloys with low silicon (silicon composition below 25 pct) can be successfully obtained by separation of hypereutectic Al-Si alloy with high silicon (silicon composition above 30 pct) under an alternating electromagnetic field after post-processing. To explore the separation mechanism in detail, experiments were conducted in this study using a high-frequency induction furnace with different pulling conditions of the crucible which is loaded with Al-45 wt pct Si melt. Results demonstrate that the separation of hypereutectic Al-Si alloy is feasible through either a pull-up or drop-down process. The height of each separation interface between the compact and sparse parts of the primary silicon decrease as the pull-up distance rose. When the pulling rate is very low, resultant morphologies of compact primary silicon are rounded and polygonal, allowing for more effective separation of the primary silicon. A novel physical model is presented here based on the experimental results and simulation. The model can be used to effectively describe the separation mechanism of primary silicon from hypereutectic Al-Si melts under alternating electromagnetic fields.

  9. Characteristics and Microstructure of a Hypereutectic Al-Si Alloy Powder by Ultrasonic Gas Atomization Process

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A hypereutectic Al-Si alloy powder was prepared by ultrasonic gas atomization process. The morphologies, microstructure and phase constituent of the alloy powder were studied. The results showed that powder of the alloy was very fine and its rnicrostructure was mainly consisted of Si crystals plus intermetallic compound Al9FeSi3, which were. very fine and uniformly distributed.

  10. Crystallographic Characteristic of Intermetallic Compounds in Al-Si-Mg Casting Alloys Using Electron Backscatter Diffraction

    Institute of Scientific and Technical Information of China (English)

    ZOU Yongzhi; XU Zhengbing; HE Juan; ZENG Jianmin

    2010-01-01

    The Al-Si-Mg alloy which can be strengthened by heat treatment is widely applied to the key components of aerospace and aeronautics. Iron-rich intermetallic compounds are well known to be strongly influential on mechanical properties in Al-Si-Mg alloys. But intermetallic compounds in cast Al-Si-Mg alloy intermetallics are often misidentified in previous metallurgical studies. It was described as many different compounds, such as AlFeSi, Al8Fe2Si, Al5(Fe, Mn)3Si2 and so on. For the purpose of solving this problem, the intermetallic compounds in cast Al-Si alloys containing 0.5% Mg were investigated in this study. The iron-rich compounds in Al-Si-Mg casting alloys were characterized by optical microscope(OM), scanning electron microscope(SEM), energy dispersive X-ray spectrometer(EDS), electron backscatter diffraction(EBSD) and X-ray powder diffraction(XRD). The electron backscatter diffraction patterns were used to assess the crystallographic characteristics of intermetallic compounds. The compound which contains Fe/Mg-rich particles with coarse morphologies was Al8FeMg3Si6 in the alloy by using EBSD. The compound belongs to hexagonal system, space group P2m, with the lattice parameter a=0.662 nm, c=0.792 nm. The β-phase is indexed as tetragonal Al3FeSi2, space group I4/mcm, a=0.607 nm and c=0.950 nm. The XRD data indicate that Al8FeMg3Si6 and Al3FeSi2 are present in the microstructure of Al-7Si-Mg alloy, which confirms the identification result of EBSD. The present study identified the iron-rich compound in Al-Si-Mg alloy, which provides a reliable method to identify the intermetallic compounds in short time in Al-Si-Mg alloy. Study results are helpful for identification of complex compounds in alloys.

  11. Liquid phase sintering of compacts in elemental powder mixtures for Al, Si and Cu; Al, Si oyobi Cu so funmatsu kongobutsu atsufuntai no ekiso shoketsu

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, M.; Kogure, Y.; Arai, T. [Teikyo University, of Science and Technology, Yamanashi (Japan)

    2000-02-15

    Si and Cu powders are added to Al powder and the mixtures compacted are heated at 620 or 600 degree C for 1 hr. in an argon atmosphere. Based on isothermal phase diagrams of Al-Si-Cu system (Al comer) at 620 and 600 degree C, the amounts of liquid phase are varied from 10 to 60 mass%. The relative densities of the sintered compacts are analyzed by using a regression analysis program; the relative densities are expressed as functions of sintering temperature, amount of liquid phase, ratio of Cu/(Cu+Si), and the others. Uniformity of shrinkage after liquid phase sintering is also analyzed. (author)

  12. “Estudio del comportamiento tribológico de aleaciones metálicas biocompatibles

    OpenAIRE

    González Morales, Noelia

    2013-01-01

    En este trabajo se han realizado ensayos de fricción y desgaste lubricados con suero fisiológico para determinar el comportamiento tribológico del Titanio, Molibdeno y sus aleaciones. El titanio y sus aleaciones presentan una excelente biocompatibilidad. Ello se debe a que dicho material es bioinerte y presenta una buena resistencia a la corrosión. Parece así mismo demostrado que la liberación de iones titanio al medio fisiológico circundante es muy bajo. Al parecer la capa de óxido que se...

  13. Research on an AlSiNx bi-material thermal-mechanical uncooled infrared FPA pixel

    Science.gov (United States)

    Zhang, Xia; Zhang, Da-cheng

    2011-08-01

    AlSiNx bi-material thermal strain structure is used in uncooled optic readout infrared focal plane array (UOR IR FPA) pixel based on Micro-Electro-Mechanical Systems (MEMS) technology. In this paper, the problems that the AlSiNxstructure prevents FPA pixel scaling down and fill factor improving, and the Au reflection layer of the pixel leads to larger readout light energy loss are analyzed. The feasibility of AlSiNx instead of AlSiNx in the UOR IR FPA fabrication is researched in detail. The theoretical analyzing and simulation results demonstrate that, with optimized thicknesses and their matching designing of SiNx and Al, the thermal-mechanical response of AlSiNx bi-material structure is improved to 1.8 times and the intensity of optic readout signal is improved to about 2 times compared with AuSiNAlSiNx one.

  14. Reliability and microstructure of Al-Si-V-Pd alloy films for use in ultralarge scale integration

    Science.gov (United States)

    Dirks, A. G.; Augur, R. A.

    1994-02-01

    New data on a highly reliable interconnect material based on aluminum will be presented. As compared with conventional Al-Si-Cu alloy films, quaternary Al-Si-V-Pd films with only 0.1 at. % vanadium and 0.1 at. % palladium combine excellent plasma etchability with good corrosion resistance. Electromigration tests of Al-Si-V-Pd films have shown a surprisingly high stability at 180 °C. Studies of microstructural attributes show: (a) for Al-Si-V-Pd relative to Al-Si, texture is not significantly changed and average grain size is slightly increased, and (b) the dominant factor leading to a highly stable microstructure is the combined presence of finely dispersed, small precipitates of both (Al,V) and (Al,Pd) phases.

  15. 稀土Sm元素对铸态Al-Si-Cu合金组织和力学性能的影响%Effects of samarium addition on microstructure and mechanical properties of as-cast Al-Si-Cu alloy

    Institute of Scientific and Technical Information of China (English)

    胡志; 闫洪; 饶远生

    2013-01-01

    通过光学显微镜、扫描电镜及能谱分析,研究了稀土元素钐对铸态Al-Si-Cu 合金组织和力学性能的影响。结果表明:稀土元素钐的添加不仅能有效地细化Al-Si-Cu合金中的α(Al)枝晶和共晶硅相,而且使得富铁相的体积分数下降,其形状从中国汉字状转变为板条状。发现了两种富钐的金属间化合物:AlSiSm相和AlSiCuSm相,块状的 AlSiCuSm 相通常与针状的AlSiSm相连。稀土元素钐的添加使得Al-Si-Cu合金的力学性能得到改善,当钐含量为1.0%时,合金的抗拉强度和伸长率分别为220 MPa和3.1%。%The effects of rare earth samarium (Sm) additions on the microstructure and mechanical properties of as-cast Al-Si-Cu alloy were investigated by optical microscopy and scanning electron microscopy (SEM). The results show that Sm can effectively refine theα(Al) dendrite and the eutectic silicon. In addition, the shape of iron-rich phases changes from the Chinese script-like to slender-like ones and the volume fraction of iron-rich phases is decreased by the addition of Sm. Two kinds of Sm-rich intermetallics are found: AlSiSm and AlSiCuSm. The plate-like AlSiCuSm phase always associates with the needle-like AlSiSm phase. The mechanical properties are improved by the addition of Sm, and the good ultimate tensile strength (220 MPa) and elongation (3.1%) are obtained from the Al-Si-Cu-1.0Sm alloy.

  16. Irradiation-induced Interdiffusion between U-Mo vs. Al-Si

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Ho Jin; Lee, Kyu Hong; Jeong, Yong Jin; Yoo, Byung Ok; Jung, Yang Hong; Park, Jong Man [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    It is deduced that Si would stabilize the interaction layer also during irradiation not to form gross fission gas voids. Irradiation tests, such as RERTR-6 and IRIS-3 irradiation tests, using Al-Si matrices instead of an Al matrix have shown remarkable reductions in the interaction layer growth. However, the US AFIP-1 irradiation test at ATR and the European E-FUTURE1 test showed that interaction layers grow significantly due to their high fuel temperatures. It is proposed that the performance of Si on the interaction reduction would be decreased when the interaction layer grows since the Si content in the interaction layer becomes diluted. Also it is found that it is difficult to obtain high Si content in the interaction layer by interdiffusion between the U-Mo particle and Al-Si matrix during irradiation. Post-irradiation examination (PIE) of the KOMO-3 irradiation test using U-7wt%Mo/Al-2wt%Si has shown that the concentration of Si content in the interaction layer is less than 11 at% as shown in Fig. 1. One way to enrich Si in the interaction layer higher than 11 at% is pre-irradiation annealing of U-Mo/Al dispersion fuel. As shown in Fig. 1, more than 20 at% of Si could be enriched in the interaction layer by out-of-pile annealing at 580 .deg. C. The KOMO-4 and KOMO-5 irradiation tests at HANARO have irradiated pre-irradiation annealed U-Mo/Al-Si dispersion fuel in order to estimate the performance of the Si-rich layer as a diffusion barrier during irradiation. In this study, the interdiffusion behavior of the preirradiation annealed U-Mo/Al-Si dispersion fuel and as extruded U-Mo/Al-Si dispersion fuel during irradiation are analyzed. By pre-irradiation forming of Si-rich layers, in-pile interdiffusion mechanisms depending on the Si distribution can be understood for U-7wt%Mo/Al-5wt%Si. The preferential pile up of Si at the periphery of interaction layers reduces the interaction during irradiation. The presence of Si in the interaction layers does not stabilize

  17. Microstructure and mechanical properties of AC AlSi9CuX alloys

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2007-10-01

    Full Text Available Purpose: In order to gain a better understanding of how to control the as-cast microstructure, it is important to understand the evaluation of microstructure during solidification and understanding how influence the changes of chemical concentration on this microstructure and mechanical properties. In this research, the effect of Cu content on the microstructure and mechanical properties of AC AlSi9CuX series alloys has been investigated.Design/methodology/approach: The experimental alloy used in this investigation were prepared at the University of Windsor (Canada in the Light Metals Casting Laboratory, by mixing the AC AlSi5Cu1(Mg commercial alloys and two master alloys AlSi49 and AlCu55, in a 10 kg capacity ceramic crucible. Optical microscope, transition electron microscope and scanning electron microscope were used to characterize the microstructure and intermetallic phases. Secondary dendrite arm spacing measurements were carried out using an Leica Q-WinTM image analyzer. Compression tests were conducted at room temperature using a Zwick universal testing machine. Rockwell F–scale hardness tests were conducted at room temperature using a Zwick HR hardness testing machine. Vickers microhardness tests were conducted using a DUH 202 microhardness testing machine.Findings: It was found that the increase of Cu content to 2 wt% leads to change of the Al+Si eutectic morphology, resulting in a grate increase in the ultimate tensile strength and ductility values compared to the alloys include 1 and 4 wt % of Cu. Based on the X–ray phase analysis was found, that change of Cu content don’t influences on the phases composition of investigated alloy.Practical implications: The aim of this work is describe in detail the solidification process in a number of AC AlSi9CuX foundry alloys. In investigated alloys there were identified five phases, which can suggest together witch thermal analysis, that in these alloys occur four solidification reactions

  18. Microstructures and Tensile Properties of Die-Cast Al-Si-Cu-Zn Aluminum Alloy%Al-Si-Cu-Zn压铸铝合金的显微组织及拉伸性能

    Institute of Scientific and Technical Information of China (English)

    李锋; 王珏; 车欣; 陈立佳

    2009-01-01

    针对不同处理状态Al-Si-Cu-Zn压铸铝合金的显微组织及拉伸变形行为进行研究,并与重力铸造Al-Si-Cu-Zn合金进行比较.结果表明,压铸态Al-Si-Cu-Zn合金的组织更为细小;与重力铸造Al-Si-Cu-Zn合金相比,压铸态Al-Si-Cu-Zn合金的室温抗拉强度可提高27%左右,室温屈服强度可提高18%左右,在室温、150℃和200℃下的断裂伸长率可分别提高约72%、86%和90%;固溶处理导致Al-Si-Cu-Zn压铸铝合金的拉伸性能降低;Al-Si-Cu-Zn压铸铝合金在拉伸加载条件下主要发生韧性断裂.

  19. Preparation of Al/Si functionally graded materials using ultrasonic separation method

    Directory of Open Access Journals (Sweden)

    Zhang Zhongtao

    2008-08-01

    Full Text Available Functionally graded materials (FGM have been widely used in many industries such as aerospace, energy and electronics. In this experimental study of fabricating FGM, an approach was developed to prepare Al/Si FGM using power ultrasonic separation method. Material sample with continuously changing composition and performance/properties was successfully produced. Results showed that the microstructure of the FGM sample transited, from its top to bottom, from the hypereutectic structure with a large quantity of primary Si gradually to the eutectic, and fi nally to the hypoeutectic with numerous primary Al dendrites. The distribution of primary Si and microhardness of the FGM sample also presented graded characteristics, resulting that the wear resistance of the FGM sample decreased from top to bottom. Preliminary discussion was made on the mechanism of the formation of Al/Si FGM.

  20. Preparation of Al/Si functionally graded materials using ultrasonic separation method

    Institute of Scientific and Technical Information of China (English)

    Zhang Zhongtao; LI Tingju; Yue Hongyun; Zhang Jian; Li Jie

    2008-01-01

    Functionally graded materials (FGM) have been widely used in many industries such as aerospace, energy and electronics. In this experimental study of fabricating FGM, an approach was developed to prepare Al/Si FGM using power ultrasonic separation method. Material sample with continuously changing composition and performance/properties was successfully produced. Results showed that the microstructure of the FGM sample transited, from its top to bottom, from the hypereutectic structure with a large quantity of primary Si gradually to the eutectic, and finally to the hypoeutectic with numerous primary AI dendrites. The distribution of primary Si and microhardness of the FGM sample also presented graded characteristics, resulting that the wear resistance of the FGM sample decreased from top to bottom. Preliminary discussion was made on the mechanism of the formation of Al/Si FGM.

  1. Local analysis of Eu2+ emission in CaAlSiN3

    International Nuclear Information System (INIS)

    We have investigated the local luminescence properties of Eu-doped CaAlSiN3 by using low-energy electron beam (e-beam) techniques. The particles yield broad emission centered at 655 nm with a shoulder at higher wavelength under light excitation, and a broad band around 643 nm with a tail at 540 nm under e-beam excitation. Using cathodoluminescence (CL) in a scanning electron microscope (SEM), we have observed small and large particles, which, although with different compositions, exhibit Eu2+-related emissions at 645 and 635 nm, respectively. Local CL measurements reveal that the Eu2+ emission may actually consist of several bands. In addition to the red broad band, regularly spaced sharp peaks have been occasionally observed. These luminescence variations may originate from a variation in the composition inside CaAlSiN3. (paper)

  2. Interfacial valence electron localization and the corrosion resistance of Al-SiC nanocomposite

    Science.gov (United States)

    Mosleh-Shirazi, Sareh; Hua, Guomin; Akhlaghi, Farshad; Yan, Xianguo; Li, Dongyang

    2015-01-01

    Microstructural inhomogeneity generally deteriorates the corrosion resistance of materials due to the galvanic effect and interfacial issues. However, the situation may change for nanostructured materials. This article reports our studies on the corrosion behavior of SiC nanoparticle-reinforced Al6061 matrix composite. It was observed that the corrosion resistance of Al6061 increased when SiC nanoparticles were added. Overall electron work function (EWF) of the Al-SiC nanocomposite increased, along with an increase in the corrosion potential. The electron localization function of the Al-SiC nanocomposite was calculated and the results revealed that valence electrons were localized in the region of SiC-Al interface, resulting in an increase in the overall work function and thus building a higher barrier to hinder electrons in the nano-composite to participate in corrosion reactions. PMID:26667968

  3. Physicochemical preparation of the AlSi11 alloy for castings of fire-fighting equipment

    Directory of Open Access Journals (Sweden)

    M. Dudyk

    2010-04-01

    Full Text Available The paper presents results of reaction kinetics investigation of crystallization processes of refined, modified with Sr and Sb as well as filtered silumin destined to casting of fire-fighting equipment. It has been determined an effect of performed upgrading processes of: refining, modification and filtering on changes of mechanical properties (Rm, A5, HB and KCV of the AlSi11 (AK11 alloy. There were performed metallographic examinations of the upgraded alloys and flooded foamed filters. It has been proved, that developed and set into production upgrading technology of the AlSi11 (AK11 alloy enables casting of fire-fighting equipment, complying with rquirements of the European Union.

  4. Evaluation of Cracking Causes of AlSi5Cu3 Alloy Castings

    Directory of Open Access Journals (Sweden)

    Eperješi Š.

    2014-10-01

    Full Text Available Recently, the castings made from aluminum-silicon alloys by pressure die casting are increasingly used in the automotive industry. In practice, on these castings are high demands, mainly demands on quality of their structure, operating life and safety ensuring of their utilization. The AlSi5Cu3 alloy castings are widely used for production of car components. After the prescribed tests, the cracks and low mechanical properties have been identified for several castings of this alloy, which were produced by low pressure casting into a metal mould and subsequent they were heat treated. Therefore, analyses of the castings were realized to determine the causes of these defects. Evaluation of structure of the AlSi5Cu3 alloy and causes of failure were the subjects of investigation presented in this article.

  5. Low Cost Al-Si Casting Alloy As In-Situ Composite for High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A.

    2000-01-01

    A new aluminum-silicon (Al-Si) alloy has been successfully developed at NASA- Marshall Space Flight Center (MSFC) that has significant improvement in tensile and fatigue strength at elevated temperatures (500 F-700 F). The alloy offers a number of benefits such as light weight, high hardness, low thermal expansion and high surface wear resistance. In hypereutectic form, this alloy is considered as an in-situ Al-Si composite with tensile strength of about 90% higher than the auto industry 390 alloy at 600 F. This composite is very economically produced by using either conventional permanent steel molds or die casting. The projected material cost is less than $0.90 per pound, and automotive components such as pistons can be cast for high production rate using conventional casting techniques with a low and fully accounted cost. Key Words: Metal matrix composites, In-situ composite, aluminum-silicon alloy, hypereutectic alloy, permanent mold casting, die casting.

  6. Improvement of mechanical properties of AlSi7Mg alloy with fast cooling homogenous modifier

    Directory of Open Access Journals (Sweden)

    T. Lipiński

    2008-04-01

    Full Text Available The results of modification of eutectic and hypoeutectic aluminum-silicon alloys by sodium, strontium, antimony and other additions in the metallurgic process have been already analyzed and described. Literature on the topic provides scant information on silumin modification with modifiers obtained from the treated alloy by fast coolingResults of studies on the modification of AlSi7Mg alloy with a homogenous modifier obtained by fast cooling of AlSi7Mg alloy at rate 300oC/s are presented in the paper. The effects of cooling rate and w/w concentration of the modifier in the melt on tensile strength, percentage elongation, Brinell hardness and abrasive wear are illustrated graphically.

  7. Solidification, growth mechanisms, and associated properties of Al-Si and magnesium lightweight casting alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hosch, Timothy [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    Continually rising energy prices have inspired increased interest in weight reduction in the automotive and aerospace industries, opening the door for the widespread use and development of lightweight structural materials. Chief among these materials are cast Al-Si and magnesium-based alloys. Utilization of Al-Si alloys depends on obtaining a modified fibrous microstructure in lieu of the intrinsic flake structure, a process which is incompletely understood. The local solidification conditions, mechanisms, and tensile properties associated with the flake to fiber growth mode transition in Al-Si eutectic alloys are investigated here using bridgman type gradient-zone directional solidification. Resulting microstructures are examined through quantitative image analysis of two-dimensional sections and observation of deep-etched sections showing three-dimensional microstructural features. The transition was found to occur in two stages: an initial stage dominated by in-plane plate breakup and rod formation within the plane of the plate, and a second stage where the onset of out-of-plane silicon rod growth leads to the formation of an irregular fibrous structure. Several microstructural parameters were investigated in an attempt to quantify this transition, and it was found that the particle aspect ratio is effective in objectively identifying the onset and completion velocity of the flake to fiber transition. The appearance of intricate out-of-plane silicon instability formations was investigated by adapting a perturbed-interface stability analysis to the Al-Si system. Measurements of silicon equilibrium shape particles provided an estimate of the anisotropy of the solid Si/liquid Al-Si system and incorporation of this silicon anisotropy into the model was found to improve prediction of the instability length scale. Magnesium alloys share many of the benefits of Al-Si alloys, with the added benefit of a 1/3 lower density and increased machinability. Magnesium castings

  8. Brazeability of a 3003 Aluminum alloy with Al-Si-Cu-based filler metals

    Science.gov (United States)

    Tsao, L. C.; Weng, W. P.; Cheng, M. D.; Tsao, C. W.; Chuang, T. H.

    2002-08-01

    Al-Si-Cu-based filler metals have been used successfully for brazing 6061 aluminum alloy as reported in the authors’ previous studies. For application in heat exchangers during manufacturing, the brazeability of 3003 aluminum alloy with these filler metals is herein further evaluated. Experimental results show that even at such a low temperature as 550 °C, the 3003 alloys can be brazed with the Al-Si-Cu fillers and display bonding strengths that are higher than 77 MPa as well. An optimized 3003 joint is attained in the brazements with the innovative Al-7Si-20Cu-2Sn-1Mg filler metal at 575 °C for 30 min, which reveals a bonding strength capping the 3003 Al matrix.

  9. Local crystallography and stress voiding in Al-Si-Cu versus copper interconnects

    Science.gov (United States)

    Keller, R. R.; Kalnas, C. E.; Phelps, J. M.

    1999-07-01

    We compare the local crystallographic orientations associated with stress voids in Al-1Si-0.5Cu (wt %) with those in pure copper interconnects. Orientations were sorted by whether grains were immediately adjacent to voids. Grains adjacent to voids in Al-Si-Cu showed a fiber texture that was slightly stronger than those in intact regions. This is in contrast to copper, which showed weaker local texture around voids. We postulate the difference to be due to the relative effectiveness of the diffusion paths available in the lines. For Al-Si-Cu, the presence of defects associated with precipitates may allow more rapid diffusion than grain boundaries. Voiding in copper, which is free from such defects, depends more on grain boundary structure.

  10. Microstructural Characteristic and Mechanical Behavior of Nodular Silicon Hypereutectic Al-Si Alloys

    Science.gov (United States)

    Wang, Ruyao; Lu, Weihua

    2012-02-01

    The microstructure and mechanical properties of Al-Si-Cu-Mg alloys containing 12 wt.% to 30 wt.% Si are discussed. The eutectic and primary silicon particles are nodulized by a designed modification practice followed by a solution heat treatment of 6 h to 8 h at 510°C to 520°C. Metallographic analysis was used to measure structural characteristics of the Si-rich structures. Spheroidization of silicon phase leads to an increase in tensile strength and ductility of alloys at room temperature and 300°C compared with commercial Al-Si alloy. Increasing Si concentration causes the ultimate tensile strength and elongation at room temperature to fall due to the appearance of coarse silicon particles, but the ultimate tensile strength at 300°C remains unchanged.

  11. Autoradiographic and gamma spectrometric investigation of AlSi-1 microwire

    International Nuclear Information System (INIS)

    For determining the homogeneity reeled-up wire (25 μm diameter) was activated for 90 h applying a neutron flux of 3 to 5 x 1013 n cm-2s-1. The activated impurities were identified by gamma spectrometry and by autoradiography after various decay times. The studies were performed with a view to improve the quality, in particular the ductility of AlSi-1 wire for bonding in microelectronics. (author)

  12. Preparation of Al/Si functionally graded materials using ultrasonic separation method

    OpenAIRE

    Zhang Zhongtao; Li Tingju; Yue Hongyun

    2008-01-01

    Functionally graded materials (FGM) have been widely used in many industries such as aerospace, energy and electronics. In this experimental study of fabricating FGM, an approach was developed to prepare Al/Si FGM using power ultrasonic separation method. Material sample with continuously changing composition and performance/properties was successfully produced. Results showed that the microstructure of the FGM sample transited, from its top to bottom, from the hypereutectic structure with a ...

  13. Derivative thermo analysis of the near eutectic Al-Si-Cu alloy

    OpenAIRE

    L.A. Dobrzański; M. Krupiński; K. Labisz

    2008-01-01

    For determining of the dependence between cooling Speer, chemical composition and structure of the Al–Si–Cu aluminium cast alloy the thermo-analysis was carried out, using the UMSA device (Universal Metallurgical Simulator and Analyzer), next the optical and electron scanning microscopy was used for investigation of the structure, phase and chemical composition of the AC-AlSi7Cu3Mg grade Al cast alloy also using the EDS microanalysis as well the EBSD technique.

  14. Investigation of the brittle fracture behavior of intermetallic Ti-Al-Si-Nd-alloys

    International Nuclear Information System (INIS)

    The object of this paper is the fracture behaviour of three Ti-Al-Si-Nb alloys. Fracture mechanical data are experimentally determined and their statistical properties are investigated. To describe the fracture process of disordered heterogeneous brittle materials a statistical model was developed, based on damage mechanics. With the aid of this model it was possible to attribute the fracture behaviour, the fracture mechanical data and their statistical properties to the microstructure of the materials studied. (orig.)

  15. AlSi10Mg parts produced by selective laser melting (SLM)

    OpenAIRE

    Godino Martinez, Miguel

    2013-01-01

    Selective Laser Melting (SLM) is an Additive Manufacturing technique, which allows the production of parts starting from powder, using a laser beam and the aid of CAD computer techniques. Due to the layer wise production, complex geometrical pieces can be built achieving very good dimensional tolerances and high quality parts related to the mechanical properties. The goal of this thesis is to study the microstructure and the mechanical properties of AlSi10Mg parts produced by SLM, dependin...

  16. On the Precipitation Hardening of Selective Laser Melted AlSi10Mg

    Science.gov (United States)

    Aboulkhair, Nesma T.; Tuck, Chris; Ashcroft, Ian; Maskery, Ian; Everitt, Nicola M.

    2015-08-01

    Precipitation hardening of selective laser melted AlSi10Mg was investigated in terms of solution heat treatment and aging duration. The influence on the microstructure and hardness was established, as was the effect on the size and density of Si particles. Although the hardness changes according to the treatment duration, the maximum hardening effect falls short of the hardness of the as-built parts with their characteristic fine microstructure. This is due to the difference in strengthening mechanisms.

  17. Derivative thermo analysis of the near eutectic Al-Si-Cu alloy

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2008-12-01

    Full Text Available For determining of the dependence between cooling Speer, chemical composition and structure of the Al–Si–Cu aluminium cast alloy the thermo-analysis was carried out, using the UMSA device (Universal Metallurgical Simulator and Analyzer, next the optical and electron scanning microscopy was used for investigation of the structure, phase and chemical composition of the AC-AlSi7Cu3Mg grade Al cast alloy also using the EDS microanalysis as well the EBSD technique.

  18. Effect of Squeeze Cast Process Parameters on Fluidity of Hypereutectic Al-Si Alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The effects of processing variables on the fluidity of hypereutectic Al-Si alloy melt during squeeze casting were investigated. The maximum fluidity of Al-16.0%Si alloy during squeeze casting was obtained under the applied pressure of 30 MPa. The fluidity increased with superheat. The fluidity increased with silicon content in the range from 12.0% to 20.0%. That was decreased respectively by eutectic modification and primary silicon refinement.

  19. Corrosion performance of Al-Si-Cu hypereutectic alloys in a synthetic condensed automotive solution

    OpenAIRE

    Hamilta de Oliveira Santos; Fernando Morais dos Reis; Clarice Terui Kunioshi; Jesualdo Luiz Rossi; Isolda Costa

    2005-01-01

    In this investigation the corrosion resistance of four Al-Si hypereutectic alloys in a solution typical of condensate from automotive fuel combustion products, and referred to here as synthetic condensed automotive solution, has been studied. Three commercial alloys that are used for cylinder liners, and a laboratory made alloy, were studied by electrochemical impedance spectroscopy and measurements were taken after increasing times of immersion in this solution. Comparison of the electrochem...

  20. Refinement of primary Si in hypereutectic Al-Si alloys by intensive melt shearing

    OpenAIRE

    Zhang, Z.; Li, H-T; Stone, IC; Fan, Z.

    2011-01-01

    Hypereutectic Al-Si based alloys are gaining popularity for applications where a combination of light weight and high wear resistance is required. The high wear resistance arising from the hard primary Si particles comes at the price of extremely poor machine tool life. To minimize machining problems while exploiting outstanding wear resistance, the primary Si particles must be controlled to a uniform small size and uniform spatial distribution. The current industrial means of refining primar...

  1. Hot extrusion for Al-Si-(Fe, Cu) hyper-eutectic cast alloys

    OpenAIRE

    Yokoyama, Hisanaga; Umezawa, Osamu; Nagai, Kotobu; Kokubo, Kunio

    1999-01-01

    For hyper-eutectic Al-Si-(Fe, Cu) cast materials in large scale ingots, we have studied microstructural modification by thermomechanical treatment to produce a heavily deformable material. Cast materials contained coarse primary Si crystals in a few hundred micron diameter or acicular intermetallic compound in several hundred micron length. Even by multiple-step cold-rolling, sample fracture of the cast alloys occurred with more extrusion step to the cast materials. A novel process, repeated ...

  2. Mechanical properties of thermomechanical treated hyper-eutectic Al-Si-(Fe, Mn, Cu) materials

    OpenAIRE

    Umezawa, Osamu

    2005-01-01

    Tensile and high-cycle fatigue behavior of thermomechanical treated hyper-eutectic Al-Si-(Fe, Mn, Cu) materials were studied. Through the repeated thermomechanical treatment (RTMT) which is a repeat of the multi steps cold-working followed by heat treatment, Si crystals and/or intermetallic compounds were broken into some fragments and dispersed in the aluminum matrix. Fine dispersion of the second phase particles exhibited good ductility, since early fracture was overcome. A few large Si cry...

  3. Spray cast Al-Si base alloys for stiffness and fatigue strength requirements

    OpenAIRE

    Courbiere, M.; Mocellin, A.

    1993-01-01

    Hypereutectic AlSiFe spray-cast alloys exhibit properties similar to those of metal-matrix composite (MMC's) : high Young's modulus and a low coefficient of thermal expansion. These physical properties can be adjusted by changing the Si content of the alloy. The refinement of the microstructure is produced by formation of a large amount of nuclei in the spray. Consolidation done by extrusion (bars, tubes or profiles) and/or forging leads to high mechanical properties, especially very good dyn...

  4. Nano-Crystallization of High-Entropy Amorphous NbTiAlSiWxNy Films Prepared by Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    Wenjie Sheng

    2016-06-01

    Full Text Available High-entropy amorphous NbTiAlSiWxNy films (x = 0 or 1, i.e., NbTiAlSiNy and NbTiAlSiWNy were prepared by magnetron sputtering method in the atmosphere of a mixture of N2 + Ar (N2 + Ar = 24 standard cubic centimeter per minute (sccm, where N2 = 0, 4, and 8 sccm. All the as-deposited films present amorphous structures, which remain stable at 700 °C for over 24 h. After heat treatment at 1000 °C the films began to crystalize, and while the NbTiAlSiNy films (N2 = 4, 8 sccm exhibit a face-centered cubic (FCC structure, the NbTiAlSiW metallic films show a body-centered cubic (BCC structure and then transit into a FCC structure composed of nanoscaled particles with increasing nitrogen flow rate. The hardness and modulus of the as-deposited NbTiAlSiNy films reach maximum values of 20.5 GPa and 206.8 GPa, respectively. For the as-deposited NbTiAlSiWNy films, both modulus and hardness increased to maximum values of 13.6 GPa and 154.4 GPa, respectively, and then decrease as the N2 flow rate is increased. Both films could be potential candidates for protective coatings at high temperature.

  5. Influence of Lanthanum on Solidification, Microstructure, and Mechanical Properties of Eutectic Al-Si Piston Alloy

    Science.gov (United States)

    Ahmad, R.; Asmael, M. B. A.

    2016-07-01

    The effects of Lanthanum (La) concentration on the solidification parameters of the α-Al, Al-Si, and Al-Cu phases and on the microstructure, tensile, and hardness properties of eutectic Al-Si-Cu-Mg alloy were systematically investigated. The solidification parameters were examined using computer-aided cooling curve thermal analysis (CA-CCTA). The cooling curve and microstructure analysis showed that La altered the Si structure. The nucleation and growth temperatures of eutectic Si decreased when 0.3 wt.% La was added, and a high depression temperature was obtained with 1.0 wt.% La. High amounts of La considerably modified the Si structure and decreased the area and aspect ratio by 69.9 and 51%, respectively. The thermal analysis result recorded a faster freezing time with the La addition and a 36% alteration in the secondary dendrite arm spacing. Two secondary or ternary La-rich intermetallic phases were formed with needle- and plate-like structures. Furthermore, the mechanical properties were investigated by hardness and tensile tests with different La concentrations. The addition of small amounts of La (0.1 wt.%) significantly improved the ultimate tensile strength and quality index of the Al-Si-Cu-Mg alloy. In addition, the hardness value of Al-11Si-Cu increased by 7-8% with the increasing amount of La added.

  6. The influence of chemical composition on the properties and structure Al-Si-Cu(Mg alloys

    Directory of Open Access Journals (Sweden)

    M. Kaczorowski

    2007-04-01

    Full Text Available The mechanical properties of different chemical composition AlSiCuMg type cast alloys after precipitation hardening are presented. The aim of the study was to find out how much the changes in chemistry of aluminum cast alloys permissible by EN-PN standards may influence the mechanical properties of these alloys. Eight AlSi5Cu3(Mg type cast alloys of different content alloying elements were selected for the study. The specimens cut form test castings were subjected to precipitation hardening heat treatment. The age hardened specimens were evaluated using tensile test, hardness measurements and impact test. Moreover, the structure investigation were carried out using either conventional light Metallography and scanning (SEM and transmission (TEM electron microscopy. The two last methods were used for fractography observations and precipitation process observations respectively. It was concluded that the changes in chemical composition which can reach even 2,5wt.% cause essential differences of the structure and mechanical properties of the alloys. As followed from quantitative evaluation and as could be predicted theoretically, copper and silicon mostly influenced the mechanical properties of AlSi5Cu3(Mg type cast alloys. Moreover it was showed that the total concentration of alloying elements accelerated and intensifies the process of decomposition of supersaturated solid solution. The increase of Cu and Mg concentration increased the density of precipitates. It increases of strength properties of the alloys which are accompanied with decreasing in ductility.

  7. The mechanism of PEO process on Al-Si alloys with the bulk primary silicon

    International Nuclear Information System (INIS)

    This study focuses on mechanism of ceramic coating on Al-Si alloys with bulk primary Si using plasma electrolytic oxidation (PEO) technology. Al-Si alloys with 27-32%Si in weight were used as substrates. The morphologies, composition and microstructure of PEO coatings were investigated by scanning electron microscopy (SEM) with energy dispersive X-ray system (EDX). Results showed that the PEO process had four different stages. The effect of bulk Si is greatly on the morphology and composition of coatings at first three stages. Anodic oxide films formed on Al and Si phases, respectively. When the voltage exceeded 40 V, glow appeared and concentrated on the localized zone of interface of Al and Si phase. Al-Si-O compounds formed and covered on the dendrite Si phase surface, and the coating on bulk Si, which was silicon oxide, was rougher than that on other phase. If the treatment time was long enough, the coatings with uniform surface morphologies and elements distribution will be obtained but the microstructure of inner layer is looser due to the bulk Si.

  8. Hard gradient (Ti,Al,SiN coating deposited on composite tool materials

    Directory of Open Access Journals (Sweden)

    T. Gawarecki

    2009-04-01

    Full Text Available Purpose: This paper presents investigation of gradient coating of (Ti,Al,SiN deposited on the Al2O3+SiC(w oxide ceramics substrate deposited with the PVD process.Design/methodology/approach: Structure of substrate and coating was investigated with use of scanning electron microscopy (SEM; The X-Ray Photoelectron Spectrometry (XPS and Auger Electron Spectrometry (AES examinations was carried out for proving the gradient character of the (Ti,Al,SiN coating. The investigation includes also microhardness and roughness tests of the deposited coating and used substrate. Scratch test results was analysed to introduce adherence of the investigated coating.Findings: Gradient structure and main properties of the investigated materials were introduced. It has been stated, that properties of the coated with gradient (Ti,Al,SiN coating oxide tool ceramic increase in comparison with uncoated material.Practical implications: Depositing the wear resistant gradient coating onto the Al2O3+SiC(w oxide tool ceramic results in a significant increase of the surface layer microhardness, contributing most probably in this way in machining to the decrease of the wear intensity of cutting tools’ flanks made from the Al2O3+SiC(w oxide tool ceramic.Originality/value: Gradient coatings are an innovative idea. The composition, microstructure and properties of gradient materials change continuously from the surface to the interior of the material.

  9. Influence of Lanthanum on Solidification, Microstructure, and Mechanical Properties of Eutectic Al-Si Piston Alloy

    Science.gov (United States)

    Ahmad, R.; Asmael, M. B. A.

    2016-05-01

    The effects of Lanthanum (La) concentration on the solidification parameters of the α-Al, Al-Si, and Al-Cu phases and on the microstructure, tensile, and hardness properties of eutectic Al-Si-Cu-Mg alloy were systematically investigated. The solidification parameters were examined using computer-aided cooling curve thermal analysis (CA-CCTA). The cooling curve and microstructure analysis showed that La altered the Si structure. The nucleation and growth temperatures of eutectic Si decreased when 0.3 wt.% La was added, and a high depression temperature was obtained with 1.0 wt.% La. High amounts of La considerably modified the Si structure and decreased the area and aspect ratio by 69.9 and 51%, respectively. The thermal analysis result recorded a faster freezing time with the La addition and a 36% alteration in the secondary dendrite arm spacing. Two secondary or ternary La-rich intermetallic phases were formed with needle- and plate-like structures. Furthermore, the mechanical properties were investigated by hardness and tensile tests with different La concentrations. The addition of small amounts of La (0.1 wt.%) significantly improved the ultimate tensile strength and quality index of the Al-Si-Cu-Mg alloy. In addition, the hardness value of Al-11Si-Cu increased by 7-8% with the increasing amount of La added.

  10. Hypereutectic AlSi Alloy: Gathering of 3D Microstructure Data

    Science.gov (United States)

    Schaberger-Zimmermann, E.; Mathes, M.; Zimmermann, G.

    2016-06-01

    Hypereutectic and eutectic AlSi-base alloys find frequent application in casting automotive components. The properties of this type of alloy depend significantly on their solidification microstructure, especially the size, shape, and distribution of primary and eutectic silicon. The serial sectioning technique was applied for determining the three-dimensional (3D) microstructure of an Al-18wt.%Si alloy. For clear identification of both the larger primary Si particles grown in the melt and the fine lamellar eutectic Si, a series of two-dimensional equidistant cross sections were metallographically prepared. The microstructure in these cross sections was detected and observed at high resolution using a light microscope. The images were stored in a digital library. The 3D reconstruction of primary Si particles and AlSi eutectic was achieved through the application of various software tools. This provided data about the faceted growth behavior of octahedral Si particles and feathery eutectic Si. The image stack was also imported to hierarchical data format (version 5) (HDF5) open source format, thus, enabling availability of the 3D image data to the wider community. In this way, 3D reconstructions of this kind can contribute to a greater understanding of processing/microstructure property relationships in hypereutectic AlSi alloys.

  11. EBSD study of crystallographic identification of Fe-Al-Si intermetallic phases in Al-Si coating on Cr-Mo steel

    International Nuclear Information System (INIS)

    5Cr-0.5Mo steel was coated by hot-dipping in a molten Al-10 wt.% Si bath at 700 deg. C for 10, 60, 120 or 180 s. The identification of the phases in the Fe-Al-Si intermetallic phases formed in the aluminide layers during hot-dipping was carried out by using a combination of scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and electron backscatter diffraction (EBSD). The EDS results show a τ5(H)-Al7Fe2Si phase, which exhibited 2 distinct morphologies, small particles widely dispersed and a continuous layer. Also revealed by EDS were τ6-Al4FeSi and τ4-Al3FeSi2 phases, which showed plate-shaped morphology, in an Al-Si topcoat. However, the XRD results show the intermetallic phases in the aluminide layer were composed of outer cubic τ5(C)-Al7(Fe,Cr)2Si and inner hexagonal τ5(H)-Al7Fe2Si. EBSPs and mapping functions in EBSD helped to clarify the confused phase identifications yielded by EDS and XRD. In this way, the small intermetallic particles and the continuous intermetallic layer were identified as cubic τ5(C)-Al7(Fe,Cr)2Si and hexagonal τ5(H)-Al7Fe2Si, respectively, and the plate-shaped intermetallic phase was identified as monoclinic τ6-Al4FeSi and tetragonal τ4-Al3FeSi2 with the same metallographic morphology. EBSD proved to be a very effective technique for local phase identification of aluminide layers with complicated multiphase morphologies.

  12. The impact of major alloying elements and refiner on the SDAS of Al-Si-Cu alloy; Der Einfluss von Hauptlegierungselementen und Kornfeinern auf den sekundaeren Dendritenarmabstand der Al-Si-Cu-Legierung

    Energy Technology Data Exchange (ETDEWEB)

    Djurdjevic, Mile; Byczynski, Glenn [Nemak Europe GmbH, Frankfurt am Main (Germany). Frankfurt Airport Center 1; Pavlovic, Jelena [Magdeburg Univ. (Germany). Inst. fuer Fertigungstechnik und Qualitaetssicherung

    2009-02-15

    This paper investigates the effect of some major alloying elements (silicon and copper) and the effect of grain refiner (titanium boride) on the size of the secondary dendrite arm spacing (SDAS) in series of Al-Si-Cu alloys. It has been shown that both silicon and copper have significant influence on this solidification parameter. The addition of grain refining master alloys to aluminium alloys is common practice in many commercial foundries aiming to reduce the grain size of Al-Si alloys. However, it was shown in the present paper that master alloy based on TiB had an unexpected impact on the SDAS, decreasing the size of SDAS. In addition, there is a minimum of SDAS corresponding to the presence of 0.12 wt% of titanium in Al-Si alloy. Such findings could have important implications for Al-Si alloys in particular, due to their wide spread applications in the automotive industry. (orig.)

  13. Superhard nanocomposite Ti-Al-Si-N films deposited by reactive unbalanced magnetron sputtering

    International Nuclear Information System (INIS)

    Nanocomposite Ti-Al-Si-N films (Al content ranging from 0 to 16.7 at.% and Si from 0 to 11.8 at.%, respectively) were prepared on Si(1 0 0) substrates at 500 deg. C by reactive close-field unbalanced magnetron sputtering in an Ar-N2 mixture. The chemical composition, bonding structure, surface morphology, microstructure, stress and mechanical properties of these films were systematically investigated by means of energy dispersive spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), X-ray diffraction (XRD), optical interference system and nanoindentation measurements. The XPS measurements reveal evolution of chemical composition and bonding structure of the deposited Ti-Al-Si-N films. The observed nonlinear peak shift of Ti 2p and N 1s indicates the bonding evolution of crystalline TiN. The spectra from Al 2p at 73.7 eV and Si 2p at 101.1 eV indicates the evolution of film composition from TiSiN to TiAlN with the incorporation of Al, and also implies that their chemical states are mainly in the form of SiN x and AlN, respectively. The (1 1 1) diffraction peak from the XRD θ-2θ patterns shows a variation either on peak width or on peak position, indicating the variation of grain size and lattice constant. The calculated lattice constant reveals a mixture of different phases whose structures are similar to TiN. The nonlinear variation of grain size and lattice constant is considered due to the competition between two processes, i.e. Al addition and the underlying Si reduction. In order to further understand the microstructure evolution, the XRD spectra and corresponding calculations of the Ti-Al-Si-N films without heating during deposition are also shown for comparison. The effect of substrate heating is discussed. The present results show that the influence of Si and Al addition on the grain growth is different. The surface roughness of Ti-Al-Si-N films also exhibits a nonlinear variation, which is due to the variation of grain

  14. Microstructures in Centrifugal Casting of SiCp/AlSi9Mg Composites with Different Mould Rotation Speeds

    Institute of Scientific and Technical Information of China (English)

    WANG Kai; SUN Wenju; LI Bo; XUIE Hansong; LIU Changming

    2011-01-01

    Two ingots were produced by centrifugal casting at mould rotational speeds of 600 rpm and 800 rpm using 20 vol% SiCp/AlSi9Mg composite melt, respectively. The microstructure along the radial direction of cross-sectional sample of ingots was presented. SiC particles migrated towards the external circumference of the tube, and the distribution of SiC particles became uniform under centrifugal force. Voids in 20 vol% SiCp/AlSi9Mg composite melt migrated towards the inner circumference of the tube. The quantitative analysis results indicated that not only SiC particles but also primary a phases segregated greatly in centrifugal casting resulting from the transportation behavior of constitutions with different densities in the SiCp/AlSi9Mg composite melt. In addition, the eutectic Si was broken owing to the motion of SiCp/AlSi9Mg composite melt during centrifugal casting.

  15. Functions and mechanism of modification elements in eutectic solidification of Al-Si alloys: A brief review

    Directory of Open Access Journals (Sweden)

    Zu Fangqiu

    2014-07-01

    Full Text Available Being used more and more widely in engineering, Al-Si alloys comprise about 80% of all kinds of aluminum alloys, which are the most widely utilized nonferrous alloys. Although most Al-Si alloys consist of multiple components, the eutectics in the structure accounts for 50%-90% of the sum volume of such alloys. Therefore, understanding the modification mechanism and function rules of the Al-Si eutectic solidification is the technical key in controlling the structures and properties of such casting alloys. The present paper chiefly reviews recent investigation developments and important conclusions along the lines of the functions of modification elements and their modification mechanism in the eutectic solidification of Al-Si alloys.

  16. THE INFLUENCE OF HEAT TREATMENT WITH THE LIQUID PHASE ON FORMATION OF A MICROSTRUCTURE OF EUTECTIC Al-Si-ALLOY

    Directory of Open Access Journals (Sweden)

    A. Anikin

    2015-04-01

    Full Text Available The effect of heat treatment on the structure of the eutectic Al-Si-alloy, a theoretical substantiation process based on thermal analyzer and cooked microstructures was presented in this paper.

  17. Photoluminescence Properties of Red-Emitting Mn2+-Activated CaAlSiN3 Phosphor for White-LEDs

    NARCIS (Netherlands)

    Zhang, Z.; Delsing, A.C.A.; Notten, P.H.L.; Zhao, J.; Dorenbos, P.; Hintzen, H.T.

    2013-01-01

    Mn2+-doped CaAlSiN3 phosphors have been prepared by a solid-state reaction method at high temperature and the solubility of Mn2+ in the host lattice as well as their photoluminescence properties were investigated. In CaAlSiN3, not only Ca2+ sites, but also Al3+ sites can be substituted by Mn2+ ions.

  18. The constitution of alloys in the Al-rich corner of the Al-Si-Sm ternary system

    International Nuclear Information System (INIS)

    The constitution of alloys and the liquidus surface in the Al-rich corner of the Al-Si-Sm ternary system were determined by the examination of controlled heated and cooled specimens, as well as heat-treated specimens by means of optical and scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential thermal analysis and X-ray diffraction. The Al-rich corner of the Al-Si-Sm ternary system comprises five regions of primary crystallisation (αAl, βSi, Al3Sm, Al2Si2Sm and AlSiSm) with following characteristic invariant reaction sequences: ternary eutectic reaction L → αAl + βSi + Al2Si2Sm, and two liquidus transition reactions, i. e., L + Al3Sm → αAl + AlSiSm, and L + AlSiSm → αAl + Al2Si2Sm. Along with the position of ternary eutectic and both interstitial points in the Al-rich corner of the Al-Si-Sm ternary system, the temperatures for each reaction were determined. (orig.)

  19. Al-Si-Cu/TiN multilayer interconnection and Al-Ge reflow sputtering technologies for quarter-micron devices

    Science.gov (United States)

    Kikkawa, Takamaro; Kikuta, Kuniko

    1993-05-01

    Issues of interconnection technologies for quarter-micron devices are the reliability of metal lines with quarter-micron feature sizes and the formation of contact-hole-plugs with high aspect ratios. This paper describes a TiN/Al-Si-Cu/TiN/Al-Si-Cu/TiN/Ti multilayer conductor structure as a quarter-micron interconnection technology and aluminum-germanium (Al-Ge) reflow sputtering as a contact-hole filling technology. The TiN/Al-Si-Cu/TiN/Al-Si-Cu/TiN/Ti multilayer conductor structure could suppress stress-induced voiding and improve the electromigration mean-time to failure. These improvements are attributed to the fact that the grain boundaries for the Al-Si-Cu film and the interfaces between the Al-Si-Cu and the TiN films are strengthened by the rigid intermetallic compound, TiAl3. The Al-Ge alloy reflow sputtering is a candidate for contact- and via-hole filling technologies in terms of reducing fabrication costs. The Al-Ge reflow sputtering achieved low temperature contact hole filling at 300 degree(s)C. Contact holes with a diameter of 0.25 micrometers and aspect ratio of 4 could be filled. This is attributed to the low eutectic temperature for Al-Ge (424 degree(s)C) and the effect of thin polysilicon underlayer on the enhancement of Al-Ge reflow.

  20. Characterization of fuel miniplates fabricated with U(Mo) particles dispersed in Al-Si matrices

    International Nuclear Information System (INIS)

    In 2011 ECRI facility (Depto. ECRI, GCCN, CNEA) restarted the development for the fabrication of dispersion miniplates fuel elements in Al-Si matrix. This miniplates are fabricated with atomized U-7wt%Mo particles dispersed in a matrix formed by a mixture of pure Al and pure Si powders. The first results for an Al-4wt%Si matrix were presented at the AATN 2011 Annual Meeting. In this work, new results from the microstructural characterization of the meat in Al- 2wt%Si and pure Al miniplates are presented and compared with the previous ones. It is the intention to study the influence of the fabrication parameters as well as different Si concentration in the matrix, on the formation and characteristics of the interaction layer formed between the particles and the matrix at the end of the fabrication process. According to the results presented in this work an improvement can be observed on miniplates with Al-Si matrix respect to the one with pure Al. On the miniplates with Al- Si matrix, almost 100 % of the U(Mo) particles presented, at least in some fraction of its surface, an interaction layer composed by phases that contain Si. Moreover its morphological characteristics are independent of the crystallographic state of the U(Mo) particles. However, the oxide layer formed on the U(Mo) during the hot rolling acts as a barrier to the formation of the interaction layer. As a consequence, it is then mandatory to introduce some changes on the fabrication parameters to avoid, or at least minimize, this oxide layer (author)

  1. Laser beam interactions with metal matrix AlSi-alloy/SiCp composites

    Directory of Open Access Journals (Sweden)

    A. Grabowski

    2008-12-01

    Full Text Available Purpose: The purpose of the research discussed in this paper was to identify the physical processes that take place when a focused laser beam acts on a metal matrix composites reinforced with silicon carbide particles (AlSi alloy/SiCp.Design/methodology/approach: Based on theoretical models, an analysis was carried out of the interaction between a focused laser beam and the individual components of an AlSi alloy/SiCp composite material: the reinforcement particles, SiC, and the AlSi-alloy metal matrix. Assuming effective parameters of the composite material, the energy necessary to melt a unit thickness of the composite was determined according to basic principles.Findings: It has been shown that the time during which the melting point of the composites’ individual components is achieved varies. Modelling based on the energy and mass conservation law provides for the necessary laser beam energy to melt a unit thickness of a composite.Research limitations/implications: In the case of cutting of a composite, however, some effects connected with the thermal field fluctuation occur, which are not explained in the model. A striated structure appears on the composite edges cut with a laser.Practical implications: The research results enable optimization of laser machining parameters, such as laser radiation intensity or the laser beam operation time. This allows reducing the thermal overload that appears in the case of too high density of the laser energy.Originality/value: Application of thermophysical and optical parameters of composite’s individual components yields more information about the processes that take place when scanning the metal matrix composite surface with a high intensity laser beam.

  2. Cooling rate and chemical composition influence on structure of Al-Si-Cu alloys

    Directory of Open Access Journals (Sweden)

    M. Krupiński*, K. Labisz, Z. Rdzawski, M. Pawlyta

    2011-03-01

    Full Text Available Purpose: The aim of this work is to perform the investigation of cooling rate influence as well as rare earth metals modification on microstructure of the AC-AlSi7Cu3Mg and AC-AlSi12CuNiMg cast aluminium alloys. In the work also artificial neural networks were applied for investigations of the influence of the alloying additives on the properties of the AC-4XXX alloy.Design/methodology/approach: In the work the thermo – derivative analysis was applied for the reason to determine changes occurred in the Al-Si-Cu alloy caused by cooling rate change in a range between 0.1 and 1.4°C/s as well chemical composition of the investigated alloy. Also artificial neural networks were applied for prediction of the chemical composition and heat treatment parameters and influence on mechanical properties of the investigated aluminium alloys.Findings: The performed investigation are discussed for the reason of an possible improvement of thermal and structural properties of the alloy.Practical implications: The aim of the carried out investigations was to work out a computer aided tool for prediction of mechanical properties on the basis of registered parameters during the technological process as well as controlling the process in real time, which can be useful for foundry and cast industry for achieving of material with assumed properties.Originality/value: Chemical composition and cooling rate applied for the alloy influences the crystallisation process of the phases and eutectics, and that fore also the microstructure and determines at the same time the properties of these aluminium alloys. The achieved results can be used also for liquid metal processing in science and industry and obtaining of a required alloy microstructure and properties influenced by a proper production conditions. The determination of the technological process parameters as well chemical composition allows it to predict the material properties.

  3. Melt Processing and Characterization of Al-SiC Nanocomposite, Al, and Mg Foam Materials

    Directory of Open Access Journals (Sweden)

    Ahmed M. Nabawy

    2016-05-01

    Full Text Available In the present work, metallic foams of Al, Mg and an Al-SiC nanocomposite (MMNC have been fabricated using a new manufacturing technique by employing melt infiltration assisted with an electromagnetic force. The aim of this investigation was to study and to develop a reliable manufacturing technique consisting of different types of metallic foams. In this technique, an electromagnetic force was used to assist the infiltration of Al-SiC slurry and of pure liquid metal into a leachable pattern of NaCl, thus providing perfect cellular structures with micro-sized porosities. A high frequency induction coil unit equipped with a vacuum chamber and a hydraulic press was used to manufacture the foam materials. Microstructures of the produced foam materials were explored by using Field Emission Scanning Electron Microscopy (FESEM. The mechanical behavior of the manufactured foams was investigated by applying compression testing. The results indicate a high applicability of the new technique in producing metallic foams of pure metals and of a metal matrix nanocomposite . The produced foam materials displayed isotropic cellular structures with excellent compressive behaviors. Microstructure measurements indicate that the average pore size and strut thickness that can be achieved are in the ranges of 100–500 μm and 50–100 μm, respectively. The produced foam of the Al-SiC nanocomposite material provided the highest strength of 50 MPa prior to the densification stage, which equates to 25 times, and 10 times higher than the strength levels that were obtained by Al, and Mg foams, respectively.

  4. Improvement in mechanical properties of hypereutectic Al-Si-Cu alloys through sono-solidiifed slurry

    Institute of Scientific and Technical Information of China (English)

    Yoshiki Tsunekawa; Shinpei Suetsugu; Masahiro Okumiya; Naoki Nishikawa; Yoshikazu Genma

    2014-01-01

    For the wider applications, it is necessary to improve the ductility as wel as the strength and wear-resistance of hypereutectic Al-Si-Cu aloys, which are typical light-weight wear-resistant materials. An increase in the amounts of primary silicon particles causes the modiifed wear-resistance of hypereutectic Al-Si-Cu aloys, but leads to the poor strength and ductility. It is known that dual phase steels composed of hetero-structure have succeeded in bringing contradictory mechanical properties of high strength and ductility concurrently. In order to apply the idea of hetero-structure to hypereutectic Al-Si-Cu alloys for the achievement of high strength and ductility along with wear resistance, ultrasonic irradiation of the molten metal during the solidiifcation, which is caled sono-solidiifcation, was carried out from its molten state to just above the eutectic temperature. The sono-solidiifed Al-17Si-4Cu aloy is composed of hetero-structure, which are, hard primary silicon particles, soft non-equilibriuma-Al phase and the eutectic region. Rheo-casting was performed at just above the eutectic temperature with sono-solidiifed slurry to shape a disk specimen. After the rheo-casting with modiifed sono-solidiifed slurry held for 45 s at 570 ºC, the quantitative optical microscope observation exhibits that the microstructure is composed of 18area% of hard primary silicon particles and 57area% of softa-Al phase. In contrast, there exist only 5 area% of primary silicon particles and noa-Al phase in rheo-cast specimen with normaly solidiifed slurry. Hence the tensile tests of T6 treated rheo-cast specimens with modified sono-solidified slurry exhibit improved strength and 5% of elongation, regardless of having more than 3 times higher amounts of primary silicon particles compared to that of rheo-cast specimen with normaly solidiifed slurry.

  5. Improvement in mechanical properties of hypereutectic Al-Si-Cu alloys through sono-solidified

    Directory of Open Access Journals (Sweden)

    Yoshiki Tsunekawa

    2014-07-01

    Full Text Available For the wider applications, it is necessary to improve the ductility as well as the strength and wear-resistance of hypereutectic Al-Si-Cu alloys, which are typical light-weight wear-resistant materials. An increase in the amounts of primary silicon particles causes the modified wear-resistance of hypereutectic Al-Si-Cu alloys, but leads to the poor strength and ductility. It is known that dual phase steels composed of hetero-structure have succeeded in bringing contradictory mechanical properties of high strength and ductility concurrently. In order to apply the idea of hetero-structure to hypereutectic Al-Si-Cu alloys for the achievement of high strength and ductility along with wear resistance, ultrasonic irradiation of the molten metal during the solidification, which is called sono-solidification, was carried out from its molten state to just above the eutectic temperature. The sono-solidified Al-17Si-4Cu alloy is composed of hetero-structure, which are, hard primary silicon particles, soft non-equilibrium a -Al phase and the eutectic region. Rheo-casting was performed at just above the eutectic temperature with sono-solidified slurry to shape a disk specimen. After the rheo-casting with modified sonosolidified slurry held for 45 s at 570 篊, the quantitative optical microscope observation exhibits that the microstructure is composed of 18area% of hard primary silicon particles and 57area% of soft a -Al phase. In contrast, there exist only 5 area% of primary silicon particles and no a -Al phase in rheo-cast specimen with normally solidified slurry. Hence the tensile tests of T6 treated rheo-cast specimens with modified sono-solidified slurry exhibit improved strength and 5% of elongation, regardless of having more than 3 times higher amounts of primary silicon particles compared to that of rheo-cast specimen with normally solidified slurry.

  6. The effect of cast Al-Si-Cu alloy solidification rate on alloy thermal characteristics

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2006-04-01

    Full Text Available Purpose: In the metal casting industry, an improvement of component quality depends mainly on better control over the production parameters. Thus, a thermal analysis cooling curve of the alloy is used for process control in the aluminum casting industry. In this work effect of cooling rate on the size of the grains, SDAS, size of the β precipitation and thermal characteristic results of AC AlSi9Cu cast alloy have been described. The solidification process was studied using the cooling curve and crystallization curve at solidification rate ranging from 0,16 ºCs-1 up to 1,04 ºCs-1Design/methodology/approach: The experimental alloy used in this investigation was prepared by mixing the ACAlSi5Cu commercial alloys and two master alloys AlSi49 and AlCu55. Thermal analysis tests were conducted using the UMSA Technology Platform. Cooling curve thermal analysis was performed on all samples using high sensitivity thermocouples of K type. Data were acquired by a high speed data acquisition system linked to a PC computer. Each chilled sample was sectioned horizontally where the tip of the thermocouple was located and it was prepared by standard grinding and polishing procedures. Optical microscopy was used to characterize the microstructure and intermetallic phases. Secondary Dendrite Arm Spacing measurements were carried out using an Leica Q-WinTM image analyzer.Findings: Increasing the cooling rate increases significantly the liquidus temperature, nucleation undercooling temperature, solidification range and decreases the recalescence undercooling temperature. Increasing cooling rate refines all microstructural features.Research limitations/implications: This paper presents results for one alloy - AC AlSi9Cu only, for the assessment of the Silicon Modification Level didn’t include the arrangement of a Si crystal in a matrix.Originality/value: Original value of the work is applied the artificial intelligence for the assessment of the Silicon

  7. Development of high plasticity Al-Si alloy and its casting process

    Institute of Scientific and Technical Information of China (English)

    郭国文; 李元元; 陈维平; 张大童; 龙雁

    2002-01-01

    Aiming to meet the challenge of the shape complexity and high plasticity demanded for the upper connective plate(UCP) in motorcycle, a high plasticity Al-Si alloy named HGZL-02 was developed by optimizing the chemical composition and casting process. Premium UCP castings were obtained by using optimized casting process. Results show that fine and dense microstructure are obtained in the UCP castings. An average of 224MPa in ultimate tensile strength, 149MPa in yield strength and 13.2% in elongation are achieved for T6 heat-treated UPS castings.

  8. Elasticity of (K,Na)AlSi3O8 hollandite from lattice dynamics calculations

    OpenAIRE

    Caracas, Razvan; Ballaran, T. Boffa

    2010-01-01

    We compute the elastic constants tensor and the seismic properties of KAlSi(3)O(8) and K(0.8)Na(0.2)AlSi(3)O(8) up to the ferroelastic transition using density-functional theory and density-functional perturbation theory in the ABINIT implementation. We observe a softening of the tetragonal shear with pressure that precedes the ferroelastic transition. The Reuss shear moduli become negative at respectively 23 GPa and 13 GPa for the two compositions considered in here. The ferroelastic transit...

  9. Thermal processing of CMnAlSi steel at (α+γ temperature range

    Directory of Open Access Journals (Sweden)

    B. Gajda

    2006-08-01

    Full Text Available Purpose: Investigations of microstructure changes in the modern high-strength CMnAlSi steel afteraustenitization at (α+γ temperature 900°C/60s were presented in order to determine the influence of thecooling rate on the phase transformations and obtaining multiphase TRIP-aided microstructure. Also the effectof alloying elements on the Ac1 and Ac3 temperatures and the volume fractions of austenite in various (α+γaustenitization temperatures for the investigated steel were presented.Design/methodology/approach: Thermo-calc program was used in order to determine influence of alloyingelements such as Al, Si on Ac1 and Ac3 temperatures. Dilatometric experiments of the CMnAlSi steel were donefor the temperature 900°C from (α+γ temperature range. Microstructures were investigated by light opticalmicroscopy and scanning electron microscopy. The amount of retained austenite in the obtained microstructureswas investigated with X-ray diffraction technique. The quantitative analysis of phases in microstructure weredone using Image pro Plus computer program. Mechanical properties of investigated steel were examined.Findings: The multiphase microstructure containing about 10% retained austenite can be obtained in steel of0.15 % C, 1.55 % Mn, 1% Si and 1% Al through continuous cooling from 900°C/60s to the room temperaturewithout isothermal holding at bainitic transformation temperature range.Practical implications: Steel CMnAlSi is well suited for production of TRIP grade in a large range oftemperatures from 800°C to 900°C at the cooling rates of about 10°C /s to 40°C/s. The amount of 50 % austeniteat temperature 900°C allows for production of TRIP microstructure with stable retained austenite.Originality/value: The TRIP steels can be processed only if annealing parameters are perfectly adjusted to thechemical composition of the steel. The Ac1¬ and Ac3 temperatures differ for the various chemical compositionsand they strongly depend

  10. Energy loss of swift H and He projectiles in Al, Si, Ni and Cu targets

    OpenAIRE

    Denton Zanello, Cristian D.; Abril Sánchez, Isabel; Moreno Marín, Juan Carlos; Heredia Ávalos, Santiago; García Molina, Rafael

    2008-01-01

    We have calculated the stopping power of Al, Si, Ni and Cu for swift H and He ion beams. Furthermore, the energy loss straggling corresponding to Ni is also evaluated. The dielectric formalism is used combined with the MELF-GOS method, which describes the energy loss function of the target by a linear combination of Mermin type energy loss functions for the electron outer-shell electrons and by generalized oscillator strengths for the electron inner-shell electrons. We take into account the c...

  11. Microstructure and Mechanical Properties of Hyper-eutectic Al-Si Alloys Fabricated by Spray Casting

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Microstructure and mechanical properties of hyper-eutectic Al-Si alloy fabricated by spray casting were investigated and then these results were compared with those by squeeze cast. The spray-cast specimen was found to have finer Si particles (~5μm) compared to the squeeze-cast specimen (10-25μm). The tensile strength and elongation of the spray-cast specimen are also higher than those of the squeeze cast one. It was considered that the increased mechanical properties of the spray-cast specimen were mainly due to finer size of the Si particles distributed in Al matrix.

  12. Structure and properties of the Al/SiC composite material

    Science.gov (United States)

    Pugacheva, N. B.; Michurov, N. S.; Bykova, T. M.

    2016-06-01

    Structure has been studied and the distribution of the filler in the samples of the metal-matrix Al/SiC composite containing 50% SiC has been analyzed. The sizes and shapes of the particles of the filler have been determined; the cohesion of the metallic matrix with the filler has been investigated. The analysis of the mechanism of fracture after tensile tests at 350°C and uniaxial compression of the samples of composite at 300 and 600°C has been carried out.

  13. Benzimidazole as corrosion inhibitor for heat treated 6061 Al- SiCp composite in acetic acid

    Science.gov (United States)

    Chacko, Melby; Nayak, Jagannath

    2015-06-01

    6061 Al-SiCpcomposite was solutionizedat 350 °C for 30 minutes and water quenched. It was then underaged at 140 °C (T6 treatment). The aging behaviour of the composite was studied using Rockwell B hardness measurement. Corrosion behaviour of the underaged sample was studied in different concentrations of acetic acid and at different temperatures. Benzimidazole at different concentrations was used for the inhibition studies. Inhibition efficiency of benzimidazole was calculated for different experimental conditions. Thermodynamic parameters were found out which suggested benzimidazole is an efficient inhibitor and it adsorbed on to the surface of composite by mixed adsorption where chemisorption is predominant.

  14. Influence of heat treatment on the Al-Si coating adhesion to steel strips

    OpenAIRE

    K. Żaba

    2010-01-01

    A division of methods of coatings adhesion investigations, with special emphasis on qualitative methods is presented in the paper. Theobtained results the Al-Si coating adhesion to a steel strips of DX52D grade are given. This strip was examined before and after the heattreatment in temperatures 250-700oC during 30-1440 minutes. Methods of thermal shock, bending, filing, network of cuts and tensile wereapplied in examinations. The assessment of the method adequacy was performed. Structure cha...

  15. Nano-hardness and microstructure of selective laser melted AlSi10Mg scan tracks

    Science.gov (United States)

    Aboulkhair, Nesma T.; Maskery, Ian; Tuck, Chris; Ashcroft, Ian; Everitt, Nicola

    2015-07-01

    Selective laser melting (SLM) of aluminium alloys faces more challenges than other ongoing alloys such as stainless steels and titanium alloys because of the material's properties. It is important to study single scan tracks if high density large parts are to be made since they are the primary building blocks. In this study, the geometrical features of AlSi10Mg tracks indicated keyhole mode melting domination. Chemical composition mapping and nanoindentation showed enhanced nano-hardness in SLM material over conventional material with no spatial variation. This is due to a homogeneous elemental distribution and fine microstructure developed by fast solidification.

  16. The annealing behavior of hydrogen implanted into Al-Si alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ogura, Masahiko; Yamaji, Norisuke; Imai, Makoto; Itoh, Akio; Imanishi, Nobutsugu [Kyoto Univ. (Japan). Faculty of Engineering

    1997-03-01

    We have studied effects of not only defects but also an added elements on trap-sites of hydrogen in metals. For the purpose, we observed depth profiles and thermal behaviors of hydrogen implanted into Al-1.5at.%Si alloy samples in an implantation-temperature range of liquid nitrogen temperature (LNT) to 373K at different doses. The results were compared with those for pure aluminum samples. It was found that hydrogen is trapped as molecules in grain boundaries of Al/Si. (author)

  17. Evaluating Primary Dendrite Trunk Diameters in Directionally Solidified Al-Si Alloys

    Science.gov (United States)

    Grugel, R. N.; Tewari, S. N.; Poirier, D. R.

    2014-01-01

    The primary dendrite trunk diameters of Al-Si alloys that were directionally solidified over a range of processing conditions have been measured. These data are analyzed with a model based primarily on an assessment of secondary dendrite arm dissolution in the mushy zone. Good fit with the experimental data is seen and it is suggested that the primary dendrite trunk diameter is a useful metric that correlates well with the actual solidification processing parameters. These results are placed in context with the limited results from the aluminium - 7 wt. % silicon samples directionally solidified aboard the International Space Station as part of the MICAST project.

  18. On grain refinement and titanium segregation in Al-Si alloy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The influence of holding time and distance from sample bottom on segregation and grain refinement of Ti was studied. Results show that Al-5Ti-1B has an obvious effect on refinement in Al-Si alloy after 4 h holding time. The segregation of Ti shows different morphology at different positions of casting. More segregation is at the bottom of castings because of localized congregation of Ti. The research shows that the difference in Ti concentration is as high as 25.6% between the top and bottom of castings.

  19. Furnace bottom rise mechanism in preparation of Al-Si alloys by electrothermal process

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The experiments of preparation of Al-Si alloys by electrothermal process were carried out respectively in 20 kW, 100 kW and 1 800 kW DC arc furnaces. The mechanism of furnace bottom rise was studied.It was found that the bottom rise can be divided into three types, including the low bottom temperature, abnormal reducing reaction and carbide deposition. The furnace bottom rise is related to the carbon ratio of the briquet, the heating speed of the briquet and the parameters and operation of furnace.

  20. Multiple silicon nanotwins formed on the eutectic silicon particles in Al-Si alloys

    International Nuclear Information System (INIS)

    Multiple precipitating nanotwins of {1 1 1}/[1 1 2] type have been observed forming on the eutectic Si particles in Al-Si alloys upon annealing. High-resolution transmission electron microscopy (HRTEM) reveals that these precipitating nanotwins may possess very rich microstructures, including 5-fold nanotwins and various twin junctions. The formed Si nanotwins are very thin objects that are naturally appropriate for HRTEM observations. It is very likely that the formation and the morphology of the nanotwins are related to the aging conditions.

  1. Microstructural evolution during friction stir welding of AlSi1MgMn alloy

    Directory of Open Access Journals (Sweden)

    M. Janjić

    2012-01-01

    Full Text Available This paper provides the research of the infl uence of geometric and kinematic parameters on the microstructure and mechanical properties of welded joint of aluminum alloy AlSi1MgMn (6082-T6 obtained through the Friction Stir Welding (FSW process. The experiment parameters were welding speed, rotation speed, angle of pin slope, pin diameter and shoulder diameter. On the obtained welded workpieces the dynamic testing on the impact toughness, and determination of microstructural zones were carried out.

  2. Effect of Yttrium Addition on Glass Forming Ability of ZrCuAlSi Alloy

    International Nuclear Information System (INIS)

    The effect of yttrium addition on glass formation of a ZrCuAlSi alloy is investigated. The maximum diameter 8mm of the glassy rods for (Zr46.3Cu43.3Al8.9Si1.5)100−xYx alloy with x = 2.5 is obtained by copper mould casting. Apparent enhancement of the glass formation ability is found with addition of yttrium, mainly due to the purification of the alloy melt and the suppression of formation of the primary phases by yttrium. (condensed matter: structure, mechanical and thermal properties)

  3. Discovery of dmisteinbergite (hexagonal CaAlSi O) in the Allende meteorite

    DEFF Research Database (Denmark)

    Ma, C.; Krot, A.N.; Bizzarro, Martin

    2013-01-01

    Dmisteinbergite, CaAlSiO with P63/mcm structure, was identified in a rounded coarse-grained igneous Type B2 Ca-,Al-rich inclusion (CAI) STP-1 from the Allende CV3 carbonaceous chondrite. STP-1 belongs to a very rare type of refractory inclusions, Fractionation and Unknown Nuclear effects (FUN) CA...... temperature (∼1200-1400 °C) via rapid cooling. Dmisteinbergite in Allende, the first find in a meteorite, is a new member of refractory silicates, among the first solid materials formed in the solar nebula....

  4. Effect of Cooling Rate on Phosphorus Removal During Al-Si Solvent Refining

    Science.gov (United States)

    Li, Yanlei; Ban, Boyuan; Li, Jingwei; Zhang, Taotao; Bai, Xiaolong; Chen, Jian; Dai, Songyuan

    2015-04-01

    The effect of cooling rate on phosphorus removal during Al-Si solvent refining is studied during solar grade silicon purification. It is found that the phosphorus removal rate is controlled by kinetic factors. When the cooling rate decreases, the phosphorus removal rate increases. A concept of apparent segregation coefficient of phosphorus is introduced to characterize the phosphorous removal ability. It increases with the decrease in the average solidification temperature between 910.5 K and 1050.5 K (637.5 °C and 777.5 °C).

  5. Thermodynamics of Nitrogen in Fe-Mn-Al-Si-C Alloy Melts

    Science.gov (United States)

    Paek, Min-Kyu; Chatterjee, Saikat; Pak, Jong-Jin; Jung, In-Ho

    2016-04-01

    Thermodynamic behavior of nitrogen in the entire range of the Fe-Mn-Al-Si-C liquid solution was modeled based on the critical evaluation and optimization of all available experimental data. The Gibbs energy of liquid solution was described using the Modified Quasichemical Model (MQM) in the pair approximation, instead of classical Wagner Interaction Parameter Formalism, to consider the strong interactions between species in liquid state. In particular, the dissolution behavior of N and formation of AlN in the entire ternary and higher order liquids were accurately predicted from the MQM only with binary model parameters of N.

  6. Electromigration performance improvement of Al-Si-Cu/TiN/Ti/n+Si contact

    Science.gov (United States)

    Shi, Gang; Sun, Zhen; Xu, Geng-Fu; Min, Yun-Hao; Luo, Jun-Yi; Lu, Yong; Li, Bing-Zong; Qu, Xin-Ping; Qian, Gang; Doan, My T.; Lee, Edmund

    1998-02-01

    In this study, two different processes, with and without rapid thermal annealing (RTA), have been compared for the Al-Si- Cu/TiN/Ti multilayer contact on n+ diffusions. A series of wafer level reliability (WLR) measurement performed on a test structure with two 1.08 X 1.08 micrometer2 contacts on n+ diffusion. The results show that RTA can increase contact electromigration (EM) lifetime dramatically. The XRD, AES and TEM analysis indicate that this improvement is attributed to oxygen stuffing in TiN, phase change of TiN and TiSi2 formation at the interface of Ti and Si.

  7. Microstructural Observations in a Cast Al-Si-Cu/TiC Composite

    Science.gov (United States)

    Karantzalis, A. E.; Lekatou, A.; Georgatis, E.; Poulas, V.; Mavros, H.

    2010-06-01

    A 3-5 vol.% TiC particulate Al-Si-Cu composite was prepared by diluting Al/20 vol.% TiC composite in an Al-7Si-4Cu alloy matrix. TiC particle distribution consists of isolated and clustered particles which are both located at the primary-α grain boundaries and at the areas of the last solidified liquid. Particle pushing by the solidification front is responsible for the final particle location. The solidified microstructure consists of primary and intermetallic phases formed by a sequence of possible eutectic reactions. No evidence of TiC particle degradation was observed.

  8. Thermodynamics calculation of reactions between phosphorus and main elements in Al-Si-Cu alloys

    Science.gov (United States)

    Li, Wangxing; Zhang, Ying; Yi, Danqing; Kong, Fanxiao; Chen, Xingyu

    2011-05-01

    The Gibbs free energy was calculated between phosphorus and the main elements in Al-Si-Cu alloys sampled as A390 to study the reaction process and give theoretical directions for the adding of phosphorus in industry. The results show that the elements such as aluminum, silicon, and copper have the capabilities to react with phosphorus according to the preference of Al, Cu, Si. As temperature increases, the reactions between phosphorus and the elements become more difficult. If aluminum is in existence, the phosphides of other elements will transform to aluminum phosphide.

  9. Softening and fatigue fracture of Al-Si-X alloy casts

    OpenAIRE

    Oshikiri, Jouji; Umezawa, Osamu; Nakamura, Norio

    2011-01-01

    Ductile manner such as dimple fully covered on fatigue fracture surface of the specimens at 523 K. Softening behavior of eutectic or hyper-eutectic Al-Si-Cu-Mg-(Ni, Fe, Mn) alloy casts has been examined to estimate the influence of heating on their fatigue strength at higher temperature. The hyper-eutectic alloys showed remarkable softening rather than eutectic ones. The softening during heating over 523 K may be related to Al-Cu-Mg-Si precipitation and lowered content of Cu in the matrix.

  10. Effect of hot extrusion process on microstructure and mechanical properties of hypereutectic Al-Si alloys

    OpenAIRE

    Li Runxia; Yu Fuxiao; Zuo Liang

    2011-01-01

    The hypereutectic Al-Si alloy was fabricated by hot extrusion process after solidified under electromagnetic stirring, and the microstructure and mechanical properties of the alloy were studied. The results show that the ultimate tensile strength and elongation of the alloy reached 229.5 MPa and 4.6%, respectively with the extrusion ratio of 10, and 263.2 MPa and 5.4%, respectively with extrusion ratio of 20. This indicates that the mechanical properties of the alloy are obviously improved w...

  11. Characterization of Hypereutectic Al-Si Powders Solidified under Far-From Equilibrium Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Y.E. Kalay; L.S. Chumbley; I.E. Anderson; R.E. Napolitano

    2007-07-01

    The rapid solidification microstructure of gas-atomized Al-Si powders of 15, 18, 25, and 50 wt pct Si were examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In order of increasing particle size, the powders exhibited microcellular Al, cellular/dendritic Al, eutectic Al, and primary Si growth morphologies. Interface velocity and undercooling were estimated from measured eutectic spacing based on the Trivedi-Magnin-Kurz (TMK) model, permitting a direct comparison with theoretical predictions of solidification morphology. Based on our observations, additional conditions for high-undercooling morphological transitions are proposed as an extension of coupled-zone predictions.

  12. Microstructure and corrosion resistance of CrAlSiN, CrAlSiN+DLC, and CrN coatings

    Directory of Open Access Journals (Sweden)

    K. Lukaszkowicz

    2011-03-01

    Full Text Available Purpose: The main aim of the research was the investigation of microstructure and corrosion resistance of the nanostructured CrAlSiN, CrAlSiN+DLC, CrN coatings deposited by cathodic arc evaporation method onto hot work tool steel substrate.Design/methodology/approach: Observations of surface and microstructure of the deposited coatings were carried out on cross sections in the SUPRA 35 scanning electron microscope. Diffraction and thin film microstructure were tested with the use of the JEOL JEM 3010UHR transmission electron microscope. X-ray study for the analyzed coatings was carried out using X´Pert PRO system. A phase identification of the investigated coatings was carried out in Bragg-Brentano geometry (XRD, and in grazing incidence geometry (GIXRD. Investigation of the electrochemical corrosion behaviour of the samples done in a PGP 201 Potentiostat/Galvanostat, using a conventional three-electrode cell. To simulate the aggressive media, 1-M HCl solution was used under aerated conditions and room temperature.Findings: It was found that the microstructure of the PVD coatings consisted of fine nanocrystallites, of an average size of 8 nm -13 nm, depending on the coating type. The morphology of the coatings fracture is characteristic of a dense microstructure. Basing on the GIXRD pattern of the investigated coatings, only fcc phases was encountered. The tests carried out with the use of a GDOS technique indicate the occurrence of a transition zone between the substrate material and the coating. Deposition of the PVD coatings increases the hardness of the tool steel surface up to 22-40 GPa. The CrN coated sample showed the best corrosion resistance.Practical implications: In order to evaluate with more detail the possibility of applying these nanocomposite coatings for protection of tool steels, further investigations should be undertaken in order to determine the thermal fatigue resistance of the coatings. The very good mechanical

  13. Corrosion behaviour of the AlSi6Cu4 alloy and cast AlSi6Cu4-graphite particles composite

    Directory of Open Access Journals (Sweden)

    S. Holecek

    2009-04-01

    Full Text Available The corrosion behaviour of the AlSi6Cu4 alloy as a composite matrix and of composites with 8% vol. of graphite particles was investigated. The corrosion experiments were performed over a range of elevated temperatures and were carried out in sea water (3.5%NaCl solution. We have focused our attention to the determination of the mode of corrosion attack and to the determination of the rate ofcorrosion and other corrosion characteristics. Both as-cast and annealed matrix and composite specimens were tested, as well as the99.9% as-cast aluminium for comparison. Corrosion behaviour of the materials was assessed by the corrosion potential (Ec and bypotentiodynamic (polarization curves. As expected, composite is less corrosion resistant than the matrix alloy. In addition to pitting,a severe galvanic corrosion occurs as a result of galvanic couple aluminium/graphite formation. Corrosion potentials imply that examinedmaterials would be sufficiently resistant in non or slightly oxidizing solutions without dissolved oxygen. All studied materials corrode very slowly at potentials negative to corrosion potential, while at potentials positive to corrosion potential the corrosion rate goes up by 1 or 2 orders.

  14. Effect of layer thickness on the high temperature mechanical properties of Al/SiC nanolaminates

    Energy Technology Data Exchange (ETDEWEB)

    Lotfian, S. [IMDEA Materials Institute, c/Eric Kandel 2, 28906 Getafe, Madrid (Spain); Mayer, C.; Chawla, N. [Materials Science and Engineering, Arizona State University, Tempe, AZ 85287-6106 (United States); Llorca, J. [IMDEA Materials Institute, c/Eric Kandel 2, 28906 Getafe, Madrid (Spain); Department of Materials Science, Polytechnic University of Madrid, E.T.S. de Ingenieros de Caminos, 28040 Madrid (Spain); Misra, A.; Baldwin, J.K. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Molina-Aldareguía, J.M., E-mail: jon.molina@imdea.org [IMDEA Materials Institute, c/Eric Kandel 2, 28906 Getafe, Madrid (Spain)

    2014-11-28

    Composite laminates on the nanoscale have shown superior hardness and toughness, but little is known about their high temperature behavior. The mechanical properties (elastic modulus and hardness) were measured as a function of temperature by means of nanoindentation in Al/SiC nanolaminates, a model metal–ceramic nanolaminate fabricated by physical vapor deposition. The influence of the Al and SiC volume fraction and layer thicknesses was determined between room temperature and 150 °C and, the deformation modes were analyzed by transmission electron microscopy, using a focused ion beam to prepare cross-sections through selected indents. It was found that ambient temperature deformation was controlled by the plastic flow of the Al layers, constrained by the SiC, and the elastic bending of the SiC layers. The reduction in hardness with temperature showed evidence of the development of interface-mediated deformation mechanisms, which led to a clear influence of layer thickness on the hardness. - Highlights: • The mechanical behavior of Al/SiC nanolaminates was measured between 28 °C and 150 °C. • Room temperature hardness was controlled by the volume fraction of the constituents. • The hardness of all the nanolaminates decreased rapidly with temperature. • Reduction of hardness with temperature increased as the interface density increased.

  15. Investigations of linear contraction and shrinkage stresses development in hypereutectic al-si binary alloys

    Directory of Open Access Journals (Sweden)

    J. Mutwil

    2009-07-01

    Full Text Available Shrinkage phenomena during solidification and cooling of hypereutectic aluminium-silicon alloys (AlSi18, AlSi21 have been examined. A vertical shrinkage rod casting with circular cross-section (constant or fixed: tapered has been used as a test sample. Two type of experiments have been conducted: 1 on development of the test sample linear dimension changes (linear expansion/contraction, 2 on development of shrinkage stresses in the test sample. By the linear contraction experiments the linear dimension changes of the test sample and the metal test mould as well a temperature in six points of the test sample have been registered. By shrinkage stresses examination a shrinkage tension force and linear dimension changes of the test sample as well a temperature in three points of the test sample have been registered. Registered time dependences of the test bar and the test mould linear dimension changes have shown, that so-called pre-shrinkage extension has been mainly by mould thermal extension caused. The investigation results have shown that both: the linear contraction as well as the shrinkage stresses development are evident dependent on metal temperature in a warmest region the sample (thermal centre.

  16. Study on in-situ Mg2Si/Al-Si composites with different compositions

    Institute of Scientific and Technical Information of China (English)

    Jing Qingxiu; Zhang Caixia; Huang Xiaodong

    2009-01-01

    Effects of chemical composition and heat treatment on microstructures and mechanical properties of in-situ Mg2Si/Al-Si composites were investigated. It was found that, in the microstructure of an Al-5.7wt% Mg2Si composite with 8.2wt% extra Si, the binary eutectic Mg2Si locates at the grain boundaries with an undeveloped Chinese script-like morphology, and the primary α-Al is formed into a cell structure due to the selective modification effect of the modifiers of mischmetal and Strontium salt; whereas in the composite with a near Al-Mg2Si eutectic composition and little extra Si content, the intercrescence eutectic Mg2Si formed with the binary eutectic a-Al grows into integrated Chinese script-like shape. As Si content increases, the eutectic Mg2Si dendrite becomes coarser in morphology but less in volum e fraction. Hardness and tensile strength of the cast Mg2Si/Al-Si composites do not increase with increasing of Mg content, but they are related to the size and morphology of the eutectic and primary Mg2Si phases. Heat treatment with optimal parameters is an effective way to improve the properties of the in-situ composites.

  17. Optical, chemical, and depth characterization of Al/SiC periodic multilayers

    Science.gov (United States)

    Jonnard, P.; Le Guen, K.; Hu, M.-H.; André, J.-M.; Meltchakov, E.; Hecquet, C.; Delmotte, F.; Galtayries, A.

    2009-05-01

    We present the characterization of Al/SiC periodic multilayers designed for optical applications. In some samples, a thin layer of W or Mo is added at the SiC-on-Al interfaces. We use x-ray reflectivity (XRR) in order to determine the parameters of the stacks, i.e. thickness and roughness of all the layers. We have performed x-ray emission spectroscopy (XES) to identify the chemical state of the Al and Si atoms present within the structure from an analysis of the shape of the Al Kβ and Si Kβ emission bands. Finally, time of flight secondary ion mass spectrometry (ToF-SIMS) is used to obtain the depth profile of the different elements present within the studied stacks. A fit of the XRR curves shows that the Al/SiC multilayer present large interfacial roughness (up to 2.8 nm), which is decreased considerably (down to 1 nm or less) when the refractory metal layers are introduced in the periodic structure. The combination of XES and ToFSIMS allows us to conclude that in these systems the roughness is a purely geometrical parameter and not related to chemical interfacial reactions.

  18. Heterogeneous Nb-Based Nuclei for the Grain Refinement of Al-Si Alloys

    Science.gov (United States)

    Bolzoni, L.; Hari Babu, N.

    2016-05-01

    Nb-based intermetallics are, generally, low-density high-temperature materials used for structural applications or cryogenic superconductors. In this work, we report the development of an Al(96)-Nb(2)-B(2) master alloy where in situ-formed micrometric Nb-based intermetallics (i.e. NbB2 and Al3Nb) are used for a completely different purpose: to promote the refinement of Al-Si alloys by taking advantage of enhanced heterogeneous nucleation. Nb-based intermetallics have the right characteristics, like low density, stability at high temperature and good lattice match, to be used as heterogeneous nucleation substrates. It was found that the addition of these Nb-based intermetallics permits the significant refinement of the microstructural features of the Al-Si alloy studied. The enhanced heterogeneous nucleation makes the grain size of the material far less dependent on the cooling rate, which is one of the critical parameters influencing the variation of the properties of the alloy.

  19. Effect of layer thickness on the high temperature mechanical properties of Al/SiC nanolaminates

    International Nuclear Information System (INIS)

    Composite laminates on the nanoscale have shown superior hardness and toughness, but little is known about their high temperature behavior. The mechanical properties (elastic modulus and hardness) were measured as a function of temperature by means of nanoindentation in Al/SiC nanolaminates, a model metal–ceramic nanolaminate fabricated by physical vapor deposition. The influence of the Al and SiC volume fraction and layer thicknesses was determined between room temperature and 150 °C and, the deformation modes were analyzed by transmission electron microscopy, using a focused ion beam to prepare cross-sections through selected indents. It was found that ambient temperature deformation was controlled by the plastic flow of the Al layers, constrained by the SiC, and the elastic bending of the SiC layers. The reduction in hardness with temperature showed evidence of the development of interface-mediated deformation mechanisms, which led to a clear influence of layer thickness on the hardness. - Highlights: • The mechanical behavior of Al/SiC nanolaminates was measured between 28 °C and 150 °C. • Room temperature hardness was controlled by the volume fraction of the constituents. • The hardness of all the nanolaminates decreased rapidly with temperature. • Reduction of hardness with temperature increased as the interface density increased

  20. Spheroidization of Eutectic Silicon in Direct-Electrolytic Al-Si Alloy

    Science.gov (United States)

    Wang, Ruyao; Lu, Weihua

    2013-06-01

    The spheroidization process of direct-electrolytic Al-Si alloy (DEASA) containing Si content in the range of 7 to 12 pct heated at temperatures of 778 K to 803 K (505 °C to 530 °C) was studied. The width, length, and aspect ratio of Si particles were measured to quantitatively analyze the microstructural variety of Si phase during the heating process in terms of chemical composition and remelting. Compared to existing Al-Si alloy, the lower soaking temperature of 778 K to 783 K (505 °C to 510 °C) is required to obtain the full spheroidization of the Si phase of DEASA. When remelting DEASA, a satisfactory granulation rate can be achieved at a higher soak temperature of 788 K to 803 K (515 °C to 530 °C). The origin of the high spheroidizaton rate is attributed to the microstructural characteristic relative to the electrolysis process. It would be expected that high crystallographic defects of Si grain result in the complete spheroidization of Si phase at lower temperatures for a short period.

  1. Assessment of modification level of hypoeutectic Al-Si alloys by pattern recognition of cooling curves

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiang; GENG Hui-yuan; LI Yan-xiang

    2005-01-01

    Most evaluations of modification level are done according to a specific scale based on an American Foundry Society (AFS) standard wall chart as qualitative analysis in Al-Si casting production currently. This method is quite dependent on human experience when making comparisons of the microstructure with the standard chart. And the structures depicted in the AFS chart do not always resemble those seen in actual Al-Si castings. Therefore, this qualitative analysis procedure is subjective and can introduce human-caused errors into comparative metallographic analyses. A quantization parameter of the modification level was introduced by setting up the relationship between mean area weighted shape factor of eutectic silicon phase and the modification level using image analysis technology. In order to evaluate the modification level, a new method called "intelligent evaluating of melt quality by pattern recognition of thermal analysis cooling curves" has also been introduced. The results show that silicon modification level can be precisely assessed by comparison of the cooling curve of the melt to be evaluated with the one most similar to it in a database.

  2. Manufacture of hypoeutectic Al-Si metal powders for dispersion matriz in nuclear fuels

    International Nuclear Information System (INIS)

    Within the framework of the development of low enriched nuclear fuels for research reactors, U.Mo/Al is the most promising option that has however to be optimized. Indeed at the U.Mo/Al interfaces between U.Mo particles and the Al matrix, an interaction layer grows under irradiation inducing an unacceptable fuel swelling. Adding silicon in limited content into the Al matrix has clearly improved the in-pile fuel behaviour. This breakthrough is attributed to an U.Mo/Al.Si protective layer around U.Mo particles appeared during fuel manufacturing. The present work deals with three techniques applied to produce metal powders of hypoeutectic Al-Si alloys: ball milling, centrifugal atomization and gas atomization. Size and microstructure of the particles are analyzed in the three techniques. The best result is found with the gas atomization system, flakes and rods morphology predominates in the produced powders, with particle sizes below 150 microns and the greater mass population (65%) is between 150 and 125 microns. The particle surface is smooth and the high solidification rate provides a good distribution of the α-Al primary and eutectic phase within each particle (author)

  3. Wear mechanism for spray deposited Al-Si/SiCp composites under dry sliding condition

    Institute of Scientific and Technical Information of China (English)

    滕杰; 李华培; 陈刚

    2015-01-01

    Al-Si/15%SiCp (volume fraction) composites with different silicon contents were fabricated by spray deposition technique, and typical microstructures of these composites were studied by optical microscopy (OM). Dry sliding wear tests were carried out using a block-on-ring wear machine to investigate the effect of applied load range of 10−220 N on the wear and friction behavior of these composites sliding against SAE 52100 grade bearing steel. Scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDAX) were utilized to examine the morphologies of the worn surfaces in order to observe the wear characteristics and investigate the wear mechanism. The results show that the wear behavior of these composites is dependent on the silicon content in the matrix alloy and the applied load. Al-Si/15%SiCp composites with higher silicon content exhibit better wear resistance in the applied load range. Under lower loads, the major wear mechanisms are oxidation wear and abrasive wear for all tested composites. Under higher loads, severe adhesive wear becomes the main wear mechanisms for Al-7Si/15%SiCp and Al-13Si/15%SiCp composites, while Al-20Si/15%SiCp presents a compound wear mechanism, consisting of oxidation, abrasive wear and adhesion wear.

  4. Role of cerium, lanthanum, and strontium additions in an Al-Si-Mg (A356) alloy

    Energy Technology Data Exchange (ETDEWEB)

    Nabawy, Ahmed M.; Samuel, Agnes M.; Samuel, Fawzy H. [Universite du Quebec, Chicoutimi (Canada). Dept. des Sciences Appliquees; Alkahtani, Saleh A.; Abuhasel, Khaled A. [Salman Bin Abdulaziz Univ., Riyadh (Saudi Arabia). Mechanical Engineering Dept.

    2016-05-15

    The effects of individual and combined additions of cerium (Ce), lanthanum (La), and strontium (Sr) on the eutectic modification and solidification characteristics of an Al-Si-Mg (A356) aluminum alloy were investigated using optical microscopy and thermal analysis techniques. Addition of Ce, La, and Sr resulted in different depression levels of the eutectic nucleation temperature and eutectic growth undercooling, generating modified eutectic structures exhibiting different levels of modification. Microstructural results showed that the best modification levels using individual additions were achieved by Sr which produced a fine fibrous eutectic structure, followed by La, which produced a refined lamellar structure, with Ce providing the lowest level of modification. On the other hand, a combined addition of Ce and Sr provided the highest modification level, with the production of a very fine fibrous eutectic silicon structure. In general, the addition of Sr helped to further increase the refinement obtained in the alloys containing La or Ce + La additions. In the latter alloy, the main intermetallic phases observed were La(Al,Si){sub 2} and Al{sub 20}(La,Ce)Ti{sub 2}Si. The improved modification levels were found to be proportional to the depression in the eutectic nucleation temperature and the eutectic growth undercooling. A high cooling rate also improved the modification level by at least one level.

  5. FRACTAL ANALYSIS OF THE PLATELETS IN Al-Si EUTECTIC CAST ALLOY

    Directory of Open Access Journals (Sweden)

    Durowoju M.O

    2013-05-01

    Full Text Available Fractal analysis has been used to conduct a detailed study on the shapes and distribution of the platelets of Al-Si Eutectic Alloy. The ingot casts were analyzed in two types of mold; sand and metal, under varying proportion of strontium; low and high and heat treated at different holding times; 12hrs & 40hrs. The platelets resulting fromeach micrograph were analyzed using weighted average and a measure of dispersion (Variance, which is done by measuring the dispersion of the shapes of the platelets from that of a perfect sphere (β = 1. Sample castings with low strontium in sand mold at 12Hrs holding time in a 4700C furnace have platelets with least dispersion from being a perfect sphere and have the highest weighted average sphericity value of 0.638 and hence tending towards being a perfect sphere. Spherical platelets result into castings with higher tensile strength andmechanical property. Such platelets are from castings of Al-Si eutectic alloy in sand molds with low strontium content at 12Hr holding time. Meanwhile, metal mold result into more irregular platelets and the irregularities in shape can be improved with increase in strontium content and higher holding time. The best platelet shapes in metal molds are obtained at 40Hrs holding time and high strontium content. Platelets from metal mold on the average have the least sphericity and weighted average values hence they show the most dispersion from regular shapes.

  6. The roles of Eu during the growth of eutectic Si in Al-Si alloys

    Science.gov (United States)

    Li, Jiehua; Hage, Fredrik; Wiessner, Manfred; Romaner, Lorenz; Scheiber, Daniel; Sartory, Bernhard; Ramasse, Quentin; Schumacher, Peter

    2015-09-01

    Controlling the growth of eutectic Si and thereby modifying the eutectic Si from flake-like to fibrous is a key factor in improving the properties of Al-Si alloys. To date, it is generally accepted that the impurity-induced twinning (IIT) mechanism and the twin plane re-entrant edge (TPRE) mechanism as well as poisoning of the TPRE mechanism are valid under certain conditions. However, IIT, TPRE or poisoning of the TPRE mechanism cannot be used to interpret all observations. Here, we report an atomic-scale experimental and theoretical investigation on the roles of Eu during the growth of eutectic Si in Al-Si alloys. Both experimental and theoretical investigations reveal three different roles: (i) the adsorption at the intersection of Si facets, inducing IIT mechanism, (ii) the adsorption at the twin plane re-entrant edge, inducing TPRE mechanism or poisoning of the TPRE mechanism, and (iii) the segregation ahead of the growing Si twins, inducing a solute entrainment within eutectic Si. This investigation not only demonstrates a direct experimental support to the well-accepted poisoning of the TPRE and IIT mechanisms, but also provides a full picture about the roles of Eu atoms during the growth of eutectic Si, including the solute entrainment within eutectic Si.

  7. Corrosion of spray formed Al-Si-Cu alloys in ethanol automobile fuel

    Energy Technology Data Exchange (ETDEWEB)

    Traldi, S.M.; Costa, I. [IPEN, Inst. de Pesquisas Energeticas e Nucleares, Cidade Univ., Sao Paulo, SP (Brazil); Rossi, J.L. [Powder Processing Center CCP, Inst. de Pesquisas Energeticas e Nucleares, IPEN, Sao Paulo, SP (Brazil)

    2001-07-01

    The use of aluminium alloys in the automotive industry has the weight saving attractiveness leading to improved engine efficiency and reduced vibration. The main restriction for the use of highly alloyed aluminium-silicon alloys is the casting difficulty. The spray forming technique allows the production of preforms of uniform microstructure, fine grains and low segregation effects. There are feasible commercial markets for spray formed Al-Si alloy for pistons, con-rod and cylinder liners. The use of these alloys in the automotive industry means that their corrosion performance in fuel environments needs to be evaluated. Lately, the interest in alcoholic fuels has been increasing due to pollutant emission restrictions. In this investigation, the corrosion behaviour of two Al-Si-Cu alloys produced by spray forming has been studied by means of weight loss measurements, electrochemical impedance measurements and potentiodynamic polarisation tests. The tests were carried out in ethanol automobile fuel. The corrosion of a grey cast iron has also been investigated, in the same solution for comparison reasons. (orig.)

  8. Effect of Silicon on the Thixoformability of Al-Si-Cu Alloys

    Science.gov (United States)

    Benati, Davi Munhoz; Zoqui, Eugênio José

    2014-09-01

    The thixoformability of new Al-Si-Cu alloys was evaluated and characterized by their microstructural and rheological behavior. Alloys Al1Si2.6Cu, Al2Si2.6Cu, Al4Si2.6Cu, and Al7Si2.6Cu were produced with the addition of Al5Ti1B grain refiner alloy. The materials were heat treated under two controlled conditions: holding times of 0, 30, 90, and 210 s and solid fraction of 45 and 60%. The evaluation of the microstructure and semisolid behavior was characterized by globule size, shape factor (SF), minimum stress to flow, maximum stress, and apparent viscosity. The heat treatment times promoted the globularization of solid phase particles to achieve better apparent viscosity results for the alloys treated for 210 s. Both 45 and 60% solid fraction showed no significant differences in terms of SF, but the alloys containing lower solid fraction showed better performance for apparent viscosity. Better working ranges for these new Al-Si-Cu alloys were determined reaching average strain of 0.5 MPa and apparent viscosity of 105 Pa s.

  9. Precipitation and strengthening phenomena in Al-Si-Ge and Al-Cu-Si-Ge alloys

    International Nuclear Information System (INIS)

    The objective of this work was to determine whether Al rich Al-Si-Ge and 2000 type Al-Cu-Si-Ge alloys have sufficient hardness to be useful for structural applications. It is shown that in Al-Si-Ge it is not possible to achieve satisfactory hardness through a conventional heat treatment. This result is explained in terms of sluggish precipitation of the diamond-cubic Si-Ge phase coupled with particle coarsening. However, Al-Cu-Si-Ge displayed a uniquely fast aging response, a high peak hardness and a good stability during prolonged aging. The high hardness of the Cu containing alloy is due to the dense and uniform distribution of fine θ' precipitates (metastable Al2Cu) which are heterogeneously nucleated on the Si-Ge particles. High resolution TEM demonstrated that in both alloys all the Si-Ge precipitates start out, and remain multiply twinned throughout the aging treatment. Since the twinned section of the precipitate does not maintain a low index interface with the matrix, the Si-Ge precipitates are equiaxed in morphology. Copyright (2000) AD-TECH - International Foundation for the Advancement of Technology Ltd

  10. Preparation of anti-corrosion films by microarc oxidation on an Al-Si alloy

    International Nuclear Information System (INIS)

    Thick ceramic films over 140 μm were prepared on Al-7% Si alloy by ac microarc oxidation in a silicate electrolyte. The film growth kinetics was determined by an eddy current technique and film growth features in different stages were discussed. The microstructure and composition profiles for different thick films were analyzed by scanning electron microscopy and energy dispersive X-ray spectroscopy. Their phase components were determined by X-ray diffraction. The electrochemical corrosion behaviors of bare and coated alloys were evaluated using potentiodynamic polarization curves, and their corrosion morphologies were observed. In the initial stage of oxidation, the growth rate is slow with 0.48 μm/min due to the effect of Si element though the current density is rather high up to 33 A/dm2. After the current density has decreased to a stable value of 11 A/dm2, the film mainly grows towards the interior of alloy. The film with a three-layer structure consists of mullite, γ-Al2O3, α-Al2O3 and amorphous phases. By microarc discharge treatment, the corrosion current of the Al-Si alloy in NaCl solution was significantly reduced. However, a thicker film has to be fabricated in order to obtain high corrosion-resistant film of the Al-Si alloy. Microarc oxidation is an effective method to form an anti-corrosion protective film on Si-containing aluminum alloys

  11. Effect of hot extrusion process on microstructure and mechanical properties of hypereutectic Al-Si alloys

    Directory of Open Access Journals (Sweden)

    Li Runxia

    2011-02-01

    Full Text Available The hypereutectic Al-Si alloy was fabricated by hot extrusion process after solidified under electromagnetic stirring, and the microstructure and mechanical properties of the alloy were studied. The results show that the ultimate tensile strength and elongation of the alloy reached 229.5 MPa and 4.6%, respectively with the extrusion ratio of 10, and 263.2 MPa and 5.4%, respectively with extrusion ratio of 20. This indicates that the mechanical properties of the alloy are obviously improved with the increase of extrusion ratio. After hot extruded, the primary Si, eutectic Si, Mg2Si, AlNi, Al7Cu4Ni and Al-Si-Mn-Fe-Cr-Mo phases are refined to different extent, and the efficiency of refinement is obvious more and more with the increase of extrusion ratio. After T6 heat treatment, the sharp corners of these phases become passivated and roundish, and the mechanical properties are improved. The ultimate tensile strength of the extruded alloy after T6 heat treatment reaches 335.3 MPa with extrusion ratio of 10 and 353.6 MPa with extrusion ratio of 20.

  12. Microstructure and Wear Behavior of Solidification Sonoprocessed B390 Hypereutectic Al-Si Alloy

    Science.gov (United States)

    Khalifa, Waleed; El-Hadad, Shimaa; Tsunekawa, Yoshiki

    2013-12-01

    The hypereutectic Al-Si alloys constitute an important family of alloys because of their excellent wear resistance and low thermal expansion. However, the optimal microstructure and hence the optimal service performance of these alloys cannot be achieved by the conventional melt treatments used in industry today, because of the chemical incompatibility between the primary-Si refiners and the eutectic-Si modifiers used in microstructure control. The current study aimed at using ultrasonic vibrations to improve the microstructure and the properties of these alloys. The results of the current study showed that for the B390 Al-Si alloy (i) the ultrasonic treatment has potential refining effect on the primary Si and Fe intermetallic phases, (ii) the primary Si particles become finer as the pouring temperature decreases from 1033 K (760 °C) to 938 K (665 °C), (iii) pouring and ultrasonic treatment at temperatures below the start of primary Si precipitation result in the coexistence of large and fine Si particles in microstructure, (iv) phosphorous additions of 50 ppm did not show any substantial effect in the ultrasonically treated ingots, (v) ultrasonic-treated samples have uniform hardness over the surface while the untreated samples show large scattering (high standard deviation) in hardness levels and (vi) ultrasonic-treated samples showed better wear resistance in the absence of phosphorous.

  13. Microstructural characteristics of in situ Mg2Si/Al-Si composite by low superheat pouring

    Directory of Open Access Journals (Sweden)

    Wu Xiaofeng

    2013-09-01

    Full Text Available To control the morphology and size of the primary and eutectic Mg2Si phases in in situ Mg2Si/Al-Si composite and achieve a feasible and reliable technique to produce appropriate feedstock for the thixo-casting and rheo-casting of this type of material, three Al-Si matrix composites reinforced by 5wt.%, 9wt.% and 17wt.% Mg2Si with hypoeutectic, eutectic and hypereutectic compositions were prepared by the low superheat pouring (LSP process. The effects of the pouring temperature (superheat on the morphology and size distribution of primary phases (primary α-Al and Mg2Si, binary (α-Al + Mg2Si eutectic cell and eutectic Mg2Si were investigated. The experimental results show that low pouring temperature (superheat not only refines the grain structure of the primary α-Al and binary (α-Al + Mg2Si eutectic cell in three composites and promotes the formation of more non-dendritic structural semi-solid metal (SSM slurry of these phases; but also refines the primary and eutectic Mg2Si phases, which seems to be attributed to the creation of an ideal condition for the nucleation and the acquisition of a high survival of nuclei caused by the LSP process.

  14. Aleaciones de Al-Cr-Zr para aplicaciones a altas temperaturas

    Directory of Open Access Journals (Sweden)

    Gerique, T.

    1998-08-01

    Full Text Available The literature on Al-Cr-Zr alloys for high temperature applications is revised. In addition to a short historical review and a description of the fundamental aspects of these aluminium-transition metal alloys, comments on processing methods, including rapid solidification and various consolidation techniques are considered. The strengthening mechanisms, mainly due to incoherent intermetallic particles, the thermal stability and the mechanical properties of the Al-Cr-Zr alloys, including creep behaviour, are thoroughly examined.

    Se ha revisado la bibliografía existente sobre las aleaciones Al-Cr-Zr para alta temperatura. Además de una breve reseña del desarrollo histórico y una descripción de los fundamentos de estas aleaciones de aluminio-metal de transición, se comentan los métodos de obtención y las bases de la solidificación rápida, así como diversos métodos de consolidación. También se indican los mecanismos de refuerzo de estas aleaciones mediante intermetálicos incoherentes y se revisa en detalle la estabilidad térmica y las propiedades mecánicas de las mismas, incluido su comportamiento en fluencia.

  15. Tribological behavior of CrAlSiN/W{sub 2}N multilayer coatings deposited by DC magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Yan-Zuo [Department of Material Science and Engineering, National Tsing-Hua University, Hsinchu, Taiwan (China); Duh, Jenq-Gong, E-mail: jgd@mx.nthu.edu.t [Department of Material Science and Engineering, National Tsing-Hua University, Hsinchu, Taiwan (China)

    2010-10-01

    The CrAlSiN/W{sub 2}N multilayer coatings were fabricated by DC magnetron sputtering. The bilayer periods of multilayer films were controlled in the range from 3 to 20 nm. The cross-sectional structure of multilayer and monolayer coatings was evaluated by transmission electron microscopy (TEM). The wear behavior of monolayer and multilayer coatings was investigated by a pin-on-disc tribometer. The nano-scratch tester was employed to study the crack propagation of scratched coatings. The images of wear scars were observed by optical microscopy (OM). The cross-sectional image of scratched films was analyzed by transmission electron microscopy (TEM). Owing to the nano-layered structure and higher hardness (or H/E ratio), the multilayer coatings exhibited better wear resistance than homogeneous films. The coefficient of friction of CrAlSiN/W{sub 2}N multilayer coating with a bilayer period of 8 nm was around 0.6, and that of CrAlSiN homogeneous film was about 0.8. Different crack propagation mechanisms of CrAlSiN/W{sub 2}N multilayer and CrAlSiN monolayer coatings were proposed and discussed.

  16. Laser cutting of an AlSi alloy/SiCp composites: theory and experiments

    Directory of Open Access Journals (Sweden)

    J. Śleziona

    2006-04-01

    Full Text Available Purpose: Discontinuous silicon carbide reinforced aluminium alloy metal matrix composites have proved to be extremely to cutting using conventional cutting tools. Thus, there is a need to introduce new processing method in order to improve both the working conditions and the quality of the products made of metal matrix composites. Laser processing offer the advantages of high processing rates, no tool wear, no contact forces, and relatively high precision. Currently the mechanisms governing the laser cutting process of composites are not fully understood. It is the aim of the authors therefore to investigate the physical processes of laser composite material interactions and the phenomena occurring within the cutting front, viz. the formation of striations, and the effect they have on the resulting cutting quality.Design/methodology/approach: The analysis has taken into the consideration these AlSi alloy/SiCp composites are heterogeneous structural material consisting of two components: a semiconductor and metal alloy that have two different optical absorptions mechanisms to laser radiation. The mathematical model based on energy and mass balance model was used to calculate the maximum cutting depth for fixed cutting speed and laser beam power.Findings: Results indicated that the change in absorptivity magnitude about 0.1 led to a strong increase in power of laser energy absorbed per unit depth in AlSi alloy/SiCp composites.Research limitations/implications: In mathematical modeling the constant values of the effective absorptive parameter describing the energy input from laser to composite and a constant thermophysical properties of composite components are used. During the laser beam scanning the absorptive of the composite surface may changes.Practical implications: The proposed mathematical model is in good agreement with the experimental data obtained for a CO2 laser cut of AlSi alloy/SiCp composites. It is important to understand the

  17. The structure-property relationships of powder processed Fe-Al-Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Prichard, P.D.

    1998-02-23

    Iron-aluminum alloys have been extensively evaluated as semi-continuous product such as sheet and bar, but have not been evaluated by net shape P/M processing techniques such as metal injection molding. The alloy compositions of iron-aluminum alloys have been optimized for room temperature ductility, but have limited high temperature strength. Hot extruded powder alloys in the Fe-Al-Si system have developed impressive mechanical properties, but the effects of sintering on mechanical properties have not been explored. This investigation evaluated three powder processed Fe-Al-Si alloys: Fe-15Al, Fe-15Al-2.8Si, Fe-15Al-5Si (atomic %). The powder alloys were produced with a high pressure gas atomization (HPGA) process to obtain a high fraction of metal injection molding (MIM) quality powder (D{sub 84} < 32 {micro}m). The powders were consolidated either by P/M hot extrusion or by vacuum sintering. The extruded materials were near full density with grain sizes ranging from 30 to 50 {micro}m. The vacuum sintering conditions produced samples with density ranging from 87% to 99% of theoretical density, with an average grain size ranging from 26 {micro}m to 104 {micro}m. Mechanical property testing was conducted on both extruded and sintered material using a small punch test. Tensile tests were conducted on extruded bar for comparison with the punch test data. Punch tests were conducted from 25 to 550 C to determine the yield strength, and fracture energy for each alloy as a function of processing condition. The ductile to brittle transition temperature (DBTT) was observed to increase with an increasing silicon content. The Fe-15Al-2.8Si alloy was selected for more extensive testing due to the combination of high temperature strength and low temperature toughness due to the two phase {alpha} + DO{sub 3} structure. This investigation provided a framework for understanding the effects of silicon in powder processing and mechanical property behavior of Fe-Al-Si alloys.

  18. A study of microstructure and phase transformations of CMnAlSi TRIP steel

    Directory of Open Access Journals (Sweden)

    B. Gajda

    2008-12-01

    Full Text Available Purpose: Purpose was to obtain the TRIP-type microstructure in the CMnAlSi steel. Heat treatment consistedof the partial austenitization at 900°C/60s and continuous cooling with rates: 0.5-40°C/s, was examined. Alsothe effect of Al and Si on Ac1 and Ac3 temperatures, and the volume fractions of austenite in CMnSi, CMnAland CMnAlSi steels was investigated.Design/methodology/approach: The effect of alloying elements on Ac1 and Ac3 temperatures was investigatedusing Thermo-calc program. The influence of cooling rates on phase transformations and microstructures ofsamples austenitized at 900°C/60s was examined using dilatometer, light optical microscopy and scanningelectron microscopy. X-ray diffraction technique was used to calculate the amount of retained austenite.Quantitative analyses of phases were done using Image pro Plus 3.0 program. The mechanical properties andVickers hardness (HV10 measurements were also investigated.Findings: The TRIP-aided microstructure consisted of ferrite matrix, bainitic ferrite and metastable retainedaustenite can be obtained for the CMnAlSi steel through intercritical annealing at 900°C/60s and continuouscooling with the rate 20°C/s to the R.T. Isothermal holding at bainitic temperature range (600-400°C duringcooling is not necessary, because of the Al and Si additions to the steel.Practical implications: The CMn steel with addition of 1% Al and Si is well-suited for production of TRIP steelsheets in a large range of temperatures: 800-900°C. The advisable cooling rates are in the range from 10 to 40°C/s.Originality/value: In the TRIP steels the amount of residual austenite in structure at the R.T. strongly dependson the heat treatment parameters such as annealing temperature, cooling rates and amounts of added alloyingelements. It is very important to determine the optimal annealing parameters for each TRIP steel grade to obtainthe steel with the best mechanical properties and microstructure.

  19. Revisión sobre nitruraciones láser de aleaciones de titanio

    Directory of Open Access Journals (Sweden)

    Pérez-Artieda, M. G.

    2010-12-01

    Full Text Available A common technique used to improve the wear response of titanium alloys is to nitride the surface, using chemical or physical vapour deposition, ion implantation or surface remelting in a nitrogen atmosphere. In this revision nitriding systems with laser technology are studied, used in titanium alloys surface treatments.For high temperature, high strength applications, titanium based alloys are an attractive light-weight alternative to steel, due to their high strength to weight ratio and corrosion resistance. In applications that require good wear resistance, titanium alloys pose a problem due to their poor tribological characteristics.Titanium alloys used with a suitable nitriding treatment could allow the replacement of steel in different applications, obtaining weight savings in fabricated components.

    Una técnica comúnmente utilizada para la mejora de la resistencia a desgaste de las aleaciones de titanio es la nitruración de la superficie, utilizando la deposición física o química de vapor, la implantación iónica o el refundido de la superficie en atmósferas que contienen nitrógeno. En esta revisión se estudian los sistemas de nitruración con tecnología láser, utilizados para tratar la superficie de diferentes aleaciones de titanio. Las aleaciones de titanio son un material alternativo al acero, muy atractivo para aplicaciones que requieren alta resistencia a temperaturas elevadas, puesto que tienen una relación resistencia-dureza elevada y buena resistencia a corrosión. En aplicaciones que requieren buena resistencia a desgaste, las aleaciones de titanio suponen un problema, debido a sus pobres características tribológicas. La utilización de aleaciones de titanio junto con un tratamiento de nitruración adecuado, podría permitir la sustitución del acero en diferentes aplicaciones, consiguiendo una disminución en el peso de los componentes fabricados.

  20. Fabrication of nanostructure Al/SiC{sub P} composite by accumulative roll-bonding (ARB) process

    Energy Technology Data Exchange (ETDEWEB)

    Alizadeh, M. [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Zand St., Shiraz, Fars (Iran, Islamic Republic of); Paydar, M.H., E-mail: paaydar@shirazu.ac.i [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Zand St., Shiraz, Fars (Iran, Islamic Republic of)

    2010-03-04

    In the present study, a new manufacturing process for Al-SiC{sub P} composites was developed by using bulk aluminum sheets and micron sized SiC particles as starting materials. Nanostructured Al-SiC{sub P} composites with average grain size of 180 nm were successfully produced in the form of sheets, through accumulative roll bonding (ARB), at room temperature. To evaluate microstructure of the produced composites, scanning electron microscope (SEM) and transmission electron microscope (TEM) were applied. The microstructure of the fabricated composites revealed properly distributed SiC particles in the aluminum matrix. Mechanical properties of the Al-SiC{sub P} composites were investigated by the tensile test. The results proved that by increasing ARB cycles the tensile strength of the produced composites increases, but their ductility at first decreases and then increases.

  1. Grain refinement of hypoeutectic Al-Si alloy prepared with ELTA by Al-4B master alloy

    Institute of Scientific and Technical Information of China (English)

    WANG Ming-xing; MENG Xiang-yong; LIU Zhi-yong; LIU Zhong-xia; WENG Yong-gang; SONG Tian-fu; YANG Sheng

    2006-01-01

    Electrolytic low-titanium aluminum (ELTA) was produced by adding TiO2 powder to an industrial aluminum electrolyzer.The grain refining effect of Al-4B master alloy in the hypoeutectic Al-Si alloy prepared by using ELTA was investigated, and compared with those of Al-5Ti, Al-5Ti-1B and Al-4B master alloys in the similar alloy prepared by using pure Al. The results indicate that when Al-4B is added to the melt of the alloy prepared by using ELTA in terms of the Ti/B mass ratio of 5:1, the grain refining effect is better than those of Al-5Ti, Al-5Ti-1B and Al-4B master alloys. Thus, using Al-4B to refine the grain of Al-Si alloys prepared by using ELTA will possibly become a feasible way of obtaining Al-Si alloy with homogeneous and fine microstructure.

  2. Oxidation and microstructure evolution of Al-Si coated Ni3Al based single crystal superalloy with high Mo content

    Science.gov (United States)

    Tu, Xiaolu; Peng, Hui; Zheng, Lei; Qi, Wenyan; He, Jian; Guo, Hongbo; Gong, Shengkai

    2015-01-01

    A Si modified aluminide (Al-Si) coating was prepared on a Ni3Al based single crystal superalloy with high Mo content by high-activity pack cementation. Cyclic oxidation test at 1150 °C was carried out and the microstructure evolution of the coating was investigated. The results show that the oxidation resistance of the substrate was greatly increased by applying an Al-Si coating. During oxidation, outward diffusion of Mo was effectively blocked due to its high affinity with Si. Besides, a layered structure was formed as a result of the elements inter-diffusion. An obvious degradation of the Al-Si coating was observed after 100 h oxidation. Possible mechanisms related to the oxidation and elements inter-diffusion behaviours were also discussed.

  3. Investigation on corrosion behaviour of as-extruded near eutectic Al-Si-Mg alloy by neutral salt spray test

    Directory of Open Access Journals (Sweden)

    Wu Yuna

    2013-07-01

    Full Text Available In order to provide scientific basis for advanced applications of near eutectic Al-Si-Mg alloys as architectural profiles, a comparative study on the corrosion resistance of an as-extruded near eutectic Al-Si-Mg alloy and AA6063 aluminium alloy was carried out by means of neutral salt spray test. The corroded surfaces of the alloys were examined with optical microscopy and scanning electron microscope (SEM. Results show that the corrosion type of these two alloys is pitting corrosion. The number of corrosion pits in the AA6063 aluminium alloy is more than that in the near eutectic Al-Si-Mg alloy, but the pits in the latter alloy are much larger and deeper. Because the relatively low polarization resistance of the near eutectic alloy leads to poorer repassivation ability, autocatalytic acidification occurs once a pit forms. Thus, occluded corrosion cells are developed in this alloy.

  4. Amorphous structure in a laser clad Ni-Cr-Al coating on Al-Si alloy

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A mixing microstructure containing Ni-based amorphous structures was observed by TEM in the laser cladzones. As the uniformity of chemical composition and temperature is poor in the laser cladding, the amorphous structurewith some Ni3Al crystals coexists in the cladding. The microhardness of the mixing amorphous structure is HV 600 ~800, which is lower than that of crystal phases in the coating. Differential thermal analysis (DTA) shows that Ni-basedamorphous structure exhibits a higher initial crystallizing temperature (about 588 ℃ ), which is slightly higher than that ofthe eutectic temperature of Al-Si alloy. The wear test results indicate that there are some amorphous structures in the laserclad coating, which reduces the peeling of the granular phases from matrix, and improves the wear resistance

  5. Role of Laser Cladding Parameters in Composite Coating (Al-SiC) on Aluminum Alloy

    Science.gov (United States)

    Riquelme, Ainhoa; Escalera-Rodriguez, María Dolores; Rodrigo, Pilar; Rams, Joaquin

    2016-08-01

    The effect of the different control parameters on the laser cladding fabrication of Al/SiCp composite coatings on AA6082 aluminum alloy was analyzed. A high-power diode laser was used, and the laser control parameters were optimized to maximize the size (height and width) of the coating and the substrate-coating interface quality, as well as to minimize the melted zone depth. The Taguchi DOE method was applied using a L18 to reduce the number of experiments from 81 to only 18 experiments. Main effects, signal-noise ratio and analysis of variance were used to evaluate the effect of these parameters in the characteristics of the coating and to determine their optimum values. The influence of four control parameters was evaluated: (1) laser power, (2) scanning speed, (3) focal condition, and (4) powder feed ratio. Confirmation test with the optimal control parameters was carried out to evaluate the Taguchi method's effectivity.

  6. Analysis and optimization of process parameters in Al-SiCp laser cladding

    Science.gov (United States)

    Riquelme, Ainhoa; Rodrigo, Pilar; Escalera-Rodríguez, María Dolores; Rams, Joaquín

    2016-03-01

    The laser cladding process parameters have great effect on the clad geometry and on dilution in the single and multi-pass aluminum matrix composite reinforced with SiC particles (Al/SiCp) coatings on ZE41 magnesium alloys deposited using a high-power diode laser (HPLD). The influence of the laser power (500-700 W), scan speed (3-17 mm/s) and laser beam focal position (focus, positive and negative defocus) on the shape factor, cladding-bead geometry, cladding-bead microstructure (including the presence of pores and cracks), and hardness has been evaluated. The correlation of these process parameters and their influence on the properties and ultimately, on the feasibility of the cladding process, is demonstrated. The importance of focal position is demonstrated. The different energy distribution of the laser beam cross section in focus plane or in positive and negative defocus plane affect on the cladding-bead properties.

  7. Microstructure of AlSi17Cu5 alloy after overheating over liquidus temperature

    Directory of Open Access Journals (Sweden)

    J. Piątkowski

    2015-01-01

    Full Text Available The paper presents microstructure tests of alloy AlSi17Cu5. In order to disintegrate the primary grain of silicon the so-called time-temperature transformation TTT was applied which was based on overheating the liquid alloy way over the temperature Tliq., soaking in it for 30 minutes and casting it to a casting mould. It was found that such process causes the achievement of fine-crystalline structure and primary silicon crystals take up the form of pentahedra or frustums of pyramids. With the use of X-ray microanalysis and X-ray diffraction analysis the presence of intermetallic phases Al2Cu, Al4Cu9 which are the ingredients of eutectics α - AlCu - β and phase Al9Fe2Si which is a part of eutectic α - AlFeSi - β was confirmed.

  8. Electronic properties of Hf2X intermetallic compounds (X = Al, Si, Ni, Ga and Ge)

    International Nuclear Information System (INIS)

    The electric field gradient (EFG) parameters were calculated for the binary system Hf2X (X = Al, Si, Ni, Ga and Ge), using the full-potential linear augmented plane wave method, applying the generalized gradient approximation. The major contribution to the EFG value in these compounds comes from the p-p contribution next to the probe nucleus. The only other significant contribution is a d-d contribution to the nickel site in Hf2Ni, arises from the broad spatial distribution of the nickel 3d electrons. The similarity in the electronic properties of the Hf2X compounds, with the exception of Hf2Ni, can be attributed to the resemblance of the crystallographic structure and the alike electronic structure of the X-ligand atom, having one or two p-electrons in the external orbital with close shells below.

  9. Fatigue behavior of press hardened Al-Si coated high strength steel

    Institute of Scientific and Technical Information of China (English)

    Wang Zijian; Gui Zhongxiang; Zhang Yisheng

    2014-01-01

    The fatigue behavior of press hardened Al-Si coated high strength steel has been investigated,and the fatigue strength turns out to be about 1 000 MPa. Surface morphology of fractured and non-fractured speci-men has been observed,and the coating shows significant influence on the fatigue behavior. The difference of elastic modulus between coating and substrate led to the main cracks perpendicular to the loading direction. The coating close to fracture exfoliated thinly,while the coating far away from the fracture kept integrated. Though the specimen was polished to obtain high surface quality,3 types of cracks occurred during the fatigue test. What’s more,inclusion particles were proved to play a crucial role in causing these cracks.

  10. Investigation of carbonized layer on surface of NaAlSi glass fibers

    Science.gov (United States)

    Pentjuss, E.; Lusis, A.; Bajars, G.; Gabrusenoks, J.

    2013-12-01

    There are presented and discussed experimental results about carbonate shell on the sodium rich alumosilicate (NaAlSi) glass fibers and carbonization in wet air atmosphere and water uptake kinetic of such fiber fabrics. The analyzes of water uptake kinetic by regression technique, leaching and heating of carbonized glass fabrics helped to separate stages of fast and slow processes between fiber and carbonate shell and air atmosphere. The shell contains mixture of trona and hydrated sodium carbonate. Heating converts both substances to sodium carbonate. The weight uptake after heating encounters two fast exponential processes associated with water absorption on the surface of carbonated shell and its diffusion into volume. The slow process associates with CO2 and H2O absorption from air, hydration and sodium carbonate conversion to trona.

  11. Examination of the influence of heat treatment on the properties of Al-Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Vuksanovic, D.; Rakocevic, S. [Faculty of Metallurgy, Podgorica (RS); Markovic, S. [Faculty of Technology and Metallurgy, Belgrade (RS); Petrovic, T. [Institute ' Kirilo Savic' , Belgrade (RS); Kovacevic, K. [Institute for Ferrous Metallurgy (RS); Tripkovic, S. [H.K. Petar Drapsin, Mladenovac (RS)

    2007-08-15

    In this paper the influence of heat treatment on the structural and mechanical properties of Al-Si alloys was investigated. Silicon content in the examined alloys was in the range 11 to 14%, the contents of the other alloying elements were in the standard range but all alloys were modified with strontium. The regime of the applied heat treatment was quenching (520 C/6h - cooling in water) + aging (205oC/7h - air cooling). The examinations were carried out at room temperature as well as at 250 C and 300 C. The obtained results showed a positive influence of the applied heat treatment on the mechanical properties of the examined alloys. The improvement of the mechanical properties can be considered as a consequence of a redistribution and change of morphology of the phases present in the structure of the alloys. (orig.)

  12. Neutron absorption of Al-Si-Mg-B4C composite

    International Nuclear Information System (INIS)

    Al-Si-Mg-B4C composites containing 2-8 wt% of B4C were prepared by stir casting technique. Homogenization treatment was carried out at temperatures of 540°C for 4 houra and followed by ageing at 180°C for 2 houra. Microstructure and phase identification were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD) respectively. Neutron absorption study was investigated using neutron source Am/Be241. The result indicated that higher B4C content improved the neutron absorption property. Meanwhile homogeneity of the composite was increased by ageing processes. This composite is potential to be used as neutron shielding material especially for nuclear reactor application

  13. Investigation of carbonized layer on surface of NaAlSi glass fibers

    International Nuclear Information System (INIS)

    There are presented and discussed experimental results about carbonate shell on the sodium rich alumosilicate (NaAlSi) glass fibers and carbonization in wet air atmosphere and water uptake kinetic of such fiber fabrics. The analyzes of water uptake kinetic by regression technique, leaching and heating of carbonized glass fabrics helped to separate stages of fast and slow processes between fiber and carbonate shell and air atmosphere. The shell contains mixture of trona and hydrated sodium carbonate. Heating converts both substances to sodium carbonate. The weight uptake after heating encounters two fast exponential processes associated with water absorption on the surface of carbonated shell and its diffusion into volume. The slow process associates with CO2 and H2O absorption from air, hydration and sodium carbonate conversion to trona

  14. Fabrication of ceramic layer on an Al-Si alloy by MAO process

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The MAO (Micro-Arc Oxidation) process is applied to a eutectic Al-Si alloy (Al-12.0%Si-l.0%Cu-0.9%Mg(mass fraction)). The oxide ceramic layer was fabricated with about 220 μm thickness and 3000 Hv micro-hardness. ByXRD (X-ray diffractometry) and DSC (differential scanning calorimetry) analyses, the oxide layer consists of amorphousAl2O3, which is distinct from the results reported by the other researchers. The SEM photographs of such layer show that thelayer is fixed tightly on the substrate alloy. So this alloy can be used in the high temperature and friction environment after itis treated with such process.

  15. Nanoscale analysis on interfacial reactions in Al-Si-Cu alloys and Ti underlayer films

    Science.gov (United States)

    Yang, Jun-Mo; Lee, Sukjae; Park, Ju-Chul; Lee, Deok-Won; Lee, Tae-Kwon; Choi, Jin-Tae; Lee, Soun-Young; Kawasaki, Masahiro; Oikawa, Tetsuo

    2003-01-01

    Solid-phase reactions at the interface between sputtered Al-Si-Cu alloys and Ti films were investigated at the atomic scale by high-resolution transmission electron microscopy and energy dispersive x-ray spectroscopy (EDS) coupled with a field-emission (scanning) transmission electron microscope. The analysis results showed that the interface is composed of an amorphous-like Ti-Si layer, an intermediate-crystalline layer, and a Si-dissolved TiAl3 layer containing dissolved Si TiAl3 with a crystallographic relationship with the Al film. The nanometer-scaled interlayers effectively play a role as a barrier suppressing the interdiffusion reaction of Al and Ti during annealing treatment. Further, the quantitative composition of the interlayers was revealed by the analysis of the intensity profiles obtained from EDS elemental maps.

  16. Micro-macro modelling of microstructure and microporosity in Al-Si-Cu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chirazi, A.; Atwood, R.C.; Lee, P.D. [Imperial Coll. of Science and Technology, London (United Kingdom). Dept. of Materials

    2002-07-01

    A multi-scale, multi-phase and multi-component model of grain and pore formation was developed. The heat and mass transfer was solved at the macroscale and linked via the temperature and pressure fields to a microstructural model to predict grain structure and microporosity. The model was applied to predict microporosity in an Al-Si-Cu alloy containing soluble hydrogen. The diffusion-controlled growth of solid and gas phases, together with the interaction of these phases, was solved by a combined stochastic nucleation laws and a continuum solution of the diffusion equations. Phase interfaces were tracked using a cellular automata (CA) method. The effect of initial hydrogen content and local solidification time on grain structure, pore size, and the distribution of each phase was predicted. Simulated results were compared qualitatively and quantitatively to experimental observations. (orig.)

  17. Thermal analysis and microscopical characterization of Al-Si hypereutectic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Robles Hernandez, F.C. [Light Metals Casting Technology (LMCT) Group, Room 212A, Essex Hall, 401 Sunset Avenue, Windsor, Ont., N9B 3P4 (Canada)]. E-mail: fcrh20@yahoo.com; Sokolowski, J.H. [Light Metals Casting Technology (LMCT) Group, Room 212A, Essex Hall, 401 Sunset Avenue, Windsor, Ont., N9B 3P4 (Canada)

    2006-08-10

    In this research paper are presented the identified phases by thermal analysis and microscopy presented by four 3XX.X Al-Si hypereutectic alloys that were solidified under different conditions including natural heat exchange and quenching. In addition, a qualitative analysis of the phases was conducted by EDX scanning electron microscopy. The EDX results were used to identify the stoichiometry for the particular phases based on data reported in the literature. A total of nine reactions were detected by thermal analysis that were confirmed by optical and electron microscopy, where two additional phases (Fe and Pb enriched) were also detected. Above the liquidus temperature, the phase known as Si agglomerates was identified; the nature and principal characteristics of this phase are discussed in the present paper. Using thermal analysis, the phase identification, fraction solid and nucleation temperature for all the phases was conducted.

  18. Wear behavior and microstructure of hypereutectic Al-Si alloys prepared by selective laser melting

    Science.gov (United States)

    Kang, Nan; Coddet, Pierre; Liao, Hanlin; Baur, Tiphaine; Coddet, Christian

    2016-08-01

    This work investigates the microstructure and wear behavior of hypereutectic Al-Si alloys, in-situ fabricated using selective laser melting of a mixture of eutectic Al-12Si (wt.%) and pure Si powders. The first observation was that the size and morphology of the Si phase are strongly influenced by the laser power. In addition, it was also observed that a high laser power causes serious evaporation of aluminum during the remelting process. Dry sliding wear test and Vickers microhardness measurements were employed to characterize the mechanical properties of the material. The lowest wear rate of about 7.0 × 10-4 mm3 N-1 m-1 was observed for samples having the highest value of relative density (96%) and microhardness (105 Hv0.3).

  19. Effect of Phosphorous Inoculation on Creep Behavior of a Hypereutectic Al-Si Alloy

    Science.gov (United States)

    Faraji, Masoumeh; Khalilpour, Hamid

    2014-10-01

    Creep behavior of Al-Si hypereutectic alloys inoculated with phosphorus was investigated using the impression creep testing. The results showed that at stress regimes of up to 400-450 MPa and temperatures up to 300 °C, no significant creep deformation occurred in both uninoculated and inoculated specimens; however, at temperatures above 300 °C, the inoculated alloys presented better creep properties. Creep data were used to calculate the stress exponent of steady-state creep rate, n, and creep activation energy, Q, for different additive conditions where n was found varied between 5 and 8. Owing to the fact that most alloys have lower values for n (4, 5), threshold stress was estimated for studied conditions. The creep governing mechanisms for different conditions are discussed here, with a particular attention to the effect of phosphorous addition on the microstructural features, including number of primary silicon particles, mean primary silicon spacing, and morphology and distribution of eutectic silicon.

  20. Optimizing microstructures of hypereutectic Al-Si alloys with high Fe content via spray forming technique

    Energy Technology Data Exchange (ETDEWEB)

    Hou, L.G. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Cui, C. [Foundation Institute for Materials Science, Badgasteiner Str. 3, Bremen 28359 (Germany); Zhang, J.S., E-mail: zhangjs@skl.ustb.edu.cn [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)

    2010-09-15

    By using spray forming technique Fe-contained hypereutectic Al-Si alloys were prepared with different Mn/Cr additions for the study of their effects on the microstructures. The results show that adding 2 wt.% Mn/Cr separately can strikingly refine the Fe-bearing phase in spray-formed Al-25Si-5Fe-3Cu (wt.%) alloy into quantities of fine, uniformly distributed granular {alpha}-Al(Fe,Mn/Cr)Si phase, and Cr is more effective. But some short-plate Fe-bearing phases still exist in the spray-formed Al-Si alloys. Then, combined addition of Mn and Cr transforms these short-plate Fe-bearing phases into fine, granular {alpha}-Al(Fe,Mn,Cr)Si phase, promoting the appearance of almost single {alpha}-Al(Fe,Mn,Cr)Si phase in the spray-formed Al-Si alloys. Two mechanisms are proposed to elucidate the formation of {alpha}-Al(Fe,TM)Si phase (TM = Mn/Cr/(Mn + Cr)) during the solidification process: (1) transformed from metastable {delta}-Al(Fe,TM)Si phase in Mn/(Mn + Cr)-added alloys or (2) precipitated from liquids directly in Cr-containing alloys. Because the strong interactions and isomorphic substitution among different TM elements, the metastable {delta}-Al(Fe,TM)Si phase (clusters) can be precipitated from the liquids and transformed into stable {alpha}-Al(Fe,Mn,Cr)Si phase in Mn- or (Mn + Cr)-added alloys. The stable {alpha}-Al(Fe,Cr)Si phase can precipitate directly from the liquids because no metastable ternary intermetallics exist in Al-Cr-Si system and can be transformed into stable {alpha}-AlCrSi phase. Also the high segregation temperature of Cr in liquid Al melts promotes the microsegregation of Cr and formation of (AlCrSi) clusters/intermetallics in Cr-added alloys. As a result, both metastable {delta}-Al(Fe,TM)Si phase (clusters) and stable {alpha}-Al(Fe,TM)Si phase (clusters) can be present in (Mn + Cr)-added alloys. With further solidification, these clusters become the nucleation sites and grow up unceasingly. The coexistence of the nucleus of {delta

  1. THE APPLICATION OF Ni FOR IMPROVEMENT OF Al-Si-Fe ALLOYS

    Directory of Open Access Journals (Sweden)

    Jozef Petrík

    2009-09-01

    Full Text Available Iron, often present in secondary material (scrap forms brittle and hard needles in Al-Si alloys.These particles decrease the mechanical properties of castings. A reliable and economic method of iron elimination from aluminium alloys has not been well-known yet in metallurgical practice. The influence of nickel as an iron corrector (up to 0.7 % and iron (up to 2.5 % on the fluidity, microstructure and mechanical properties of the Al alloy with 9.75 % Si, 0.2 % Mg was evaluated. The presence of Ni results in shortening of the needles, but the segmentation of ß needles was not observed. Improvement of mechanical properties was observed despite of low affecting of microstructure.

  2. Neutron absorption of Al-Si-Mg-B{sub 4}C composite

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, Yusof, E-mail: yusofabd@nuclearmalaysia.gov.my; Yusof, Mohd Reusmaazran [Malaysian Nuclear Agency, 43000, Bangi Selangor (Malaysia); Ibrahim, Anis Syukriah; Daud, Abdul Razak [Department of Applied Physics, Faculty of Science & Technology, National University of Malaysia, 43600, Bangi Selangor (Malaysia)

    2016-01-22

    Al-Si-Mg-B{sub 4}C composites containing 2-8 wt% of B{sub 4}C were prepared by stir casting technique. Homogenization treatment was carried out at temperatures of 540°C for 4 houra and followed by ageing at 180°C for 2 houra. Microstructure and phase identification were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD) respectively. Neutron absorption study was investigated using neutron source Am/Be{sup 241}. The result indicated that higher B{sub 4}C content improved the neutron absorption property. Meanwhile homogeneity of the composite was increased by ageing processes. This composite is potential to be used as neutron shielding material especially for nuclear reactor application.

  3. Preparation of anti-corrosion films by microarc oxidation on an Al-Si alloy

    Energy Technology Data Exchange (ETDEWEB)

    Xue Wenbin [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China)]. E-mail: xuewb@bnu.edu.cn; Shi Xiuling [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China); Hua Ming [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China); Li Yongliang [Analytical and Testing Center, Beijing Normal University, Beijing 100875 (China)

    2007-05-15

    Thick ceramic films over 140 {mu}m were prepared on Al-7% Si alloy by ac microarc oxidation in a silicate electrolyte. The film growth kinetics was determined by an eddy current technique and film growth features in different stages were discussed. The microstructure and composition profiles for different thick films were analyzed by scanning electron microscopy and energy dispersive X-ray spectroscopy. Their phase components were determined by X-ray diffraction. The electrochemical corrosion behaviors of bare and coated alloys were evaluated using potentiodynamic polarization curves, and their corrosion morphologies were observed. In the initial stage of oxidation, the growth rate is slow with 0.48 {mu}m/min due to the effect of Si element though the current density is rather high up to 33 A/dm{sup 2}. After the current density has decreased to a stable value of 11 A/dm{sup 2}, the film mainly grows towards the interior of alloy. The film with a three-layer structure consists of mullite, {gamma}-Al{sub 2}O{sub 3}, {alpha}-Al{sub 2}O{sub 3} and amorphous phases. By microarc discharge treatment, the corrosion current of the Al-Si alloy in NaCl solution was significantly reduced. However, a thicker film has to be fabricated in order to obtain high corrosion-resistant film of the Al-Si alloy. Microarc oxidation is an effective method to form an anti-corrosion protective film on Si-containing aluminum alloys.

  4. Microstructures of Mg-Al-Zn and Al-Si-Cu cast alloys

    Directory of Open Access Journals (Sweden)

    T. Tański a

    2010-01-01

    Full Text Available Purpose: The aim of this paper was to investigate the structure of the MCMgAl6Zn1 magnesium and ACAlSi9Cu aluminium cast alloy in as-cast state.Design/methodology/approach: The following results concern the microstructure of the cast magnesium and aluminium alloys using ZEISS SUPRA 25, Opton DSM-940 scanning and LEICA MEF4A light microscopy, X-ray qualitative microanalysis as well as X-ray analysis.Findings: The analysis of the structure magnesium alloy consists of the solid solution α – Mg (matrix of the secondary phase g – Mg17Al12 evenly located in the structure. The structure creates agglomerates in the form of needle precipitations, partially coherent with the matrix placed mostly at the grain boundaries. The AC AlSi9Cu and AC AlSi9Cu4 cast aluminium alloys are characterised by a dendritic structure of the α solid solution - as the alloy matrix, as well are characterised by a discontinuous β–Si phase forming the α+β eutectic grains, with a morphology depending on the silicon and copper mass concentration.Research limitations/implications: Taking into account the fact that some of the properties are of great importance only for the surface of the material, the future investigation will concern modelling of the alloy surface using surface layers deposition methods like physical vapour deposition methods.Practical implications: A desire to create as light vehicle constructions as possible and connected low fuel consumption have made it possible to make use of magnesium and aluminium alloys as constructional material in automotive industry.Originality/value: Contemporary materials should possess high mechanical properties, physical and chemical, as well as technological ones, to ensure long and reliable use. The above mentioned requirements and expectations regarding the contemporary materials are met by the non-ferrous metals alloys used nowadays, including the magnesium and aluminium alloys.

  5. Thermal description of hypoeutectic Al-Si-Cu alloys using silicon equivalency

    Directory of Open Access Journals (Sweden)

    Mile B. Đurđević

    2012-01-01

    Full Text Available The modeling of casting processes has remained a topic of active interest for several decades, and availability of numerous software packages on the market is a good indication of the interest that the casting industry has in this field. Most of the data used in these software packages are read or estimated from the binary or multi-component phase diagrams. Unfortunately, except for binary diagrams, many of ternary or higher order phase diagrams are still not accurate enough. Having in mind that most of the aluminum binary systems are very well established, it has been tried to transfer a multi-component system into one well known Al-Xi pseudo binary system (in this case the Al-Si phase diagram was chosen as a reference system. The new Silicon Equivalency (SiEQ algorithm expresses the amounts of major and minor alloying elements in the aluminum melts through an 'equivalent' amount of silicon. Such a system could be used to calculate several thermo-physical and solidification characteristics of multi component as cast aluminum alloys. This lends the model the ability to make predictions of solidification characteristics of cast parts, where cooling rates are slow and the solidification process has to be known in great detail in order to avoid problems in the casting. This work demonstrates how the SiEQ algorithm can be used to calculate characteristic solidification temperatures of the multi-component hypoeutectic Al-Si-Cu alloys as well as their latent heats. SA statistical analysis of the results obtained for a wide range of alloy chemical compositions shows a very good correlation with the experimental data and the SiEQ calculations.

  6. Description of hypo eutectic Al-Si-Cu alloys based on their known chemical compositions

    Energy Technology Data Exchange (ETDEWEB)

    Djurdjevic, M. B.; Vicario, I.

    2013-07-01

    The modeling of casting processes has remained a topic of active interest for several decades, and the availability of numerous software packages on the market is a good indication of the interest that the casting industry has in this field. Most of the data used in these software packages are directly read or estimated from the binary or multi-component phase diagrams. Unfortunately, except for binary diagrams, many of ternary or higher order phase diagrams are still not accurate enough. Having in mind that most of the aluminum binary systems are very well established, it has been tried to transfer multi-component system into one well known Al-Xi pseudo binary system (in this case the Al-Si phase diagram was chosen as a reference system). The new Silicon Equivalency (SiEQ) algorithm expresses the amounts of major and minor alloying elements in the aluminum melts through an equivalent amount of silicon. Such a system could be used to calculate several thermo-physical and solidification characteristics of multi component as cast aluminum alloys. This provides to the model the capacity to predict the solidification characteristics of cast parts, where cooling rates are slow and the solidification process has to be known in great detail in order to avoid quality problems in the casting. This work demonstrates how the SiEQ algorithm can be used to calculate the characteristic solidification temperatures of the multicomponent Al-Si alloys as well as their latent heats and growth restriction factor. Statistical analysis of the results obtained for a wide range of alloy chemical compositions shows a very good correlation with the experimental data and the SiEQ calculations. The same mathematical approach might be applied for other metallic systems such as iron and magnesium, using carbon equivalency for ferrous systems and aluminum equivalency for magnesium multi-component alloys. (Author)

  7. Description of hypo eutectic Al-Si-Cu alloys based on their known chemical compositions

    International Nuclear Information System (INIS)

    The modeling of casting processes has remained a topic of active interest for several decades, and the availability of numerous software packages on the market is a good indication of the interest that the casting industry has in this field. Most of the data used in these software packages are directly read or estimated from the binary or multi-component phase diagrams. Unfortunately, except for binary diagrams, many of ternary or higher order phase diagrams are still not accurate enough. Having in mind that most of the aluminum binary systems are very well established, it has been tried to transfer multi-component system into one well known Al-Xi pseudo binary system (in this case the Al-Si phase diagram was chosen as a reference system). The new Silicon Equivalency (SiEQ) algorithm expresses the amounts of major and minor alloying elements in the aluminum melts through an equivalent amount of silicon. Such a system could be used to calculate several thermo-physical and solidification characteristics of multi component as cast aluminum alloys. This provides to the model the capacity to predict the solidification characteristics of cast parts, where cooling rates are slow and the solidification process has to be known in great detail in order to avoid quality problems in the casting. This work demonstrates how the SiEQ algorithm can be used to calculate the characteristic solidification temperatures of the multicomponent Al-Si alloys as well as their latent heats and growth restriction factor. Statistical analysis of the results obtained for a wide range of alloy chemical compositions shows a very good correlation with the experimental data and the SiEQ calculations. The same mathematical approach might be applied for other metallic systems such as iron and magnesium, using carbon equivalency for ferrous systems and aluminum equivalency for magnesium multi-component alloys. (Author)

  8. The electrochemical properties of melt-spun Al-Si-Cu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Linping; Wang Fei; Liang Pu; Song Xianlei; Hu Qing [MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Sun Zhanbo, E-mail: szb@mail.xjtu.edu.cn [MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Song Xiaoping; Yang Sen; Wang Liqun [MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)

    2011-10-03

    Highlights: {yields} Non-equilibrium Al{sub 75-X}Si{sub 25}Cu{sub X} alloys exhibit high lithiation storages. {yields} The lithiation mechanism is different from melt-spun Al-Si-Mn system. {yields} The structural evolution is mitigated in the non-equilibrium alloys. {yields} Volume variation is alleviated due to the co-existence of Al{sub 2}Cu, {alpha}-Si and {alpha}-Al. - Abstract: Melt spinning was used to prepare Al{sub 75-X}Si{sub 25}Cu{sub X} (X = 1, 4, 7, 10 mol%) alloy anode materials for lithium-ion batteries. A metastable supersaturated solid solution of Si and Cu in fcc-Al, {alpha}-Si and Al{sub 2}Cu co-existed in the alloys. Nano-scaled {alpha}-Al grains, as the matrix, formed in the as-quenched ribbons. The Al{sub 74}Si{sub 25}Cu{sub 1} and Al{sub 71}Si{sub 25}Cu{sub 4} anodes exhibited initial discharge specific capacities of 1539 mAh g{sup -1}, 1324 mAh g{sup -1} and reversible capacities above 472 mAh g{sup -1}, 508 mAh g{sup -1} at the 20th cycle, respectively. The specific capacities reduced as the increase of the Cu content. AlLi intermetallic compound was detected in the lithiated alloys. It is concluded that the lithiation mechanism of the Al-Si-based alloys can be affected by the third component. The structural evolution and volume variation can be mitigated due to the formation of non-equilibrium state and the co-existence of nano-scaled {alpha}-Al, {alpha}-Si, and Al{sub 2}Cu for the present alloys.

  9. The electrochemical properties of melt-spun Al-Si-Cu alloys

    International Nuclear Information System (INIS)

    Highlights: → Non-equilibrium Al75-XSi25CuX alloys exhibit high lithiation storages. → The lithiation mechanism is different from melt-spun Al-Si-Mn system. → The structural evolution is mitigated in the non-equilibrium alloys. → Volume variation is alleviated due to the co-existence of Al2Cu, α-Si and α-Al. - Abstract: Melt spinning was used to prepare Al75-XSi25CuX (X = 1, 4, 7, 10 mol%) alloy anode materials for lithium-ion batteries. A metastable supersaturated solid solution of Si and Cu in fcc-Al, α-Si and Al2Cu co-existed in the alloys. Nano-scaled α-Al grains, as the matrix, formed in the as-quenched ribbons. The Al74Si25Cu1 and Al71Si25Cu4 anodes exhibited initial discharge specific capacities of 1539 mAh g-1, 1324 mAh g-1 and reversible capacities above 472 mAh g-1, 508 mAh g-1 at the 20th cycle, respectively. The specific capacities reduced as the increase of the Cu content. AlLi intermetallic compound was detected in the lithiated alloys. It is concluded that the lithiation mechanism of the Al-Si-based alloys can be affected by the third component. The structural evolution and volume variation can be mitigated due to the formation of non-equilibrium state and the co-existence of nano-scaled α-Al, α-Si, and Al2Cu for the present alloys.

  10. Modelling of mechanical properties of Al-Si-Cu cast alloys using the neural network

    Directory of Open Access Journals (Sweden)

    M. Krupiński

    2007-01-01

    Full Text Available Purpose: The paper presents some results of the research connected with the development of new approach basedon the neural network to predict the chemical composition and cooling rate to the mechanical properties of Al–Si–Cu cast alloys. The independent variables in the model are chemical composition of Al–Si–Cu cast alloys andcooling rate. The dependent parameters are hardness, microhardess, yield strength and apparent elastic limit.Design/methodology/approach: The experimental alloy used for training of neural network was prepared at theUniversity of Windsor (Canada in the Light Metals Casting Laboratory, in a 10 kg capacity ceramic crucible.Thermal analysis tests were conducted using the UMSA Technology Platform. Compression tests were conductedat room temperature using a Zwick universal testing machine. Prior to testing, an extensometer was used tominimize frame bending strains. Compression specimens were tested corresponding to each of the three coolingrate. Rockwell F–scale hardness tests were conducted at room temperature using a Zwick HR hardness testingmachine. Vickers microhardness tests were conducted using a DUH 202 microhardness testing machine.Findings: The results of this investigation show that there is a good correlation between experimental and predicteddates and the neural network has a great potential in mechanical behavior modeling of Al–Si–Cu castings.Practical implications: The worked out model can be applied in computer system of Al–Si–Cu casting alloysselection and designing for Al-Si-Cu casting parts.Originality/value: Original value of the work is applied the artificial intelligence as a tools for designing therequired mechanical properties of Al-Si-Cu castings.

  11. Preparation of Al-Si-Ti Master Alloys by Electrolysis of Silica and Titania in Cryolite-Alumina Melts

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Aluminum-silicon-titanium master alloys were prepared in the laboratory by electrolysis of silica and titania dissolved in cryolite-alumina melts. Alloys containing up to 12 mass% Si and 2.6 mass% Ti were formed after about 90 min of electrolysis at 950℃. The current efficiency for the preparation of the Al-Si-Ti alloys varied with time, temperature and cathodic current density. It is concluded that this electrolytic method may be an interesting alternative to the direct metal mixing process for formation of Al-Si-Ti master alloys.

  12. Influence of selected parameters of AlSi/CrFeC composite castings manufacturing on the resulted structure

    OpenAIRE

    A. Dulęba; M. Cholewa

    2012-01-01

    Purpose: The main aim of studies was to determine influence: size of reinforcing particles, frequency and the current intensity on the morphology of reinforcing phase precipitates in AlSi11/CrFe30C8 composites castings produced of rotating electromagnetic field.Design/methodology/approach: In this paper the technology of AlSi11/CrxCy composites produced with Cr30Fe8C ex situ particles is described. Technological conception of investigations was based on assumption that Cr-Fe matrix of particl...

  13. Influence of titanium content on wear resistance of electrolytic low-titanium eutectic Al-Si piston alloys

    OpenAIRE

    Yan Shuqing; Xie Jingpei; Wang Jiefang

    2008-01-01

    The wear resistance of six kinds of the electrolytic low-titanium eutectic Al-Si piston alloys with various Ti content ranging from 0.00wt.% to 0.21wt.% has been studied. A new method of adding Ti is adopted in the electrolytic low-titanium aluminum alloy ingots. The electrolytic low-titanium eutectic Al-Si piston alloys are produced by remelting the electrolytic low-titanium aluminum alloy, crystal silicon, pure magnesium, Al-50%Cu and Al-10%Mn master alloy. The wear experiments are conducte...

  14. The influence of remelting on the properties of AlSi6Cu4 alloy modified by antimony

    Directory of Open Access Journals (Sweden)

    D. Medlen

    2012-01-01

    Full Text Available The paper deals with the problem of multiple remelting influence on AlSi6Cu4 alloy modified by antimony on chosen mechanical characteristics, microstructure and gas content. This foundry alloy is used mostly in automotive industry. Foundry Aluminum-Silicon alloys are also used in number of industrial weight sensitive applications because of their low weight and very good castability and good mechanical properties. Modifiers are usually added to molten aluminum-silicon alloys to refine the eutectic phase particle shape and improve the mechanical properties of the final cast products and Al-Si alloys cast properties.

  15. Numerical Simulation Microstructure Morphology Evolution and Solute Microsegregation of Al-Si-Cu Ternary Alloys during Solidification Process

    Science.gov (United States)

    Xie, Shuisheng; Huang, Guojie; Cheng, Lei; Fu, Yao; Li, Qiang

    2011-06-01

    A 2D microstructure and solute microsegregation model of Al-Si-Cu ternary alloys is presented by using cellular automaton(CA) method. In CA model, an improved algorithm was presented that abandoned the assumption of solid/liquid interface position and velocity so as to calculate the solid fraction in the solid/liquid interface unit. Then, using CA model, a dendrite of Al-Si-Cu ternary alloys is simulated. Finally, solidification microstructure and solute microsegregation are simulated, and the simulated results can reflect the microstructure and different solute microsegregation during solidification process.

  16. Revealing heterogeneous nucleation of primary Si and eutectic Si by AlP in hypereutectic Al-Si alloys

    OpenAIRE

    Jiehua Li; Hage, Fredrik S.; Xiangfa Liu; Quentin Ramasse; Peter Schumacher

    2016-01-01

    The heterogeneous nucleation of primary Si and eutectic Si can be attributed to the presence of AlP. Although P, in the form of AlP particles, is usually observed in the centre of primary Si, there is still a lack of detailed investigations on the distribution of P within primary Si and eutectic Si in hypereutectic Al-Si alloys at the atomic scale. Here, we report an atomic-scale experimental investigation on the distribution of P in hypereutectic Al-Si alloys. P, in the form of AlP particles...

  17. Corrosion and protection of heterogeneous cast Al-Si (356) and Al-Si-Cu-Fe (380) alloys by chromate adn cerium inhibitors

    Science.gov (United States)

    Jain, Syadwad

    presence of soluble cerium cations showed that of anodic and cathodic activity was not as strongly inhibited as was observed for chromate ions. Overall cerium conversion coating showed good performance on Al-Si (356) ally, but poor performance on Fe- and Cu-rich alloy (380).

  18. Study on Fabrication and Crystallization of Mg-Cu-(Al-Si)-Y Bulk Amorphous Alloy%Mg-Cu-(Al-Si)-Y大块非晶合金的制备及晶化研究

    Institute of Scientific and Technical Information of China (English)

    张伟; 陈刚; 李宝贵

    2006-01-01

    采用Al-Si合金部分替代Mg65u25Y10大块非晶合金中的Cu元素,形成Mg-Cu-(Al-Si)-Y非晶合金.通过铜模浇注法制备Mg-Cu-(Al-Si)-Y大块非晶合金,发现Al-Si合金的添加对非晶合金的玻璃形成能力没有明显改善,但改善了非晶合金的室温塑性.在晶化温度附近低于晶化温度的条件下对铜辊旋淬法制备的Mg-Cu-(Al-Si)-Y非晶条带进行了处理.结果表明,Mg-Cu-(Al-Si)-Y非晶合金随加热温度的提高和处理的时间的延长晶化程度也随之提高,同时加热晶化增大了合金的室温脆性.

  19. Optimización de las aleaciones de NiTi porosas para aplicaciones biomédicas

    OpenAIRE

    Barrabés, Maite

    2005-01-01

    Por sus únicas características de memoría de forma y superelasticidad, las aleaciones de NiTi son interesantes para aplicaciones biomédicas. Una de las limitaciones de estas aleaciones es su uso como prótesis óseas, debido a los problemas de reabsorción que presentan. El uso de una aleación de NiTi porosa evita esta problemática, gracias a su mayor similitud con las propiedades mecánicas del hueso. Además la presencia de porosidad permite que haya crecimiento de tejido entre lo...

  20. Study on selective laser melting process and forming of AlSi10 Mg alloy powder%选择性激光熔化AlSi10 Mg合金粉末的成形工艺

    Institute of Scientific and Technical Information of China (English)

    刘锦辉; 史金光; 李亚

    2015-01-01

    This paper deals with the single-layer single-channel experiment and single-layer multi-channel experiment performed by using different process parameters to study the selective laser melting (SLM) forming process of AlSi10Mg alloy powder. This study consists of analyzing the effects of laser power, laser scanning speed, scanning interval on melting channel width and surface quality;testing the density of SLM AlSi10 Mg samples formed under different parameters and analyzing the relationship be-tween energy density and the sample density; and testing the microstructure and property, and micro-hardness. The results show that the optimal scanning track quality is governed the given process parame-ters:laser power between 240~280 W, scanning speed between 1 000~1 400 mm/s, scanning interval between 0 . 06~0 . 08 mm; SLM-produced AlSi10 Mg parts perform much better than conventionally cast AlSi10 Mg ones .%为了研究AlSi10 Mg合金粉末的选择性激光熔化成形,采用不同的工艺参数,进行了单层单道扫描实验和单层多道扫描实验。分析激光功率、激光扫描速度、扫描间距对激光扫描轨迹宽度和表面质量的影响。检测不同参数下选择性激光熔化成形的AlSi10 Mg合金块的致密度,分析成形件致密度与能量密度的关系,成形件的组织和性能,对成形件进行硬度测试。结果表明:激光功率在240~280 W,扫描速度在1000~1400 mm/s,扫描间距在0.06~0.08 mm时,扫描轨迹成形质量最佳。与传统铸造AlSi10Mg合金零件相比,SLM成形的零件具有更好的性能。

  1. Alloy 690 in PWR type reactors; Aleaciones base niquel en condiciones de primario de los reactores tipo PWR

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Briceno, D.; Serrano, M.

    2005-07-01

    Alloy 690, used as replacement of Alloy 600 for vessel head penetration (VHP) nozzles in PWR, coexists in the primary loop with other components of Alloy 600. Alloy 690 shows an excellent resistance to primary water stress corrosion cracking, while Alloy 600 is very susceptible to this degradation mechanisms. This article analyse comparatively the PWSCC behaviour of both Ni-based alloys and associated weld metals 52/152 and 82/182. (Author)

  2. Prediction of U-Mo dispersion nuclear fuels with Al-Si alloy using artificial neural network

    International Nuclear Information System (INIS)

    Dispersion nuclear fuels, consisting of U-Mo particles dispersed in an Al-Si matrix, are being developed as fuel for research reactors. The equilibrium relationship for a mixture component can be expressed in the phase diagram. It is important to analyze whether a mixture component is in equilibrium phase or another phase. The purpose of this research it is needed to built the model of the phase diagram, so the mixture component is in the stable or melting condition. Artificial neural network (ANN) is a modeling tool for processes involving multivariable non-linear relationships. The objective of the present work is to develop code based on artificial neural network models of system equilibrium relationship of U-Mo in Al-Si matrix. This model can be used for prediction of type of resulting mixture, and whether the point is on the equilibrium phase or in another phase region. The equilibrium model data for prediction and modeling generated from experimentally data. The artificial neural network with resilient backpropagation method was chosen to predict the dispersion of nuclear fuels U-Mo in Al-Si matrix. This developed code was built with some function in MATLAB. For simulations using ANN, the Levenberg-Marquardt method was also used for optimization. The artificial neural network is able to predict the equilibrium phase or in the phase region. The develop code based on artificial neural network models was built, for analyze equilibrium relationship of U-Mo in Al-Si matrix

  3. INFLUENCE OF RAPID QUENCHING AND SAMPLE TREATMENT ON THE STRUCTURE OF MELT SPUN Al-Si ALLOYS

    OpenAIRE

    Chevrier, Joël; Sainfort, P.; Germi, P.; Pavuna, D.

    1985-01-01

    We have studied the structural characteristics of the range of melt spun Al-Si alloys. We find that the dominant feature is the existence of sursaturated Si in f.c.c. Al grains which well explains the metastability of these systems as well as related thermal and electronic properties.

  4. Prediction of U-Mo dispersion nuclear fuels with Al-Si alloy using artificial neural network

    Science.gov (United States)

    Susmikanti, Mike; Sulistyo, Jos

    2014-09-01

    Dispersion nuclear fuels, consisting of U-Mo particles dispersed in an Al-Si matrix, are being developed as fuel for research reactors. The equilibrium relationship for a mixture component can be expressed in the phase diagram. It is important to analyze whether a mixture component is in equilibrium phase or another phase. The purpose of this research it is needed to built the model of the phase diagram, so the mixture component is in the stable or melting condition. Artificial neural network (ANN) is a modeling tool for processes involving multivariable non-linear relationships. The objective of the present work is to develop code based on artificial neural network models of system equilibrium relationship of U-Mo in Al-Si matrix. This model can be used for prediction of type of resulting mixture, and whether the point is on the equilibrium phase or in another phase region. The equilibrium model data for prediction and modeling generated from experimentally data. The artificial neural network with resilient backpropagation method was chosen to predict the dispersion of nuclear fuels U-Mo in Al-Si matrix. This developed code was built with some function in MATLAB. For simulations using ANN, the Levenberg-Marquardt method was also used for optimization. The artificial neural network is able to predict the equilibrium phase or in the phase region. The develop code based on artificial neural network models was built, for analyze equilibrium relationship of U-Mo in Al-Si matrix.

  5. Optimization of Stir Casting Process Parameters to Minimize the Specific Wear of Al-SiC Composites by Taguchi Method

    Directory of Open Access Journals (Sweden)

    Sadi

    2015-02-01

    Full Text Available The aim of this research is to optimize of stir casting process parameters to minimize the specific wear of Al-SiC composites by Taguchi method. Composite material used in this research was Al- Si aluminum alloy as the matrix and SiC (silicon carbide particles size 400 mesh as the reinforcement. Experimental design used L16 orthogonal arrays Taguchi method standards. Experimental factors used in the making of composite samples were SiC content, melt temperature, rotation speed and stirring duration, each with 4 levels or variations. The microstructures of Al-SiC composite were observed by scanning electron microscope (SEM. Experimental result showed that the optimum of stir casting process parameters are SiC content of 15 wt.%, melt temperature of 740 oC, rotation speed of 300 rpm and stirring duration of 10 minutes. The most significant parameter which affected on specific wear was SiC content which contributes 88.67%. Adding content of SiC from 0 to 15 wt. % can decrease the specific wear of Al-SiC composites about 90.08 %.

  6. Effect of Pouring Process on the Microstructures of Semi-Solid AlSi7Mg Alloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effect of different pouring temperatures and different pouring heights, the distance between the mouth of the pouring ladle and the top of the mold, on the microstructure of AlSi7Mg alloy have been researched in the paper. When the pouring temperature is close to the liquidus temperature, the primary α-Al in'the billets of AlSi7Mg alloy solidified into spherical and nodular fine grains distributed homogeneously. The optimum pouring temperature for semi-solid AlSi7Mg billet with spherical or nodular primary c-Al is 615℃. At the same pouring temperature, the higher the pouring ladle, the more easily the spherical and nodular primary α-Al obtained in the semi-solid AlSi7Mg billet. When the pouring temperature is close to the liquidus temperature and the pouring ladle is relatively high, it is the great cooling rate, the flow of the molten alloy caused by pouring and the large simultaneous solidification region induced by the near liquidus temperature, that promote the formation of spherical or nodular primary c-Al.

  7. Effect of Cd and Sn Addition on the Microstructure and Mechanical Properties of Al-Si-Cu-Mg Cast Alloy

    Institute of Scientific and Technical Information of China (English)

    LI Rong-de; LI Run-xia; YU Li; HU Zhuang-qi

    2004-01-01

    The present work has investigated the effect of trace elements Cd and Sn on the microstructure and mechanical properties of Al-Si-Cu-Mg cast alloy. With the increase of Cd addition the strength of alloy rises at first and then drops. The optimal amount of Cd and Sn addition for Al-Si-Cu-Mg alloy is about 0.27% and 0.1% respectively. Due to the formation of some coarse Cd-rich phases and pure Cd particles the mechanical properties of alloy decrease when Cd amount exceeds0.27%. When more than 0.1% Sn added, some Sn atoms form low-melting eutectic compound at grain boundary, and then cause over-burning in alloy when solution treated, which may deteriorate properties of alloy, especially ductility of alloy.On the other hand, the addition of Cd and Sn remarkably increases the peak hardness and reduces the time to reach aging peak in Al-Si-Cu-Mg alloy. The action of Cd/Sn in quaternary Al-Si-Cu-Mg alloy is effectively the same as that occur in binary Al-Cu alloy that the enhanced hardening associated with Cd / Sn addition is due to the promotion of the θ' phase.

  8. Analysis of structural properties for AlSi11 alloy with use of thermal derivative gradient analysis TDGA

    Directory of Open Access Journals (Sweden)

    M. Cholewa

    2008-08-01

    Full Text Available In this paper a basis of thermal derivative gradient analysis was shown. Authors presented methodology of the studies, results and analysis. Studies of crystallization kinetics were conducted on non-modified AlSi11 eutectic alloy. Analyzing the results authors proposed some parameters for description of crystallization kinetics and their relation to microstructure and mechanical properties.

  9. Influence of titanium content on wear resistance of electrolytic low-titanium eutectic Al-Si piston alloys

    Directory of Open Access Journals (Sweden)

    Yan Shuqing

    2008-11-01

    Full Text Available The wear resistance of six kinds of the electrolytic low-titanium eutectic Al-Si piston alloys with various Ti content ranging from 0.00wt.% to 0.21wt.% has been studied. A new method of adding Ti is adopted in the electrolytic low-titanium aluminum alloy ingots. The electrolytic low-titanium eutectic Al-Si piston alloys are produced by remelting the electrolytic low-titanium aluminum alloy, crystal silicon, pure magnesium, Al-50%Cu and Al-10%Mn master alloy. The wear experiments are conducted using MM200 wear testing machine under lubricating condition. The results indicate that the better wear resistance and the less weight loss are achieved in the study for the eutectic Al-Si piston alloys with 0.08wt.%–0.12wt.% Ti content. The highest ultimate tensile strength of 135.94 MPa at 300℃ and HV141.70 hardness of the alloys are obtained at 0.12wt.% and 0.08wt.% Ti content, respectively. The wear mechanism of the eutectic Al-Si piston alloys under lubricating condition is abrasive wear.

  10. The influence of ternary alloying elements on the Al-Si eutectic microstructure and the Si morphology

    Science.gov (United States)

    Darlapudi, A.; McDonald, S. D.; Terzi, S.; Prasad, A.; Felberbaum, M.; StJohn, D. H.

    2016-01-01

    The influence of the ternary alloying elements Cu, Mg and Fe on the Al-Si eutectic microstructure is investigated using a commercial purity Al-10 wt%Si alloy in unmodified and Sr-modified conditions. A change in the Al-Si eutectic microstructure was associated with a change in the nucleation density of the eutectic grains caused by the addition of ternary alloying elements. When the ternary alloying element addition resulted in an increase in the eutectic nucleation frequency, a fibrous to flake-like transition was observed within the eutectic grain. When the ternary alloying element addition decreased the eutectic nucleation frequency significantly, a change in the eutectic morphology from flake-like to a mixture of flake-like and fibrous morphologies was observed. The mechanism of Al-Si eutectic modification is discussed. The growth velocity of the eutectic grain - liquid interface and the constitutional driving force available for growth are proposed as important parameters that influence the degree of eutectic modification in Al-Si alloys.

  11. Validated thermodynamic prediction of AlP and eutectic (Si) solidification sequence in Al-Si cast alloys

    Science.gov (United States)

    Liang, S. M.; Schmid-Fetzer, R.

    2016-03-01

    The eutectic microstructure in hypoeutectic Al-Si cast alloys is strongly influenced by AlP particles which are potent nuclei for the eutectic (Si) phase. The solidification sequence of AlP and (Si) phases is, thus, crucial for the nucleation of eutectic silicon with marked impact on its morphology. This study presents this interdependence between Si- and P-compositions, relevant for Al-Si cast alloys, on the solidification sequence of AlP and (Si). These data are predicted from a series of thermodynamic calculations. The predictions are based on a self-consistent thermodynamic description of the Al-Si-P ternary alloy system developed recently. They are validated by independent experimental studies on microstructure and undercooling in hypoeutectic Al-Si alloys. A constrained Scheil solidification simulation technique is applied to predict the undercooling under clean heterogeneous nucleation conditions, validated by dedicated experimental observations on entrained droplets. These specific undercooling values may be very large and their quantitative dependence on Si and P content of the Al alloy is presented.

  12. Microstructure modification and related mechanism of spray-formed Fe-bearing hypereutectic Al-Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hou, L.G.; Cui, H. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology, Beijing (China); Cai, Y.H. [School of Materials Science and Engineering, University of Science and Technology, Beijing (China); Zhang, J.S.

    2010-07-15

    The Fe-bearing hypereutectic Al-Si alloys with/without Cr/(Cr+Mn) addition have been prepared by Spray Forming (SF) process. With 2 wt.% Cr addition, the short-rod {beta}-Al{sub 5}FeSi phase in spray-formed Al-25Si-5Fe-3Cu (wt.%, denoted as 3C) alloy can be substituted by particulate {alpha}-Al(Fe,Cr)Si phase with sizes less than 5-6 {mu}m. But small quantity of blocky {beta}-Al{sub 5}(Fe,Cr)Si phase still appears in Cr-added hypereutectic Al-Si alloy. When (2Cr+1Mn) (wt.%) are added simultaneously into 3C alloy, almost all the short-rod {beta}-Al{sub 5}FeSi phase or blocky {beta}-Al{sub 5}(Fe,Cr)Si phase disappear, instead, the {alpha}-Al(Fe,Cr,Mn)Si phase become the only Fe-bearing phase. During heat treatments, the other two spray-formed hypereutectic Al-Si alloys (besides SF-3C alloy) are thermodynamically stable for the appearance of high thermodynamically stable particulate {alpha}-Al(Fe,Cr)Si/{alpha}-Al(Fe,Cr,Mn)Si phase. Also the phase transformation occurred during the heating/cooling process of the present hypereutectic Al-Si alloys are investigated and the mechanism of microstructural formation of the spray-formed alloys are discussed. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  13. Characteristics of CrAlSiN + DLC coating deposited by lateral rotating cathode arc PVD and PACVD process

    Energy Technology Data Exchange (ETDEWEB)

    Lukaszkowicz, Krzysztof, E-mail: krzysztof.lukaszkowicz@polsl.pl [Institute of Engineering Materials and Biomaterials, Silesian University of Technology, Konarskiego St. 18A, 44-100 Gliwice (Poland); Sondor, Jozef, E-mail: j.sondor@liss.cz [LISS, a.s., Dopravni 2603, 756 61 Roznov p.R. (Czech Republic); Balin, Katarzyna, E-mail: katarzyna.balin@us.edu.pl [A. Chełkowski Institute of Physic, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland); Kubacki, Jerzy, E-mail: jerzy.kubacki@us.edu.pl [A. Chełkowski Institute of Physic, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland)

    2014-09-01

    Highlights: • The chemical composition of the CrAlSiN + DLC coatings was studied. • The coatings have nanostructural character with fine crystallites. • Their average size grain is less than 10 nm. • The coatings demonstrate friction coefficient within the range 0.05–0.07. • The coating demonstrated a dense cross-sectional morphology as well as good adhesion to the substrate. - Abstract: Coating system composed of CrAlSiN film covered by diamond-like carbon (DLC)-based lubricant, deposited on hot work tool steel substrate was the subject of the research. The CrAlSiN and DLC layers were deposited by PVD lateral rotating ARC-cathodes (LARC) and PACVD technology on the X40CrMoV5-1 respectively. HRTEM investigation shows an amorphous character of DLC layer. It was found that the tested CrAlSiN layer has a nanostructural character with fine crystallites while their average size is less than 10 nm. Based on the XRD pattern of the CrAlSiN, the occurrence of fcc phase was only observed in the coating, the texture direction 〈3 1 1〉 is perpendicular to the sample surface. Combined SEM, AES and ToF-SIMS studies confirmed assumed chemical composition and layered structure of the coating. The chemical distribution of the elements inside the layers and at the interfaces was analyzed by SEM and AES methods. It was shown that additional CrN layer is present between substrate and CrAlSiN coating. The atomic concentration of the particular elements of DLC and CrAlSiN layer was calculated from the XPS measurements. In sliding dry friction conditions the friction coefficient for the investigated elements is set in the range between 0.05 and 0.07. The investigated coating reveals high wear resistance. The coating demonstrated a dense cross-sectional morphology as well as good adhesion to the substrate.

  14. Structure investigation of the Al-Si-Cu alloy using derivative thermo analysis

    Directory of Open Access Journals (Sweden)

    M. Krupiński

    2009-05-01

    Full Text Available Purpose: This research work presents the investigation results of derivative thermoanalysis performed using the UMSA device (Universal Metallurgical Simulator and Analyzer. The material used for investigation was an Al-Si-Cu alloy known as AC-AlSi7Cu3Mg grade aluminium cast alloy.Design/methodology/approach: As a result of this research the cooling rate influence on structure and mechanical properties changes, especially HB Hardness was investigated. The cooling rate was set in a variable range of ~0.2 ºC/s to ~1.25 ºC/s. In this work structure changes were determined concerning the structure, especially the dendrites and grains and particle distribution in the aluminium matrix.Findings: The reason of this work was to determine the optimal cooling rate values, to achieve good mechanical properties for protection of this aluminium cast alloy from losing their work stability and to make it more resistant to action in hard working conditions. For investigations of the aluminium samples hardness measurements of the different sample areas were performed. The material was examined metallographically and analyzed qualitatively using light and scanning electron microscope as well as the area mapping and point-wise EDS microanalysis. The performed investigation are discussed for the reason of an possible improvement of thermal and structural properties of the alloy. The investigation revealed the formation of aluminium reach (α -Al dendrites and also the occurrence of the α+β eutectic, the ternary eutectic α+Al2Cu+β, as well the occurrence of the Fe and Mn containing phase was confirmed.Practical implications: In the metal casting industry, an improvement of component quality depends mainly on better control over the production parameters.Originality/value: This work provides also a better understanding of the thermal characteristics and processes occurred in the new developed near eutectic Al–Si-Cu alloy. The achieved results can be used for

  15. Microstructure of as-fabricated UMo/Al(Si) plates prepared with ground and atomized powder

    Science.gov (United States)

    Jungwirth, R.; Palancher, H.; Bonnin, A.; Bertrand-Drira, C.; Borca, C.; Honkimäki, V.; Jarousse, C.; Stepnik, B.; Park, S.-H.; Iltis, X.; Schmahl, W. W.; Petry, W.

    2013-07-01

    UMo-Al based fuel plates prepared with ground U8wt%Mo, ground U8wt%MoX (X = 1 wt%Pt, 1 wt%Ti, 1.5 wt%Nb or 3 wt%Nb) and atomized U7wt%Mo have been examined. The first finding is that that during the fuel plate production the metastable γ-UMo phases partly decomposed into two different γ-UMo phases, U2Mo and α'-U in ground powder or α″-U in atomized powder. Alloying small amounts of a third element to the UMo had no measurable effect on the stability of the γ-UMo phase. Second, the addition of some Si inside the Al matrix and the presence of oxide layers in ground and atomized samples is studied. In the case with at least 2 wt%Si inside the matrix a Silicon rich layer (SiRL) forms at the interface between the UMo and the Al during the fuel plate production. The SiRL forms more easily when an Al-Si alloy matrix - which is characterized by Si precipitates with a diameter ⩽1 μm - is used than when an Al-Si mixed powder matrix - which is characterized by Si particles with some μm diameter - is used. The presence of an oxide layer on the surface of the UMo particles hinders the formation of the SiRL. Addition of some Si into the Al matrix [7-11]. Application of a protective barrier at the UMo/Al interface by oxidizing the UMo powder [7,12]. Increase of the Mo content or use of UMo alloys with ternary element addition X (e.g. X = Nb, Ti, Pt) to stabilize the γ-UMo with respect to α-U or to control the UMo-Al interaction layer kinetics [9,12-24]. Use of ground UMo powder instead of atomized UMo powder [10,25] The points 1-3 are to limit the formation of the undesired UMo/Al layer. Especially the addition of Si into the matrix has been suggested [3,7,8,10,11,26,27]. It has been often mentioned that Silicon is efficient in reducing the Uranium-Aluminum diffusion kinetics since Si shows a higher chemical affinity to U than Al to U. Si suppresses the formation of brittle UAl4 which causes a huge swelling during the irradiation. Furthermore it enhances the

  16. Phases morphology and distribution of the Al-Si-Cu alloy

    Directory of Open Access Journals (Sweden)

    K. Labisz

    2009-12-01

    Full Text Available Purpose: In this paper results of phase morphology investigation are presented of a newly developed Al-Si-Cu alloy. Such studies are of great interest for the metal casting industry, mainly the automotive industry, where improvement of cast elements quality is crucial for economic and quality reason and depends mainly on properly performed controlling process of the production parametersDesign/methodology/approach: The basic assumptions of this work are realised with Universal Metallurgical Simulator and Analyzer. The solidification process itself is analysed using the UMSA device using the Derivative Thermo Analysis.Findings: During the investigation the formation of aluminium reach (α-Al dendrites was revealed and also the occurrence of the α+β eutectic, the ternary eutectic α+Al2Cu+β, as well as iron and manganese containing phase was confirmed. This work shows that the thermal modification of the Al-Si-Cu can be quantitatively assessed by analysis of the microstructure evaluation as well as of the cooling curve thermal characteristics.Research limitations/implications: The investigations were performed using standard metallographic investigation as optical, scanning and transmission electron microscopy methods; also the EBSD phase identification method based on the kikuchi lines identification was used. The results in this paper are valuable only for the Al2Cu, Fe and Mg containing phases, and are not performed for the assessment of the Silicon Modification Level.Practical implications: As an effect of this study it will be possible to understand and to influence the mechanism of structure forming, refinement and nucleation. Also better understanding of the thermal characteristics will be provided to achieve a desirable phase morphology required for specific application of this material under production conditions.Originality/value: The originality of this work is based on applying of regulated cooling rate of aluminium alloy for

  17. Evaluación de la dureza superficial en amalgamas en función de tipos de aleaciones, momentos y tipos de pulimentos

    Directory of Open Access Journals (Sweden)

    Ramos Juliana Panazzolo

    2003-01-01

    Full Text Available The aim of this study was to analyze in vitro surface hardness (micro-indentation tester Wolpert of different types of amalgam alloys varying the technique and polishing time. Tested were the amalgam: Velvalloy, Permite e Dispersalloy. For each material, 2 polishing techniques were accomplished: T1 (bladed finishing burs + abrasive rubber points + pumice-water slurry in Robinson polishing brush and; T2 (abrasive rubber points + pumice-water slurry in Robinson polishing brush, at 2 periods of time: P1 (immediately - 15 min after condensation and P2 (after 24 h. For each experimental condition, 5 samples were prepared. For each sample, 2 indentations were taken and the average was determined. Were made analysis using ANOVA and Tukey test. Were concluded that: a using the Permite alloy with polishing after 24 h the surface hardness of restoration will be higher; b the technique T2 enhances the hardness of dental amalgams and c alloy Permite with polished immediately were statisticaly equal than Velvalloy polished after 24 h.

  18. Transformation of Ba-Al-Si precursors to celsian by high-temperature oxidation and annealing

    Energy Technology Data Exchange (ETDEWEB)

    Schmutzler, H.J.; Sandhage, K.H. (Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering)

    1995-02-01

    Celsian (monoclinic BaO [center dot] Al[sub 2]O[sub 3] [center dot] 2SiO[sub 2]) is being considered as a matrix material for ceramic composites used in high-temperature structural applications. The present article describes the synthesis of celsian by the oxidation and annealing of solid, malleable, metallic Ba-Al-Si precursors. The phase and microstructural evolution after various stages of oxidation at 300 C to 1,260 C in pure oxygen at 1 atm pressure have been examined by X-ray diffraction (XRD) and electron microprobe analyses (EPMA). Barium peroxide, BaO[sub 2], formed rapidly during oxidation at 300 C, with aluminum and silicon remaining largely as unoxidized particles in a BaO[sub 2] matrix. Between 300 C and 500 C, barium orthosilicate, Ba[sub 2]SiO[sub 4], formed by a solid-state reaction between barium peroxide and unoxidized silicon. Further exposure to temperatures between 500 C and 1,200 C resulted in the oxidation of aluminum and of residual silicon. The oxidized silicon reacted with the barium orthosilicate matrix to yield higher silica-containing barium silicates that, in turn, reacted with alumina or mullite to form metastable hexacelsian (hexagonal BaO [center dot] Al[sub 2]O[sub 3] [center dot] 2SiO[sub 2]). Celsian was then obtained by further exposure to peak temperatures [le] 1,260 C.

  19. Transformation of Ba-Al-Si precursors to celsian by high-temperature oxidation and annealing

    Science.gov (United States)

    Schmutzler, Hans J.; Sandhage, Kenneth H.

    1995-02-01

    Celsian (monoclinic BaO · A12O3 · 2SiO2) is being considered as a matrix material for ceramic composites used in high-temperature structural applications. The present article describes the synthesis of celsian by the oxidation and annealing of solid, malleable, metallic Ba-Al-Si precursors. The phase and microstructural evolution after various stages of oxidation at 300 °C to 1260 °C in pure oxygen at 1 atm pressure have been examined by X-ray diffraction (XRD) and electron microprobe analyses (EPMA). Barium peroxide, BaO2, formed rapidly during oxidation at 300 °C, with aluminum and silicon remaining largely as unoxidized particles in a BaO2 matrix. Between 300 °C and 500 °C, barium orthosilicate, Ba2Si04, formed by a solid-state reaction between barium peroxide and unoxidized silicon. Further exposure to temperatures between 500 °C and 1200 °C resulted in the oxidation of aluminum and of residual silicon. The oxidized silicon reacted with the barium orthosilicate matrix to yield higher silica-containing barium silicates that, in turn, reacted with alumina or mullite to form metastable hexacelsian (hexagonal BaO-A12O3 · 2SiO2). Celsian was then obtained by further exposure to peak temperatures ≤1260°C.

  20. Microstructure variation and growth mechanism of hypoeutectic Al-Si alloy solidifi ed under high pressure

    Directory of Open Access Journals (Sweden)

    Zhang Guozhi

    2009-05-01

    Full Text Available The microstructure of hypoeutectic Al-9.21wt.%Si alloy solidified under 5.5 GPa was studied. The results show that the solidifi cation microstructure is refi ned. The primary α phase is the extended solid solution. The solid solubility of Si in α phase is up to 8.26wt.%. The growth mode of the α phase is cellular, and this cellular growth mechanism is interpreted in terms of the decrease of the diffusivity and the extended solid solution under high pressure. By calculation, it can be known that the the diffusivity of solute in the liquid under normal pressure is as high as two hundred times that under high pressure. The microhardness of the hypoeutectic Al-Si alloy solidified under high pressure is higher than that of solidifi ed under normal pressure. After annealing, Si precipitates from the solid solution, the microhardness of the alloy decrease, but, still higher than that of solidifi ed under normal pressure.

  1. Corrosion Behavior of Extruded near Eutectic Al-Si-Mg and 6063 Alloys

    Institute of Scientific and Technical Information of China (English)

    Yuna Wu; Hengcheng Liao

    2013-01-01

    In this work,a comparison study on corrosion behavior of extruded near eutectic Al-12.3%Si-0.26%Mg and 6063 alloys has been carried out by mass loss test in 4% H2SO4 aqueous solution in the open air and potentiodynamic polarization test in 3.5 wt.% NaCl aqueous solution.Results indicate that the corrosion resistance of the near eutectic Al-Si-Mg alloy is less than that of 6063 alloy.Macro/microscopy and scanning electron microscopy results clearly show the difference of the corrosion progress of these two alloys in 4% H2SO4 aqueous solution.The corrosion type of 6063 alloy is pitting corrosion.The Mg2Si and AlFeSi particles and surface defects act as nucleation sites for pitting,and the amount and distribution of them have a significant effect on the pitting behavior.For the near eutectic alloy,there are two types of corrosion cells.One is between the extruded primary α-Al and the eutectic,the other is between the eutectic Al and eutectic Si particles.Combination of these two types of corrosion cells leads to a lower corrosion resistance,a higher mass loss of the near eutectic alloy compared with 6063 alloy,and the formation of the paralleling corroded grooves.

  2. Time and Strain Response of Repeated Ageing Treatments on Recycled Al-Si-Cu Alloy

    Directory of Open Access Journals (Sweden)

    D.T. GUNDU

    2013-07-01

    Full Text Available The objective of this study was to investigate the time response of 3-stage artificial ageing treatments on strength properties of recycled Al-Si-Cu alloy with a view to obtaining useful empirical relationships for predicting required treatment cycles. True compressive stress, micro hardness and strain (% were evaluated in response to ageing time and repeated ageing. The results of compression and hardness tests showed that alloy hardness and compressive stress increased with ageing time, and that these properties also increased with repeated ageing. The results also showed that alloy strain (% reduced with ageing time and repeated ageing, indicating increasing strength or strain hardening of the alloy with repeated ageing. Using these results, empirical models of the form ϕn = ϕ0eαt, and ϕn = ϕ0eαN are established for predicting the required ageing time and/or number of ageing treatments to raise the strength (or hardness of an alloy to desired levels to meet service requirements. The strain response of the alloy is modelled as εn = ε0e−αt.

  3. Influence of carbon on sintering of the Al-Si-C-N system composite

    International Nuclear Information System (INIS)

    The composite in Al4SiC4-AlN and Al4SiC4-AlN-C system were sintered by a spark plasma sintering method. The powders of metal Al, Si and carbon black and AlN as starting materials were mixed. The mixture was calcined at 1300degC and sintered at 1600degC to 1800degC by spark plasma sintering. Shrinkage during sintering, density, microstructure and phase of sintered bodies were measured. X-ray diffraction analysis gave Al5SiC4N (15R) and AlN (2H) phases in the bodies sintered at 1750degC. Densification did not occur in some composition in 50 to 80% AlN of the system Al4SiC4-AlN, but their densification was accelerated by addition of carbon. By the analysis of shrinkage during sintering and SEM observation of microstructure, the grain of Al5SiC4N (15R) and AlN (2N) grew, and pore exclusion was obstructed in the system Al4SiC4-AlN, though the grain did not grow, and pore exclusion was accelerated in the system Al4SiC4-AlN-C. (author)

  4. Microstructure Evolution and Rheological Behavior of Cooling Slope Processed Al-Si-Cu-Fe Alloy Slurry

    Science.gov (United States)

    Das, Prosenjit; Samanta, Sudip K.; Bera, Supriya; Dutta, Pradip

    2016-05-01

    In the present work, microstructure evolution during semi-solid slurry generation of Al-Si-Cu-Fe alloy, using a cooling slope, was studied and the effect of microstructural morphology of the slurry on its rheological behavior was investigated. Microstructure evolution during melt flow along the slope was studied by extracting samples from various locations of the slope and performing rapid oil quenching experiments. Quantitative investigation was performed to evaluate primary phase shape and size for different process conditions of the semi-solid slurry, and subsequently rheological investigations were performed to correlate slurry morphology with its flow behavior. Three different types of rheological experiments were performed: isothermal test, shear jump test, and shear time test, in order to investigate rheological behavior of the semi-solid slurry. In addition, effect of melt treatment, by adding modifier (0.1 wt pct of Al-10Sr) and grain refiner (0.15 wt pct of Al-5Ti-1B), on the microstructure evolution during slurry generation, flow behavior of the slurry, and intermetallics formation was studied.

  5. Rapid Solidification: Selective Laser Melting of AlSi10Mg

    Science.gov (United States)

    Tang, Ming; Pistorius, P. Chris; Narra, Sneha; Beuth, Jack L.

    2016-03-01

    Rapid movement of the melt pool (at a speed around 1 m/s) in selective laser melting of metal powder directly implies rapid solidification. In this work, the length scale of the as-built microstructure of parts built with the alloy AlSi10Mg was measured and compared with the well-known relationship between cell size and cooling rate. Cooling rates during solidification were estimated using the Rosenthal equation. It was found that the solidification structure is the expected cellular combination of silicon with α-aluminum. The dependence of measured cell spacing on calculated cooling rate follows the well-established relationship for aluminum alloys. The implication is that cell spacing can be manipulated by changing the heat input. Microscopy of polished sections through particles of the metal powder used to build the parts showed that the particles have a dendritic-eutectic structure; the dendrite arm spacings in metal powder particles of different diameters were measured and also agree with literature correlations, showing the expected increase in secondary dendrite arm spacing with increasing particle diameter.

  6. Average thermal stress in the Al+SiC composite due to its manufacturing process

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Carlos A.J.; Libardi, Rosani M.P.; Marcelino, Sergio; Boari, Zoroastro M., E-mail: cmiranda@ipen.br, E-mail: rmpenha@ipen.br, E-mail: sergio.marcelino@gmail.com, E-mail: zoroastr@uol.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear

    2013-07-01

    The numerical analyses framework to obtain the average thermal stress in the Al+SiC Composite due to its manufacturing process is presented along with the obtained results. The mixing of Aluminum and SiC powders is done at elevated temperature and the usage is at room temperature. A thermal stress state arises in the composite due to the different thermal expansion coefficients of the materials. Due to the particles size and randomness in the SiC distribution, some sets of models were analyzed and a statistical procedure used to evaluate the average stress state in the composite. In each model the particles position, form and size are randomly generated considering a volumetric ratio (VR) between 20% and 25%, close to an actual composite. The obtained stress field is represented by a certain number of iso stress curves, each one weighted by the area it represents. Systematically it was investigated the influence of: (a) the material behavior: linear x non-linear; (b) the carbide particles form: circular x quadrilateral; (c) the number of iso stress curves considered in each analysis; and (e) the model size (the number of particles). Each of above analyzed condition produced conclusions to guide the next step. Considering a confidence level of 95%, the average thermal stress value in the studied composite (20% ≤ VR ≤ 25%) is 175 MPa with a standard deviation of 10 MPa. Depending on its usage, this value should be taken into account when evaluating the material strength. (author)

  7. AN IN SITU SURFACE COMPOSITE AND GRADIENT MATERIALOF Al-Si ALLOY PRODUCED BY ELECTROMAGNETIC FORCE

    Institute of Scientific and Technical Information of China (English)

    Z.M. Xu; T.X. Li; Z.L. Zhu; Y.H. Zhou

    2001-01-01

    Because of the different conductivities between the primary phase (law electric conductivity) and the metal melt, electromagnetic force scarcely acts on the primary phase.Thus, an electromagnetic repulsive force applied by the metal melt exerts on the primary phase when the movement of the melt in the direction of electromagnetic force is limited. As a result, the repulsive force exerts on the primary phase to push them to move in the direction opposite to that of the electromagnetic force when the metal melt with primary phase solidifies under an electromagnetic force field. Based on this,a new method for production of in situ surface composite and gradient material by electromagnetic force is proposed. An in situ primary Si reinforced surface composite of Al-15wt%Si alloy and gradient material of Al-19wt%Si alloy were produced by this method. The microhardness of the primary Si is HV1320. The reinforced phase size is in the range from 40μm to 100μm. The wear resistance of Al-Si alloy gradient material can be more greatly increased than that of their matrix material.``

  8. Temperature and microstructure characteristics of silumin casting AlSi9 made with investment casting method

    Directory of Open Access Journals (Sweden)

    S. Pietrowski

    2011-07-01

    Full Text Available This work presents the research result of the temperature distribution and the microstructure in certain parts of the field-glass body frame casting made from silumin AlSi9 using the investment casting method in the ceramic mould. It was proved that the highest temperature of the silumin appears in the sprue in which the silumin is in the liquid-solid state, though the process of silumin crystallization in the casting is finished. It was stated that in certain elements of the casting the side opposite to the runner crystallizes and cools fastest. The differences in the rate of crystalline growth and cooling of certain casting elements cause differ- ent microstructure in them which can also influence the mechanic properties.It is necessary to state that the temperature of the initial heating of the ceramic mold equal to 60oC guarantees obtaining of the castings without defects and of little porosity. Incomplete modification of the silumin with strontium causes silica precipitation to appear close to the spherical ones.

  9. New Quality Assessment Criterion of AlSi5Cu1 Alloy

    Directory of Open Access Journals (Sweden)

    M. Wierzbińska

    2007-07-01

    Full Text Available The paper presents the discussion of the results of mechanical testing for aluminium foundry alloy AlSi5Cu1Mg for high-loaded machine elements. Values of yield strength (Rp0.2, tensile strength (Rm, elongation(A5 and hardness (HB are usually considered as the primary quality assessment criterion for a manufacturing process. It was concluded, that this criterion, A5 index particularly, is unsatisfactory to estimate the plasticity of the alloy and its crack resistance in the presence of sharp-pointed stress concentrators or microcracks. More adequate parameter is plane strain fracture toughness KIc. However, size of the samples appeared to be twice as large as would be needed to fulfill requirements of test conditions, and the test itself is laborious and time-consuming that it becomes impractical as a acceptance test. Therefore, substitute test for quality assessment – determination of tensile strength in the presence of a sharp notch kmR was applied. The comparative analysis of kmR/Rp0.2 ratio, as a more enhanced fatigue resistance criterion than kmR and plane strain fracture toughness KIc of the alloy was performed. It was assumed that kmR/Rp0.2 parameter has good correlation with the critical stress intensity factor KIc Thus, under manufacturing process conditions, being unable to carry out KIc test, it may be successfully replaced by kmR test.

  10. Reduced interaction layer growth of U-Mo dispersion in Al-Si

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yeon Soo, E-mail: yskim@anl.gov [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Park, Jong Man; Ryu, Ho Jin; Jung, Yang Hong [Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong, Daejeon 305-353 (Korea, Republic of); Hofman, G.L. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2012-11-15

    Development of high U-density U-Mo fuel particle dispersion in Al is needed to convert high power research and test reactors from HEU to LEU. Interaction layer growth between U-Mo and Al poses a challenge to this goal. The KOMO-4 test was designed at KAERI and irradiated in the HANARO reactor to {approx}50% burnup of initial 19.75% U-235 enrichment at {approx}200 Degree-Sign C. The main objective of the test was to examine the effect of the Si content in the matrix up to 8 wt.%. U-Mo/Al-Si dispersion samples with a Si addition in the range 0-8 wt.% in the matrix were tested. A sample with pre-irradiation Si-containing interaction layers (ILs) was also tested. As the Si content in the matrix increases, the IL growth was progressively reduced. Contrary to the thermodynamics prediction and out-of-pile observations, however, Si accumulation in the ILs occurred near the IL-matrix interface with only a slight increase in concentration. The effect of the pre-formed ILs was insignificant in reducing IL growth.

  11. Analysis of hardness, porosity, and microstructure on AlSi alloys produced by squeezed casting technique

    International Nuclear Information System (INIS)

    A research on physical and mechanical properties of AlSi alloy was achieved out using squeezed casting technique. Flens which is commonly produced by sand casting technique can wrap out easily. The end part of flens is susceptible to wearing. To overcome this weakness another technique is called squeezed casting applied to generate some specimens of the flens. The parameter's of the specimen productions are temperatures at 450oC, 500oC and pressures at 70 MPa, 100 MPa, and 130 MPa for each temperatures of die. Characterization produced conducted include composition test, hardness test, density and microstructure analysis. The hardness of the sample made by sand casting (CP) is 76.57 Kg/mm2 and the hardness sample made by squeezed casting (SQ) is 88.270 Kg/mm2. Meanwhile the porosity of CP is 6.53% and the porosity of SQ is 0.79%. Microstructure analysis indicated that the analysis produced by squeezed casting consists of finer dendrite. This research concludes that the squeezed casting technique improves specimen's hardness and microstructure and reduces its porosity

  12. Microstructure analysis of Al-Si-Cu alloys prepared by gradient solidification technique

    Science.gov (United States)

    Borkar, Hemant; Seifeddine, Salem; Jarfors, Anders E. W.

    2015-03-01

    Al-Si-Cu alloys were cast with the unique gradient solidification technique to produce alloys with two cooling rates corresponding to secondary dendrite arm spacing (SDAS) of 9 and 27 μm covering the microstructural fineness of common die cast components. The microstructure was studied with optical microscopy and scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and electron backscattered diffraction (EBSD). The alloy with higher cooling rate, lower SDAS, has a more homogeneous microstructure with well distributed network of eutectic and intermetallic phases. The results indicate the presence of Al-Fe-Si phases, Al-Cu phases and eutectic Si particles but their type, distribution and amount varies in the two alloys with different SDAS. EBSD analysis was also performed to study the crystallographic orientation relationships in the microstructure. One of the major highlights of this study is the understanding of the eutectic formation mechanism achieved by studying the orientation relationships of the aluminum in the eutectic to the surrounding primary aluminum dendrites.

  13. Mechanistic Selection and Growth of Twinned Bicrystalline Primary Si in Near Eutectic Al-Si Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Choonho Jung

    2006-12-12

    Morphological evolution and selection of angular primary silicon is investigated in near-eutectic Al-Si alloys. Angular silicon arrays are grown directionally in a Bridgman furnace at velocities in the regime of 10{sup -3} m/sec and with a temperature gradient of 7.5 x 10{sup 3} K/m. Under these conditions, the primary Si phase grows as an array of twinned bicrystalline dendrites, where the twinning gives rise to a characteristic 8-pointed star-shaped primary morphology. While this primary Si remains largely faceted at the growth front, a complex structure of coherent symmetric twin boundaries enables various adjustment mechanisms which operate to optimize the characteristic spacings within the primary array. In the work presented here, this primary silicon growth morphology is examined in detail. In particular, this thesis describes the investigation of: (1) morphological selection of the twinned bicrystalline primary starshape morphology; (2) primary array behavior, including the lateral propagation of the starshape grains and the associated evolution of a strong <100> texture; (3) the detailed structure of the 8-pointed star-shaped primary morphology, including the twin boundary configuration within the central core; (4) the mechanisms of lateral propagation and spacing adjustment during array evolution; and (5) the thermosolutal conditions (i.e. operating state) at the primary growth front, including composition and phase fraction in the vicinity of the primary tip.

  14. Refinement of primary Si in hypereutectic Al-Si alloys by intensive melt shearing

    Science.gov (United States)

    Zhang, Z.; Li, H.-T.; Stone, I. C.; Fan, Z.

    2012-01-01

    Hypereutectic Al-Si based alloys are gaining popularity for applications where a combination of light weight and high wear resistance is required. The high wear resistance arising from the hard primary Si particles comes at the price of extremely poor machine tool life. To minimize machining problems while exploiting outstanding wear resistance, the primary Si particles must be controlled to a uniform small size and uniform spatial distribution. The current industrial means of refining primary Si chemically by the addition of phosphorous suffers from a number of problems. In the present paper an alternative, physical means of refining primary Si by intensive shearing of the melt prior to casting is investigated. Al-15wt%Si alloy has been solidified under varying casting conditions (cooling rate) and the resulting microstructures have been studied using microscopy and quantitative image analysis. Primary Si particles were finer, more compact in shape and more numerous with increasing cooling rate. Intensive melt shearing led to greater refinement and more enhanced nucleation of primary Si than was achieved by adding phosphorous. The mechanism of enhanced nucleation is discussed.

  15. Thermodynamic evaluation of hypereutectic Al-Si (A390) alloy with addition of Mg

    Energy Technology Data Exchange (ETDEWEB)

    Hekmat-Ardakan, Alireza [Ecole Polytechnique de Montreal, Dep. de Genie Chimique, P.O. Box 6079, Centre-Ville, Montreal, Quebec, H3C 3A7 (Canada); Ajersch, Frank, E-mail: frank.ajersch@polymtl.ca [Ecole Polytechnique de Montreal, Dep. de Genie Chimique, P.O. Box 6079, Centre-Ville, Montreal, Quebec, H3C 3A7 (Canada)

    2010-05-15

    This paper presents the thermodynamic evaluation of A390 hypereutectic Al-Si alloy (Al-17% Si-4.5% Cu-0.5% Mg) and alloys up to 10% Mg, using the Factsage (registered) software. Two critical compositions were detected at 4.2% and 7.2% Mg where the temperatures of the liquidus, the start of the binary and of the ternary eutectic reaction are changed. These critical compositions show differences in the formation of Mg{sub 2}Si intermetallic particles during the solidification interval. For compositions up to 4.2% Mg, the Mg{sub 2}Si intermetallic phase first appears in the ternary eutectic zone. With Mg contents between 4.2% and 7.2%, Mg{sub 2}Si particle appears in both the binary and ternary eutectic reactions. Above 7.2% Mg, it solidifies as a primary phase and also during the binary and ternary reactions. The calculated liquid fraction vs. temperature curves also showed a decrease of the eutectic formation temperature (knee point temperature) with the addition of Mg content up to 4.2% Mg. This temperature becomes almost constant up to 10% Mg. The calculation of eutectic formation temperature shows a good agreement with differential scanning calorimetry (DSC) tests.

  16. Modification mechanism of hypereutectic Al-Si alloy with P-Na addition

    Institute of Scientific and Technical Information of China (English)

    吴树森; 涂小林; 福田葉椰; 菅野利猛; 中江秀雄

    2003-01-01

    Effect of P-Na united modification on Al-22%Si-1.0%Cu-0.5%Mg-0.5%Mn alloy was studied.The results show that the refining effect of P-Na addition on primary silicon is superior to that of P and the former could modify eutectic silicon at the same time.Effects of P-Na modification on crystallization and microstructure of hypereutectic Al-Si alloys were studied with Electron-Scanning Microscope,Electron-Probe and X-ray diffractometer.The modification mechanism represents that on one hand,the primary silicon is refined by AlP as heterogeneous nucleus;on the other hand,when Na is added at the same time,P atoms are difficult to diffuse in the melt,and then enrichs on the growing faces of silicon phase.Moreover,a SiP compound was also discovered in Si crystals,which prevents the growth of silicon phase and refines the primary silicon.

  17. Microstructure and mechanical properties of hypereutectic Al-Si alloy modified with Cu-P

    Institute of Scientific and Technical Information of China (English)

    ZHANG Henghua; DUAN Haiti; SHAO Guangjie; XU Luoping

    2008-01-01

    The microstructure and mechanical properties of Al-14.6Si castings modified by Cu-P master alloy under different conditions were studied with optical microscope (OM) and mechanical testing and simulation (MTS).The results indicate that the Cu-P master alloy possesses not only obvious modification effect,but also longevity effect with more than 8 h on the hypereutectic Al-Si alloy.It is shown from thermal calculation,scanning electron microscope (SEM),and energy dispersive analysis of X-rays (EDAX) that the modification mechanism of Cu-P on primary silicon in the castings is heterogeneous nucleation around AlP particles.The Cu-P master alloy has no or little modifying effect on eutectic silicon,even though it has obvious modification on primary silicon in the castings.This may be because of the fast transformation of eutectic silicon at a very narrow temperature,which will notably weaken the role of AlP particles as heterogeneous nuclei for eutectic silicon.

  18. Corrosion performance of Al-Si-Cu hypereutectic alloys in a synthetic condensed automotive solution

    Directory of Open Access Journals (Sweden)

    Hamilta de Oliveira Santos

    2005-06-01

    Full Text Available In this investigation the corrosion resistance of four Al-Si hypereutectic alloys in a solution typical of condensate from automotive fuel combustion products, and referred to here as synthetic condensed automotive solution, has been studied. Three commercial alloys that are used for cylinder liners, and a laboratory made alloy, were studied by electrochemical impedance spectroscopy and measurements were taken after increasing times of immersion in this solution. Comparison of the electrochemical response of the four alloys in the corrosive solution was carried out. Although the mechanisms by which the four alloys corroded were similar, the results indicated differences in corrosion resistances of these alloys, and these differences could be related to their microstructures. The laboratory prepared alloy showed increased susceptibility to pitting corrosion compared to the commercial alloys. The surfaces of the alloys were examined, before and after the corrosion test, by scanning electron microscopy and analyzed by energy dispersive spectroscopy. The results indicated preferential attack of the aluminium matrix phase in all the alloys. The alloy with higher copper content and prepared by spray forming was more susceptible to pitting compared to the other alloys. The EIS response at low frequencies indicated a diffusion-controlled process, probably that of oxygen to the alloy interface.

  19. AlSi7Mg连杆半固态挤压铸造成形数值模拟%Numerical Simulation of Semi-solid Squeeze Casting Forming AlSi7Mg Connecting Rod

    Institute of Scientific and Technical Information of China (English)

    朱晓红; 张卫东; 卢艳宏

    2012-01-01

    The semi-solid squeeze casting forming process of AlSi7Mg connecting rod was simulated by Ostaward-de WaeJe apparent viscosity model of Magmasoft software, and solidification process was analyzed. Through numerical simulation, effects of the pouring temperature, preheating mould temperature and extruding speed on performance of connecting rod was obtained. The results show that the optimized forming parameters of the semi-solid squeeze casting forming process of AlSi7Mg connecting rod are as follows: The pouring temperature is 576-585℃, the mould temperature is 200-250℃, the extruding speed is 0.1-0.5 mm/s. In the semi-solid squeeze casting forming process with aforementioned reasonable process parameters, the metal slurry flows equably, the time of solidification is short and the defects of AlSi7Mg connecting rod is less.%通过Magmasoft软件的Ostaward-de Waele粘度模型,对AlSi7Mg连杆的半固态挤压铸造成形过程进行了模拟,并对凝固过程进行了分析.通过数值模拟,获得了浇注温度、模具预热温度、冲头速度对连杆成形质量的影响规律.结果表明,优化的AlSi7Mg连杆半固态挤压铸造成形工艺参数为:浇注温度为576~585℃、模具温度为200~250℃、冲头速度为0.1~0.5m·s-1.在该工艺参数下进行半固态挤压铸造成形,金属浆料流动平稳,凝固时间较短,AlSi7Mg连杆铸件缺陷少.

  20. Caracterización mecánica y microestructural de nuevas aleaciones multifuncionales de Titanio B libres de Ni para aplicaciones biomédicas

    OpenAIRE

    Arciniegas Angarita, Milena Patricia; Peña, J.; Manero Planella, José María; Planell Estany, Josep Anton; Gil, F. J.

    2008-01-01

    El objetivo del presente trabajo es diseñar, obtener y caracterizar, mecánica y microestructuralmente, aleaciones de Ti en fase B , libre de Níquel, con memoria de forma y/o bajo módulo elástico para aplicaciones médicas. Con este propósito se utilizaron elementos aleantes biocompatibles, no tóxicos como Ta, Nb y Zr. Para el diseño de las aleaciones se uso uso de método teórico basado en orbitales moleculares resultando las aleaciones Ti-8Zr-19Nb y Ti-2Ta-11Nb. Las aleaciones fueron fabric...

  1. Effect of Tool Cutter Immersion on Al-Si Bi-Metallic Materials in High-Speed-Milling

    Directory of Open Access Journals (Sweden)

    J.H. Sokołowski

    2006-04-01

    Full Text Available Purpose: Aluminum-Silicon (Al-Si alloys are commonly used in the automotive industry. At high Si levels they offer good wear resistance. Abrasive wear however, has been identified as the main insert cutter damage mechanism during High-Speed-Milling (HSM. This study investigates the effect of the tool cutter immersion on Al-Si bi-metallic materials in HSM operation.Design/methodology/approach: This study considers the effects of the tool cutter immersion on the resultant cutting forces, associated machined surface roughness, and machined subsurface microstructural damage caused by the tool cutter during the Minimum Quantity Lubricant – High Speed Milling (MQL-HSM operation of Al-Si bi-metallic materials with varying amounts and morphologies of the silicon phase.Findings: Experimental results indicate that a combination of gray cast iron with the W319 microstructure yields the greatest resistance to the tool cutter rake face during the face milling operation for all investigated tool cutter radial immersions. Machined surface roughness measurements reveal that surface roughness is a function of both the silicon content and morphology, as well as the percentage of tool cutter immersion. Matrix hardness measurements indicate that machining at all immersions has the same effect on compressing the matrix structure.Research limitations/implications: This study considers the effects of the radial tooling immersion and material selection while the speed, feed, and axial depth-of-cut are kept constant. Future work should address variability in the machining parameters in an attempt to maximize tool life, while optimizing the machined surface quality.Practical implications: Material selection affects the machining conditions in HSM of Al-Si bi-metallic materials. As a result careful consideration should be given when tailoring the machining conditions to the cast microstructures.Originality/value: North American automakers rely heavily on Al-Si precision

  2. Crystallization of LiAlSiO4 Glass in Hydrothermal Environments at Gigapascal Pressures-Dense Hydrous Aluminosilicates.

    Science.gov (United States)

    Spektor, Kristina; Fischer, Andreas; Häussermann, Ulrich

    2016-08-15

    High-pressure hydrothermal environments can drastically reduce the kinetic constraints of phase transitions and afford high-pressure modifications of oxides at comparatively low temperatures. Under certain circumstances such environments allow access to kinetically favored phases, including hydrous ones with water incorporated as hydroxyl. We studied the crystallization of glass in the presence of a large excess of water in the pressure range of 0.25-10 GPa and at temperatures from 200 to 600 °C. The p and T quenched samples were analyzed by powder X-ray diffraction, scanning electron microscopy, and IR spectroscopy. At pressures of 0.25-2 GPa metastable zeolite Li-ABW and stable α-eucryptite are obtained at low and high temperatures, respectively, with crystal structures based on tetrahedrally coordinated Al and Si atoms. At 5 GPa a new, hydrous phase of LiAlSiO4, LiAlSiO3(OH)2 = LiAlSiO4·H2O, is produced. Its crystal structure was characterized from single-crystal X-ray diffraction data (space group P21/c, a = 9.547(3) Å, b = 14.461(5) Å, c = 5.062(2) Å, β = 104.36(1)°). The monoclinic structure resembles that of α-spodumene (LiAlSi2O6) and constitutes alternating layers of chains of corner-condensed SiO4 tetrahedra and chains of edge-sharing AlO6 octahedra. OH groups are part of the octahedral Al coordination and extend into channels provided within the SiO4 tetrahedron chain layers. At 10 GPa another hydrous phase of LiAlSiO4 with presently unknown structure is produced. The formation of hydrous forms of LiAlSiO4 shows the potential of hydrothermal environments at gigapascal pressures for creating truly new materials. In this particular case it indicates the possibility of generally accessing pyroxene-type aluminosilicates with crystallographic amounts of hydroxyl incorporated. This could also have implications to geosciences by representing a mechanism of water storage and transport in the depths of the Earth. PMID:27482770

  3. The Refining Effect of Al-Ti-B-Sr Master Alloy on the Al- Si - Mg Alloy%Al-Ti-B-Sr对Al-Si-Mg合金的变质细化作用

    Institute of Scientific and Technical Information of China (English)

    亓效刚; 王玉厚; 边秀房

    2000-01-01

    用快速凝固和热变形处理的Al-Ti-B-Sr中间合金.对Al-Si-Mg铝轮毂材料进行处理.试验结果表明:Al-Ti-B-Sr中间合金可以对Al-7Si-0.35Mg合金有效地细化与变质;改善Al-Ti-B-Sr的细化与变质效果,Al-Si-Mg合金的抗拉强度和延伸率较Al-Ti-B、Al-Sr两种中间合金分别加入时提高了约10%和25%.

  4. Production and behaviour of aluminium foams with different density by AlSi12 precursor; Fabricacion y comportamiento de espumas de aluminio con diferente densidad a partir de un precursor AlSi12

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez-Vazquez, J. A.; Onoro, J.

    2010-07-01

    Closed cell aluminium foams were prepared by powder metallurgical method in three different ranges of density using AlSi12 precursor. The objective has been to determine by means of tests the effect that has the density of these materials regarding its mechanical behaviour. The used precursor contained 0.4% of foaming agent of titanium hydride (TiH{sub 2}), mixed with aluminum and silicon in appropriate amounts to achieve the commercial composition of the AlSi12 precursor. Once cut the samples thermal treatments of foaming were made of 630 degree centigrade to 750 degree centigrade, by 3 to 20 minutes. The best solidification conditions were determined to avoid the collapse by means of forced air. The samples were prepared with the same weight to different densities, having itself obtained that the best mechanical behaviour was achieved in the high density foams, of 0.70 to 0.81 g/cm{sup 3}. (Author) 26 refs.

  5. Hydrogen bridging in the compounds X2H (X=Al,Si,P,S)

    Science.gov (United States)

    Owens, Zachary T.; Larkin, Joseph D.; Schaefer, Henry F.

    2006-10-01

    X2H hydrides (X =Al, Si, P, and S) have been investigated using coupled cluster theory with single, double, and triple excitations, the latter incorporated as a perturbative correction [CCSD(T)]. These were performed utilizing a series of correlation-consistent basis sets augmented with diffuse functions (aug-cc-pVXZ, X =D, T, and Q). Al2H and Si2H are determined to have H-bridged C2v structures in their ground states: the Al2H ground state is of B12 symmetry with an Al-H-Al angle of 87.6°, and the Si2H ground state is of A12 symmetry with a Si-H-Si angle of 79.8°. However, P2H and S2H have nonbridged, bent Cs structures: the P2H ground state is of A'2 symmetry with a P-P-H angle of 97.0°, and the S2H ground state is of A'2 symmetry with a S-S-H angle of 93.2°. Ground state geometries, vibrational frequencies, and electron affinities have been computed at all levels of theory. Our CCSD(T)/aug-cc-pVQZ adiabatic electron affinity of 2.34eV for the Si2H radical is in excellent agreement with the photoelectron spectroscopy experiments of Xu et al. [J. Chem. Phys. 108, 7645 (1998)], where the electron affinity was determined to be 2.31±0.01eV.

  6. Microstructure and microhardness evolution of melt-spun Al-Si-Cu alloy

    Science.gov (United States)

    Ahmed, Emad M.; Ebrahim, M. R.

    2014-04-01

    Al-11 wt.% Si-11 wt.% Cu (11.29 at.% Si-5.1 at.% Cu) melt was rapidly solidified into ribbons and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and microhardness technique. The Rietveld X-ray diffraction analysis was applied successfully to analyze the microstructure and phase precipitations. The high cooling rate obtained in rapid solidification has a significant influence on the microstructure and microhardness of this alloy. On the basis of the Al peaks shift measured in the XRD scans, a solid solubility extension value of 3.95 at.% Si and 3.54 at.% Cu in α-Al were determined. No XRD peaks of the Si phase have been detected. XRD peaks of the intermetallic Al2Cu phase have been observed clearly with estimated content of 12.6 wt.%. During prolonged annealing process at 350°C/25 h, XRD peaks of the Si phase clearly appeared with estimated content of 8.6 wt.% and, moreover, the Al2Cu phase content increased to 16 wt.%. The estimated crystallite size and micro-strain % of α-Al are 30 nm and 0.056, respectively. The melt-spun wheel side ribbon represents ultra-fine microstructure with particles size less than 1μm and exhibits enhancement of hardness to 241 HV. Hardness has further increased to 291 HV during heat treatment (150°C/12 h). Rapid solidification exhibited a great influence on microstructure and microhardness of the Al-Si-Cu alloy.

  7. Metallurgical Parameters Controlling the Eutectic Silicon Charateristics in Be-Treated Al-Si-Mg Alloys

    Directory of Open Access Journals (Sweden)

    Mohamed F. Ibrahim

    2016-01-01

    Full Text Available The present work was carried out on Al-7%Si-0.4%Mg-X alloy (where X = Mg, Fe, Sr or Be, where the effect of solidification rate on the eutectic silicon characteristics was investigated. Two solidification rates corresponding to dendrite arm spacings (DAS of 24 and 65 μm were employed. Samples with 24 μm DAS were solution heat-treated at 540 °C for 5 and 12 h prior to quenching in warm water at 65 °C. Eutectic Si particle charateristics were measured using an image analyzer. The results show that the addition of 0.05% Be leads to partial modification of the Si particles. Full modification was only obtained when Sr was added in an amount of 150–200 ppm, depending on the applied solidification rate. Increasing the amount of Mg to 0.8% in Sr-modified alloys leads to a reduction in the effectiveness of Sr as the main modifier. Similar observations were made when the Fe content was increased in Be-treated alloys due to the Be-Fe interaction. Over-modification results in the precipitation of hard Sr-rich particles, mainly Al4SrSi2, whereas overheating causes incipient melting of the Al-Cu eutectic and hence the surrounding matrix. Both factors lead to a deterioration in the alloy mechanical properties. Furthermore, the presence of long, acicular Si particles accelerates the occurrence of fracture and, as a result, yields poor ductility. In low iron (less than 0.1 wt% Al-Si-Mg alloys, the mechanical properties in the as cast, as well as heat treated conditions, are mainly controlled by the eutectic Si charatersitics. Increasing the iron content and, hence, the volume fraction of Fe-based intermetallics leads to a complex fracture mode.

  8. Influencia de la distribución de las fibras en la conductividad térnnica de materiales compuestos con matrices de aleaciones de titanio y de magnesio

    Directory of Open Access Journals (Sweden)

    Alcaraz, D.

    2005-12-01

    Full Text Available Metal matrix composites are materials with an increasing use in industrial applications. Generally, the estimation of their thermal conductivity does not take into account the type of reinforcements distribution within the matrix. By applying the Network Simulation Method, a 2-D network model is designed and simulated to determinate precise numerical values of thermal conductivity of composites with random distributions. The proposed model is applied to titanium and magnesium matrix composites reinforced with different types of continuous fibers.

    Los "composites" de matriz metálica son materiales de uso creciente en distintas aplicaciones industriales. En general, la determinación de su conductividad térmica no considera el tipo de distribución de los refuerzos en el seno de las matrices. Aplicando el Método de Redes, se diseña un modelo (2D cuya simulación numérica permite obtener valores precisos de conductividad en "composites" con distribuciones aleatorias. El modelo se aplica a "composites" con matrices de aleaciones de titanio y magnesio reforzados con diferentes tipos de fibras continuas.

  9. Numerical simulation of thermal-mechanical process of Al-Si-Pb alloy treated by high current pulsed electron beam

    Institute of Scientific and Technical Information of China (English)

    L(U) Xiao-xia; LI Rong-guang; AN Jian

    2006-01-01

    The modified microstructure of Al-Si-Pb alloys irradiated by high current electron beam (HCPEB) reveals three distinct regions: a molten zone, an overlapped zone of heat-affected and quasistatic thermal stress-affected zone, and a transition zone followed by the substrate. The hardness and wear properties of the alloys were significantly improved. To better understand these changes in microstructure and properties, the physical model for the simulation of temperature and quasistatic stress fields was established. Based on experimental investigation and physical models, the temperature field and stress field were simulated for Al-Si-Pb alloy. The starting melting position, largest crater depth, melting layer thickness, and quasistatic stress distribution were obtained. These results reveal the mechanism of crater formation on the surface and improvement of hardness and wear resistance.

  10. Microstructure and phase constitution near the interface of Cu/3003 torch brazing using Al Si La Sr filler

    International Nuclear Information System (INIS)

    It has been mainly studied in this paper on brazing of Cu to Al using Al.Si filler metal. The optimized scanning rate of 2.5 mm/s is first obtained through simulating the temperature field of Cu Al brazing process based on ANSYS software. Then the brazing of Cu C11000 to Al 3003 using Al.Si.La.Sr filler is carried out by torch brazing technology. It is found that the brazing seam region is mainly consisted of α Al solid solution and CuAl2 IMC. Further experimental results also show that the rare earth element La in filler metal can not only refine the grain, but also promote the dispersion of intermetallic compounds into the brazing seam, which significantly improves the brazing seam microstructure and mechanical properties of the joints

  11. AlSi17Cu5Mg alloy as future material for castings of pistons for internal combustion engines

    Directory of Open Access Journals (Sweden)

    J. Piątkowski

    2015-07-01

    Full Text Available The paper presents chosen properties and microstructure of AlSi17Cu5Mg alloy as future material for casting pistons in automotive industry. Tests were conducted to elaborate technology of preparation, assessment of crystallisation parameters and shaping the primary structure of the silumin with the aim to improve the working parameters and the functioning efficiency in cylinder-piston system. Refinement of Si crystals, achieved due to overheating above the temperature Tliq. causes that the alloy reaches satisfactory properties in working chamber of the engine are optimised. Such condition of material characteristics causes that hypereutectic silumins, for chosen applications in transport, may serve as an alternative to Al - Si alloys of hypoeutectic and near - eutectic type.

  12. Effect of applied pressure on the quality of squeeze cast parts made from AlSi9Mg alloy

    Directory of Open Access Journals (Sweden)

    T. Reguła

    2011-07-01

    Full Text Available The results of the study of an influence of pressure in the direct squeeze casting process on the physical and mechanical properties of an AlSi9Mg alloy are presented. The specimens were made by casting the tested AlSi9Mg alloy under the conditions of variable squeeze pressure, using a PHM 160c type hydraulic press. Analyzing the results of the experiment, it has been found that, the applied pressure has an important impact on the quality of castings squeezed in liquid state. The effect of squeeze pressure proves the advisability of continuing the application of various liquid-phase methods using external pressure to improve the properties of castings produced.

  13. Synthesis and characterization of Al/SiC and Ni/Al2O3 functionally graded materials

    International Nuclear Information System (INIS)

    Two-multilayered functionally graded materials (FGMs), namely aluminium-silicon carbide (Al/SiC) and nickel-alumina (Ni/Al2O3) systems are designed, synthesized and characterized considering 10, 20, 30 and 40 vol.% ceramic concentrations. Two, three and five-layered FGMs are fabricated into flat beam samples following powder metallurgy route for Al/SiC and thermal spraying technique for Ni/Al2O3 system. Apart from microstructural studies, porosity content and microhardness are also determined. Three bulk properties are evaluated for FGM characterizations, namely effective flexural strength, thermal fatigue behavior and thermal shock resistance. Progressive and appreciable enhancement in FGM performance is observed as the number of layers is increased from two to five keeping the extreme layers same. Microhardness variation across the interfaces is found to be consistent with the analytically obtained jump in the inplane stresses at the interfaces

  14. The Microstructures and Properties of SiC/Al2O3/Al-Si Composites Prepared by Reactive Penetration

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xi-ya

    2004-01-01

    The composition, microstructures and properties of SiC /Al2O3/Al-Si composites formed by reactive penetration of the molten aluminum into the preforms of SiO2 and SiC were investigated. The composition of the composites was measured by X-ray diffraction (XRD). The microstructures of the composites were also measured by scanning electron microscopy (SEM) and optical microscopy. In addition, the factors affecting the properties of the composites were discussed.The experiments show that the mechanical properties of the composites depend on their relative densities and the sizes of the fillers"SiC grains".The denser the SiC/Al2O3/Al-Si composites,the higher their bending strength.As the filler "SiC grains" become fine,the bending strength of the composites increases.

  15. Aluminium EN AC-AlSi12 alloy matrix composite materials reinforced by Al2O3 porous preforms

    OpenAIRE

    Nagel, A.; M. Kremzer; L.A. Dobrzański,

    2007-01-01

    Purpose: The purpose of this work is to elaborate the method of manufacturing of composite materials based on porous ceramic preforms infiltrated by eutectic aluminium alloy.Design/methodology/approach: The material for investigations was fabricated by pressure infiltration method of ceramic porous preforms. The eutectic aluminium alloy EN AC – AlSi12 was use as a matrix while as reinforcement were used ceramic preforms fabricated by sintering of Al2O3 Alcoa CL 2500 powder with addition of po...

  16. On the performance of a novel grain refiner in hyper-eutectic Al-Si cast alloys

    OpenAIRE

    Bolzoni, L.; Nowak, M.; Hari Babu, N

    2014-01-01

    The stringent requirements for pollution reduction are pushing the automotive industry towards the employment of lightweight structures and, therefore, aluminium and its alloys play a remarkable role. Al-Si casting alloy with eutectic or hyper- eutectic compositions are, normally, employed for the production of high performance automotive products such as pistons and engine blocks which have to withstand critical loading conditions (i.e. high temperature, high pressure and corrosive exhaust g...

  17. Accuracy of Ceramic Mould Filling with Liquid AlSi9 Aluminium Alloy in the Process Using Back-pressure

    OpenAIRE

    A. Karwiński; R. Haratym; R. Biernacki

    2013-01-01

    The paper presents the effect of suction pressure exerted on the liquid AlSi alloy when it is introduced into a ceramic mould made in the investment process and the results compared with data obtained on gravity poured castings.The study used special pattern sets and ceramic moulds made with the alternately applied soluble silicate binder and ethyl silicate.Additionally, self-supported moulds based entirely on the Ekosil binder were used. In the analysis of castings, the following parameters ...

  18. Texture, microstructure and anti-wear characteristics in isostructural CrAlSiN/W2N multilayer coatings

    International Nuclear Information System (INIS)

    CrAlSiN/W2N multilayer coatings are fabricated periodically by DC magnetron sputtering. Crystal phases and preferred orientations of thin films are characterized by an X-ray diffractometer. The microstructure of multilayer coatings is examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. Through high-resolution and dark-field TEM images, superlattice characteristics in multilayer coating are demonstrated. Owing to the densified architecture and interfacial strengthening with plenty of interfaces, CrAlSiN/W2N multilayer coatings exhibit superior mechanical responses. With an appropriate bilayer period of 8 nm, the hardness boosts to a maximum around 41 GPa. In the ball-on-disk wear tests, it's found that all the multilayer coatings exhibit preferable anti-wear and friction characteristics, especially the one with a bilayer period of 20 nm. The worn surface of CrAlSiN monolayer is severely damaged with lots of cracks and delaminations, while that of multilayer coating is intact. Only thickness reduction in multilayer coating is observed in the cross-sectional view of wear scar. An anti-wear mechanism on the basis of microstructure evolution is proposed to elucidate the favorable durability in such a particular multilayer system. - Highlights: • Unusual CrAlSiN/W2N multilayers are fabricated by DC magnetron sputtering. • Superlattice characteristics are demonstrated. • Hardness reaches a maximum around 41 GPa in multilayer. • Hybrid anti-wear mechanisms are proposed to elucidate the favorable durability

  19. Influence of the Chemical Composition on Electrical Conductivity and Mechanical Properties of the Hypoeutectic Al-Si-Mg Alloys

    OpenAIRE

    Dybowski B.; Szymszal J.; Poloczek Ł.; Kiełbus A.

    2016-01-01

    Due to low density and good mechanical properties, aluminium alloys are widely applied in transportation industry. Moreover, they are characterized by the specific physical properties, such as high electrical conductivity. This led to application of the hypoeutectic Al-Si-Mg alloys in the power generation industry. Proper selection of the alloys chemical composition is an important stage in achievement of the demanded properties. The following paper presents results of the research on the inf...

  20. The influence of remelting on the properties of AlSi6Cu4 alloy modified by antimony

    OpenAIRE

    D. Medlen; D. Bolibruchova

    2012-01-01

    The paper deals with the problem of multiple remelting influence on AlSi6Cu4 alloy modified by antimony on chosen mechanical characteristics, microstructure and gas content. This foundry alloy is used mostly in automotive industry. Foundry Aluminum-Silicon alloys are also used in number of industrial weight sensitive applications because of their low weight and very good castability and good mechanical properties. Modifiers are usually added to molten aluminum-silicon alloys to refine the eut...

  1. Synthesis and Study on Effect of Parameters on Dry Sliding Wear Characteristics of AL-SI Alloys

    OpenAIRE

    Francis Uchenna OZIOKO

    2012-01-01

    The effect of parameters on dry sliding wear characteristics of Al-Si alloys was studied. Aluminium-silicon alloys containing 7%, 12% and 14% weight of silicon were synthesized using casting method. Dry sliding wear characteristics of sample were studied against a hardened carbon steel (Fe-2.3%Cr-0.9%C) using a pin-on-disc. Observations were recorded keeping two parameters (sliding distance, sliding speed and load) constant against wear at room temperature. Microstructural characterization wa...

  2. Cerium-, terbium- and europium-activated CaScAlSiO6 as a full-color emitting phosphor

    International Nuclear Information System (INIS)

    We reported a single-phased CaScAlSiO6:Ce3+, Tb3+, Eu3+ as a potential full-color emitting phosphor for the application in fluorescent lamps. The CaScAlSiO6:Ce3+, Tb3+, Eu3+ phosphor exhibits three bands under 254 nm excitation: one band situated at 380 nm is attributed to the 5d→4f transitions of Ce3+ ions, the second band with sharp lines peaked at 542 nm is assigned to the 5D4→7FJ transitions of Tb3+ ions, the third band in the orange–red region (580–700 nm) is originated from 5D0→7FJ transitions of Eu3+ ions. The Commission Internationale de I’Eclairage (CIE) chromaticity coordinates (0.30, 0.30) and high color rendering index (CRI=88) can be achieved upon excitation of 254 nm light. It is suggested that CaScAlSiO6:Ce3+, Tb3+, Eu3+ can serve as a potential single-phased full-color emitting phosphor for phosphor-converted fluorescent lamps. -- Highlights: • A novel full-color emitting phosphor CaScAlSiO6:Ce3+, Tb3+, Eu3+ are synthesized and investigated. • The obtained phosphor exhibits three emission bands. • The CIE chromaticity coordinates (0.30, 0.30) and high color rendering index CRI=88 can be achieved. • These results indicated that CSAS:Ce3+, Tb3+, Eu3+ is a promising single-composition full-color emitting phosphor

  3. Effect of Electromagnetic Vibration on the Agglomeration Behavior of Primary Silicon in Hypereutectic Al-Si Alloy

    Science.gov (United States)

    Han, Yecong; Li, Qiulin; Liu, Wei; He, Yanjie

    2012-05-01

    An experimental apparatus that enables the simultaneous application of an alternating electric field and a stationary magnetic field was developed. Electromagnetic vibration was induced in a hypereutectic Al-Si alloy melt during solidification at a constant cooling rate. The results showed that the silicon particles collide with each other and agglomerate into clusters with the application of an electromagnetic vibration. With the increase of the electromagnetic force F, the sizes of the silicon clusters decrease and the clusters become more compact.

  4. An electrochemical investigation of the corrosion behavior of Al-Si-Cu hypereutectic alloys in alcoholic environments

    OpenAIRE

    Traldi, S. M.; J. L Rossi; Costa, I.

    2003-01-01

    Al-Si-Cu hypereutetic alloys produced by spray forming are mostly used in the automotive industry, especially for cylinder liners. They have the advantage of low weight associated with low coefficient of thermal expansion and excellent mechanical properties - mainly wear resistance at high temperatures. The corrosion resistance of these alloys in fuels, particularly alcoholic media, however is not yet known. In this investigation, electrochemical impedance spectroscopy (EIS) and potentiodynam...

  5. Density, Viscosity, and Diffusion Coefficients in Hypoeutectic Al-Si Liquid Alloys: An Assessment of Available Data

    Science.gov (United States)

    Poirier, David R.

    2014-08-01

    This article is a review of empirical and calculated data on density, viscosity, and diffusion coefficients in hypereutectic Al-Si liquid alloys. Many regressions of the data were effected in order to consolidate the data as functions, which can be used to calculate each property as a function of temperature and concentration of Si. The chemical diffusion coefficient in the alloys was derived based on the Sutherland model, which relates the diffusion coefficient to viscosity.

  6. Formation of hypereutectic silicon particles in hypoeutectic Al-Si alloys under the influence of high-intensity ultrasonic vibration

    OpenAIRE

    Xiaogang Jian; Qingyou Han

    2013-01-01

    The modification of eutectic silicon is of general interest since fine eutectic silicon along with fine primary aluminum grains improves mechanical properties and ductilities. In this study, high intensity ultrasonic vibration was used to modify the complex microstructure of aluminum hypoeutectic alloys. The ultrasonic vibrator was placed at the bottom of a copper mold with molten aluminum. Hypoeutectic Al-Si alloy specimens with a unique in-depth profile of microstructure distribution were o...

  7. Microstructural refinement of hyper-eutectic Al?Si?Fe?Mn cast alloys to produce a recyclable wrought material

    OpenAIRE

    Umezawa, Osamu; Nakamoto, Munefumi; Osawa, Yoshiaki; Suzuki, Kenta; Kumai, Shinji

    2005-01-01

    Although the cascade of material flow is presently suitable for the aluminum recycling, a better utilization of secondary alloys is required. In order to establish an upgradeable recycling design for developing wrought products from secondary aluminum alloys, a fine distribution of the primary phases in hyper-eutectic Al?Si?Fe?Mn cast materials has been achieved. Two novel processes were adopted. One was repeated thermomechanical treatment (RTMT), which involves a repetition of a multi-step c...

  8. Breaking through the strength-ductility trade-off dilemma in an Al-Si-based casting alloy.

    Science.gov (United States)

    Dang, B; Zhang, X; Chen, Y Z; Chen, C X; Wang, H T; Liu, F

    2016-01-01

    Al-Si-based casting alloys have a great potential in various industrial applications. Common strengthening strategies on these alloys are accompanied inevitably by sacrifice of ductility, known as strength-ductility trade-off dilemma. Here, we report a simple route by combining rapid solidification (RS) with a post-solidification heat treatment (PHT), i.e. a RS + PHT route, to break through this dilemma using a commercial Al-Si-based casting alloy (A356 alloy) as an example. It is shown that yield strength and elongation to failure of the RS + PHT processed alloy are elevated simultaneously by increasing the cooling rate upon RS, which are not influenced by subsequent T6 heat treatment. Breaking through the dilemma is attributed to the hierarchical microstructure formed by the RS + PHT route, i.e. highly dispersed nanoscale Si particles in Al dendrites and nanoscale Al particles decorated in eutectic Si. Simplicity of the RS + PHT route makes it being suitable for industrial scaling production. The strategy of engineering microstructures offers a general pathway in tailoring mechanical properties of other Al-Si-based alloys. Moreover, the remarkably enhanced ductility of A356 alloy not only permits strengthening further the material by work hardening but also enables possibly conventional solid-state forming of the material, thus extending the applications of such an alloy. PMID:27502444

  9. Micro-yield behaviors of Al2O3-SiO2(sf)/Al-Si metal matrix composites

    Institute of Scientific and Technical Information of China (English)

    LIU Guan-jun; LI Wen-fang; PENG Ji-hua; DU Jun

    2007-01-01

    Effects of the volume fraction and the size of crystallized alumina silicate short fibers as well as heat treatment processes on micro-yield strength(MYS) of Al2O3-SiO2(sf)/Al-Si metal matrix composite(MMC) that was fabricated by squeezing cast, were investigated by using continuous loading method on an Instron 5569 tester with a special extensometer with an accuracy of 10-7. The results show that MYS of MMC decreases with the increase of volume fraction and length of the alumina silicate short fibers in the metal matrix composite, respectively. MYS of quenched Al2O3-SiO2(sf)/Al-Si MMC is the lowest, MYS of the MMC through peak-aging treatment is higher than that through other heat treatment methods. And before the peak-aging, MYS of MMC aging treated gradually increases with the increase of the aging time. Aging treatment after solution treatment is a preferred way that enhances micro and macro-yield strength of Al2O3-SiO2(sf)/Al-Si MMC.

  10. Effect of graphite and transition elements (Cu, Ni) on high temperature tensile behaviour of Al-Si Alloys

    International Nuclear Information System (INIS)

    Highlights: → High temperature tensile studies up to 300 deg. C. → Brittle to ductile failure mode transition takes place at a temperature of beyond 200 deg. C for alloy and for composites; mixed mode of fracture is observed beyond 200 deg. C. → Strain hardening exponent value is decreased with increasing temperature. → Ultimate tensile strength of composite is higher than that of alloy for all testing temperatures. - Abstract: The high temperature tensile behaviour of Al-Si alloy and Al-Si alloy reinforced with graphite particulate was investigated. The composite was developed by stir casting method. Tensile behaviour of alloy and composite were studied at different temperatures from room temperature to 300 deg. C. It was found that the tensile strength of alloy and composites were decreasing with increase in temperature. It was further noticed that Al-Si alloy with graphite and transition elements was stronger than alloy. The % elongation of the alloy was more than that of composites. The fractographic observations of fracture surface was analysed by scanning electron microscopy to understand the fracture mechanisms. Fractography revealed that the fracture behaviour of alloy changed from cleavage mode at room temperature to complete ductile mode at high temperature.

  11. Structure determination of the hexagonal quasicrystal approximant μ'-(Al,Si)4Cr by the strong reflections approach

    International Nuclear Information System (INIS)

    A number of different crystalline phases have been found in Al-rich Al-Cr-Si alloys by transmission electron microscopy (TEM). Among these, the new hexagonal phase μ'-(Al,Si)4Cr (a=2.01 and c=1.24 nm) often found coexisting with the hexagonal μ-(Al,Si)4Cr (a=1.998 and c=2.4673 nm, isostructural with μ-Al4Mn) and also with the hexagonal λ-(Al,Si)4Cr (a=2.839 and c=1.239 nm, isostructural with λ-Al4Mn). It is evident from their electron diffraction patterns that the structures of these three phases are related. The strong reflections in all three are distributed in a similar way. They all exhibit a pseudo-icosahedral symmetry. The structure factor amplitudes and phases for the strong reflections of the μ' phase could therefore be adopted from those of the λ phase, according to the strong reflections approach. A structure model of the μ' phase is thus deduced from the known λ-Al4Mn. μ' consists of chains of 3+3 or 4+2 interpenetrated icosahedra along the directions. Similar to the λ phase, there are two flat layers (F) and four puckered layers (P) in each unit cell of μ', stacked along the c-axis in a sequence of PFP(PFP)' where the (PFP)' block is related to the PFP block by a 63 screw

  12. Breaking through the strength-ductility trade-off dilemma in an Al-Si-based casting alloy

    Science.gov (United States)

    Dang, B.; Zhang, X.; Chen, Y. Z.; Chen, C. X.; Wang, H. T.; Liu, F.

    2016-08-01

    Al-Si-based casting alloys have a great potential in various industrial applications. Common strengthening strategies on these alloys are accompanied inevitably by sacrifice of ductility, known as strength-ductility trade-off dilemma. Here, we report a simple route by combining rapid solidification (RS) with a post-solidification heat treatment (PHT), i.e. a RS + PHT route, to break through this dilemma using a commercial Al-Si-based casting alloy (A356 alloy) as an example. It is shown that yield strength and elongation to failure of the RS + PHT processed alloy are elevated simultaneously by increasing the cooling rate upon RS, which are not influenced by subsequent T6 heat treatment. Breaking through the dilemma is attributed to the hierarchical microstructure formed by the RS + PHT route, i.e. highly dispersed nanoscale Si particles in Al dendrites and nanoscale Al particles decorated in eutectic Si. Simplicity of the RS + PHT route makes it being suitable for industrial scaling production. The strategy of engineering microstructures offers a general pathway in tailoring mechanical properties of other Al-Si-based alloys. Moreover, the remarkably enhanced ductility of A356 alloy not only permits strengthening further the material by work hardening but also enables possibly conventional solid-state forming of the material, thus extending the applications of such an alloy.

  13. Development of dispersion U(Mo)/Al-Si miniplates fabricated at 500 °C with Al 6061 as cladding

    Science.gov (United States)

    Mirandou, M. I.; Aricó, S. F.; Balart, S. N.; Fabro, J. O.

    2015-02-01

    In the frame of U(Mo) dispersion fuel elements qualification, Si additions to Al matrix arose as a promising solution to the unacceptable failures found when pure Al is used. Analysis of as-fabricated fuel plates made with Al-Si matrices demonstrated that good irradiation behavior is correlated with the formation during fabrication of a Si-containing interaction layer around the U(Mo) particles. Thus, the analysis of the influence of fabrication parameters becomes important. Studies on Al-Si dispersion miniplates fabricated in CNEA, Argentina, have been initiated to determine how to obtain the better interaction layer characteristics with the lesser modifications to the fabrication process and the smaller amount of Si in the matrix. In this work results for miniplates made of atomized U-7 wt%Mo particles dispersed in Al-2 wt%Si and Al-4 wt%Si matrices, obtained by mixing pure Al and Si powders, and Al 6061 as cladding are presented. Interaction layer grown during fabrication process (500 °C) consists of Si-containing phases being U(Al, Si)3 its principal component. Its uniformity is not satisfactory due to the formation of an oxide layer.

  14. Effect of dispersion hardening on impact resistance of EN AC-AlSi12Cu2Fe silumin

    Directory of Open Access Journals (Sweden)

    J. Pezda

    2009-04-01

    Full Text Available Development of modern technology have generated supply of better and better, more resistant structural materials not attainable earlier.Weight of metal structures is of a great importance, and as a consequence, also weight of materials used for a given structure. More often, for metal structures are used lightweight metals and their alloys, from which aluminum and its alloys have become the most widespread. These alloys, based on Al-Si equilibrium system, contain additional constituents (e.g.: Mg, Cu enabling, except modification,improvement of mechanical properties obtained in result of heat treatment. The paper presents an effect of modification process and heat treatment on impact resistance of EN AC-AlSi12Cu2Fe alloy. Solutioning and ageing temperatures were selected on base of registered curves of the ATD method. For the neareutectic EN AC-AlSi12Cu2Fe silumin one obtained growth of the impact resistance both due to performed modification treatment and performed heat treatments of the alloy.

  15. Nucleation Effects in Thermally Managed Graphite Fiber-Reinforced Al-Cu and Al-Si Composites

    Science.gov (United States)

    Seong, H. G.; Lopez, H. F.; Gajdardziska-Josifovska, M.; Rohatgi, P. K.

    2007-11-01

    The influence of heat extraction through fiber reinforcements on the resultant solidification morphologies was investigated in cast Al-Cu and Al-Si alloy composites reinforced with graphite fibers (GRFs). For this purpose, the GRFs were externally cooled by exposing their ends to ambient air during pressure infiltration. It was found that in the Al-Cu system, heat extraction through the fiber ends promoted the development of single α-Al envelopes around the GRFs. In particular, radial growth of the α envelopes occurred with a planar solid/liquid solidification front as a result of heat extraction. Apparently, the high thermal conductivity of GRFs causes significant heat extraction to enable the development of a positive temperature gradient at the GRF/melt interface. High-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAD) unveiled the occurrence of (002) α-Al//(0002)GR orientation relationship at α-Al/GRF interfaces. Preferential nucleation of primary Si along the graphite surfaces of the GRF-reinforced Al-Si alloy composite was also promoted by external fiber heat extraction. However, in this case, numerous nucleation events along the fiber interfaces were common, as well as nucleation at active substrates within the constrained melt. Finally, differential thermal analysis (DTA) indicated that the onset temperatures for nucleation shift toward higher values (by 7 °C for the Al-Cu composite and 2 °C for the Al-Si composite) when compared with their corresponding matrix alloys.

  16. Thermodynamics of open networks: Ordering and entropy in NaAlSiO4 glass, liquid, and polymorphs

    Science.gov (United States)

    Richet, P.; Robie, R.A.; Rogez, J.; Hemingway, B.S.; Courtial, P.; Tequi, C.

    1990-01-01

    The thermodynamic properties of carnegieite and NaAlSiO4 glass and liquid have been investigated through Cp determinations from 10 to 1800 K and solution-calorimetry measurements. The relative entropies S298-S0 of carnegieite and NaAlSiO4 glass are 118.7 and 124.8 J/mol K, respectively. The low-high carnegieite transition has been observed at 966 K with an enthalpy of transition of 8.1??0.3 kJ/mol, and the enthalpy of fusion of carnegieite at the congruent melting point of 1799 K is 21.7??3 kJ/mol. These results are consistent with the reported temperature of the nepheline-carnegieite transition and available thermodynamic data for nepheline. The entropy of quenched NaAlSiO4 glass at 0 K is 9.7??2 J/mol K and indicates considerable ordering among AlO4 and SiO4 tetrahedra. In the liquid state, progressive, temperature-induced Si, Al disordering could account for the high configurational heat capacity. Finally, the differences between the entropies and heat capacities of nepheline and carnegieite do not seem to conform to current polyhedral modeling of these properties ?? 1990 Springer-Verlag.

  17. An electrochemical investigation of the corrosion behavior of Al-Si-Cu hypereutectic alloys in alcoholic environments

    International Nuclear Information System (INIS)

    Al-Si-Cu hypereutectic alloys produced by spray forming are mostly used in the automotive industry, especially for cylinder liners. they the advantage of low weight associated with low coefficient of thermal expansion and excellent mechanical properties- mainly wear resistance at high temperatures. The corrosion s resistance of these alloys in fuels, particularly alcoholic media, however is not yet known. In this investigation, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarisation hove been used to evaluate the corrosion resistance of a hyper eutectic Al-Si-Cu alloy in alcoholic environments. the EIS tests carried out in pure ethanol, and ethanol with small additions (1 mM) of acid an chloride to investigate the effect of these contaminants on corrosion resistance. The corrosion resistance of a grey cast iron has also been evaluated in pure ethanol for comparison. The Al-Si-Cu alloy showed high corrosion resistance in pure ethanol, far superior to that of grey cast iron in the same medium. (Author) 13 refs

  18. An electrochemical investigation of the corrosion behavior of Al-Si-Cu hypereutectic alloys in alcoholic environments

    Energy Technology Data Exchange (ETDEWEB)

    Traldi, S. M.; Rossi, J. L.; Costa, I.

    2003-07-01

    Al-Si-Cu hypereutectic alloys produced by spray forming are mostly used in the automotive industry, especially for cylinder liners. they the advantage of low weight associated with low coefficient of thermal expansion and excellent mechanical properties- mainly wear resistance at high temperatures. The corrosion s resistance of these alloys in fuels, particularly alcoholic media, however is not yet known. In this investigation, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarisation hove been used to evaluate the corrosion resistance of a hyper eutectic Al-Si-Cu alloy in alcoholic environments. the EIS tests carried out in pure ethanol, and ethanol with small additions (1 mM) of acid an chloride to investigate the effect of these contaminants on corrosion resistance. The corrosion resistance of a grey cast iron has also been evaluated in pure ethanol for comparison. The Al-Si-Cu alloy showed high corrosion resistance in pure ethanol, far superior to that of grey cast iron in the same medium. (Author) 13 refs.

  19. Revealing heterogeneous nucleation of primary Si and eutectic Si by AlP in hypereutectic Al-Si alloys

    Science.gov (United States)

    Li, Jiehua; Hage, Fredrik S.; Liu, Xiangfa; Ramasse, Quentin; Schumacher, Peter

    2016-04-01

    The heterogeneous nucleation of primary Si and eutectic Si can be attributed to the presence of AlP. Although P, in the form of AlP particles, is usually observed in the centre of primary Si, there is still a lack of detailed investigations on the distribution of P within primary Si and eutectic Si in hypereutectic Al-Si alloys at the atomic scale. Here, we report an atomic-scale experimental investigation on the distribution of P in hypereutectic Al-Si alloys. P, in the form of AlP particles, was observed in the centre of primary Si. However, no significant amount of P was detected within primary Si, eutectic Si and the Al matrix. Instead, P was observed at the interface between the Al matrix and eutectic Si, strongly indicating that P, in the form of AlP particles (or AlP ‘patch’ dependent on the P concentration), may have nucleated on the surface of the Al matrix and thereby enhanced the heterogeneous nucleation of eutectic Si. The present investigation reveals some novel insights into heterogeneous nucleation of primary Si and eutectic Si by AlP in hypereutectic Al-Si alloys and can be used to further develop heterogeneous nucleation mechanisms based on adsorption.

  20. Magnetic Exchange-Coupled Sm(Co,R)/Cr (R=Al, Si, Ti, Nb, Cu) Series Films for Ultrahigh-Density Longitudinal Recording Media

    Institute of Scientific and Technical Information of China (English)

    王翔; 李佐宜; 李震; 蔡长波; 黄志新; 廖红伟; 王浩敏; 林更琪

    2003-01-01

    SmCoR (R=Al,Si, Ti,Nb, Cu)/Cr series films were fabricated as one kind of promising materials for the ultrahigh density longitudinal magnetic recording media. The Sm(Co,Al, Si)/Cr thin films with coercivity up to 2.36 kOe, squareness ratio S near 0.94 and coercive squareness ratio S* about 0.9 were obtained. The Cr interlayer caused magnetic decoupling in Sm(Co,Al,Si)/Cr/Sm(Co,Al,Si) thin films. High coercivity of 3400-3840 Oe and extremely fine grain size of 5-8 nm for the magnetic layer were examined. Using different substrate bias among the Sm(Co,Al,Si)(deposited with substrate bias of-150 V)/Sm(Co, Al,Si)(deposited with no substrate bias)/Sm(Co,Al, Si)(deposited with substrate bias of-150 V), the multilayer exhibited high coercivity of 2960 Oe and S* of 0.96. Sm(Co,Al, Si)/Sm(Co, Ti, Cu)/Sm(Co,Nb, Cu) trilayer improved matching between the magnetic layer and the Cr underlayer, and led to increasing in-plane anisotropy, high coercivity of 3280 Oe and S* of 0.92. Lattice matching of SmCoR {1121} and Cr {110}, etc. were found under various conditions. The microstructures of these four kinds of medium were also examined. The results suggest that it is possible to produce Sm(Co, Al, Si, Ti, Nb, Cu) multi-layer media with the combined magnetic properties required for the ultrahigh density magnetic recording.

  1. Identification of phase composition of AlSi5Cu2Mg aluminium alloy in T6 condition

    Directory of Open Access Journals (Sweden)

    M. Wierzbińska

    2008-04-01

    Full Text Available Purpose: The purpose of this paper is to present the results of studies of AlSi5Cu2Mg cast alloy in T6 condition at an angle of intermetallic phases composition. It was found that the investigated alloy microstructure consists of three different, as regards shape intermatallic phases.Design/methodology/approach: In this study, several methods were used, such as: optical light microscopy (LM scanning electron microscopy (SEM in combination with X-ray analysis (EDS using polished samples, and calorimetric analysis (DSC, to identify of phase composition in AlSi5Cu2Mg alloy.Findings: The results show that three intermetallic phases in AlSi5Cu2Mg alloy microstructure presented only one type of the phase, the α–AlFeMnSi phase. The chemical composition, morphology, shape (needle or “Chinese script” and distribution of α – AlFeMnSi phase depend on the parameters of the crystallization process. Netherless, it is possible to change this parameters during heat treatment process.Research limitations/implications: Although the morphology and α – AlFeMnSi phase particles distribution have a significant impact on the mechanical properties (especially on the crack resistance of the AlSi5Cu2Mg alloy, the main strengthening factor is the existence of the dispersion phase which was not subjected to examination in the research presented in this paper. Therefore, in order to complete and confirm obtained results it is recommended to perform further analysis of the alloy by using transmission electron microscopy technique (TEM.Practical implications: From a practical point of view it is important, that there is a possibility to influence morphology, shape and distribution of intermetallic α – AlFeMnSi phase by heat treatment parameters, to obtain optimal mechanical properties of AlSi5Cu1Mg alloy according to application.Originality/value: This paper proposes the best experimental techniques for analysis of the intermetallic phases occurrnig in the 4

  2. Structure, tribological and electrochemical properties of low friction TiAlSiCN/MoSeC coatings

    Energy Technology Data Exchange (ETDEWEB)

    Bondarev, A.V.; Kiryukhantsev-Korneev, Ph.V.; Sheveyko, A.N.; Shtansky, D.V., E-mail: shtansky@shs.misis.ru

    2015-02-01

    Highlights: • TiAlSiCN/MoSeC coatings for tribological applications. • Doping with MoSeC reduces friction coefficient in humid air from 0.8–0.9 to 0.05. • Doping with MoSeC increases wear resistance by one-two orders of magnitude. • TiAlSiCN/MoSeC coatings demonstrated low friction coefficient in distilled water. • TiAlSiCN/MoSeC coatings showed superior tribological properties at moderate temperatures. - Abstract: The present paper is focused on the development of hard tribological coatings with low friction coefficient (CoF) in different environments (humid air, distilled water) and at elevated temperatures. TiAlSiCN/MoSeC coatings were deposited by magnetron sputtering of four-segment targets consisting of quarter circle TiAlSiCN segments, obtained by self-propagating high-temperature synthesis, and one or two cold pressed segments made of MoSe{sub 2} and C powders in a ratio 1:1 wt%. The structure and phase composition of coatings were investigated by means of X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. The coatings were characterized in terms of their hardness, elastic modulus, and elastic recovery. The tribological properties of coatings were investigated first at room temperature against Al{sub 2}O{sub 3} and WC–Co balls, after which studied in distilled water and during continuous heating in air in the temperature range of 25–400 °C against Al{sub 2}O{sub 3} counterpart material. To evaluate their electrochemical characteristics, the coatings were tested in 1 N H{sub 2}SO{sub 4} solution. The obtained results show that the coating hardness depends on the amount of MoSeC additives and decreased from 40 to 28 (one MoSeC segment) and 12 GPa (two MoSeC segments). Doping with MoSeC resulted in a significant reduction of CoF values measured in humid air (RH 60 ± 5%) from 0.8–0.9 to 0.05 and an increase of wear resistance by one or two orders of magnitude depending on

  3. INFLUENCE OF NONEQUILIBRIUM CONDITIONS OF HARDENING ON MECHANICAL PROPERTIES FOUNDINGS RECEIVED ON THE BASIS OF ALLOYS OF SYSTEM Al-Si-Cu

    OpenAIRE

    Доценко, Юрий Валериевич

    2010-01-01

    The analysis of results of researches on modifying influence by ultradisperse modifier TiCN and gaz-dynamyc influences on mechanical foundings properties received of aluminium alloys of system Al-Si-Cu is resulted.

  4. Construction and evaluation of multi-component Zn-Al based bearing alloys (Zn-Al-Si, Zn-Al-Cu)

    International Nuclear Information System (INIS)

    Zn-Al based alloys, with excellent mechanical properties, are finding increasing applications in various industries, especially bearing and bushing fields. Observed dimensional instabilities, in their multicomponent systems, (e. g. Zn-Al-Si and, Zn-Al Si-Cu), is believed to be as the result of some kinds of phase transformation, due to the temperature variations, while in service. Profound understanding of the phase transformations due to the temperature variation, requires detailed evaluations of the isothermal sections of the multi-components phase diagrams of Zn-Al-Si and, Zn-Al-Si-Cu alloy systems. In the present article, the isothermal sections of the aforementioned ternary and quaternary systems in the solid state regions have been investigated and observed phase transitions have been critically evaluated

  5. Influence of the selected structural parameter on a depth of intergranular corrosion of Al-Si7-Mg0,3 aluminum alloy

    Directory of Open Access Journals (Sweden)

    L. Bernat

    2015-10-01

    Full Text Available The paper presents an influence of the Dendrite Arm Spacing (DAS microstructure parameter on the intergranular corrosion of AlSi7Mg aluminum alloy. The samples were subjected to the corrosion process for: 2,5; 12; 24; 48 and 96 hours in NaCl + HCl + H2O solution. It was noted that the DAS parameter significantly influenced on a distribution and depth of the intergranular corrosion of the hypoeutectic Al - Si - Mg silumin.

  6. Effects of P+Cr complex modification and solidification conditions on microstructure of hypereutectic Al-Si alloys by wedge-shaped copper mould casting

    OpenAIRE

    Zhang Haitao; Zuo Kesheng; Han Xing

    2014-01-01

    Large and segregated primary Si particles may drastically decrease the mechanical properties of Al-Si alloys. To solve this problem, a P-Cr complex modifier was added into the alloy, and the effects of P-Cr complex modification and solidification conditions on the microstructure of hypereutectic Al-Si alloys casting produced in wedge-shaped copper mould were studied. The thermal analysis technique was applied to calculate the cooling rate during solidification. The microstructures were observ...

  7. CARACTERIZACIÓN SUPERFICIAL, ELECTROQUÍMICA Y DE COMPOSICIÓN DE ALEACIONES ZINC NÍQUEL ELECTRODEPOSITADAS

    Directory of Open Access Journals (Sweden)

    ULISES PIRATOBA

    2008-01-01

    Full Text Available La gran demanda de láminas de acero recubiertas con Zinc o con aleaciones de Zinc, es atendida conprocesos de electro deposición en continuo; estos requieren de altas densidades de corriente, obtenidas en electrolitos ácidos. En este trabajo se presenta la composición, morfología superficial y la caracterización electroquímica de aleaciones Zinc Níquel fase gamma sobre láminas de acero, depositadas con altas densidades de corriente. Estas fueron determinadas mediante Análisis de Energía Dispersa de Rayos EDX, Microscopias Electrónica de Barrido SEM y de Fuerza Atómica AFM, e Impedancia Electroquímica EI y polarización Táfel. Se encontraron recubrimientos de grano fino que se pasivan y exhiben un comportamiento anódico frente al sustrato de acero.

  8. Caracterización microestructural de aleaciones base cobre obtenidas mediante molienda reactiva

    Directory of Open Access Journals (Sweden)

    Palma, R.

    2010-06-01

    Full Text Available The micro and nanostructure of Cu-Al, Cu-V and Cu-Ti alloys produced by reactive milling were analyzed using X-ray diffraction (XRD and transmission electron microscopy (TEM. Samples with different milling times (t= 0, 10, 20 and 30 h were considered. The grain size, dislocation density and residual microstrain were evaluated form the XRD data using the Williamson-Hall and Klug-Alexander methods. The evolution of texture as a function of milling time was also studied using XRD. It was found, using TEM, that the grain size and dispersoid size were nanometric in all three alloys considered.

    Se analizó la micro y nano estructura de aleaciones Cu-Al, Cu-V y Cu-Ti obtenidas por molienda reactiva, mediante difracción de rayos X (XRD y microscopía electrónica de transmisión (TEM. Se consideraron muestras con distintos tiempos de molienda (t= 0, 10, 20 y 30 h. A partir de los datos XRD, usando los métodos de Williamson- Hall y Klug-Alexander, se evaluaron el tamaño de grano, la densidad de dislocaciones y la microdeformación residual; también se estudió la evolución de la textura de la matriz de cobre en función del tiempo de molienda. En los polvos molidos durante 30 h, de las tres aleaciones consideradas, se encontró, por TEM, que los tamaños de grano y de los dispersoides desarrollados son nanométricos.

  9. Microstructure of interaction interface between Al-Si, Zn-Al alloys and Al2O3p/6061Al composite

    Institute of Scientific and Technical Information of China (English)

    许志武; 闫久春; 吕世雄; 杨士勤

    2004-01-01

    Interaction behaviors between Al-Si, Zn-AI alloys and Al2O3p/6061AI composite at different heating temperatures were investigated. It is found that Al2O3p/6061Al composite can be wetted well by AlSi-1, AlSi-4 and Zn-Al alloys and an interaction layer forms between the alloy and composite during interaction. Little Al-Si alloys remain on the surface when they fully wet the composite and Si element in Al-Si alloy diffuses into composite entirely and assembles in the composite near the interface of Al-Si alloy/composite to form a Si-rich zone. The microstructure in interaction layer with Si penetration is still dense. Much more residual Zn-Al alloy exists on the surface of composite when it wets the composite, and porosities appear at the interface of Zn-Al alloy/composite. The penetration of elements Zn, Cu of Zn-Al alloy into composite leads to the generation of shrinkage cavities in the interaction layer and makes the microstructure of Al2 O3p/6061A1 composite loose.

  10. Tribological Behavior of Aluminum Alloy AlSi10Mg-TiB2 Composites Produced by Direct Metal Laser Sintering (DMLS)

    Science.gov (United States)

    Lorusso, Massimo; Aversa, Alberta; Manfredi, Diego; Calignano, Flaviana; Ambrosio, Elisa Paola; Ugues, Daniele; Pavese, Matteo

    2016-06-01

    Direct metal laser sintering (DMLS) is an additive manufacturing technique for the production of parts with complex geometry and it is especially appropriate for structural applications in aircraft and automotive industries. Aluminum-based metal matrix composites (MMCs) are promising materials for these applications because they are lightweight, ductile, and have a good strength-to-weight ratio This paper presents an investigation of microstructure, hardness, and tribological properties of AlSi10Mg alloy and AlSi10Mg alloy/TiB2 composites prepared by DMLS. MMCs were realized with two different compositions: 10% wt. of microsize TiB2, 1% wt. of nanosize TiB2. Wear tests were performed using a pin-on-disk apparatus on the prepared samples. Performances of AlSi10Mg samples manufactured by DMLS were also compared with the results obtained on AlSi10Mg alloy samples made by casting. It was found that the composites displayed a lower coefficient of friction (COF), but in the case of microsize TiB2 reinforcement the wear rate was higher than with nanosize reinforcements and aluminum alloy without reinforcement. AlSi10Mg obtained by DMLS showed a higher COF than AlSi10Mg obtained by casting, but the wear rate was higher in the latter case.

  11. Study of multi-carbide B4C-SiC/(Al, Si) reaction infiltrated composites by SEM with EBSD

    International Nuclear Information System (INIS)

    In the definition of conceptual developments and design of new materials with singular or unique properties, characterisation takes a key role in clarifying the relationships of composition, properties and processing that define the new material. B4C has a rare combination of properties that makes it suitable for a wide range of applications in engineering: high refractoriness, thermal stability, high hardness and abrasion resistance coupled to low density. However, the low self-diffusion coefficient of B4C limits full densification by sintering. A way to overturn this constraint is by using an alloy, for example Al-Si, forming composites with B4C. Multi-carbide B4C-SiC/(Al, Si) composites were produced by the reactive melt infiltration technique at 1200 – 1350 °C with up to 1 hour of isothermal temperature holds. Pressed preforms made from C-containing B4C were spontaneously infiltrated with Al-Si alloys of composition varying from 25 to 50 wt% Si. The present study involves the characterisation of the microstructure and crystalline phases in the alloys and in the composites by X-ray diffraction and SEM/EDS with EBSD. Electron backscatter diffraction is used in detail to look for segregation and spatial distribution of Si and Al containing phases during solidification of the metallic infiltrate inside the channels of the ceramic matrix when the composite cools down to the eutectic temperature (577 °C). It complements elemental maps of the SEM/EDS. The production of a flat surface by polishing is intrinsically difficult and the problems inherent to the preparation of EBSD qualified finishing in polished samples of such type of composites are further discussed

  12. Influence of selected parameters of AlSi/CrFeC composite castings manufacturing on the resulted structure

    Directory of Open Access Journals (Sweden)

    A. Dulęba

    2012-05-01

    Full Text Available Purpose: The main aim of studies was to determine influence: size of reinforcing particles, frequency and the current intensity on the morphology of reinforcing phase precipitates in AlSi11/CrFe30C8 composites castings produced of rotating electromagnetic field.Design/methodology/approach: In this paper the technology of AlSi11/CrxCy composites produced with Cr30Fe8C ex situ particles is described. Technological conception of investigations was based on assumption that Cr-Fe matrix of particles dissolved in Al-Si composite matrix and carbide phases became actual reinforcement of the composite.Findings: The results of investigations and their analysis shown, that contribution of these variables parameters essentially influence on the morphology of reinforcing phase. On the basis of analysis results determined the most effective technological parameters to produced composite casting.Research limitations/implications: In the further research, authors of this paper are going to extend the scope of research about the another shape of the trial composite casting. Presented the technological process of composites producing created the possibility selection of different reinforcing particles depending on the technological and commercial properties.Practical implications: Determined possibility to control of volume fraction and distribution of reinforcing phase with used of the electromagnetic field, it can be used for example in the control of utility properties wear-resistant materials with a high coefficient of friction such as brake discs.Originality/value: The work presents the use of the electromagnetic field to shaping the structure and distribution of reinforcing phase in composite matrix. Within the range of this investigation created the new experimental stand to production of composites under electromagnetic field.

  13. X-ray video microscopy studies of irregular eutectic solidification microstructures in Al-Si-Cu alloys

    International Nuclear Information System (INIS)

    In-situ studies of Al-Si eutectic growth has been carried out for the first time by X-ray video microscopy during directional solidification of Al-Si-Cu alloys with and without Sr-additions. The unmodified eutectics showed distinctive non-isothermal growth dynamics, where Si-crystals attained needle-like tip morphologies and progressed under significantly higher undercooling than Al, leading to formation of an irregular eutectic with Si as the leading phase and subsequent nucleation of Al on the Si-surfaces. In the Sr-modified alloys, the eutectic reaction was found to be strongly suppressed, occurring with low nucleation frequencies at undercoolings in the range 10-18 K. In the Cu-enriched melt, the eutectic front was found to attain meso-scale interface perturbations, sometimes evolving into equiaxed cellular rosettes in order to accommodate to the long-range redistribution of Cu from the composite eutectic interface. The eutectic front also attained short-range microscale interface perturbations consistent with characteristics of a fibrous Si growth. However, further improvements in spatial resolution are required in order to study the microscale structure formation in greater detail. Evidence was found in support of Si-nucleation occurring on potent particles suspended in the melt. Yet, both with Sr-modified and unmodified alloys Si precipitation alone was not sufficient to facilitate the eutectic reaction, which apparently required additional undercooling for Al to form on the Si-particles. To what extent nucleation mechanisms in the Cu-enriched systems are transferable to binary or commercial Al-Si alloys remains uncertain. (author)

  14. Formation of hypereutectic silicon particles in hypoeutectic Al-Si alloys under the influence of high-intensity ultrasonic vibration

    Directory of Open Access Journals (Sweden)

    Xiaogang Jian

    2013-03-01

    Full Text Available The modification of eutectic silicon is of general interest since fine eutectic silicon along with fine primary aluminum grains improves mechanical properties and ductilities. In this study, high intensity ultrasonic vibration was used to modify the complex microstructure of aluminum hypoeutectic alloys. The ultrasonic vibrator was placed at the bottom of a copper mold with molten aluminum. Hypoeutectic Al-Si alloy specimens with a unique in-depth profile of microstructure distribution were obtained. Polyhedral silicon particles, which should form in a hypereutectic alloy, were obtained in a hypoeutectic Al-Si alloy near the ultrasonic radiator where the silicon concentration was higher than the eutectic composition. The formation of hypereutectic silicon near the radiator surface indicates that high-intensity ultrasonic vibration can be used to influence the phase transformation process of metals and alloys. The size and morphology of both the silicon phase and the aluminum phase varies with increasing distance from the ultrasonic probe/radiator. Silicon morphology develops into three zones. Polyhedral primary silicon particles present in zone I, within 15 mm from the ultrasonic probe/radiator. Transition from hypereutectic silicon to eutectic silicon occurs in zone II about 15 to 20 祄 from the ultrasonic probe/radiator. The bulk of the ingot is in zone III and is hypoeutectic Al-Si alloy containing fine lamellar and fibrous eutectic silicon. The grain size is about 15 to 25 祄 in zone I, 25 to 35 祄 in zone II, and 25 to 55 祄 in zone III. The morphology of the primary ?Al phase is also changed from dendritic (in untreated samples to globular. Phase evolution during the solidification process of the alloy subjected to ultrasonic vibration is described.

  15. Microstructural and mechanical characteristics of AlSiMnFe alloy processed by equal channel angular pressing

    OpenAIRE

    V. A. Andreyachshenko; Naizabekov, A. B.

    2016-01-01

    In the present research, equal channel angular pressing (ECAP) was conducted. The defectness degree of the alloy for one pass and maximum strain was determined. Ultra fine grained AlSiMnFe alloy was produced by refining grained annealed bulk by multi-pass ECAP at room temperature. The results reveal two regimes: from 1 to 2 passes the microstructure evolves to a equiaxed of ultrafine grains and from 2 to 4 passes there is no strict change in the average grain size.

  16. Microstructural and mechanical characteristics of AlSiMnFe alloy processed by equal channel angular pressing

    Directory of Open Access Journals (Sweden)

    V. A. Andreyachshenko

    2016-07-01

    Full Text Available In the present research, equal channel angular pressing (ECAP was conducted. The defectness degree of the alloy for one pass and maximum strain was determined. Ultra fine grained AlSiMnFe alloy was produced by refining grained annealed bulk by multi-pass ECAP at room temperature. The results reveal two regimes: from 1 to 2 passes the microstructure evolves to a equiaxed of ultrafine grains and from 2 to 4 passes there is no strict change in the average grain size.

  17. EFFECT OF FLY ASHES AND SEWAGE SLUDGE ON Fe, Mn, Al, Si AND Co UPTAKE BY GRASS MIXTURE

    OpenAIRE

    Jacek Antonkiewicz

    2014-01-01

    Application of sewage sludge for environmental management of fly ashes landfill site affects chemical composition of plants. The aim of the present investigations was learning the effect of growing doses of municipal sewage sludge on the yield and uptake of Fe, Mn, Al, Si and Co by grass mixture used for environmental management of fly ashes landfill. The experimental design comprised of 5 objects differing by a dose of municipal sewage sludge supplied per 1 hectare: I. control, II. 25 t d.m....

  18. Influence of the scan speed on the microstructure of AlSi10Mg processed by additive manufacturing

    OpenAIRE

    Delroisse, Pauline; Jacques, Pascal; Rigo, Olivier; Maire, Eric; Simar, Aude; Thermec 2016

    2016-01-01

    The aeronautic industry seeks constant improvement of manufacturing techniques in order to improve the mechanical performances to cost ratio. Thus, additive manufacturing is seen as a promising process. Due to the infancy of the process, the influence of the process parameters such as laser power, layer thickness or scanning strategy on the microstructure requires further investigation. In the present project, bulk samples 10x10x10 mm³ in size made of AlSi10Mg are processed by Laser Beam Melt...

  19. A planar Al-Si Schottky barrier metal–oxide–semiconductor field effect transistor operated at cryogenic temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Purches, W. E. [School of Physics, UNSW, Sydney 2052 (Australia); Rossi, A.; Zhao, R. [School of Electrical Engineering and Telecommunications, UNSW, Sydney 2052 (Australia); Kafanov, S.; Duty, T. L. [School of Physics, UNSW, Sydney 2052 (Australia); Centre for Engineered Quantum Systems (EQuS), School of Physics, UNSW, Sydney 2052 (Australia); Dzurak, A. S. [School of Electrical Engineering and Telecommunications, UNSW, Sydney 2052 (Australia); Australian Centre of Excellence for Quantum Computation and Communication Technology (CQC2T), UNSW, Sydney 2052 (Australia); Rogge, S.; Tettamanzi, G. C., E-mail: g.tettamanzi@unsw.edu.au [School of Physics, UNSW, Sydney 2052 (Australia); Australian Centre of Excellence for Quantum Computation and Communication Technology (CQC2T), UNSW, Sydney 2052 (Australia)

    2015-08-10

    Schottky Barrier-MOSFET technology offers intriguing possibilities for cryogenic nano-scale devices, such as Si quantum devices and superconducting devices. We present experimental results on a device architecture where the gate electrode is self-aligned with the device channel and overlaps the source and drain electrodes. This facilitates a sub-5 nm gap between the source/drain and channel, and no spacers are required. At cryogenic temperatures, such devices function as p-MOS Tunnel FETs, as determined by the Schottky barrier at the Al-Si interface, and as a further advantage, fabrication processes are compatible with both CMOS and superconducting logic technology.

  20. The influence of copper on an Al-Si-Mg alloy (A356) - Microstructure and mechanical properties

    OpenAIRE

    Bogdanoff, Toni; Dahlström, Jimmy

    2009-01-01

    Aluminum alloys are widely used in many manufacturing areas due to good castability, lightness and mechanical properties. The purpose of this research is to investigate copper’s influence on an Al-Si-Mg alloy (A356). Copper in the range of 0.6 – 1.6 wt. % has been used in an A356 aluminum based alloy. In this work a simulation of three different casting processes, sand-, die- and high pressure die-casting has been employed with the help of gradient solidification equipment. The microstructure...

  1. Effect of grain refinement and modification of eutectic phase on shrinkage of AlSi9Cu3 alloy

    Directory of Open Access Journals (Sweden)

    M. Petrič

    2011-04-01

    Full Text Available Paper describes influence of grain refining and of modification on feeding behavior of Al – alloys. Research was made with the AlSi9Cu3 alloy. Three samples of basic, grain refined, and modified alloy were cast by the newly developed method for determining susceptibility to shrinkage and into the Quick cup measuring cells for simple thermal analyses which were simultaneously done with all these samples. Castings were then analyzed with X-raying, density measurements, visually observed and metallographically examined. Also grain size was determined with light microscopy and polarized light.

  2. Determination of Na, Mg, Al, Si, K, Cl, Ca and Fe in cigarette tobacco by fast neutron activation analysis

    International Nuclear Information System (INIS)

    FNAA has been, for many years, a technique for the non-destructive analysis of a wide variety of sample materials - liquids, solids and powders. The important advantages of fast neutron activation analysis are good analytical sensitivity without sample preparation, accuracy and total analysis in a short time. In our work, the concentrations of the elements Na, Mg, Al, Si, K, Cl, Ca and Fe, were determined in cigarette tobacco of two brands commercially available in Turkey using 14.6 MeV neutron activation analysis. (author)

  3. The influence of material of mould and modification on the structure of AlSi11 alloy

    OpenAIRE

    M. Łągiewka; Z. Konopka

    2012-01-01

    The presented work discusses the influence of material of foundry mould on the effect of modification of AlSi11 alloy. For this purpose castings were produced in moulds made of four various materials. Castings of the first type were cast in a metal die, the second ones in the conventional mould of bentonite-bound sand, those of the third type in the sand mould with oil binder, the last ones in a shell mould where phenol-formaldehyde resin was applied as a binder. All the castings were made of...

  4. Effect of bariun on the refinement of primary aluminum and eutectics in a hypoeutectic Al-Si alloy

    Institute of Scientific and Technical Information of China (English)

    LI Wei; FAN Hongyuan; ZHANG Xianju; SHEN Baoluo

    2003-01-01

    The effect of barium on the refinement of primary aluminum and on the modification of eutectics in a hypoeutectic aluminm-silicon alloy was investigated. The results indicate that barium not only modifies the eutectic silicon but also refines the primary aluminum and there is a relationship between the retained barium and the second spacing of primary aluminum. Experiments of barium-treated commercial Al-Si hypoeutectic alloy show that barium is a better modifier than sodium when there is a longer holding time.

  5. A planar Al-Si Schottky barrier metal–oxide–semiconductor field effect transistor operated at cryogenic temperatures

    International Nuclear Information System (INIS)

    Schottky Barrier-MOSFET technology offers intriguing possibilities for cryogenic nano-scale devices, such as Si quantum devices and superconducting devices. We present experimental results on a device architecture where the gate electrode is self-aligned with the device channel and overlaps the source and drain electrodes. This facilitates a sub-5 nm gap between the source/drain and channel, and no spacers are required. At cryogenic temperatures, such devices function as p-MOS Tunnel FETs, as determined by the Schottky barrier at the Al-Si interface, and as a further advantage, fabrication processes are compatible with both CMOS and superconducting logic technology

  6. Effective elastic properties of an Al-SiC composite using two-point statistical mechanics approach

    International Nuclear Information System (INIS)

    In this paper, statistical continuum mechanics modeling is applied to predict the elastic mechanical properties of an anisotropic Al-SiC composite. Two-point statistics are measured on vertical metallographic planes in three-dimensional microstructures. As a result of anisotropy the correlation functions are orientation dependent. Longitudinal and transverse elastic moduli are calculated for two samples with different PSR and clustering, and the results are compared with upper and lower bound and experimental data. It's observed that the theoretical results are in good agreement with experimental data and two-point statistics significantly contribute to the estimation of the elastic modulus

  7. EFFECT OF TI ADDITION ON THE TRIBOLOGICAL WEAR BEHAVIOR OF HYPEREUTECTIC AL-SI ALLOYS AT ELEVATED TEMPERATURES

    OpenAIRE

    Mallesh Jakanur*

    2016-01-01

    Effect of titanium addition on the dry sliding wear behaviour of hypereutectic Al-Si alloys are investigated at elevated temperatures. Wear tests are conducted for varying normal pressure from 0.20 N/mm2 to 0.98 N/mm2, for varying sliding velocity from 0.94m/s to 3.77 m/s and varying sliding distance from 282.74 m to 1696.46 m. In this present investigation, hyper eutectic aluminium based alloys containing 13% and 20% weight of silicon; with addition of titanium is synthesized using casting m...

  8. The effect of cooling rate on microstructure and mechanical properties of AC AlSi9Cu alloy

    Directory of Open Access Journals (Sweden)

    J.H. Sokolowski

    2007-01-01

    Full Text Available Purpose: In this work the effect of cooling rate on the size of the grains, SDAS, size of the β precipitation andthermal characteristic results of AC AlSi9Cu cast alloy have been described. The solidification process was studiedusing the cooling curve and crystallization curve at solidification rate ranging from 0,16 ºCs-1 up to 1,04 ºCs-1.Design/methodology/approach: The experimental alloy used in this investigation was prepared by mixing insuitable proportion the AC AlSi5Cu1(Mg commercial alloys and two master alloys AlSi49 and AlCu55. Thermalanalysis tests were made using the UMSA Technology Platform. Cooling curve thermal analysis was performedon all samples using high sensitivity thermocouples of K type that were protected in a stainless steel sheath anddata were acquired by a high speed data acquisition system linked to a PC computer. Each chilled sample wassectioned horizontally where the tip of the thermocouple was located and it was prepared by standard grindingand polishing procedures. The final stage of polishing was done using commercial silicon oxide slurry. Opticalmicroscopy was used to characterize the microstructure and intermetallic phases. Secondary dendrite arm spacingmeasurements were carried out using a Leica Q-WinTM image analyzer. The UTM measurements were carried outusing a Zwick testing machine.Findings: Increasing the cooling rate increases significantly the liquidus temperature, nucleation undercoolingtemperature, solidification range and decreases the recalescence undercooling temperature. Increasing cooling raterefines all microstructural features including secondary dendrite arm spacing (SDAS and intermetallic compoundsand improves silicon modification level.Research limitations/implications: The results presented in this paper show results only for the one alloy- AC AlSi9Cu, and for the assessment of the Silicon Modification Level didn’t include the arrangement of a Sicrystal in a matrix.Practical implications

  9. Fanatismo: tres tipos ideales

    OpenAIRE

    Taguenca Belmonte, Juan Antonio

    2013-01-01

    Objetivo: comprender, teóricamente, el fanatismo en el Mundo de Occidente, identificando y presentando sus tipos ideales en diferentes momentos históricos. Metodología: la investigación se inserta en lo que Max Weber denomina el método científico, pero que desarrolla como un método comprensivo, dado que su interés lo lleva a comprender la realidad sobre la que indaga a través de la interpretación de textos, buscando identificar los tipos de ideales. A partir de ello, alejarse de la subjetivid...

  10. New insights on pressure, temperature, and chemical stability of CsAlSi5O12, a potential host for nuclear waste

    Science.gov (United States)

    Gatta, G. D.; Brundu, A.; Cappelletti, P.; Cerri, G.; de'Gennaro, B.; Farina, M.; Fumagalli, P.; Guaschino, L.; Lotti, P.; Mercurio, M.

    2016-06-01

    A Cs-bearing polyphase aggregate with composition (in wt%): 76(1)CsAlSi5O12 + 7(1)CsAlSi2O6 + 17(1)amorphous, was obtained from a clinoptilolite-rich epiclastic rock after a beneficiation process of the starting material (aimed to increase the fraction of zeolite to 90 wt%), cation exchange and then thermal treatment. CsAlSi5O12 is an open-framework compound with CAS topology; CsAlSi2O6 is a pollucite-like material with ANA topology. The thermal stability of this polyphase material was investigated by in situ high-T X-ray powder diffraction, the combined P-T effects by a series of runs with a single-stage piston cylinder apparatus, and its chemical stability following the "availability test" ("AVA test") protocol. A series of additional investigations were performed by WDS-electron microprobe analysis in order to describe the P-T-induced modification of the material texture, and to chemically characterize the starting material and the run products. The "AVA tests" of the polyphase aggregate show an extremely modest release of Cs+: 0.05 mg/g. In response to applied temperature and at room P, CsAlSi5O12 experiences an unquenchable and displacive Ama2-to-Amam phase transition at about 770 K, and the Amam polymorph is stable in its crystalline form up to 1600 K; a crystalline-to-amorphous phase transition occurs between 1600 and 1650 K. In response to the applied P = 0.5 GPa, the crystalline-to-amorphous transition of CsAlSi5O12 occurs between 1670 and 1770 K. This leads to a positive Clapeyron slope (i.e., dP/dT > 0) of the crystalline-to-amorphous transition. When the polyphase aggregate is subjected at P = 0.5 GPa and T > 1770 K, CsAlSi5O12 melts and only CsAlSi2O6 (pollucite-like; dominant) and Cs-rich glass (subordinate) are observed in the quenched sample. Based on its thermo-elastic behavior, P-T phase stability fields, and Cs+ retention capacity, CsAlSi5O12 is a possible candidate for use in the immobilization of radioactive isotopes of Cs, or as potential

  11. A novel yellow-emitting SrAlSi4N7:Ce3+ phosphor for solid state lighting: Synthesis, electronic structure and photoluminescence properties

    International Nuclear Information System (INIS)

    Ce3+-doped and Ce3+/Li+-codoped SrAlSi4N7 phosphors were synthesized by gas pressure sintering of powder mixtures of Sr3N2, AlN, α-Si3N4, CeN and Li3N. The phase purity, electronic crystal structure, photoluminescence properties of SrAlSi4N7:Ce3+(Ce3+/Li+) were investigated in this work. The band structure calculated by the DMol3 code shows that SrAlSi4N7 has a direct band gap of 3.87 eV. The single crystal analysis of Ce3+-doped SrAlSi4N7 indicates a disordered Si/Al distribution and nitrogen vacnacy defects. SrAlSi4N7 was identified as a major phase of the fired powders, and Sr5Al5Si21N35O2 and AlN as minor phases. Both Ce3+ and Ce3+/Li+ doped SrAlSi4N7 phosphors can be efficiently excited by near-UV or blue light and show a broadband yellow emission peaking around 565 nm. A highest external quantum efficiency of 38.3% under the 450 nm excitation was observed for the Ce3+/Li+-doped SrAlSi4N7 (5 mol%). A white light LED lamp with color temperature of 6300 K and color rendering index of Ra=78 was achieved by combining Sr0.97Al1.03Si3.997N/94/maccounttest14=t000518193 7:Ce3+0.03 with a commercial blue InGaN chip. It indicates that SrAlSi4N7:Ce3+ is a promising yellow emitting down-conversion phosphor for white LEDs. - Graphical abstract: One-phosphor converted white light-emitting diode (LED) was fabricated by combining a blue LED chip and a yellow-emitting SrAlSi4N7:Ce3+ phosphor (see inset), which has the color rendering index of 78 and color temperature of 6300 K. - Highlights: • We reported a new yellow nitride phosphor suitable for solid state lighting. • We solved the crystal structure and evidenced a disordered Si/Al distribution. • We fabricated a high color rendering white LEDs by using a single SrAlSi4N7:Ce

  12. Relación entre factores micro- estructurales e impacto repetido en aleaciones de alto cromo para bolas de molino.

    Directory of Open Access Journals (Sweden)

    E. Albertin

    2008-01-01

    Full Text Available Las aleaciones de alto cromo son empleadas para la fabricación de bolas de molino en industrias de procesamiento de minerales. Los usuarios y fabricantes requieren lograr mejores resultados técnicos-económicos en sus aplicaciones, por lo que necesitan aumentar los conocimientos relacionados con los aspectos estructurales de estos materiales. En este trabajo se realiza una investigación con vistas a establecer relaciones entre la estructura de las aleaciones y su comportamiento ante el impacto repetido que es un fenómeno característico en estos procesos. Se funden bolas con varias aleaciones hipo eutécticas, eutécticas, e hipereutécticas; se prueban en un equipo que simula el impacto repetido. Los resultados permiten comprobar los buenos resultados de aleaciones hipo eutécticas con relaciones de Cr/C altas y a su vez altos contenidos de Cr y de aleaciones eutécticas para menores relaciones de Cr/C y menores contenidos de Cr, en ambos casos los carburos eutécticos son de forma simétrica, regulares y no forman redes continuas de carburos asimétricos bordeando los granos, que presentan peores comportamiento en el impacto repetido y que son el caso de las hipoeutécticas con bajas relaciones Cr/C y las hipereutécticas donde aparecen también grandes carburos primarios.High Chromium alloys are used to manufacture grinding balls for the Industry of Construction Materials. Customers and users need to improve their knowledge about the relationships between microstructure and the parts damage in these alloys to obtain better technical-economics results. In this paper the results of a research to obtain different microstructures of eutectics, hipoeutectics and hipereutectics alloys are presented, searching for the lesser damage in these alloys. These alloys are tested in a repeated impact testing machine that simulate its mechanical behaviour .The results show a good behaviour for hipoeutectic alloys with high relations of Cr/C and high

  13. Amorphous structure and properties in laser-clad Ni-Cr-Al coating on Al-Si alloy

    Science.gov (United States)

    Liang, Gongying; Wong, T. T.; Su, J. Y.; Woo, C. H.

    1999-09-01

    A Ni-Cr-Al coating was clad by a 5 kW CO2 laser with different laser power on Al-Si alloy. Using transmission electron microscopy, a mixing microstructure containing Ni- based amorphous structures was observed in the laser clad zones. As the uniformity of chemical composition and temperature is poor in the laser cladding, the amorphous structure with some Ni3Al crystals coexisted in the cladding. According to the morphologies of Ni-based amorphous structures, the amorphous structure existed not only in the net-like boundaries surrounding the granular structure but also in the granular structure. The microhardness of the mixture amorphous structure is between HV 600 - 800, which is lower than that of crystal phases in the coating. A differential thermal analysis showed that Ni- based amorphous structure exhibits a higher initial crystallizing temperature (about 588 degree(s)C), which is slightly higher than that of the eutectic temperature of Al- Si alloy. The wear experimental results showed that some amorphous structure exist in the laser cladding can reduce the peeling of the granular phases from matrix, and improve the its wear resistance.

  14. Influence of titanium content on wear resistance of electrolytic low-titanium eutectic Al-Si piston alloys

    Institute of Scientific and Technical Information of China (English)

    Wang Jiefang; Xie Jingpei; Yan Shuqing; Liu Zhongxia; Weng Yonggang; Wang Mingxing; Song Tianfu

    2008-01-01

    The wear resistance of six kinds of the electrolytic low-titanium eutectic Al-Si piston alloys with various Ti content ranging from 0.00wt.% to 0.21wt.% has been studied. A new method of adding Ti is adopted in the electrolytic low-titanium aluminum alloy ingots. The electrolytic low-titanium eutectic AI-Si piston alloys are produced by remelting the electrolytic low-titanium aluminum alloy, crystal silicon, pure magnesium, Al-50%Cu and Al-10%Mn master alloy. The wear experiments are conducted using MM200 wear testing machine under lubricating condition. The results indicate that the better wear resistance and the less weight loss are achieved in the study for the eutectic AI-Si piston alloys with 0.08wt.%-0.12wt.% Ti content. The highest ultimate tensile strength of 135.94 MPa at 300℃ and HV141.70 hardness of the alloys are obtained at 0.12wt.% and 0.08wt.% Ti content, respectively. The wear mechanism of the eutectic Al-Si piston alloys under lubricating condition is abrasive wear.

  15. Effect of water absorption of dielectric underlayers on crystal orientation in Al-Si-Cu/Ti/TiN/Ti metallization

    Science.gov (United States)

    Yoshida, Tomoyuki; Hashimoto, Shoji; Hosokawa, Hideki; Ohwaki, Takeshi; Mitsushima, Yasuichi; Taga, Yasunori

    1997-05-01

    The influence of the exposure of underlying dielectric (phophosilicate glass and borophosphosilicate glass) films to a humid air ambient on crystallographic orientations in Al-Si-Cu/Ti/TiN/Ti layered structures has been investigated as a function of the boron content and exposure time of the dielectric films. The Al(111) orientation in the layered structures was found to improve drastically with increasing boron content and exposure time of the dielectric films. The full width at half maximum value of an Al(111) x-ray rocking curve reached less than 1°. It was also found that the Al-Si-Cu surface becomes smoother and the average grain size increases as the Al(111) orientation improves. The improved Al(111) orientation was attributed to the improved Ti(002) orientation of the bottom Ti films. The mechanism of the improved Ti(002) orientation was investigated. It was confirmed that the improved orientation is closely related with the surface concentration of the absorbed water in the dielectric films. Further, it was demonstrated that interconnects fabricated from the improved layered structure have excellent electromigration performance.

  16. Ultratrace characterization of AlSiCu sputter targets for Th, U and 35 other elements by neutron activation analysis

    International Nuclear Information System (INIS)

    Instrumental and radiochemical neutron activation analysis has been applied to a comprehensive trace characterization of AlSiCu sputter targets. By instrumental neutron activation analysis via long-lived indicator radionuclides, up to 33 elements were assayed with detection limits between 0.01 and 200 ng x g-1. The high activity of 64Cu and 24Na produced from the matrix significantly limits the instrumental performance via short- and medium-lived indicator dionuclides. For this reason, a radiochemical separation was developed based on adsorption of 24Na on hydrated antimony pentoxide and extraction of 64Cu by diethylammonuim diethyldithiocarbamate from HCl medium. By this radiochemical method, As, Ga, K, La, Mn, Mo, Re, Sb, U and W could be assayed via medium-lived radionuclides and the achievable limits of detection were between 0.1 and 25 ng x g-1. Further improvement of detection limits for U and Th was achieved by a selective radiochemical separation of 239Np and 233Pa on a Dowex 1 x 8 column in HF and HF/NH4F medium providing limits of detection for U and Th of 0.06 and 0.02ng x g-1 respectively. These techniques were applied to the analysis of two AlSiCu sputter target materials. Results are compared with those of glow discharge mass spectrometry. (author). 24 refs., 4 figs., 5 tabs

  17. Eutectic Al-Si-Cu-Fe-Mn alloys with enhanced mechanical properties at room and elevated temperature

    International Nuclear Information System (INIS)

    Highlights: → Fabricated a kind of high performance Al-Si alloy with low production costs. → Clarified two different morphologies of α-Fe and corresponding crystal structures. → Analyzed the crystallography of Cu-rich phases before and after T6 treatment. → Fracture mechanism of precipitates in experimental alloys during tensile process. -- Abstract: In this paper, we report a novel kind of eutectic Al-Si-Cu-Fe-Mn alloy with ultimate tensile strength up to 336 MPa and 144.3 MPa at room temperature and 300 oC, respectively. This kind of alloy was prepared by metal mold casting followed by T6 treatment. The microstructure is composed of eutectic and primary Si, α-Fe, Al2Cu and α-Al phases. Iron-rich phases, which were identified as BCC type of α-Fe (Al15(Fe,Mn)3Si2), exist in blocky and dendrite forms. Tiny blocky Al2Cu crystals disperse in α-Fe dendrites or at the grain boundaries of α-Al. During T6 treatment, Cu atoms aggregate from the super-saturation solid solution to form GP zones, θ'' or θ'. Further analysis found that the enhanced mechanical properties of the experimental alloy are mainly attributed to the formation of α-Fe and copper-rich phases.

  18. Effects of Melt Thermal-Rate Treatment on Fe-Containing Phases in Hypereutectic Al-Si Alloy

    Science.gov (United States)

    Wang, Qinglei; Geng, Haoran; Zhang, Shuo; Jiang, Huawei; Zuo, Min

    2013-11-01

    In this paper, effects of melt thermal-rate treatment (MTRT) on Fe-containing phases in hypereutectic Al-Si alloy were investigated. Results show that MTRT can refine microstructures and improve castability, mechanical properties, wear characteristics, and corrosion resistance of Fe-containing Al-Si alloy. When Al-15Si-2.7Fe alloy is treated with MTRT by 1203 K (930 °C) melt: coarse primary Si and plate-like Fe-containing phase both can be refined to small blocky morphology, and the long needle-like Fe-containing phase disappears almost entirely; ultimate tensile strength and elongation are 195 MPa and 1.8 pct, and increase by 12.7 and 50 pct, respectively; and the wear loss and coefficient of friction decrease 7 to 17 and 24 to 30 pct, respectively, compared with that obtained with conventional casting technique. Corrosion resistance of the alloy treated with MTRT by 1203 K (930 °C) melt is the best, that is it has the lowest i corr value and the highest E corr value. Besides, effects of MTRT on Al-15Si-xFe (x = 0.2, 0.7, 1.7, 3.7, 4.7) alloys were also studied, MTRT can only refine microstructure and improve mechanical properties of Al-15Si alloy with 0.7 to 3.7 pct Fe content greatly in the present work.

  19. Separation and purification of Si from solidification of hypereutectic Al-Si melt under rotating magnetic field

    Science.gov (United States)

    Jie, J. C.; Zou, Q. C.; Wang, H. W.; Sun, J. L.; Lu, Y. P.; Wang, T. M.; Li, T. J.

    2014-08-01

    A low-cost and high-efficiency method to purify Si directly from cheap MG-Si at low temperature was proposed and demonstrated in this paper, which used power frequency rotating magnetic field (RMF) to separate the primary Si from a hypereutectic Al-Si alloy and was followed by the acid peeling. The separation mechanism was based on the flow characteristic of melt under RMF and the cooling condition of the liquid metal. A Si-rich layer with Si content of 65-59 wt% was formed in the periphery of alloy, while the inner microstructure of the alloy was mainly the Al-Si eutectic structure. The refined silicon was collected after aqua regia leaching, and had much fewer typical impurities (Fe, Ti, Ca, B, P) than those in MG-Si, and the metallic impurities besides Al had removal fraction higher than 98%, which is mainly ascribed to the segregation effect of Al-30Si alloy during solidification under RMF.

  20. Effect of Different Al/Si Ratios on the Structure and Energy Storage Properties of Strontium Barium Niobate-Based Glass-Ceramics

    Science.gov (United States)

    Xiu, Shaomei; Xiao, Shi; Xue, Shuangxi; Shen, Bo; Zhai, Jiwei

    2016-02-01

    Strontium barium niobate-based glass-ceramics (BSN-AS) with various Al/Si ratios have been prepared through melt casting followed by controlled crystallization. The effect of the various Al/Si ratios on the phase evolution, microstructure, dielectric properties, and energy storage density, and the relationship between the breakdown strength properties and the activation energy E a of BSN-AS glass-ceramics, were investigated. The results reveal that the microstructure of BSN-AS glass-ceramics gradually becomes dense and uniform, and the phenomenon of reunited grains is effectively improved in a certain range of Al/Si ratios. With the Al/Si ratios increasing, the breakdown strength increases to a maximum value and then decreases drastically. For the relationship between breakdown strength properties and activation energy E a, it was found that the various trends between breakdown properties and activation energy E a of the BSN-AS glass-ceramics are opposite. In this study, the energy storage densities reach 4.8 J/cm3 by adjusting the Al/Si ratios in the BSN-AS glass-ceramics.

  1. Influence of high temperature annealing on the structure, hardness and tribological properties of diamond-like carbon and TiAlSiCN nanocomposite coatings

    Science.gov (United States)

    Xie, Z. W.; Wang, L. P.; Wang, X. F.; Huang, L.; Lu, Y.; Yan, J. C.

    2011-11-01

    Diamond-like carbon (DLC) and TiAlSiCN nanocomposite coatings were synthesized and annealed at different temperatures in a vacuum environment. The microstructure, hardness and tribological properties of as-deposited and annealed DLC-TiAlSiCN nanocomposite coatings were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, nano-indentation and friction tests. The TEM results reveal that the as-deposited DLC-TiAlSiCN coating has a unique nanocomposite structure consisting of TiCN nanocrystals embedded in an amorphous matrix consisting of a-Si3N4, a-SiC, a-CN and DLC, and the structure changed little after annealing at 800 °C. However, XPS and Raman results show that an obvious graphitization of the DLC phase occurred during the annealing process and it worsened with annealing temperature. Because of the graphitization, the hardness of the DLC-TiAlSiCN coating after annealing at 800 °C decreased from 45 to 36 GPa. In addition, the DLC-TiAlSiCN coating after annealing at 800 °C has a similar friction coefficient to the as-deposited coating.

  2. Influence of high temperature annealing on the structure, hardness and tribological properties of diamond-like carbon and TiAlSiCN nanocomposite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Z.W. [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Wang, L.P., E-mail: aplpwang@hit.edu.cn [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Wang, X.F.; Huang, L.; Lu, Y.; Yan, J.C. [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China)

    2011-11-15

    Diamond-like carbon (DLC) and TiAlSiCN nanocomposite coatings were synthesized and annealed at different temperatures in a vacuum environment. The microstructure, hardness and tribological properties of as-deposited and annealed DLC-TiAlSiCN nanocomposite coatings were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, nano-indentation and friction tests. The TEM results reveal that the as-deposited DLC-TiAlSiCN coating has a unique nanocomposite structure consisting of TiCN nanocrystals embedded in an amorphous matrix consisting of a-Si{sub 3}N{sub 4}, a-SiC, a-CN and DLC, and the structure changed little after annealing at 800 Degree-Sign C. However, XPS and Raman results show that an obvious graphitization of the DLC phase occurred during the annealing process and it worsened with annealing temperature. Because of the graphitization, the hardness of the DLC-TiAlSiCN coating after annealing at 800 Degree-Sign C decreased from 45 to 36 GPa. In addition, the DLC-TiAlSiCN coating after annealing at 800 Degree-Sign C has a similar friction coefficient to the as-deposited coating.

  3. Influence of high temperature annealing on the structure, hardness and tribological properties of diamond-like carbon and TiAlSiCN nanocomposite coatings

    International Nuclear Information System (INIS)

    Diamond-like carbon (DLC) and TiAlSiCN nanocomposite coatings were synthesized and annealed at different temperatures in a vacuum environment. The microstructure, hardness and tribological properties of as-deposited and annealed DLC-TiAlSiCN nanocomposite coatings were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, nano-indentation and friction tests. The TEM results reveal that the as-deposited DLC-TiAlSiCN coating has a unique nanocomposite structure consisting of TiCN nanocrystals embedded in an amorphous matrix consisting of a-Si3N4, a-SiC, a-CN and DLC, and the structure changed little after annealing at 800 °C. However, XPS and Raman results show that an obvious graphitization of the DLC phase occurred during the annealing process and it worsened with annealing temperature. Because of the graphitization, the hardness of the DLC-TiAlSiCN coating after annealing at 800 °C decreased from 45 to 36 GPa. In addition, the DLC-TiAlSiCN coating after annealing at 800 °C has a similar friction coefficient to the as-deposited coating.

  4. CU、Mg对Al-Si-CU-Mg合金力学性能的影响%Effects of Cu, Mg on Mechanical Properties of Al-Si-Cu-Mg Alloy

    Institute of Scientific and Technical Information of China (English)

    陈大辉; 黄文淑; 汤进军; 侯立群; 费良军

    2011-01-01

    通过调整Cu(3.0%~3.8%)、Mg(0~0.4%)的含量,研究了在砂型铸造条件下Cu、Mg含量对Al-Si-Cu-Mg合金力学性能的影响.结果表明,少量的Mg(0.2%~0.3%)能有效提高合金的强度,Cu为3.5%、Mg为0.3%时合金的性能最佳,室温抗拉强度和伸长率分别为355 MPa和5%.

  5. Sn、Cu及Al-Ti5-B1对Al-Si-Sn-Cu轴承合金的组织和性能的影响%The influence of Sn, Cu and Al-Ti5-B1 to the microstructure and mechanical properties of Al-Si-Sn-Cu bearing alloy

    Institute of Scientific and Technical Information of China (English)

    徐洁

    2015-01-01

    By changing the amount of Sn, Cu and Al-Ti5-B1 intermediate alloy was added to improve the Al-Si-Sn-Cu alloy microstructure and mechanical properties. Results showed that with the increase of Sn content,the Al-Si-Sn-Cu alloy organization obviously refined, but the hardness decrease; Along with the increase of the content of Cu, the Al-Si- Sn-Cu alloy organization do not have obvious change, but the hardness increases; By Al-Ti5-B1 intermediate alloy 's refining effect, the Al-Si-Sn-Cu alloy organization obviously refined, the hardness is increased, so as to improve the comprehensive mechanical properties.%通过改变Sn、Cu加入量以及添加Al-Ti5-B1中间合金来改善Al-Si-Sn-Cu合金的显微组织和力学性能.结果显示:随着Sn含量的增加,Al-Si-Sn-Cu合金的组织明显细化,但硬度下降;随着Cu含量的增加,Al-Si-Sn-Cu合金的组织没有明显变化,但硬度增大;通过Al-Ti5-B1中间合金细化处理,Al-Si-Sn-Cu合金的组织明显细化,硬度也有所增大,从而提高其综合力学性能.

  6. Effects of B4C Addition on the Laser Beam Welding Characteristics of Al/SiC MMCs Produced By P/M

    Directory of Open Access Journals (Sweden)

    Serdar KARAOĞLU

    2011-01-01

    Full Text Available Fusion weldability characteristics of metal matrix composites (MMC produced by powder metallurgy (P/M are usually insufficient due to unwanted micro-structural changes that occur during welding. This study aims to investigate the effects of B4C addition as reinforcement on the weld quality of Al/SiC MMCs. After the production of Al/SiC MMCs by P/M with or without the addition of B4C, laser beam welding (LBW characteristics of the materials were investigated by focusing on the integrity of the welds. Optical microscopy (OM, scanning electron microscopy (SEM, and energy dispersive X-ray analysis (EDX were utilized for the characterization of the welds. Results show that Al/SiC MMCs produced by P/M can not be easily welded by LBW, but weldability characteristics of the material can be improved by the addition of B4C.

  7. Growth and Device Performance of AlGaN/GaN Heterostructure with AlSiC Precoverage on Silicon Substrate

    Directory of Open Access Journals (Sweden)

    Jae-Hoon Lee

    2014-01-01

    Full Text Available A crack-free AlGaN/GaN heterostructure was grown on 4-inch Si (111 substrate with initial dot-like AlSiC precoverage layer. It is believed that introducing the AlSiC layer between AlN wetting layer and Si substrate is more effective in obtaining a compressively stressed film growth than conventional Al precoverage on Si surface. The metal semiconductor field effect transistor (MESFET, fabricated on the AlGaN/GaN heterostructure grown with the AlSiC layer, exhibited normally on characteristics, such as threshold voltage of −2.3 V, maximum drain current of 370 mA/mm, and transconductance of 124 mS/mm.

  8. Global Mg/Si and Al/Si Distributions on the Lunar Surface Derived from Chang'E-2 X-ray Spectrometer

    International Nuclear Information System (INIS)

    The technique of X-ray fluorescence remote sensing plays a significant role in research related to the chemical compositions of the Moon. Here we describe the data analysis method for China's Chang'E-2 X-ray spectrometer in detail and present the preliminary results about the first global Mg/Si and Al/Si maps of the lunar surface. Our results show that the distributions of Mg/Si and Al/Si correlate well with terrains on the Moon. The higher Mg/Si ratio corresponds to the mare regions while the lower value corresponds to the highland terrains. The map of the Al/Si ratio shows a reversed distribution compared with the map of the Mg/Si ratio. (paper)

  9. Global Mg/Si and Al/Si Distributions on Lunar Surface Derived from Chang'E-2 X-ray Spectrometer

    CERN Document Server

    Dong, Wu-Dong; Zhu, Meng-Hua; Xu, Aoao; Tang, Zesheng

    2015-01-01

    X-ray fluorescence remote sensing technique plays a significant role in the chemical compositions research of the Moon. Here we describe the data analysis method for China's Chang'E-2 X-ray spectrometer (CE2XRS) in detail and present the preliminary results: the first global Mg/Si and Al/Si maps on the lunar surface. Our results show that the distributions of Mg/Si and Al/Si correlate well with the terrains of the Moon. The higher Mg/Si ratio corresponding to the mare regions while the lower value corresponding to the highland terrains. The map of Al/Si ratio shows a reverse relationship with the map of Mg/Si ratio.

  10. Three-dimensional rigid multiphase networks providing high-temperature strength to cast AlSi10Cu5Ni1-2 piston alloys

    OpenAIRE

    Z. Asghar; Requena, G.; Boller, E.

    2011-01-01

    The three-dimensional (3-D) architecture of rigid multiphase networks present in AlSi10Cu5Ni1 and AlSi10Cu5Ni2 piston alloys in as-cast condition and after 4 h spheroidization treatment is characterized by synchrotron tomography in terms of the volume fraction of rigid phases, interconnectivity, contiguity and morphology. The architecture of both alloys consists of α-Al matrix and a rigid long-range 3-D network of Al7Cu4Ni, Al4Cu2Mg8Si7, Al2Cu, Al15Si2(FeMn)3 and AlSiFeNiCu aluminides and Si....

  11. Theoretical investigation of superconductivity in ternary silicide NaAlSi with layered diamond-like structure

    Science.gov (United States)

    Tütüncü, H. M.; Karaca, Ertuǧrul; Srivastava, G. P.

    2016-04-01

    We have investigated the electronic structure, phonon modes and electron-phonon coupling to understand superconductivity in the ternary silicide NaAlSi with a layered diamond-like structure. Our electronic results, using the density functional theory within a generalized gradient approximation, indicate that the density of states at the Fermi level is mainly governed by Si p states. The largest contributions to the electron-phonon coupling parameter involve Si-related vibrations both in the x-y plane as well as along the z-axis in the x-z plane. Our results indicate that this material is an s-p electron superconductor with a medium level electron-phonon coupling parameter of 0.68. Using the Allen-Dynes modification of the McMillan formula we obtain the superconducting critical temperature of 6.98 K, in excellent agreement with experimentally determined value of 7 K.

  12. Effect of different heat treatment process on damping peak of 6061Al/SiCp MMC produced by spray codeposition

    Institute of Scientific and Technical Information of China (English)

    顾金海; 张清霄; 顾敏; 王西科; 王灿; 朱震刚

    2002-01-01

    Effects of five typical heat treatment processes on the damping properties and the damping peak of 6061Al/SiCp MMC fabricated by spray codeposition were studied. The results show that the internal friction spectra of various heat treated samples exhibit the damping peak versus temperature between 130℃ and 200℃. Furthermore, the peak temperature as well as the peak height increases with increasing frequencies. By Arrhenius equation the active energy of the damping peak can be gotten, which is above 1eV. On the other hand, different quenching treatments affect the damping peak remarkably, when the rate of cooling is above that of water quenching, the damping peak will shift to higher temperature as cooling speed is enhanced.

  13. Quantitative analysis of reinforcing phase in AlSi11/CrFe30C8 composite castings

    Directory of Open Access Journals (Sweden)

    A. Dulęba

    2011-07-01

    Full Text Available In this paper assessment of the morphology and segregation of the reinforcing phase based on optical quantitative analysis was achieved. Microscopic observation of AlSi11/CrFe30C8 composite gravity castings was carried out in electromagnetic field. The purpose of investigation was the analysis of current frequency influence supplying the inductor of electromagnetic field on segregation, quantity and morphology of reinforcement phase in aluminum matrix composite. Technological conception of investigations was based on assumption that chromium-iron matrix of particles dissolved in aluminum composite matrix and carbide phases became actual reinforcement of the composite. Gravity segregation was analyzed. Graphs containing distribution of reinforcing phase in metal matrix were shown.

  14. Tuning electronic and magnetic properties of blue phosphorene by doping Al, Si, As and Sb atom: A DFT calculation

    Science.gov (United States)

    Sun, Minglei; Hao, Yitong; Ren, Qingqiang; Zhao, Yiming; Du, Yanhui; Tang, Wencheng

    2016-09-01

    Using density functional theory computations, we systematically investigated the structural, electronic and magnetic properties of Al, Si, As and Sb doped blue phosphorene. The electronic properties of blue phosphorene can be effectively turned by substitutional doping. Especially, Al and Sb lead to an indirect-to-direct-gap transition. The interaction between the impurity and P atoms should be responsible for the transition. In addition, blue phosphorene can exhibit dilute magnetic semiconductor property with doping of Si impurity. The magnetic moment in Si-substituted blue phosphorene predominantly originates from the hybridization of Si-s pz and P-pz orbitals. These results provide many useful applications of blue phosphorene in electronics, optoelectronics and spintronics.

  15. Effect of Si content on the dry sliding wear properties of spray-deposited Al-Si alloy

    International Nuclear Information System (INIS)

    In the present investigation, Al-12Si, Al-20Si and Al-25Si (wt%) alloys were synthesized by spray atomization and deposition technique. The wear resistance of the alloys was studied using a pin-on-disc machine under four loads, namely 8.9, 17.8, 26.7 and 35.6 N. The microstructures, worn surfaces and the debris were analyzed in a scanning electron microscope. It has been found that the effect of Si content on dry sliding wear of spray-deposited Al-Si alloy was associated with applied loads. At lower load (8.9 N), with increasing Si content, the wear rate of the alloy was decreased. At higher load (35.6 N), spray-deposited Al-20Si alloy exhibited superior wear resistance to the Al-12Si and Al-25Si alloys

  16. Abrasive and sliding wear characteristics of Al-Si cast alloys before and after coating by plasma electrolytic oxidation process

    Energy Technology Data Exchange (ETDEWEB)

    Aydin, H.; Bayram, A. [Uludag Univ., Bursa (Turkey). Dept. of Mechanical Engineering; Uguz, A. [Science Park Ulutek (Turkey)

    2008-07-01

    The wear resistance of a series of Al-Si cast alloys with 5%, 8% and 11% silicon contents have been investigated after spheroidising heat treatments, and after coating these alloys by a plasma electrolytic oxidation (PEO) process for comparison. The alloys were subjected to wear tests by using SiC and steel counterfaces. The most remarkable observation is the increase in the wear resistance of the 5% Si containing alloy against SiC counterface, which is 70 times. However, the increase in the wear resistance is 5 times in the 11% Si containing alloy under same conditions, and only about 50% increase is observed when the counterface is steel. It is argued that, coating of these alloys by plasma electrolytic oxidation improves the wear resistance more effectively if the silicon content of the alloy is low, since the silicates (or aluminosilicates) in the coating layer has deleterious effect on wear resistance. (orig.)

  17. Synthesis and Study on Effect of Parameters on Dry Sliding Wear Characteristics of AL-SI Alloys

    Directory of Open Access Journals (Sweden)

    Francis Uchenna OZIOKO

    2012-08-01

    Full Text Available The effect of parameters on dry sliding wear characteristics of Al-Si alloys was studied. Aluminium-silicon alloys containing 7%, 12% and 14% weight of silicon were synthesized using casting method. Dry sliding wear characteristics of sample were studied against a hardened carbon steel (Fe-2.3%Cr-0.9%C using a pin-on-disc. Observations were recorded keeping two parameters (sliding distance, sliding speed and load constant against wear at room temperature. Microstructural characterization was done using optical microscope (OM and scanning electron microscope (SEM. Hardness and wear characteristics of different samples have shown near uniform behaviour. The wear rate decreased when the percentage of silicon increases. Wear was observed to increase at higher applied load, higher sliding speed and higher sliding distance. The wear characteristics of Al-14%Si was observed superior to those of Al-7%Si and Al-12%Si due to the degree of refinement of their eutectic silicon.

  18. Identification of phases in the interaction layer between U-Mo-Zr/Al and U-Mo-Zr/Al-Si

    International Nuclear Information System (INIS)

    Out-of-pile diffusion experiments were performed between U-7wt.% Mo-1wt.% Zr and Al or Al A356 (7,1wt.% Si) at 550 deg. C. In this work morphological characterization and phase identification on both interaction layer are presented. They were carried out by the use of different techniques: optical and scanning electron microscopy, X-Ray diffraction and WDS microanalysis. In the interaction layer U-7wt.% Mo-1wt.% Zr/Al, the phases UAl3, UAl4, Al20Mo2U and Al43Mo4U6 were identified. In the interaction layer U-7wt.% Mo-1wt.% Zr/Al A356, the phases U(Al, Si) with 25at.% Si and Si5U3 were identified. This last phase, with a higher Si concentration, was identified with XRD Synchrotron radiation performed at the National Synchrotron Light Laboratory (LNLS), Campinas, Brasil. (author)

  19. Effect of T6 heat treatment on the microstructural and mechanical properties of Al-Si-Cu-Mg alloys

    Science.gov (United States)

    Patel, Dhruv; Davda, Chintan; Solanki, P. S.; Keshvani, M. J.

    2016-05-01

    In this communication, it is aimed to optimize the conditions for T6 heat treatment of permanent die cast Al-Si-Cu-Mg alloys. Various solutionizing temperatures, aging treatments and soaking times were used to improve / modify the mechanical properties of presently studied alloys. Formation mechanism of the particles was understood by carrying out optical microscopy and energy dispersive X-ray (EDX) spectroscopy measurements. Spherical particles of alloys were studied for their microstructural properties using scanning electron microscopy (SEM). Microhardness test was performed to investigate their mechanical properties. Dependence of cluster formation and microhardness of the alloys on the adequate solutionizing temperature, aging treatment and soaking time has been discussed in detail.

  20. Al-Si alloy point contact formation and rear surface passivation for silicon solar cells using double layer porous silicon

    International Nuclear Information System (INIS)

    Lowering the rear surface recombination velocities by a dielectric layer has fascinating advantages compared with the standard fully covered Al back-contact silicon solar cells. In this work the passivation effect by double layer porous silicon (PS) (wide band gap) and the formation of Al-Si alloy in narrow p-type Si point contact areas for rear passivated solar cells are analysed. As revealed by Fourier transform infrared spectroscopy, we found that a thin passivating aluminum oxide (Al2O3) layer is formed. Scanning electron microscopy analysis performed in cross sections shows that with bilayer PS, liquid Al penetrates into the openings, alloying with the Si substrate at depth and decreasing the contact resistivity. At the solar cell level, the reduction in the contact area and resistivity leads to a minimization of the fill factor losses.

  1. Use of sodium salt electrolysis in the process of continuous modification of eutectic EN AC-AlSi12 alloy

    Indian Academy of Sciences (India)

    J Pezda; A Białobrzeski

    2015-04-01

    This paper presents test results concerning the selection of sodium salt for the technology of continuous modification of the EN AC-AlSi12 alloy, which is based on electrolysis of sodium salts, occurring directly in a crucible with liquid alloy. Sodium ions formed as a result of the sodium salt dissociation and the electrolysis are 'transferred' through walls of the retort made of solid electrolyte. Upon contact with the liquid alloy, which functions as a cathode, sodium ions are transformed into the atomic state, modifying the alloy. As a measure of the alloy modification extent, the obtained increase of the tensile strength m and change of metallographic structure are used, confirming obtained modification effect of the investigated alloy.

  2. Effects of chill casting processes on secondary dendrite arm spacing and densification of Al-Si-Mg alloy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on the resin bonded sand casting process, the effects of chill processes on the secondary dendrite arm spacing(SDAS) and densification of Al-Si-Mg alloy were studied. The influences of the chill thickness and effective distance of chill operating on the SDAS were researched; and the effect of chillheat capacity on SDAS was investigated. The result reveals that,SDAS decreases with increasing the thickness of chill but the effect of chill is finite. The effective distance of chill operating for the chill with different thickness were obtained, and the functional relations among modulus, length of castings and thickness of chill were discussed, and the synthetical network chart of the relation among them was plotted. The relationship between local solidification rate and SDAS was defined by means of quadratic polynomial regression.

  3. Growth and deformation structure of gradient and layer-gradient Ti-Al-Si-Cu-N coatings

    Energy Technology Data Exchange (ETDEWEB)

    Ovchinnikov, Stanislav V., E-mail: ovm@spti.tsu.ru; Pinzhin, Yurii P., E-mail: pinzhin@phys.tsu.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Korotaev, Alexandr D., E-mail: korotaev@phys.tsu.ru [National Research Tomsk State University, Tomsk, 634050 (Russian Federation)

    2014-11-14

    The features of the growth structure and modification of gradient and layer-gradient Ti-Al-Si-Cu-N coatings in the areas of deformation and fracture during indentation and scratch testing were investigated using transmission and scanning electron microscopy methods. The influence of the concentration of alloying elements and displacement potential in the substrate on the secondary sputtering, phase composition and the level of combined torsion and bending of the crystal lattice of doped TiN were determined. It was found out that the size of the crystals in deformation location bands grows with deformation of gradient nanocrystal coatings. The article shows that layer-gradient coatings combining submicrocrystalline and nanocrystalline structures have the increased plasticity and fracture toughness due to enhanced density of interfaces and formation of the soft metal phase (Cu) in the surface layer.

  4. Growth and deformation structure of gradient and layer-gradient Ti-Al-Si-Cu-N coatings

    International Nuclear Information System (INIS)

    The features of the growth structure and modification of gradient and layer-gradient Ti-Al-Si-Cu-N coatings in the areas of deformation and fracture during indentation and scratch testing were investigated using transmission and scanning electron microscopy methods. The influence of the concentration of alloying elements and displacement potential in the substrate on the secondary sputtering, phase composition and the level of combined torsion and bending of the crystal lattice of doped TiN were determined. It was found out that the size of the crystals in deformation location bands grows with deformation of gradient nanocrystal coatings. The article shows that layer-gradient coatings combining submicrocrystalline and nanocrystalline structures have the increased plasticity and fracture toughness due to enhanced density of interfaces and formation of the soft metal phase (Cu) in the surface layer

  5. Interfacial microstructure and mechanical property of resistance spot welded joint of high strength steel and aluminium alloy with 4047 AlSi12 interlayer

    International Nuclear Information System (INIS)

    Highlights: • Steel and aluminium alloy were resistance spot welded with interlayer successfully. • Welded joint of steel and aluminium alloy with 4047 interlayer was a brazed joint. • Fe2(Al,Si)5 and Fe4(Al,Si)13 were formed at the steel/aluminium interface. • Reaction diffusion at the interface was inhibited by introduction of silicon atoms. • Welded joint property was improved greatly with the interlayer thickness of 300 μm. - Abstract: Dissimilar materials of H220YD galvanised high strength steel and 6008-T66 aluminium alloy were welded by means of median frequency direct current resistance spot welding with employment of 4047 AlSi12 interlayer. Effects of interlayer thickness on microstructure and mechanical property of the welded joints were studied. The welded joint with interlayer employed could be recognised as a brazed joint. The nugget diameter had a decreased tendency with increasing thickness of interlayer under optimised welding parameters. An intermetallic compound layer composed of Fe2(Al,Si)5 and Fe4(Al,Si)13 was formed at the interfacial zone in the welded joint, the thickness and morphology of which varying with the increase of interlayer thickness. Reaction diffusion at the steel/aluminium interface was inhibited by introduction of silicon atoms, which restricted growth of Fe2(Al,Si)5. Tensile shear load of welded joints experienced an increased tendency with increasing interlayer thickness from 100 to 300 μm, and the maximum tensile shear load of 6.2 kN was obtained with interlayer thickness of 300 μm, the fractured welded joint of which exhibiting a nugget pullout failure mode

  6. Thermal and Microstructure Characterization of Zn-Al-Si Alloys and Chemical Reaction with Cu Substrate During Spreading

    Science.gov (United States)

    Berent, Katarzyna; Pstruś, Janusz; Gancarz, Tomasz

    2016-04-01

    The problems associated with the corrosion of aluminum connections, the low mechanical properties of Al/Cu connections, and the introduction of EU directives have forced the potential of new materials to be investigated. Alloys based on eutectic Zn-Al are proposed, because they have a higher melting temperature (381 °C), good corrosion resistance, and high mechanical strength. The Zn-Al-Si cast alloys were characterized using differential scanning calorimetry (DSC) measurements, which were performed to determine the melting temperatures of the alloys. Thermal linear expansion and electrical resistivity measurements were performed at temperature ranges of -50 to 250 °C and 25 to 300 °C, respectively. The addition of Si to eutectic Zn-Al alloys not only limits the growth of phases at the interface of liquid solder and Cu substrate but also raises the mechanical properties of the solder. Spreading test on Cu substrate using eutectic Zn-Al alloys with 0.5, 1.0, 3.0, and 5.0 wt.% of Si was studied using the sessile drop method in the presence of QJ201 flux. Spreading tests were performed with contact times of 1, 8, 15, 30, and 60 min, and at temperatures of 475, 500, 525, and 550 °C. After cleaning the flux residue from solidified samples, the spreadability of Zn-Al-Si on Cu was determined. Selected, solidified solder/substrate couples were cross-sectioned, and the interfacial microstructures were studied using scanning electron microscopy and energy dispersive x-ray spectroscopy. The growth of the intermetallic phase layer was studied at the solder/substrate interface, and the activation energy of growth of Cu5Zn8, CuZn4, and CuZn phases were determined.

  7. Preparation of Al-Si Master Alloy by Electrochemical Reduction of Volcanic Rock in Cryolite Molten Salt

    Science.gov (United States)

    Liu, Aimin; Shi, Zhongning; Xu, Junli; Hu, Xianwei; Gao, Bingliang; Wang, Zhaowen

    2016-06-01

    Volcanic rock found in the Longgang Volcano Group in Jilin Province of China has properties essentially similar to Apollo lunar soils and previously prepared lunar soil simulants, such as Johnson Space Center Lunar simulant and Minnesota Lunar simulant. In this study, an electrochemical method of preparation of Al-Si master alloy was investigated in 52.7 wt.%NaF-47.3 wt.%AlF3 melt adding 5 wt.% volcanic rock at 1233 K. The cathodic electrochemical process was studied by cyclic voltammetry, and the results showed that the cathodic reduction of Si(IV) is a two-step reversible diffusion-controlled reaction. Si(IV) is reduced to Si(II) by two electron transfers at -1.05 V versus platinum quasi-reference electrode in 52.7 wt.%NaF-47.3 wt.%AlF3 molten salt adding 5 wt.% volcanic rock, while the reduction peak at -1.18 V was the co-deposition of aluminum and silicon. In addition, the cathodic product obtained by galvanostatic electrolysis for 4 h was analyzed by means of x-ray diffraction, x-ray fluorescence, scanning electron microscopy and energy dispersive spectrometry. The results showed that the phase compositions of the products are Al, Si, Al5FeSi, and Al3.21Si0.47, while the components are 90.5 wt.% aluminum, 4.4 wt.% silicon, 1.9 wt.% iron, and 0.2 wt.% titanium.

  8. Effect of (Mn + Cr) addition on the microstructure and thermal stability of spray-formed hypereutectic Al-Si alloys

    International Nuclear Information System (INIS)

    Microstructures and thermal stability of hypereutectic Al-Si alloys with or without (Mn + Cr) addition, prepared via Spray Forming technique, are studied and compared with traditional cast alloys with same composition, using scanning electron microscopy with energy diffraction spectrum, X-ray diffraction, transmission electron microscopy and differential scanning calorimeter. The results show that the Fe-bearing and primary silicon phases in SF-3C alloy can be refined to less than 10 μm, especially in SF-MC21 alloy the Fe-bearing phase is refined into uniformly distributed α-Al(Fe,Mn,Cr)Si phase particles with sizes smaller than 5-6 μm, contributing to the decrease/elimination of the deleterious effect of needle-like Fe-bearing phases. The results of different heat treatments show SF-MC21 alloy possesses excellent thermal stability than SF-3C alloy which is unstable below 750 K for the coarsening of β-Al5FeSi phase and formation of Al7Cu2Fe phase. The study indicates that both the existence of thermodynamically stable α-Al(Fe,Mn,Cr)Si particles and the increase of solidus temperature of SF-3C alloy induced by adding (2Mn + 1Cr) elements contribute to the high thermal stability of SF-MC21 alloy. Contemporarily, combined the phase reactions or transformation occurred during the melting and solidification processes of both spray-formed hypereutectic Al-Si alloys, the microstructure formation of spray-formed alloys is discussed.

  9. Effect of (Mn + Cr) addition on the microstructure and thermal stability of spray-formed hypereutectic Al-Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hou, L.G. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Cui, H. [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Cai, Y.H. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, J.S., E-mail: zhangjs@skl.ustb.edu.cn [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)

    2009-12-15

    Microstructures and thermal stability of hypereutectic Al-Si alloys with or without (Mn + Cr) addition, prepared via Spray Forming technique, are studied and compared with traditional cast alloys with same composition, using scanning electron microscopy with energy diffraction spectrum, X-ray diffraction, transmission electron microscopy and differential scanning calorimeter. The results show that the Fe-bearing and primary silicon phases in SF-3C alloy can be refined to less than 10 {mu}m, especially in SF-MC21 alloy the Fe-bearing phase is refined into uniformly distributed {alpha}-Al(Fe,Mn,Cr)Si phase particles with sizes smaller than 5-6 {mu}m, contributing to the decrease/elimination of the deleterious effect of needle-like Fe-bearing phases. The results of different heat treatments show SF-MC21 alloy possesses excellent thermal stability than SF-3C alloy which is unstable below 750 K for the coarsening of {beta}-Al{sub 5}FeSi phase and formation of Al{sub 7}Cu{sub 2}Fe phase. The study indicates that both the existence of thermodynamically stable {alpha}-Al(Fe,Mn,Cr)Si particles and the increase of solidus temperature of SF-3C alloy induced by adding (2Mn + 1Cr) elements contribute to the high thermal stability of SF-MC21 alloy. Contemporarily, combined the phase reactions or transformation occurred during the melting and solidification processes of both spray-formed hypereutectic Al-Si alloys, the microstructure formation of spray-formed alloys is discussed.

  10. Al-Si 二元合金の流動性と溶湯の性状について

    OpenAIRE

    照元, 弘行; 尾崎, 良平; 三宅, 秀和; MIYAKE, Hidekazu; 岡田, 明

    1991-01-01

    The flow length of liquid Al-Si alloys was measured by using spiral shell moulds. The influence of silicon content, sodium or phosphorus modifier treatment on the fludity of Al-Si alloys was investigated. 1) The change of the flow length with the increase of silicon content was similar to previous works obtained by using different apparatus. The change of the flow length of hypereutectic alloys could be explained by undercooling of the melt, floating and the latent heat of primary silicon cry...

  11. The effect of Nb-B inoculation on binary hypereutectic and near-eutectic LM13 Al-Si cast alloys

    OpenAIRE

    Nowak, M.; Bolzoni, L.; Nadendla, HB

    2015-01-01

    This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Hyper-eutectic Al-Si alloys are used for wear-resistant components, such as pistons, because their microstructure is composed by ductile aluminium dendrites and hard primary silicon particles. In this study the effect of Nb-B inoculation on the microstructural features of binary hyper-eutectic and near-eutectic LM13 Al-Si alloys is assessed. It is found that the inoculation with Nb-based c...

  12. Obtención de aleaciones eutécticas PbLi mediante procesos de fusión

    Directory of Open Access Journals (Sweden)

    Barrena, M. I.

    2012-12-01

    Full Text Available The development of thermonuclear experimental reactor (ITER, whose objective is to produce energy from nuclear fusion, has raised the study of Pb-Li eutectic alloys, as they have been selected for the manufacture of test blanket modules (TBM. However, during the manufacturing process of the Pb-Li alloys, thermal conditions used result in a loss of litium element, which inhibits the formation of eutectic structures. In this work we have done fusion of pure lead and lithium, evaluating different process parameters to obtain Pb-Li (17 at. % eutectic alloys. The alloys manufactured were characterized by DSC, SEM-EDX and microhardness tests. From these studies we noted that the used of an induction reactor and the process parameters optimized to obtain Pb-Li alloy allow for completely eutectic ingots and high chemical homogeneity and microstructural.

    El desarrollo del reactor experimental termonuclear (ITER, cuyo objetivo es la producción de energía a partir de la fusión nuclear, ha suscitado el estudio de las aleaciones eutécticas Pb-Li, ya que éstas han sido seleccionadas para la fabricación de las envolturas regeneradoras del reactor (TBM. Sin embargo, durante el proceso de fabricación de las aleaciones Pb-Li se produce una pérdida de litio, que inhibe la formación de estructuras eutécticas. En el presente trabajo se han realizado fusiones partiendo de plomo y litio puros evaluando diferentes parámetros de proceso para la obtención de aleaciones eutécticas Pb-Li (17 % at.. Las aleaciones obtenidas fueron caracterizadas mediante calorimetría diferencial de barrido, microscopía SEM-EDX y microdureza. De estos estudios podemos señalar, que la utilización de hornos de inducción y los parámetros de proceso optimizados para la obtención de la aleación Pb-Li, permiten obtener lingotes completamente eutécticos y con gran homogeneidad química y microestructural.

  13. Comportamiento mecánico en función de la temperatura de aleaciones wolframio-vanadio.

    OpenAIRE

    Palacios García, Teresa; Aguirre Cebrian, Maria Vega; Martin Sanz, Antonia; Pastor Caño, Jose Ignacio; Llorca Martinez, Francisco Javier; Monge, M. A.; A. Muñoz; Pareja, R.

    2010-01-01

    En esta investigación se evalúa el comportamiento mecánico del wolframio puro y de dos de sus aleaciones con contenidos de 2% y 4% de vanadio, fabricadas mediante prensado isostático en caliente (HIP). La caracterización mecánica se ha realizado mediante ensayos de flexión en tres puntos en atmósfera oxidante a distintas temperaturas comprendidas entre temperatura ambiente y 1000 ºC. Adicionalmente, se han realizado ensayos en inmersión en nitrógeno líquido para los de -197 ºC. Estos últi...

  14. Diffusion mobilities in the fcc{sub A}1 Cu-Si, Al-Si and Al-Cu-Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Dachun [School of Mechanical Engineering, Xiangtan University, Xiangtan, Hunan Province 411105 (China); Liu, Ya [School of Materials Science and Engineering, Changzhou University, 1 Gehu Road, Changzhou, Jiangsu Province 213164 (China); Su, Xuping, E-mail: sxping@cczu.edu.cn [School of Mechanical Engineering, Xiangtan University, Xiangtan, Hunan Province 411105 (China); School of Materials Science and Engineering, Changzhou University, 1 Gehu Road, Changzhou, Jiangsu Province 213164 (China); Wang, Jianhua; Tu, Hao [School of Materials Science and Engineering, Changzhou University, 1 Gehu Road, Changzhou, Jiangsu Province 213164 (China); Huang, Jianfeng [School of Mechanical Engineering, Xiangtan University, Xiangtan, Hunan Province 411105 (China)

    2013-02-25

    Highlights: Black-Right-Pointing-Pointer The atomic mobilities of fcc Cu-Si, Al-Si and Al-Cu-Si alloys have been assessed. Black-Right-Pointing-Pointer The calculated results agree well with various experimental diffusivities. Black-Right-Pointing-Pointer The temperature and concentration dependence are taken into consideration. Black-Right-Pointing-Pointer The mobility parameters obtained can be used to predict many diffusion phenomena. - Abstract: Based on the available thermodynamic parameters and experimental data of self-diffusivity, impurity diffusivity, intrinsic diffusivity, tracer diffusivity and interdiffusivity in the Cu-Si, Al-Si and Al-Cu-Si alloys, the atomic mobilities of Cu, Al and Si in face-centered cubic (fcc{sub A}1) Cu-Si, Al-Si and Al-Cu-Si alloys have been critically assessed as a function of temperature and composition using the CALPHAD-type and DICTRA software package. Comparisons between the calculated and measured coefficients reveal that most of the diffusivities can be reproduced satisfactorily. The obtained mobility parameters can be used to study diffusion-related characteristics for fcc{sub A}1 Cu-Si, Al-Si and Al-Cu-Si alloys.

  15. Observation of free electron cyclotron resonance in NaAlSi3O8 feldspar: Direct determination of the effective electron mass

    DEFF Research Database (Denmark)

    Poolton, N.R.J.; Nicholis, J.E.; Bøtter-Jensen, L.; Smith, G.M.; Riedi, P.C.

    2001-01-01

    We report the first observation of cyclotron resonances in alkali feldspars, using highly sensitive optical detection methods. In Na-feldspar (NaAlSi3O8). a near isotropic effective electron mass value of m(c)(*) = 0.79m, has been determined. The significance of this measurement in terms of the...

  16. Fatigue Strength Degradation of AlSi12CuNiMg Alloy Due to High Temperature Exposure: A Structural Investigation

    Czech Academy of Sciences Publication Activity Database

    Konečná, R.; Nicoletto, G.; Kunz, Ludvík; Svoboda, Milan; Bača, A.

    Amsterdam : Elsevier, 2014 - (Gulagliano, M.; Vergani, L.), s. 43-46 ISSN 1877-7058. - (Procedia Engineering. 74). [ICMFM 2014 International Colloquium on Mechanical Fatigue of Metals /17./. Verbania (IT), 25.06.2014-27.06.2014] Institutional support: RVO:68081723 Keywords : Al-Si alloys * Fatigue strength * Structural investigation * Age hardening * Precipitates Subject RIV: JL - Materials Fatigue, Friction Mechanics

  17. Li3AlSiO5: the first aluminosilicate as a potential deep-ultraviolet nonlinear optical crystal with the quaternary diamond-like structure.

    Science.gov (United States)

    Chen, Xinglong; Zhang, Fangfang; Liu, Lili; Lei, Bing-Hua; Dong, Xiaoyu; Yang, Zhihua; Li, Hongyi; Pan, Shilie

    2016-02-14

    Deep-ultraviolet (deep-UV) nonlinear optical (NLO) crystals play a crucial role in modern laser frequency conversion technology. Traditionally, the exploration of deep-UV NLO crystals is mainly focused on borates, while, the use of phosphates recently opened up a novel and promising non-boron pathway for designing new deep-UV NLO crystals. Extending this pathway to aluminosilicates led to the discovery of Li3AlSiO5, the first NLO crystal in this system. It crystallizes in the polar space group Pna21 (no. 33) with a quaternary diamond-like structure composed of LiO4, AlO4 and SiO4 tetrahedral groups. The compound exhibits a deep-UV cut-off edge below 190 nm and is phase matchable with moderate powder second harmonic generation (SHG) intensity (0.8KH2PO4). The band gap calculated using PBE0 is 7.29 eV, indicating that the cut-off edge of the Li3AlSiO5 crystal can be down to 170 nm. In addition, the compound is nonhygroscopic and thermally stable up to ∼1472 K. These results suggest that Li3AlSiO5 is a potential deep-UV NLO crystal. First-principles studies were performed to elucidate the structure-property relationship of Li3AlSiO5. PMID:26788988

  18. Analysis of the interaction products in U(Mo,X)/Al and U(Mo,X)/Al(Si) diffusion couples, with X = Cr, Ti, Zr

    International Nuclear Information System (INIS)

    In the framework of the development of a low 235U enriched nuclear fuel for material testing reactors, γ-U(Mo)/Al based materials are considered as the most interesting prospect. In the process to optimize their composition, addition to both γ-U(Mo) and Al have been proposed. In this paper, the crystallographic composition of Interaction Layers (ILs) in γ-U(Mo,X)/Al and γ-U(Mo,X)/AlSi7 diffusion couples, with X = Cr, Ti, Zr, heat-treated at 600 °C for 2 h, were studied by micro-X-ray diffraction (μ-XRD). When compared to the U(Mo)/Al and U(Mo)/Al(Si) reference systems, all investigated systems involving either Al or Al(Si) as counterparts show interaction products composed of similar phases and related sequences of phase formation. Only relative thicknesses of sub-layers and relative fractions of intermediate phases are correlated with the nature of the X element in the γ-U(Mo,X) alloy. More generally this work shows that γ-U(Mo)/Al and γ-U(Mo)/Al(Si) ILs are now robustly described down to the micrometer scale

  19. Effect of Microstructure of Al-Si-alloy on the Quality of the Layer Formed with Micro-Arc Oxidation Method

    Directory of Open Access Journals (Sweden)

    Kiseleva S.K.

    2015-09-01

    Full Text Available This investigation is on the properties of hardened layers, developed with the micro-arc oxidation method (MAO on the surface of the ingots from an Al-Si alloy. It has been established that the properties (microhardness, thickness, porosity of the generated surfaces depend on the structure of the alloy.

  20. Resistance to cyclic oxidation of Al-Si diffusion coatings deposited by Arc-PVD on TiAlCrNb alloy

    International Nuclear Information System (INIS)

    One of the candidates to replace superalloys in some engine applications is γ-(TiAl) which is characterized by a density almost half of that of superalloys. Titanium aluminides exhibit a strong TiO2 forming tendency rather than formation of the protective Al2O3 at high temperatures. The oxidation resistance is further reduced with decreasing Al content. The article presents research results of cyclic oxidation of γ-(TiAl) alloy with Al-Si coatings and without coatings. Protective coatings were deposited by Arc-PVD method in two steps. In the first one AlSi layer was deposited. In the second step the temperature of samples in vacuum chamber was increased and diffusion Ti AlSi coating was formed. After coating deposition the heat treatment of samples in vacuum was made. The temperature of heat treatment was 950 oC and the time 2 hours. At temperature of 950 oC cyclic oxidation tests were carried out. The time of reaching the temperature and cooling was 5 minutes. Mass changes of the specimens were recorded every 100 cycles. The total number of cycles amounted to 2400. Phase composition, morphology and the distribution of elements were defined by EDX, XRD and SEM in AlSi layers as well as in the scale. (author)

  1. EBSD Study of the Influence of a High Magnetic Field on the Microstructure and Orientation of the Al-Si Eutectic During Directional Solidification

    Science.gov (United States)

    Li, Xi; Fautrelle, Yves; Gagnoud, Annie; Ren, Zhongming; Moreau, Rene

    2016-06-01

    The effect of a high magnetic field on the morphology of the Al-Si eutectic was investigated using EBSD technology. The results revealed that the application of the magnetic field modified the morphology of the Al-Si eutectic significantly. Indeed, the magnetic field destroyed the coupled growth of the Al-Si eutectic and caused the formation of the divorced α-Al and Si dendrites at low growth speeds (≤1 μm/s). The magnetic field was also found to refine the eutectic grains and reduce the eutectic spacing at the initial growth stage. Moreover, the magnetic field caused the occurrence of the columnar-to-equiaxed transition of the α-Al phase in the Al-Si eutectic. The abovementioned effects were enhanced as the magnetic field increased. This result should be attributed to the magnetic field restraining the interdiffusion of Si and Al atoms in liquid ahead of the liquid/solid interface and the thermoelectric magnetic force acting on the eutectic lamellae under the magnetic field.

  2. Internally consistent thermodynamic data for aqueous species in the system Na-K-Al-Si-O-H-Cl

    Science.gov (United States)

    Miron, George D.; Wagner, Thomas; Kulik, Dmitrii A.; Heinrich, Christoph A.

    2016-08-01

    A large amount of critically evaluated experimental data on mineral solubility, covering the entire Na-K-Al-Si-O-H-Cl system over wide ranges in temperature and pressure, was used to simultaneously refine the standard state Gibbs energies of aqueous ions and complexes in the framework of the revised Helgeson-Kirkham-Flowers equation of state. The thermodynamic properties of the solubility-controlling minerals were adopted from the internally consistent dataset of Holland and Powell (2002; Thermocalc dataset ds55). The global optimization of Gibbs energies of aqueous species, performed with the GEMSFITS code (Miron et al., 2015), was set up in such a way that the association equilibria for ion pairs and complexes, independently derived from conductance and potentiometric data, are always maintained. This was achieved by introducing reaction constraints into the parameter optimization that adjust Gibbs energies of complexes by their respective Gibbs energy effects of reaction, whenever the Gibbs energies of reactant species (ions) are changed. The optimized thermodynamic dataset is reported with confidence intervals for all parameters evaluated by Monte Carlo trial calculations. The new thermodynamic dataset is shown to reproduce all available fluid-mineral phase equilibria and mineral solubility data with good accuracy and precision over wide ranges in temperature (25-800 °C), pressure (1 bar to 5 kbar) and composition (salt concentrations up to 5 molal). The global data optimization process adopted in this study can be readily repeated any time when extensions to new chemical elements and species are needed, when new experimental data become available, or when a different aqueous activity model or equation of state should be used. This work serves as a proof of concept that our optimization strategy is feasible and successful in generating a thermodynamic dataset reproducing all fluid-mineral and aqueous speciation equilibria in the Na-K-Al-Si-O-H-Cl system within

  3. Superplastic forming of the Cd-17.4Zn alloy; Conformado superplastico de la aleacion Cd-17.4Zn

    Energy Technology Data Exchange (ETDEWEB)

    Llanes-Briceno, J. A.; Torres-Villasenor, G. [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    2000-06-01

    In the present work the necessary steps to carry on the superplastic forming of the Cd-17.4Zn alloy are defined. The use of either atmospheric pressure or gas pressure as forming tools is analyzed. The optimum values of the variable involved (temperature, maximum strain and sensitivity index) are determined while a method for the characterization of futures superplastic alloys is set forth. The experimental characterization of the superplastic forming is achieved with free bulging of circular membranes of 12, 16, 24, 32 and 40 mm in diameter and with three different membrane thicknesses (0.4, 0.6, 0.8 mm). [Spanish] Se definen los pasos necesarios para el conformado superplastico de la aleacion Cd-17.4 Zn. Se comparan la presion atmosferica y el gas a presion como herramientas de conformado. Se determinan los valores optimos de la variables involucradas (temperatura, deformacion maxima e indice de sensibilidad) y se plantea una metodologia para la caracterizacion de futuras aleaciones superplasticas. El conformado superplastico se caracteriza experimentalmente mediante el inflado libre de membranas circulares de 12, 16, 24, 32 y 40 mm de diametro y tres diferentes espesores (0.4, 0.6 y 0.8 mm). Se muestra la estructura perlitica (enfuiada al aive Cd-17.4Zn) y la estructura grano fino. Se muestra la profundidad de deformacion en tres espesores (0.4, 0.6, 0.8 mm) a P=200 Kpa y T = 200 y a T = 230.

  4. Effect of nano Cu coating on porous Si prepared by acid etching Al-Si alloy powder

    International Nuclear Information System (INIS)

    As a promising anode material for lithium ion battery, nano-Cu coated porous Si powder was fabricated through two stages: first, preparation of porous nano Si fibers by acid-etching Al-Si alloy powder; second, modified by nano-Cu particles using an electroless plating method. The nano-Cu particles on the surface of nano-Si fibers, not only increase the conductivity of material, but also inhibit the fuse process between nano Si fibers during charge/discharge cycling process, resulting in increased cycling stability of the material. In 1 M LiPF6/EC: DMC (1:1) + 1.5 wt% VC solution at current density of 200 mA g−1, the 150th discharge capacity of nano-Cu coated porous Si electrode was 1651 mAh g−1 with coulombic efficiency of 99%. As anode material for lithium ion battery, nano-Cu coated porous Si nano fiber material is easier to prepare, costs less, and produces higher performance, representing a promising approach for high energy lithium ion battery application

  5. Study of deformation behavior, structure and mechanical properties of the AlSiMnFe alloy during ECAP-PBP.

    Science.gov (United States)

    Naizabekov, A B; Andreyachshenko, V A; Kocich, Radim

    2013-01-01

    The presented article deals with the effects of equal channel angular pressing (ECAP) with a newly adjusted die geometry on the microstructure and mechanical properties of the Al-Si-Mn-Fe alloy. This alloy was subjected to two modes of heat treatment followed by the ECAP process, which led to partial back pressure (ECAP-PBP). Ultra-fine grained (UFG) structure formed through ECAP-PBP process has been studied by methods of optical as well as electron microscopy. The obtained results indicate that quenched alloys, in comparison to slowly cooled alloys, do not contain large brittle particles which subsequently initiate a premature creation of cracks. It was shown that the mechanical properties of these alloys after such processing depend first and foremost on the selected type of heat treatment and on the number of performed passes. The maximum of ultimate tensile strength (417 MPa) was obtained for quenched alloy after 3 passes. On the other hand, maximum ductility was found in slowly cooled alloy after second pass. Further passes reduced strength due to the brittle behavior of excluded particles. One of the partial findings is that there is only a small dependency of the resulting size of grains on previously applied thermal processing. The minimum grain sizes were obtained after 3 passages, where their size ranged between 0.4 and 0.8 μm. The application of quick cooling after heat processing due to the occurrence of finer precipitates in the matrix seems to produce better results. PMID:22796374

  6. Laser cladding of a Mg based Mg-Gd-Y-Zr alloy with Al-Si powders

    Science.gov (United States)

    Chen, Erlei; Zhang, Kemin; Zou, Jianxin

    2016-03-01

    In the present work, a Mg based Mg-Gd-Y-Zr alloy was subjected to laser cladding with Al-Si powders at different laser scanning speeds in order to improve its surface properties. It is observed that the laser clad layer mainly contains Mg2Si, Mg17Al12 and Al2(Gd,Y) phases distributed in the Mg matrix. The depth of the laser clad layer increases with decreasing the scanning speed. The clad layer has graded microstructures and compositions. Both the volume fraction and size of Mg2Si, Mg17Al12 and Al2(Gd,Y) phases decreases with the increasing depth. Due to the formation of these hardening phases, the hardness of clad layer reached a maximum value of HV440 when the laser scanning speed is 2 mm/s, more than 5 times of the substrate (HV75). Besides, the corrosion properties of the untreated and laser treated samples were all measured in a NaCl (3.5 wt.%) aqueous solution. The corrosion potential was increased from -1.77 V for the untreated alloy to -1.13 V for the laser clad alloy with scanning rate of 2 mm/s, while the corrosion current density was reduced from 2.10 × 10-5 A cm-2 to 1.64 × 10-6 A cm-2. The results show that laser cladding is an efficient method to improve surface properties of Mg-Rare earth alloys.

  7. Identification of mould influence on columnar-to-equiaxial-transition zone position in Al-Si alloys castings

    Directory of Open Access Journals (Sweden)

    Z. Ignaszak

    2008-08-01

    Full Text Available The course of process validation of CAFE-Calcosoft (ESI-Group models was presented. It was shown the short description of Cellular Automaton Finite Element (CAFE-3D method which was applied to system to solidification process identification and to predict the structure of chosen Al-Si alloy. It was determined the sensitivity of thermal model and model to forecast the microstructure on the variabiity of particular parameters applied to the models taking into consideration the columnar-to-equiaxed transition (CET zone. The cylindrical casts which solidified in homogenous silica (quartz-Q sand mould (A and also in high insulation (HI mould with chill (B which coerces high axial temperature gradient, was investigated. The experiment gave the basis to the validation test of CAFE model considering the CET zone which was preceded by two corresponding cases of solidification in respect to thermal conditions of cast-mould system. The virtual structures of studied casts were compared with real structures. It was shown the satisfactory agreement of both structures.

  8. Effects of vibration and grain refiner on microstructure of semisolid slurry of hypoeutectic Al-Si alloy

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jun-wen; WU Shu-sen; XIE Li-zhi; AN Ping; MAO You-wu

    2008-01-01

    The effects of vibration and grain refiner on the microstructure of semisolid slurry of hypoeutectic Al-Si alloy were studied. The impact of vibration on the convection of liquid was conducted by using a system of water-particle tracer. The 356 melt at temperature of 630-660 ℃ with or without grain refiner Al-5%Ti-1%B was poured into a metal cup as the vibrating vessel, then it was cooled to 590-610 ℃ in the semisolid zone and kept for some time, subsequently vibration with different frequencies was applied. The results show that the primary α(Al) particles become finer and rounder with the increase of vibration frequency. The slurry with primary α(Al) equivalent particle diameter(EPD) of about 90 μm and average shape coefficient(ASC) of about 0.5 can be prepared under vibration of 20 Hz. With the combined action of vibration and grain refiner Al-5Ti-B, even smaller and rounder spheroids with EPD of about 85 μm and ASC of about 0.6 are obtained.

  9. Accuracy of Ceramic Mould Filling with Liquid AlSi9 Aluminium Alloy in the Process Using Back-pressure

    Directory of Open Access Journals (Sweden)

    A. Karwiński

    2013-01-01

    Full Text Available The paper presents the effect of suction pressure exerted on the liquid AlSi alloy when it is introduced into a ceramic mould made in the investment process and the results compared with data obtained on gravity poured castings.The study used special pattern sets and ceramic moulds made with the alternately applied soluble silicate binder and ethyl silicate.Additionally, self-supported moulds based entirely on the Ekosil binder were used. In the analysis of castings, the following parameters were examined: a linear dimensional accuracy, the state of surface microgeometry and the possibility of metal penetration into a complex ceramic mould, allowing also for the presence of capillary phenomena. In the process of casting with back-pressure, the pressure values of 500 hPa, 600 hPa and 700 hPa were applied in the chamber where the ceramic mould was located, with the temperature of the said mould kept at a level of 150  10C.

  10. Selection of heat treatments temperature of AlSi13Cu2Fe silumin on base of ATD method

    Directory of Open Access Journals (Sweden)

    J. Pezda

    2008-08-01

    Full Text Available Nowadays tendency connected with reduction of design structures’ mass effects in growing significance of usage of silumins, which are the most widespread alloys of aluminum. Mechanical and technological properties of machine parts manufactured from Al-Si alloys are determined by their structure. In case of cast parts, structure of alloy is a derivative of properly performed process of melting and pouring, as well as design of the casting and mould. Mechanical properties of alloys destined to machine parts made in casting process can be upgraded by modification. Possible heat treatment performed for a cast products effects in further improvement of their mechanical properties, based on precipitation processes. Selection of proper parameters of heat treatment process impacts directly on reduction of production costs of the castings.The paper presents an attempt of implementation of ATD method to determination of solution heat treatment and ageing treatment of AK132 silumin. Obtained results concern registered curves of ATD method, strength tests and determination of an effect of heat treatment temperatures on Rm tensile strength of modified AK132 silumin. On base of preliminary tests results there was determined an impact of temperature changes of solution heat treatment and ageing treatment on Rm tensile strength of AK132 silumin.

  11. The effects of individual metal contents on isochrones for C, N, O, Na, Mg, Al, Si, and Fe

    CERN Document Server

    Beom, Minje; Ferguson, Jason W; Kim, Y -C

    2016-01-01

    The individual characteristics of C, N, O, Na, Mg, Al, Si, and Fe on isochrones have been investigated in this study. Stellar models have been constructed for various mixtures in which the content of each element is changed up to the extreme value reported in recent studies, and the changes in isochrone shape have been analyzed for the various mixtures. To express the abundance variation of different elements with a single parameter, we have focused on the relative changes in the total number of metal ions. A review of the shape changes revealed that Na, Mg, and Al work the same way in stellar models, as the well-known fact that C, N, and O have the same reactions in the stellar interior. In addition, it was found that in high-metallicity conditions the influence of Si and Fe on the red giant branch becomes smaller than that of Na, Mg, and Al closer to the tip. Furthermore, the influence of Fe on the main sequence is larger than that of Na, Mg, Al, and even Si.

  12. A COMBINATORIAL APPROACH TO THE OXIDATION RESISTANCE OF(Ti,Al)N AND Ti-Al-Si-N HARD COATINGS

    Institute of Scientific and Technical Information of China (English)

    R.Cremer; D.Neuschütz

    2002-01-01

    The increasing complexity of modern functional materials leads to the demand of acost efficient tool for the development of new products. One possible approach to thisquestion is the adaptation of combinatorial methods to the specific requirements of ma-terials industry. These methods, originally developed for the pharmaceutical industry,have recently been applied to the screening of superconductive, magnetoresistant andphotoluminescent materials. The principle of these combinatorial approaches is thedeposition of large materials libraries in one process combined with fast methods forthe determination of the resulting properties. In this paper, the deposition and charac-terization of laterally graded materials libraries (composition spread) is presented. Thefilms have been deposited by reactive magnetron sputtering, using two or three metallictargets at a low angle to the substrate surface as well as a system of apertures. Toillustrate the advantages of combinatorial approaches for the development of advancedmaterials, the multicomponent metastable hardcoatings (Ti, Al)N and Ti-Al-Si-N arediscussed with special emphasis on the relations between structure and composition onthe one hand and the oxidation resistance of these coatings on the other. The resultsillustrate that the composition spread approach is a powerful and cost efficient tool forthe development and optimization of new multicomponent functional materials.

  13. Effect of pouring temperature on cooling slope casting of semi-solid Al-Si-Mg alloy

    Institute of Scientific and Technical Information of China (English)

    Prosenjit Das; Sudip K. Samanta; Himadri Chattopadhyay; Pradip Dutta

    2012-01-01

    Present trend of semi-solid processing is directed towards rheocasting route which allows manufacturing of near-net-shape cast components directly from the prepared semi-solid slurry.Generation of globular equi-axed grains during solidification of rheocast components,compared to the columnar dendritic structure of conventional casting routes,facilitates the manufacturing of components with improved mechanical properties and structural integrity.In the present investigation,a cooling slope has been designed and indigenously fabricated to produce semi solid slurry of Al-Si-Mg (A356) alloy and successively cast in a metallic mould.The scope of the present work discusses about development of a numerical model to simulate the liquid metal flow through cooling slope using Eulerian two-phase flow approach and to investigate the effect of pouring temperature on cooling slope semi-solid slurry generation process.The two phases considered in the present model are liquid metal and air.Solid fraction evolution of the solidifying melt is tracked at different locations of the cooling slope,following Schiel's equation.The continuity equation,momentum equation and energy equation are solved considering thin wall boundary condition approach.During solidification of the liquid metal,a modified temperature recovery scheme has been employed taking care of the latent heat release and change of fraction of liquid.The results obtained from simulations are compared with experimental findings and good agreement has been found.

  14. Assessment of Post-eutectic Reactions in Multicomponent Al-Si Foundry Alloys Containing Cu, Mg, and Fe

    Science.gov (United States)

    Javidani, Mousa; Larouche, Daniel; Grant Chen, X.

    2015-07-01

    Post-eutectic reactions occurring in Al-Si hypoeutectic alloys containing different proportions of Cu, Mg, and Fe were thoroughly investigated in the current study. As-cast microstructures were initially studied by optical and electron microscopy to investigate the microconstituents of each alloy. Differential scanning calorimetry (DSC) was then used to examine the phase transformations occurring during the heating and cooling processes. Thermodynamic calculations were carried out to assess the phase formation under equilibrium and in nonequilibrium conditions. The Q-Al5Cu2Mg8Si6 phase was predicted to precipitate from the liquid phase, either at the same temperature or earlier than the θ-Al2Cu phase depending on the Cu content of the alloy. The AlCuFe-intermetallic, which was hardly observed in the as-cast microstructure, significantly increased after the solution heat treatment in the alloys containing high Cu and Fe contents following a solid-state transformation of the β-Al5FeSi phase. After the solution heat treatment, the AlCuFe-intermetallics were mostly identified with the stoichiometry of the Al7Cu2Fe phase. Thermodynamic calculations and microstructure analysis helped in determining the DSC peak corresponding to the melting temperature of the N-Al7Cu2Fe phase. The effect of Cu content on the formation temperature of π-Al8Mg3FeSi6 is also discussed.

  15. Matrix Structure Evolution and Nanoreinforcement Distribution in Mechanically Milled and Spark Plasma Sintered Al-SiC Nanocomposites

    Directory of Open Access Journals (Sweden)

    Nouari Saheb

    2014-09-01

    Full Text Available Development of homogenous metal matrix nanocomposites with uniform distribution of nanoreinforcement, preserved matrix nanostructure features, and improved properties, was possible by means of innovative processing techniques. In this work, Al-SiC nanocomposites were synthesized by mechanical milling and consolidated through spark plasma sintering. Field Emission Scanning Electron Microscope (FE-SEM with Energy Dispersive X-ray Spectroscopy (EDS facility was used for the characterization of the extent of SiC particles’ distribution in the mechanically milled powders and spark plasma sintered samples. The change of the matrix crystallite size and lattice strain during milling and sintering was followed through X-ray diffraction (XRD. The density and hardness of the developed materials were evaluated as function of SiC content at fixed sintering conditions using a densimeter and a digital microhardness tester, respectively. It was found that milling for 24 h led to uniform distribution of SiC nanoreinforcement, reduced particle size and crystallite size of the aluminum matrix, and increased lattice strain. The presence and amount of SiC reinforcement enhanced the milling effect. The uniform distribution of SiC achieved by mechanical milling was maintained in sintered samples. Sintering led to the increase in the crystallite size of the aluminum matrix; however, it remained less than 100 nm in the composite containing 10 wt.% SiC. Density and hardness of sintered nanocomposites were reported and compared with those published in the literature.

  16. Effect of Grain Refinement and Cooling Rate on the Microstructure and Mechanical Properties of Secondary Al-Si-Cu Alloys

    Science.gov (United States)

    Timelli, Giulio; Camicia, Giordano; Ferraro, Stefano

    2013-10-01

    The effect of AlTi5B1 grain refinement and different solidification rates on metallurgical and mechanical properties of a secondary AlSi7Cu3Mg alloy is reported. While the Ti content ranges from 0.04 up to 0.225 wt.%, the cooling rate varies between 0.1 and 5.5 °C/s. Metallographic and thermal analysis techniques have been used to quantitatively examine the macro- and microstructural changes occurring with grain refiner addition at various cooling rates. The results indicate that a small AlTi5B1 addition produces the greatest refinement, while no significant reduction of grain size is obtained with a great amount of grain refiner. On increasing the cooling rate, a lower amount of AlTi5B1 master alloy is necessary to produce a uniform grain size throughout the casting. The combined addition of AlTi5B1 and Sr does not produce any reciprocal interaction or effect on primary α-Al and eutectic solidification. The grain refinement improves the plastic behavior of the alloy and increases the reliability of castings, as evidenced by the Weibull statistics.

  17. Microstructure and mechanical properties of spray-deposited Al-Si-Fe-Cu-Mg alloy containing Mn

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Al-20Si-5Fe-3Cu-lMg alloy was synthesized by the spray atomization and deposition technique. The microstructure and mechanical properties of the spray deposited hypereutectic Al-Si alloy were studied using optical microscopy, scanning electron microscopy, X-ray diffraction, TEM (Transmission Electron Microscope) and HREM (High-resolution Electron Microscope), DSC (Differential Scanning Calorimetry), microhardness measurement, and tensile tests. The effects of Mn on the microstructural evolution of the highsilicon aluminum alloy after extrusion and heat treatment have been examined. The results show that two kinds of phases, i.e. S (Al2CuMg) and σ(Al5Cu6Mg2), precipitated from matrix and improved the tensile strength of the alloy efficiently at both the ambient and elevated temperatures (300℃). The tensile test results indicate that the spray-deposited Al-20Si-SFe-3Cu-1Mg alloy has better strength than the powder metallurgy processed Al-20Si-3Cu-1Mg alloy at elevated temperature.

  18. The Microstructure And Mechanical Properties Of The AlSi17Cu5 Alloy After Heat Treatment

    Directory of Open Access Journals (Sweden)

    Piątkowski J.

    2015-09-01

    Full Text Available In the paper results of the microstructure and mechanical properties (HB, Rm and R0,2 of AlSi17Cu5 alloy, subjected by solution heat treatment (500ºC/6h/woda and aging (200ºC/16h/piec are presented. In next step the alloy was modified and heated significantly above the Tliq temperature (separately and together. It was found that the increase in the strength properties of the tested alloy after heat treatment compared to alloys without solution heat treatment and aging was due to precipitation hardening. The applied aging treatment of ingots (preceded by solution heat treatment, causes not only increase in concentration in α(Al solid solution, but also a favorable change of the primary Si crystals morphology. During stereological measurements significant size reduction and change in the morphology of hypereutectic silicon crystals ware found. This effects can be further enhanced by overheating the alloy to a temperature of 920ºC and rapid cooling before casting of the alloy.

  19. Effect of traveling magnetic field on separation and purification of Si from Al-Si melt during solidification

    Science.gov (United States)

    Zou, Q. C.; Jie, J. C.; Liu, S. C.; Wang, T. M.; Yin, G. M.; Li, T. J.

    2015-11-01

    Separation and purification of the Si crystal during solidification process of hypereutectic Al-30Si melt under traveling magnetic field (TMF) were investigated in the present study. The results showed that under a proper condition the Si-rich layer can be formed in the periphery of the ingot while the inner microstructure is mainly the Al-Si eutectic structure. The intense melt flow carries the bulk liquid with higher Si content to promote the growth of the primary Si phase which is first precipitated close to the inner wall of the crucible with a relatively lower temperature, which resulting in the remarkable segregation of the primary Si phase. The impurity contents of the refined Si can be reduced to a very low level. The typical metallic impurities have removal fraction higher than 99.5%. In addition, there is a significant difference in the P contents between the primary and eutectic Si phases, which might be ascribed to the formation of AlP phase that acts as the heterogeneous nucleation sites. Furthermore, a considerable amount of Fe-containing particles with a size about 100-300 nm is found inside the eutectic Si phase, indicating an unintended entrapment of Fe in Si.

  20. Acero de alto silicio producido por inmersión en Al-Si y recocido de difusión

    Directory of Open Access Journals (Sweden)

    Ros-Yáñez, Tanya

    2000-10-01

    Full Text Available It is difficult to process steel sheet with a high Si content (>3.5%Si, mainly because of its brittleness and the appearance of cracks during rolling and oxidation. However, there is a market for this steel in electrical applications because of the favourable influence of Si on magnetostriction and electrical resistivity. As an alternative process, 3% Si-steel substrates were coated with hypereutectic Al-Si-alloys in a "hot-dip simulator" using different preheating and dipping times. The obtained layers were characterised by SEM and EDS analysis. Diffusion annealing experiments were performed to obtain sufficient amount of Si in the steel. It was observed that:

    • intermetallic phases appear in the coating layers as according to the ternary Fe-Si-Al diagram
    • with a double dipping primary silicon crystals are formed in the surface layer
    • the ordered DO3 structure is present if the dipping and/or diffusion time is long enough
    • homogeneous silicon gradients in the whole substrate thickness have not yet been achieved
    • theoretic calculations show that Si-gradient, also have beneficial effects on magnetic behaviour


    Es difícil procesar aceros eléctricos de alto contenido en silicio (>3,5 % Si. Esto se debe principalmente, a problemas de fragilidad, aparición de grietas durante la laminación y oxidación. Sin embargo, existe un importante mercado para este tipo de acero en aplicaciones eléctricas debido a la favorable influencia que ejerce el Si sobre la magnetoestricción, las pérdidas eléctricas y la resistividad eléctrica. Como proceso alternativo, se sumergieron substratos de acero con 3 % de silicio en una aleación hipereutéctica Al-25 % Si, en un simulador de recubrimiento por inmersión en caliente. En los ensayos se utilizaron diferentes tiempos de precalentamiento y de inmersión. En la segunda fase de la investigación se llevaron a cabo recocidos de difusión en el

  1. Effects of Al/Si ordering on feldspar dissolution: Part II. The pH dependence of plagioclases' dissolution rates

    Science.gov (United States)

    Yang, Yi; Min, Yujia; Jun, Young-Shin

    2014-02-01

    The rate of mineral dissolution in an aquatic environment is sensitive to the pH of the contacting solution. The pH dependence of mineral dissolution rate has been interpreted by the Transition State Theory-Surface Complexation Model (TST-SCM) formalism in terms of pH-sensitive variability in surface chemistry. In this study, we provide an alternative interpretation for the experimentally observed nonlinear pH dependence of feldspar dissolution rates. The interpretation is based on a new formalism for feldspar dissolution which, while compatible with the TST-SCM formalism, incorporates the effects of both surface chemistry and bulk chemistry on feldspar dissolution into the quantification of dissolution rate. The pH dependence of dissolution rate varies from one feldspar specimen to another because different TOT linkages within one solid matrix can respond differently to the attack of proton. Our results suggest that the pH dependence of feldspar dissolution rate is not a constant in general, and could be affected by pH, substitutional Al/Si ordering, chemical composition of the specimen, and the relative rapidness of linkage hydrolysis according to different mechanisms. The rate law proposed in this study is able to capture the experimentally observed pH dependence of the dissolution rates of a series of plagioclases, including albite, andesine, labradorite, bytownite, and anorthite. The effectiveness of the newly proposed formalism for feldspar dissolution, hence, suggests that dissolution reactions of minerals are combinations of surface renewal and heterogeneous chemical reactions. The currently widely used TST-SCM-based rate laws can be further improved by taking into account the effects of bulk chemistry and surface renewal in the prediction of mineral dissolution rates. An improved formalism for mineral dissolution will be mineral-specific, and will reflect the effects of the temporal decay in the availability of reactive surface sites as well as the

  2. Strain Ratio Effects on Low-Cycle Fatigue Behavior of Gravity Cast Al-Si-Cu Alloys

    Science.gov (United States)

    Fan, K. L.; Liu, X. S.; He, G. Q.; Cheng, H.; Lv, S. Q.

    2015-10-01

    The strain-controlled low-cycle fatigue properties of gravity cast Al-Si-Cu alloys for engine cylinder heads were investigated. At strain ratios of R ɛ = -2, 0, and 0.1, the cyclic stress amplitude progressively increased from initiation to the 450th cycle, and then proceeded into a steady stage until failure. At a strain ratio of R ɛ = -∞, the material exhibited a continuous cyclic hardening. The hysteresis loops in this alloy for the 2nd and half-life cycle were tension/compression asymmetry, which also corresponded well to the evolution of peak/valley stress. Transmission electron microscopy analysis suggested that cyclic hardening was caused by the dislocations multiplication/tangles at strain ratios of R ɛ = -∞ and 0. Besides, the presence of dislocation cross slip contributed to cyclic stabilization observed at later stage of deformation at a strain ratio of R ɛ = 0. Micro-analysis of specimen fracture appearance was conducted in order to obtain the fracture characteristics and crack paths for different strain ratios. It showed that the fatigue cracks initiated basically at the internal defects in the samples. Meanwhile, at strain ratios of R = -∞ and 0, the fracture surface was rough with a large number of small unequiaxed dimples and some tear ridges. Moreover, the localized pores offered a preferential crack path in the samples, where they were surrounded by silicon particles. At a strain ratio of R ɛ = -∞, the fatigue cracks preferentially initiated at pores rather than α-Fe phases. At a strain ratio of R ɛ = 0, where fatigue crack initiation was observed at the interface between plate-like branch of α-Fe phase and aluminum matrix.

  3. FIB and TEM characterization of subsurfaces of an Al-Si alloy (A390) subjected to sliding wear

    Energy Technology Data Exchange (ETDEWEB)

    Li Jian [Materials Technology Laboratory, Natural Resources Canada, 568 Booth Street, Ottawa, Ont., K1A 0G1 (Canada)]. E-mail: jili@nrcan.gc.ca; Elmadagli, M. [Department of Mechanical, Automotive and Materials Engineering, University of Windsor, 401 Sunset Avenue, Windsor, Ont., N9B 3P4 (Canada); Gertsman, V.Y. [Materials Technology Laboratory, Natural Resources Canada, 568 Booth Street, Ottawa, Ont., K1A 0G1 (Canada); Lo, J. [Materials Technology Laboratory, Natural Resources Canada, 568 Booth Street, Ottawa, Ont., K1A 0G1 (Canada); Alpas, A.T. [Department of Mechanical, Automotive and Materials Engineering, University of Windsor, 401 Sunset Avenue, Windsor, Ont., N9B 3P4 (Canada)

    2006-04-15

    The material layers underneath the worn surfaces of a hypereutectic Al-Si alloy (A390) subjected to dry sliding wear in air and argon atmospheres were characterized. The samples were tested at a constant load of 10 N and a sliding velocity of 1 m/s using a block-on-ring tribometer. The counterface material was a SAE 52100 bearing steel. The wear rate of the alloy tested in an argon atmosphere (3.05 x 10{sup -5} mm{sup 3}/m) was 10 times lower compared to that of the sample tested in air (2.96 x 10{sup -4} mm{sup 3}/m). The subsurface microstructures generated under the two different test environments were characterized using a scanning electron microscope (SEM), electron probe micro-analyzer (EPMA), focused ion beam (FIB) microscope and transmission electron microscope (TEM). Cross-sectional TEM specimens were prepared using a FIB 'lift-out' technique. TEM analysis indicated that the tribolayers formed on the sample tested in air contained significant amounts of iron, aluminum and oxygen. In addition, the tribolayers formed in air were hard and appeared to be severely fractured as an indication of their brittleness due to the large amount of oxide present. On the contrary, a much lower amount of iron and oxygen were found in the tribolayers formed in argon, which were a mechanical mixture of mainly ultra-fine grained aluminum ({approx}100 nm) and silicon. The tribolayers formed in argon were more stable on the contact surfaces, which reduced the wear rates of A390.

  4. Corrosion behavior of TiN, TiAlN, TiAlSiN-coated 316L stainless steel in simulated proton exchange membrane fuel cell environment

    Science.gov (United States)

    Nam, Nguyen Dang; Vaka, Mahesh; Tran Hung, Nguyen

    2014-12-01

    To gain high hardness, good thermal stability and corrosion resistance, multicomponent TiAlSiN coating has been developed using different deposition methods. In this study, the influence of Al and Si on the electrochemical properties of TiN-coated 316L stainless steel as bipolar plate (BP) materials has been investigated in simulated proton exchange membrane fuel cell environment. The deposited TiN, TiAlN and TiAlSiN possess high hardness of 23.9, 31.7, 35.0 GPa, respectively. The coating performance of the TiN coating is enhanced by Al and Si addition due to lower corrosion current density and higher Rcoating and Rct values. This result could be attributed to the formation of crystalline-refined TiN(200), which improves the surface roughness, surface resistance, corrosion performance, and decreased passive current density.

  5. Učinak postupka topline obrade na morfologiju intermetalne faze ljevačke legure AlSi9Cu3

    OpenAIRE

    E. Tillová; M. Panušková

    2008-01-01

    Učinak postupka topline obrade na morfologiju intermetalne faze ljevačke legure AlSi9Cu3. U članku je dano istraživanje utjecaja toplinskog otapanja na 505°C, 515°C i 525°C ± 2°C sa različitim vremenima držanja 2, 4, 8, 16 i 32 sata na mikrostrukturu komercijalne ljevačke legure AlSi9Cu3. Tijekom toplinske odredbe došlo je do sferoidizacije eutektičkog Si, postepenog raspada željeznih intermetalnih faza sa osnovom Al(FeMnMg)Si, skraćivanje i stanjivanje iglica faze Al5FeSi i otapanje intermet...

  6. The role of iron in the formation of porosity in Al-Si-Cu-based casting alloys. Part 2: A phase-diagram approach

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, J.A.; Schaffer, G.B.; StJohn, D.H. [Univ. of Queensland, Brisbane (Australia)

    1999-06-01

    The mechanism by which iron causes casting defects in the AA309 (Al-5 pct Si-1.2 pct Cu-0.5 pct Mg) may be related to the solidification sequence of the alloy. Superimposing calculated segregation lines on the liquidus projection of the ternary Al-Si-Fe phase diagram suggests that porosity is minimized at a critical iron content when solidification proceeds directly from the primary field to the ternary Al-Si-{beta}Al{sub 5}FeSi eutectic point. Solidification via the binary Al-{beta}Al{sub 5}FeSi eutectic is detrimental to casting integrity. This hypothesis was tested by comparing the critical iron content observed in the standard AA309 alloy to that of a high-silicon (10 pct Si) variant of this alloy.

  7. Sinterización de las aleaciones Alumix 321 y 6061

    Directory of Open Access Journals (Sweden)

    Romano, R.

    2005-02-01

    Full Text Available The sintering behaviour of two aluminium alloys, Alumix 321 and 6061, was studied in this paper. Both have a similar Mg, Cu and Si contents, but have been obtained by different methods. The Alumix 321 alloy is produced by mixing the initial elements as powders and the 6061 is obtained by water atomization. The work carried out includes the study of the green properties, the determination of the compressibility and green strength curves as well as the microstructural characterization of the powders. Thermal analyses (DTAs and Dilatometries were performed in order to study the behaviour of both alloys with temperature. Furthermore, different sintering temperatures were studied by characterizing the mechanical properties of the sintered materials. It can be concluded that the 6061 alloy has better properties than the Alumix 321, when both were sintered at 600 °C.

    En el presente trabajo se pretende estudiar el comportamiento en sinterización de dos aleaciones de aluminio, la Alumix 321 y la 6061. Ambas, poseen una composición muy similar en magnesio, cobre y silicio, pero han sido fabricadas por diferentes métodos. La Alumix 321 se ha obtenido a partir de polvos elementales, premezclados y la 6061 por atomización en agua de polvos prealeados. El trabajo llevado a cabo comprende el estudio de las propiedades en verde de los compactos fabricados, es decir, determinación de la curva de compresibilidad y de tensión así como un estudio microstructural del polvo. Para caracterizar el proceso se han llevado a cabo análisis térmicos, Análisis Térmico Diferencial (del inglés, DTA y dilatometría. Por último, se han propuesto diferentes temperaturas de sinterización y se han estudiado las propiedades mecánicas de los materiales sinterizados, concluyéndose que la aleación 6061 presentó, en general, mejores propiedades que la Alumix 321, sinterizadas ambas a 600 °C

  8. Simulation of automotive wrist pin joint and tribological studies of tin coated Al-Si alloy, metal matrix composites and nitrogen ceramics under mixed lubrication

    Science.gov (United States)

    Wang, Qian

    Development of automotive engines with high power output demands the application of high strength materials with good tribological properties. Metal matrix composites (MMC's) and some nitrogen ceramics are of interest to replace some conventional materials in the piston/pin/connecting rod design. A simulation study has been developed to explore the possibility to employ MMC's as bearing materials and ceramics as journal materials, and to investigate the related wear mechanisms and the possible journal bearing failure mechanisms. Conventional tin coated Al-Si alloy (Al-Si/Sn) have been studied for the base line information. A mixed lubrication model for journal bearing with a soft coating has been developed and applied to the contact and temperature analysis of the Al-Si/Sn bearing. Experimental studies were performed to reveal the bearing friction and wear behavior. Tin coating exhibited great a advantage in friction reduction, however, it suffered significant wear through pitting and debonding. When the tin wore out, the Al-Si/steel contact experienced higher friction. A cast and P/M MMC's in the lubricated contact with case hardened steel and ceramic journals were studied experimentally. Without sufficient material removal in the conformal contact situation, MMC bearings in the MMC/steel pairs gained weight due to iron transfer and surface tribochemical reactions with the lubricant additives and contact failure occurred. However, the MMC/ceramic contacts demonstrated promising tribological behavior with low friction and high wear resistance, and should be considered for new journal bearing design. Ceramics are wear resistant. Ceramic surface roughness is very crucial when the journals are in contact with the tin coated bearings. In contact with MMC bearings, ceramic surface quality and fracture toughness seem to play some important roles in affecting the friction coefficient. The wear of silicon nitride and beta sialon (A) journals is pitting due to grain

  9. Growth Directions of Precipitates in the Al-Si-Mg-Hf Alloy Using Combined EBSD and FIB 3D-Reconstruction Techniques.

    Science.gov (United States)

    Wang, Xueli; Xing, Yuan; Huang, Huilan; Li, Yanjun; Jia, Zhihong; Liu, Qing

    2015-06-01

    Nanobelt-like precipitates in an Al-Si-Mg-Hf alloy were studied using electron backscattered diffraction (EBSD) and focused ion beam (FIB) scanning electron microscopy techniques. One grain of the Al matrix with a near [111] normal direction was identified by EBSD and the three-dimensional (3D) microstructure of nanobelt-like precipitates in this grain was studied using 3D-FIB. Ten growth directions of the nanobelt-like precipitates in the grain were identified. PMID:25951774

  10. Structure and properties of selected cemented carbides and cermets covered with TiN/(Ti,Al,Si)N/TiN coatings obtained by the cathodic arc evaporation process

    OpenAIRE

    Leszek A. Dobrzañski; Klaudiusz Golombek

    2005-01-01

    This study presents the results of microstructural examinations, mechanical tests and service performance tests carried out on thin TiN/(Ti,Al,Si)N/TiN wear resistance coatings obtained by the CAE process on cermet and cemented carbide substrates. Microstructural examinations of the applied coatings and the substrate were made with an OPTON DSM 940 SEM and a LEICA MEF4A light microscope. Adhesion of the coatings on cemented carbides and cermets was measured using the scratch test. The cutting...

  11. On the interaction mechanisms between atmospheric sources of hydrogen and Al-Si coated or bare high strength steels during the hot stamping process

    OpenAIRE

    Mandy, Mélodie; Georges, Cédric; Drillet, Pascal; Sturel, Thierry; Jacques, Pascal; SF2M - workshop "Mapping the future of materials science"

    2015-01-01

    The economic and ecological challenges of the automotive industry coupled to safety considerations involve lightweight design based on the development of new ultra high strength materials. The hot stamping process of Al-Si coated steels ensures these strength levels and, moreover, allows an easy forming of the material without the necessity of a controlled atmosphere. At high temperatures, the coating is hydrogen-permeable, while at low temperatures (below 120°C), it becomes tight to hydrogen...

  12. Influence of heat treatment on microstructure of slurry aluminide coatings type TiAlSi obtained on TiAlCrNb alloy

    Directory of Open Access Journals (Sweden)

    G. Moskal

    2009-04-01

    Full Text Available Purpose: Influence of heat treatment on microstructural changes in slurry TiAlSi coating deposited with 12.5% Si concentration on Ti48Al2Cr2Nb intermetallic alloy and investigation of the influence of Si addition on the structure of obtained coatings is a purpose of this paper.Design/methodology/approach: The research allowed identifying microstructural changes that took place during annealing at 950°C of the TiAlSi coating for 2 to 10h exposure in air. A scope of the research encompassed a microstructural analysis with the use of macro and micro investigation - LM, SEM microscopy, XRD phase analysis and EDS analysis.Findings: The investigation has shown that the thickness of the TiAlSi coatings in initial conditions and after a test was in a range from 30 to 40 μm. The structure of the silicon-modified aluminide coatings is as following: the outer zone consisting of the TiAl3 phase and titanium silicides / the middle zone consisting of columnar titanium silicides in phase TiAl3 matrix / the inner zone consisting of TiAl2 phase. Basic changes were related to differences in thickness in sublayers.Research limitations/implications: The discussed research proves that main reason of much better protection of TiAlSi coated base alloy is related to high microstructure stability of Si modified in TiAl3 phases. In addition silicon decreases activity of titanium, and in consequence the susceptibility of Al to selective oxidation is much stronger. The presence of Si due to Ti-Si phase generation with high oxidation resistance is presented.Practical implications: The slurry method can be applied in aerospace and automotive industry as low-cost technology in production of aluminide coatings on intermetallics.Originality/value: New method of aluminide coatings deposition on TiAl alloys.

  13. High-field magnetization of heusler alloys Fe2 XY ( X = Ti, V, Cr, Mn, Fe, Co, Ni; Y = Al, Si)

    Science.gov (United States)

    Kourov, N. I.; Marchenkov, V. V.; Korolev, A. V.; Belozerova, K. A.; Weber, H. W.

    2015-10-01

    The magnetization curves of ferromagnetic Heusler alloys Fe2 XY (where X = Ti, V, Cr, Mn, Fe, Co, Ni are transition 3 d elements and Y = Al, Si are the s and p elements of the third period of the Periodic Table) have been measured at T = 4.2 K in the field range H ≤ 70 kOe. It has been shown that the high-field ( H ≥ 20 kOe) magnetization is described within the Stoner model.

  14. Two directional microstructure and effects of nanoscale dispersed Si particles on microhardness and tensile properties of AlSi7Mg melt-spun alloy

    International Nuclear Information System (INIS)

    Highlights: • Both surface and cross-sectional microstructure of AlSi7Mg ribbon were characterized. • 13–50 nm and 50-hundreds of nm Si particles were dispersed both in α-Al and its boundary. • Tensile property of AlSi7Mg ribbon was studied with UTS 1.5 times higher than ingot. • Effects of nanoscale Si particles on hardness and tensile properties were provided. - Abstract: The two directional microstructure and multiple mechanical properties of the AlSi7Mg ribbon produced by melt-spun were investigated by optical microscopy (OM), field emission gun scanning electron microscope (FEGSEM), X-ray diffraction (XRD), microhardness and tensile tests. Both the surface and cross-sectional microstructure of the melt-spun ribbon were characterized in detail to give a clear and integrated description of the microstructure. Two kinds of nanoscale Si particles were observed, i.e., small Si particles ranging from 13 to 50 nm and large Si particles ranging from 50 nm to several hundreds of nanometers with clear size boundary were dispersed both in the interior and boundary of fine α-Al. XRD results revealed supersaturated solution of Si in Al matrix to be 0.62 at.%. The ultimate tensile strength, yield strength, and hardness of the ribbon were 1.53, 1.75 and 1.56 times higher than that of the conventional cast ingot separately. The breaking elongation of the ribbon was 1.73% with intergranular fracture feature. The effects of nanoscale dispersed Si particles on the significant improvement of both hardness and tensile properties of the AlSi7Mg melt-spun ribbon were discussed in detail

  15. Microstructural refinement of hyper-eutectic Al-Si-X casts to produce a heavily deformable material toward recycling-based society

    OpenAIRE

    Nakamoto, Munefumi; Umezawa, Osamu; Moriya, Hideaki; Suzuki, Takashi

    2004-01-01

    Although the cascade of material flow is suitable for the aluminum recycling due to without or less dilution by raw material, better utilization of secondary alloys will be desired. To control formability in aluminum cast materials, fine microstructure with plural phases is one of candidates for the material design. A novel thermomechanical process, repeated thermomechanical treatment (RTMT) has been applied to hyper-eutectic Al-Si-X hot-worked materials. Through the hot-working and RTMT, the...

  16. Statistical Assessment of the Effect of Chemical Composition on Mechanical Properties of Hypereutectic AlSi17CuNiMg Silumin

    OpenAIRE

    J. Szymszal; J. Piątkowski; J. Kliś

    2007-01-01

    The paper presents a statistical assessment of the effect of chemical composition on mechanical properties of hypereutectic AlSi17 silumin, which is expected to act as a counterpart of alloys used by automotive industry and aviation for casting of high-duty engine parts in West European countries and USA. The studies on the choice of chemical composition of silumins were preceded by analysis of the reference literature to state what effect some selected alloying elements and manufacturing tec...

  17. Synthesis and structural characterization of amorphous alloys of the Fe-Ni-B type; Sintesis y caracterizacion estructural de aleaciones amorfas del tipo Fe-Ni-B

    Energy Technology Data Exchange (ETDEWEB)

    Cabral P, A.; Jimenez B, J.; Garcia S, I. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2004-07-01

    It was prepared the alloy FeNiB for chemical reduction, using four p H values (5, 6, 7 and 7.5). To p H=6 partially oxidized particles were obtained, between 16 and 20%. In the synthesis to other p H values, the obtained particles were highly oxidized (65-90%) according to the X-ray diffraction results, in all the preparations the particles were partially crystallized, with crystal size that varied between 4 and 10 nm. The structure of these particles can be consider that they are formed by a nucleus due to the alloy and an oxide armor recovering it. (Author)

  18. Selective Laser Melting Additive Manufacturing of TiC/AlSi10Mg Bulk-form Nanocomposites with Tailored Microstructures and Properties

    Science.gov (United States)

    Gu, Dongdong; Wang, Hongqiao; Chang, Fei; Dai, Donghua; Yuan, Pengpeng; Hagedorn, Yves-Christian; Meiners, Wilhelm

    The nanoscale TiC particle reinforced AlSi10Mg nanocomposite parts were produced by selective laser melting (SLM) additive manufacturing process. The influence of laser energy density (LED) on densification behavior, microstructural evolution, microhardness and wear properties of SLM-processed TiC/AlSi10Mg nanocomposites was studied. It showed that the near fully dense nanocomposite parts (>98% theoretical density) were achieved with increasing the applied LED. The TiC reinforcement in SLM-processed parts experienced a microstructural change from the standard nanoscale particle morphology (the average size 77-93 nm) to the relatively coarsened submicron structure (the mean particle size 154 nm) as the LED increased.The sufficiently high densification rate combined with the homogeneousdistribution of nanoscale TiC reinforcement throughout the matrix led to a high microhardness of 181.2 HV0.2, a considerably low coefficient of friction (COF) of 0.36, and a reduced wear rate of 2.94×10-5 mm3N-1m-1 for SLM-processed TiC/AlSi10Mg nanocomposite parts.

  19. Electromigration in multilayer metallization: Drift-controlled degradation and the electromigration threshold of Al-Si- Cu/TiNxOy/TiSi2 contacts

    Science.gov (United States)

    Oates, A. S.

    1991-11-01

    Metallizations that incorporate a conductive layer beneath an Al alloy (multilayers) are necessary for the improvement in electromigration performance required by the continued feature size reduction and increased integration of microelectronic devices. Degradation of contact structures that utilize multilayer metallization will result from electromigration-induced voiding of the Al layer. A detailed understanding of the mechanisms of voiding is required for the accurate prediction of contact reliability. We have examined electromigration voiding in Al-Si-Cu/TiNxOy/TiSi2 multilayer contacts. Accelerated testing reveals that a TiNxOy/TiSi2 layer formed by rapid thermal anneal of Ti is an effective Si diffusion barrier at operating temperatures (Al-Si-Cu layer. Voiding involves drift-controlled edge displacement where the Al-Si-Cu layer migrates out of positively biased contacts, leaving the TiNxOy/TiSi2 layer intact. For 1-μm-diam contacts, the drift velocity has a significant lattice diffusion component and failure times are expected to far exceed operation lifetimes of devices. Additionally, evidence is presented for an electromigation threshold that eliminates voiding degradation for contacts connected by stripes.

  20. Effects of P+Cr complex modification and solidification conditions on microstructure of hypereutectic Al-Si alloys by wedge-shaped copper mould casting

    Directory of Open Access Journals (Sweden)

    Zhang Haitao

    2014-11-01

    Full Text Available Large and segregated primary Si particles may drastically decrease the mechanical properties of Al-Si alloys. To solve this problem, a P-Cr complex modifier was added into the alloy, and the effects of P-Cr complex modification and solidification conditions on the microstructure of hypereutectic Al-Si alloys casting produced in wedge-shaped copper mould were studied. The thermal analysis technique was applied to calculate the cooling rate during solidification. The microstructures were observed by means of optical and scanning electron microscopies. Results showed that the primary Si segregates in the as-cast hypereutectic Al-Si alloys. The segregation of primary Si can be inhibited by adding a P+Cr complex modifier and increasing the cooling rate during solidification. The refinement of primary Si particles by P+Cr complex modification is due to the formation of CrSi2 and AlP particles which act as the heterogeneous nuclei for the primary Si phase. The segregation of Si was also inhibited through the adherence of heavier CrSi2 particles to the primary Si particles.

  1. Effects of P+Cr complex modification and solidification conditions on microstructure of hypereutectic Al-Si alloys by wedge-shaped copper mould casting

    Institute of Scientific and Technical Information of China (English)

    Zhang Haitao; Zuo Kesheng; Han Xing; Shao Bo; Qin Ke; Cui Jianzhong

    2014-01-01

    Large and segregated primary Si particles may drastical y decrease the mechanical properties of Al-Si al oys. To solve this problem, a P-Cr complex modifier was added into the al oy, and the effects of P-Cr complex modification and solidification conditions on the microstructure of hypereutectic Al-Si alloys casting produced in wedge-shaped copper mould were studied. The thermal analysis technique was applied to calculate the cooling rate during solidification. The microstructures were observed by means of optical and scanning electron microscopies. Results showed that the primary Si segregates in the as-cast hypereutectic Al-Si al oys. The segregation of primary Si can be inhibited by adding a P+Cr complex modifier and increasing the cooling rate during solidification. The refinement of primary Si particles by P+Cr complex modification is due to the formation of CrSi2 and AlP particles which act as the heterogeneous nuclei for the primary Si phase. The segregation of Si was also inhibited through the adherence of heavier CrSi2 particles to the primary Si particles.

  2. Intermetallic phase particles in cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminium alloys

    Directory of Open Access Journals (Sweden)

    G. Mrówka-Nowotnik

    2009-08-01

    Full Text Available Purpose: In the technical Al alloys even small quantity of impurities - Fe and Mn - causes the formation of new phase components. Intermetallic particles form either on solidification or whilst the alloy is at a relatively high temperature in the solid state, e.g. during homogenization, solution treatment or recrystallization. The exact composition of the alloy and casting condition will directly influence the selection and volume fraction of intermetallic phases. The main objective of this study was to analyze the morphology and composition of complex microstructure of intermetallic phases in cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminium alloys.Design/methodology/approach: In this study, several methods were used such as: optical light microscopy (LM, scanning (SEM electron microscopy in combination with X-ray analysis (EDS using polished sample, and X-ray diffraction (XRD to identify intermetallics in cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminum alloys.Findings: The results show that the microstructure of cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminum alloys in T6 condition consisted a wide range of intermetallic phases. By using various instruments (LM, SEM, XRD and techniques (imagine, EDS following intermetallic phases were identified: β-Al5FeSi, α-Al15(FeMn3Si - in AlSi5Cu1Mg alloy and Al7Cu4Ni, Al12Cu23Ni, Al2CuMg, AlCuFeNi - in AlCu4Ni2Mg2 alloy.Research limitations/implications: In order to complete and confirm obtained results it is recommended to perform further analysis of the investigated aluminium alloys. Therefore it is planned to include in a next studies, microstructure analysis of the alloys by using transmission electron microscopy technique (TEM.Practical implications: Since the morphology, crystallography and chemical composition affect the intermetallic properties, what involves changes of alloy properties, from a practical point of view it is important to understand their formation conditions in order to control final constituents of

  3. Fabricación de la aleación Au-Si para utilización como soldadura blanda de aleaciones de oro

    Directory of Open Access Journals (Sweden)

    Julián Tobón

    2013-09-01

    Full Text Available La Aleación Au-Si en su composición eutéctica presenta un punto de fusión cercano a los 369ºC y color similar al oro de alta ley. En este estudio se presentan resultados de fabricación de las aleaciones de oro con 2,5; 2,8 y 3,0 % de silicio, por medio de la fusión en un horno de plasma con atmósfera inerte de argón. Se realizó caracterización de composición química por espectroscopía de dispersión de energía (EDS y espectrometría de dispersión de longitud de onda (WDS, análisis metalográfico y microestructural por microscopía óptica, SEM y DRX, dureza y microdureza Vickers, evaluación del punto de fusión por DSC y determinación de las coordenadas colorimétricas SCIELab. A nivel microestructural las aleaciones muestran pequeñas formaciones dendríticas ricas en oro y el constituyente eutéctico formado por precipitados de silicio aciculares en una matriz de oro. Los resultados de dureza y microdureza dieron valores alrededor de los 110HV, presentándose un importante aumento en las propiedades mecánicas con respecto a las aleaciones tradicionales de oro de alta pureza. La temperatura de fusión para las aleaciones se ubicó en los 374°C, además de presentar un color muy cercano a los valores del oro puro.

  4. Obtención y procesado de aleaciones de grano ultrafino, nanométrico y amorfas mediante aleado mecánico

    Directory of Open Access Journals (Sweden)

    Cintas, J.

    2007-06-01

    Full Text Available Several consolidation procedures have been developed during the last fifteen years to process mechanically alloyed (MA powders at the Metallurgy and Materials Engineering Group (University of Seville. MA powders were processed by conventional cold pressing and vacuum sintering. In addition, several densification promoters were used. The resulting parts, with second phases precipitated during the consolidation, showed good tensile strength, both at room and high temperature. Nowadays, nanostructured and amorphous MA alloys are being processed by electrical resistance sintering (ERS, which prevents microstructure evolution during consolidation.

    El Grupo de Metalurgia e Ingeniería de los Materiales de la Universidad de Sevilla ha desarrollado, durante los últimos quince años, diversas técnicas para la consolidación de aleaciones de aluminio obtenidas por aleado mecánico (AM de polvos. Las aleaciones, reforzadas por segundas fases precipitadas durante el procesado, han sido prensadas y sinterizadas por procedimientos convencionales y se ha estudiado la contribución de ayudas a la sinterización, obteniéndose elevadas resistencias y buenas propiedades en caliente. En la actualidad se desarrollan, también por aleado mecánico, aleaciones nanométricas y amorfas en las que, gracias al uso de la sinterización por resistencia eléctrica (SRE, puede preservarse en gran medida la microestructura de los polvos en las piezas consolidadas.

  5. Observaciones microestructurales en el composite Al-SiC-15p obtenido por el procedimiento de compocolado

    Directory of Open Access Journals (Sweden)

    Manzano-Ramírez, A.

    1996-12-01

    Full Text Available In order to study how the processing variables of the compocasting process, such as shear rate and solid fraction, influence the mechanical entrapment of SiCp in the aluminium matrix of the Al-SiC-xxp composite. In the present work, shear rate and solid fraction were varied (γ = 27, 120 and 219 s-1 and fs = 0.3, 0.4 and 0.5, respectively. In addition, the atomic force microscope (AFM was used to investigate the surface topography of the composite, with the purpose of determine, qualitatively, the degree of interfacial bonding between aluminium matrix and reinforcement elements. By using the Chemical facilities of SEM it was attempted to determine the composition of the second phase responsible of bonding between matrix and particulate. The results obtained in the AFM confirmed that the mechanical entrapment of the particles by the solid is more efficient at high solid fractions (fs > 0.4 and high shear rates (γ > 120 s-1. In contrast, at low fs (< 0.3 and low γ (< 27 s-1 such effect is poor. In addition, qualitative evidence, recorded by optical micrographs, illustrate the mechanism of dendritic fragmentation and change (from dendritic to globular of the primary-solid phase in the compocasting process. SEM results suggested that bonding could be established through the silicon phase nevertheless it is considered that more accurate analysis is needed.

    El propósito del presente trabajo es estudiar el efecto de las variables del procedimiento de compocolado (compocasting, velocidad de agitación y fracción de sólido, sobre el atrapamiento mecánico o incorporación de partículas de SiC a la matriz de aluminio del composite Al-SiC-15p. Para ello, se variaron la velocidad de corte, γ, y la fracción de sólido fs, (γ= 27, 120 y 213 s-1 y fs = 0,3, 0,4 y 0,5, respectivamente. Se utilizó el microscopio de fuerza atómica (AFM para observar la topografía del

  6. Magnetic behaviour of Y{sub 2}Co{sub 7-x}M{sub x} intermetallic compound with M =Al, Si or Cu and x = 1 or 2

    Energy Technology Data Exchange (ETDEWEB)

    Pop, V.; Burzo, E.; Tetean, R.; Deac, I.G. [Babes-Bolyai Univ., Cluj (Romania). Faculty of Physics

    2000-07-01

    The spontaneous magnetization, mean cobalt moments and Curie temperatures are reported for Y{sub 2}Co{sub 7-x}M{sub x} (M = Al, Si or Cu, x = 1 and 2) intermetallic compounds. The magnetic behavior of cobalt is analyzed in connection with the variation of the exchange field induced by substituting a ferromagnetic metal (Co) by nonmagnetic ones (Al, Si or Cu) (orig.)

  7. Nanostructure and phases formation under mechanical alloying of binary powder mixtures of Fe and sp-elements (M); M=C, B, Mg, Al, Si, Ge, Sn

    International Nuclear Information System (INIS)

    Full text: Common and distinctive features of mechanical alloying (MA) of Fe with sp-element have been established using a complex of experimental methods including Moessbauer spectroscopy. The common regularities are the following: the formation of a nano-structural state in α-Fe particles, sp-atoms penetration along the α-Fe grain boundaries, their segregation and the first Fe-M phase formation in the interfaces (boundary and close-to-boundary distorted zones) at the initial stage of MA. In MA α-Fe with Al (Si, Ge, Sn) having approximately equal (Al, Si, Ge) or substantially larger (Sn) atomic size intermetallic compounds are formed in interfaces at the first stage. At the final stage supersaturated solid solutions (SSS) are formed in the grain bulk if sp-element concentration in the initial mixture xM≤32 at.% Si (Ge, Sn) and ≤50 at.% Al. In the Fe-Al (Si, Ge) systems the sp-element concentration in SSS becomes maximum simultaneously with the SSS formation, while in the Fe-Sn the SSS is saturated with Sn gradually. In MA α-Fe with C and B having a small radius an amorphous like phase (Am(Fe-M)) is formed in interfaces at the initial stage. The Am(Fe-B) formation is characterized by a substantially slower kinetics in comparison with that of the Am(Fe-C) one. If xM>15 at.% C(B) the second stage - the carbide and boride formation - takes place after amorphization. In the case of immiscible in equilibrium elements (Fe and Mg) mechanical alloying is a one-stage process of the SSS formation with the Mg concentration of not higher than 7 at.%

  8. Dendritic Arm Spacing Affecting Mechanical Properties and Wear Behavior of Al-Sn and Al-Si Alloys Directionally Solidified under Unsteady-State Conditions

    Science.gov (United States)

    Cruz, Kleber S.; Meza, Elisangela S.; Fernandes, Frederico A. P.; Quaresma, José M. V.; Casteletti, Luiz C.; Garcia, Amauri

    2010-04-01

    Alloys of Al-Sn and Al-Si are widely used in tribological applications such as cylinder liners and journal bearings. Studies of the influence of the as-cast microstructures of these alloys on the final mechanical properties and wear resistance can be very useful for planning solidification conditions in order to permit a desired level of final properties to be achieved. The aim of the present study was to contribute to a better understanding about the relationship between the scale of the dendritic network and the corresponding mechanical properties and wear behavior. The Al-Sn (15 and 20 wt pct Sn) and Al-Si (3 and 5 wt pct Si) alloys were directionally solidified under unsteady-state heat flow conditions in water-cooled molds in order to permit samples with a wide range of dendritic spacings to be obtained. These samples were subjected to tensile and wear tests, and experimental quantitative expressions correlating the ultimate tensile strength (UTS), yield tensile strength, elongation, and wear volume to the primary dendritic arm spacing (DAS) have been determined. The wear resistance was shown to be significantly affected by the scale of primary dendrite arm spacing. For Al-Si alloys, the refinement of the dendritic array improved the wear resistance, while for the Al-Sn alloys, an opposite effect was observed, i.e., the increase in primary dendrite arm spacing improved the wear resistance. The effect of inverse segregation, which is observed for Al-Sn alloys, on the wear resistance is also discussed.

  9. Effect of internal stresses and microstructure of sputtered TiN films on solid-phase reactions with Al-Si-Cu alloy films

    Science.gov (United States)

    Yamauchi, T.; Yamaoka, T.; Yashiro, K.; Sobue, S.

    1995-08-01

    Solid-phase reactions at the interface between Al-Si-Cu and reactively sputtered TiN thin films have been investigated by cross-sectional transmission electron microscopy, Auger electron spectroscopy, and x-ray diffraction. In the case in which the internal stress in the TiN thin film is extremely compressive at 209 MPa, a very thin amorphous Al-Ti-Si ternary compound layer (a-Al-Ti-Si) containing microcrystallites, about 4 nm thick, is found to form at the Al-Si-Cu/TiN interface by annealing at the temperature of 450 °C for 30 min. On the other hand, in the case of a minimally compressive stress of 21 MPa, it is in a marked contrast to form a polycrystalline TiAl3 layer (c-TiAl3) on the amorphous intermediate layer ununiformly. Behavior of the internal stress in the latter TiN film as a function of heating and cooling temperature shows nonlinear characteristics, indicating that a rearrangement of the TiN film actively occurs even at low temperatures below 300 °C. Monte Carlo simulations of internal microstructures based on a ballistic aggregation model suggest to us that a short migration length corresponding to the condition of low internal stress brings about numerous vacancies and disordered regions in the TiN films. It is considered that the rearrangement of the TiN films with a diffusion of Ti atoms governs the solid-phase reactions at the Al-Si-Cu/TiN interfaces and that the formation of the bilayer of c-TiAl3/a-Al-Ti-Si originates in phase separation of the resultant Al-Ti mixing layer.

  10. A comparative study on wear behavior of TiN and diamond coated WC-Co substrates against hypereutectic Al-Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chakravarthy, G.V. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Madras 600036 (India); Chandran, Maneesh, E-mail: maneesh@physics.iitm.ac.in [Nano Functional Materials Technology Centre, Department of Physics, Indian Institute of Technology, Madras 600036 (India); Bhattacharya, S.S. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Madras 600036 (India); Rao, M.S. Ramachandra [Nano Functional Materials Technology Centre, Department of Physics, Indian Institute of Technology, Madras 600036 (India); Kamaraj, M., E-mail: kamaraj@iitm.ac.in [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Madras 600036 (India)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Wear behaviors of diamond/WC-Co, TiN/WC-Co and WC-Co against Al-Si were studied. Black-Right-Pointing-Pointer Both TiN and diamond coatings were done using chemical vapor deposition technique. Black-Right-Pointing-Pointer Friction and sliding wear properties were characterized using a pin-on-disc method. Black-Right-Pointing-Pointer Diamond coated WC-Co pins showed one order less wear loss than bare WC-Co pins. Black-Right-Pointing-Pointer A weight gain was observed for the TiN coated WC-Co pins. Black-Right-Pointing-Pointer Average coefficient of friction was lowest for the diamond coated WC-Co pins. - Abstract: The demand for better tools for machining hypereutectic aluminum-silicon (Al-Si) alloys are increasing day by day since the extensive use of these alloys in internal combustion engines. In addition to the lifetime of the machining tool, surface finish of the machined piece is also equally important, as it directly affects the performance of the engine. In this paper, we compared the wear behavior of bare tungsten carbide (WC-Co), titanium nitride (TiN) coated WC-Co and diamond coated WC-Co substrates against Al-Si alloys using pin-on-disc method. Both TiN and diamond coatings were done using chemical vapor deposition technique. Diamond coated WC-Co substrates show one order less wear loss compared to the bare WC-Co substrates. Instead of weight loss, a weight gain was observed for the TiN coated WC-Co substrates. Average coefficient of friction was lowest for the diamond coated WC-Co substrates due to the different wear behavior of diamond coated tribological system, which is explained in detail.

  11. In Situ Study of Microstructure Evolution in Solidification of Hypereutectic Al-Si Alloys with Application of Thermal Analysis and Neutron Diffraction

    Science.gov (United States)

    Sediako, Dimitry G.; Kasprzak, Wojciech

    2015-09-01

    Understanding of the kinetics of solid-phase evolution in solidification of hypereutectic aluminum alloys is a key to control their as-cast microstructure and resultant mechanical properties, and in turn, to enhance the service characteristics of actual components. This study was performed to evaluate the solidification kinetics for three P-modified hypereutectic Al-19 pct Si alloys: namely, Al-Si binary alloy and with the subsequent addition of 2.8 pct Cu and 2.8 pct Cu + 0.7 pct Mg. Metallurgical evaluation included thermodynamic calculations of the solidification process using the FactSage™ 6.2 software package, as well as experimental thermal analysis, and in situ neutron diffraction. The study revealed kinetics of solid α-Al, solid Si, Al2Cu, and Mg2Si evolution, as well as the individual effects of Cu and Mg alloying additions on the solidification path of the Al-Si system. Various techniques applied in this study resulted in some discrepancies in the results. For example, the FactSage computations, in general, resulted in 281 K to 286 K (8 °C to 13 °C) higher Al-Si eutectic temperatures than the ones recorded in the thermal analysis, which are also ~278 K (~5 °C) higher than those observed in the in situ neutron diffraction. None of the techniques can provide a definite value for the solidus temperature, as this is affected by the chosen calculation path [283 K to 303 K (10 °C to 30 °C) higher for equilibrium solidification vs non-equilibrium] for the FactSage analysis; and further complicated by evolution of secondary Al-Cu and Mg-Si phases that commenced at the end of solidification. An explanation of the discrepancies observed and complications associated with every technique applied is offered in the paper.

  12. From Powders to Dense Metal Parts: Characterization of a Commercial AlSiMg Alloy Processed through Direct Metal Laser Sintering

    Directory of Open Access Journals (Sweden)

    Eleonora Atzeni

    2013-03-01

    Full Text Available In this paper, a characterization of an AlSiMg alloy processed by direct metal laser sintering (DMLS is presented, from the analysis of the starting powders, in terms of size, morphology and chemical composition, through to the evaluation of mechanical and microstructural properties of specimens built along different orientations parallel and perpendicular to the powder deposition plane. With respect to a similar aluminum alloy as-fabricated, a higher yield strength of about 40% due to the very fine microstructure, closely related to the mechanisms involved in this additive process is observed.

  13. Fabricación y comportamiento de espumas de aluminio con diferente densidad a partir de un precursor AlSi12

    Directory of Open Access Journals (Sweden)

    Gutiérrez-Vázquez, J. A.

    2010-06-01

    Full Text Available Closed cell aluminium foams were prepared by powder metallurgical method in three different ranges of density using AlSi12 precursor. The objective has been to determine by means of tests the effect that has the density of these materials regarding its mechanical behaviour. The used precursor contained 0.4% of foaming agent of titanium hydride (TiH2, mixed with aluminum and silicon in appropriate amounts to achieve the commercial composition of the AlSi12 precursor. Once cut the samples thermal treatments of foaming were made of 630 °C to 750 °C, by 3 to 20 minutes. The best solidification conditions were determined to avoid the collapse by means of forced air. The samples were prepared with the same weight to different densities, having itself obtained that the best mechanical behaviour was achieved in the high density foams, of 0.70 to 0.81 g/cm3.

    Se han fabricado espumas de aluminio de poro cerrado, de tres diferentes rangos de densidad, utilizando un precursor AlSi12 producido por pulvimetalurgia. El objetivo ha sido determinar el efecto que tiene la densidad de estos materiales respecto a su comportamiento mecánico. El precursor utilizado contenía un 0,4 % de hidruro de titanio (TiH2 como agente espumante, mezclado con aluminio y silicio en cantidades adecuadas para lograr la composición comercial del precursor AlSi12. Una vez cortadas las muestras, se efectuaron tratamientos térmicos de espumación entre 630 y 750 °C, a tiempos de espumación variables entre 3 y 20 min. Se determinaron las mejores condiciones de solidificación para evitar el colapso mediante aire forzado. Las muestras se prepararon con el mismo peso a diferentes densidades, habiéndose obtenido, que el mejor comportamiento mecánico se lograba en las espumas de mayor densidad, comprendidas entre 0,70 y 0,81 g/cm3.

  14. Reciprocating Wear Behaviour of 7075Al/SiC and 6061Al/Al2O3 Composites: A study of Effect of Reinforcement, Stroke and Load

    OpenAIRE

    J. Lakshmipathy; B. Kulendran

    2014-01-01

    The wear behaviour comparison of Al/SiC and Al/Al2O3 composites prepared by stir casting technique is investigated to find out the effects of weight percentage of SiC/Al2O3, load and the number of strokes on a reciprocating wear testing machine. The MMC pins are prepared with different weight percentage of SiC and Al2O3 (10, 15 and 20 %). The tests are carried out with different load conditions (25, 50 and 75 N) and different number of strokes (420,780 and 1605 strokes). Wear surfaces of test...

  15. Analysis of the interaction products in U(Mo,X)/Al and U(Mo,X)/Al(Si) diffusion couples, with X = Cr, Ti, Zr

    OpenAIRE

    Allenou, Jérôme; Palancher, Hervé; Iltis, Xavière; Tougait, Olivier; El Bekkachi, Houda; Bonnin, Anne; Tucoulou, Rémi

    2014-01-01

    In the framework of the development of a low 235U enriched nuclear fuel for material testing reactors, γ-U(Mo)/Al based materials are considered as the most interesting prospect. In the process to optimize their composition, addition to both γ-U(Mo) and Al have been proposed. In this paper, the crystallographic composition of Interaction Layers (ILs) in γ-U(Mo,X)/Al and γ-U(Mo,X)/AlSi7 diffusion couples, with X = Cr, Ti, Zr, heat-treated at 600 °C for 2 h, were studied by micro-X-ray diffract...

  16. Doping the Buckminsterfullerene by Substitution: Density Functional Theory Studies of C59X (X = B, N, Al, Si, P, Ga, Ge, and As

    Directory of Open Access Journals (Sweden)

    Hongcun Bai

    2013-01-01

    Full Text Available The heterofullerenes C59X (X = B, N, Al, Si, P, Ga, Ge, and As were investigated by quantum chemistry calculations based on density functional theory. These hybrid cages can be seen as doping the buckminsterfullerene by heteroatom substitution. The geometrical structures, relative stabilities, electronic properties, vibrational frequencies, dielectric constants, and aromaticities of the doped cages were studied systemically and compared with those of the pristine C60 cage. It is found that the doped cages with different heteroatoms exhibit various electronic, vibrational, and aromatic properties. These results imply the possibility to modulate the physical properties of these fullerene-based materials by tuning substitution elements.

  17. Effect of mixed rare earth oxides and CaCO3 modification on the microstructure of an in-situ Mg2Si/Al-Si composite

    Institute of Scientific and Technical Information of China (English)

    LIU Zheng; LIN Jixing; JING Qingxiu

    2009-01-01

    The effects of mixed rare earth oxides and CaCO3 on the microstructure of an in-situ Mg2Si/Al-Si hypereutectic alloy composite were investigated by optical microscope, scanning electron microscope, and energy dispersive spectrum analysis. The results showed that the morphology of the primary Mg2Si phase particles changed from irregular or crosses to polygonal shape, their sizes decreased from 75 μm to about 25 μm, and the compound of both the oxide and CaCO3 was better than either the single mixed rare earth oxides or CaCO3.

  18. The role of iron in the formation of porosity in Al-Si-Cu-based casting alloys. Part 1: Initial experimental observations

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, J.A.; Schaffer, G.B.; StJohn, D.H. [Univ. of Queensland, Brisbane, Queensland (Australia)

    1999-06-01

    Outbreaks of interconnected porosity in industrial Al-Si-based alloy castings have, on occasion, been attributed to variations in metal chemistry rather than to changes in process parameters. This work identifies the role that iron plays in porosity formation and reports a threefold effect in an Al-5 pct Si-1 pct Cu-0.5 pct Mg alloy. In addition to a detailed analysis of casting porosity profiles, metallographic and thermal studies also point to inadequacies in the existing theories regarding the role of iron and suggest that a new theory is required to understand the observed behavior.

  19. Study on nanocomposite Ti-Al-Si-Cu-N films with various Si contents deposited by cathodic vacuum arc ion plating

    Energy Technology Data Exchange (ETDEWEB)

    Shi, J. [State Key Laboratory of Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Institute of Materials Engineering, University of Siegen, Paul-Bonatz-Strasse 9-11, Siegen 57076 (Germany); Muders, C.M.; Kumar, A. [Institute of Materials Engineering, University of Siegen, Paul-Bonatz-Strasse 9-11, Siegen 57076 (Germany); Jiang, X., E-mail: xin.jiang@uni-siegen.de [Institute of Materials Engineering, University of Siegen, Paul-Bonatz-Strasse 9-11, Siegen 57076 (Germany); Pei, Z.L.; Gong, J. [State Key Laboratory of Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Sun, C., E-mail: csun@imr.ac.cn [State Key Laboratory of Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

    2012-10-01

    Highlights: Black-Right-Pointing-Pointer XRD peaks show a tendency of decreasing intensity with increasing Si content. Black-Right-Pointing-Pointer Ti-Al-Si-Cu-N films present different microstructure with increasing Si content. Black-Right-Pointing-Pointer Films with 6 at.% Si content obtain the highest hardness, elastic modulus and H{sup 3}/E{sup 2}. Black-Right-Pointing-Pointer The wear rate decreases with an increase in hardness. - Abstract: In this study, nanocomposite Ti-Al-Si-Cu-N films were deposited on high speed steel substrates by the vacuum cathode arc ion plating (AIP) technique. By virtue of X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscopy (FESEM), the influence of silicon content on the film microstructure and characteristics was investigated systematically, including the chemical composition, crystalline structure as well as cross-section morphologies. With increasing the silicon content, a deterioration of the preferred orientation and a dense globular structure were detected. In the meanwhile, atomic force microscopy (AFM), nano-indentation, Rockwell indenter and reciprocating test were also utilized to analyze the hardness, elastic modulus, H{sup 3}/E{sup 2}, friction coefficient, adhesive strength and wear rate of the Ti-Al-Si-Cu-N films. The results showed that an optimal silicon content correlated with the best mechanical and tribological properties of the presented Ti-Al-Si-Cu-N films existed. With increasing the silicon content, the hardness, elastic modulus and the ratio H{sup 3}/E{sup 2} first were improved gradually, and then were impaired sharply again. When the silicon content reached to 6 at.%, the film possessed the highest hardness, elastic modulus and ratio H{sup 3}/E{sup 2} of approximately 24 GPa, 218 GPa and 0.31, respectively. Besides, films containing both 6 at.% and 10 at.% Si contents obtained a relatively low friction coefficient and a good adhesive

  20. New approaches to casting hypereutectic Al-Si alloys to achieve simultaneous refinement of primary silicon and modification of eutectic silicon

    OpenAIRE

    Al-Helal, Kawther

    2013-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University Hypereutectic Al-Si alloys are of increasing interest for applications that require a combination of light weight and high wear resistance, such as pistons, liner-less engine blocks and pumps. The wear resistance of this class of alloys is due to the presence of hard primary Si particles formed during casting. The objective of this work was to develop one or more methods of refining primary si...

  1. Producción, procesado y caracterización de aleaciones de W reforzadas con dispersión de óxidos para reactores de fusión

    OpenAIRE

    Martínez Gómez, Javier

    2013-01-01

    El objetivo de esta tesis ha sido investigar la producción y caracterización de materiales de base de wolframio. Las aleaciones de wolframio son los materiales candidatos para formar parte de los componentes de la primera pared en los futuros reactores de fusión. En particular, estas aleaciones se consideran los materiales más prometedores en la construcción del divertor enfriado por He para el futuro reactor de fusión de demostración (DEMO) y para los elementos de blindaje de la primera pare...

  2. Influencia del rayado sobre la resistencia electroquímica de les aleaciones de NiTi tratadas por un nuevo tratamiento térmico para aplicaciones biomédicas

    OpenAIRE

    Soualah, Lakhdar

    2005-01-01

    Las aleaciones de níquel-titanio son aleaciones que se utilizan cada vez más en aplicaciones biomédicas, por sus propiedades interesantes de superelasticidad, de memoria de forma, de resistencia a la corrosión y de biocompatibilidad. Sin embargo, los resultados obtenidos de su resistencia a la corrosión son muy variables, dependiendo del estado de superficie. Así, para mejorar, la resistencia a la corrosión de este material, se diseñó en un trabajo anterior un nuevo tratamie...

  3. Desarrollo calorimétrico del proceso de precipitación en aleaciones Cu-Co-Si

    Directory of Open Access Journals (Sweden)

    Donoso, E.

    2005-12-01

    Full Text Available Using differential scanning calorimetry (DSC the precipitation processes of supersaturated solid solutions of three Cu-Co-Si alloys, with a constant cobalt composition, were studied. Thermograms, and previous studies, reveal that the decomposition begins with cobalt precipitation. Clustering of cobalt initiates the silicon precipitation, finally Co2Si stoichiometric particles are formed. Volume fractions are determined by the amount of cobalt present in these alloys. It is inferred that surplus silicon atoms retained in the solution increase the reaction rate. Kinetic parameters were calculated by a method based in the Mehl-Johnson-Avrami (MJA formalism. The lower activation energy obtained, associated with cobalt clustering is attributed to the contribution of quenched-in vacancies.

    Mediante calorimetría diferencial de barrido (DSC se estudió el proceso de precipitación de soluciones sólidas supersaturadas de tres aleaciones de Cu-Co-Si, con composición de cobalto constante. Evaluaciones entalpimétricas y estudios previos, revelaron que la descomposición comienza con la precipitación de cobalto. El agrupamiento de átomos de cobalto inicia la precipitación del silicio, formándose finalmente partículas de composición estequiométricas de Co2Si. Las fracciones volumétricas fueron determinadas en función de la cantidad de cobalto presente en estas aleaciones. Se infiere que el superávit de átomos de silicio retenidos en la solución aumenta la velocidad de reacción. Los parámetros cinéticos fueron calculados a partir de un método basado en el formalismo de Mehl- Johnson-Avrami (MJA. La energía de activación más baja obtenida, asociada con el apilamiento de cobalto, se atribuyó a la contribución de las vacantes retenidas por temple.

  4. Medida de la dureza de aleaciones amorfas de acero y de Itrio con diferentes cargas

    OpenAIRE

    Roinsol, Guillaume

    2010-01-01

    Este trabajo tiene como objetivo el estudio de una propiedad de un tipo de materiales poco utilizado hasta ahora: los vidrios metálicos. Debido al descubrimiento reciente de los vidrios metálicos, sus características no son bien conocidas y por ello proponemos el estudio de una de estas características, la Dureza. La Dureza es un parámetro mecánico cuantificando la resistencia a la penetración de un material. Se mide con un durómetro, un microdurómetro o un nanodurometro, dependiendo de la...

  5. In-situ transmission electron microscopy investigation of surface-oxide, stress-relief mechanisms during melting of sub-micrometer Al-Si alloy particles

    International Nuclear Information System (INIS)

    In-situ heating in a transmission electron microscope was used to investigate the stress-relief mechanisms occurring in the 3-4 nm thick aluminum-oxide films present on the surfaces of submicron Al-11.6% Si powder particles during melting. Experimental observations show that the aluminum-oxide shell undergoes creep to relieve the high stress generated by the expanding liquid during melting. Surface oxides that contain defects do not undergo uniform creep and are prone to cracking, which causes ejection of some of the pressurized liquid inside the particles through the crack. Calculations were performed to estimate the stresses generated on the aluminum-oxide shell by the expanding liquid and the possible effect of the stress generated by the confining oxide shell on the melting temperature of the Al-Si alloy. The calculations show that the oxide film creeps to avoid the high tangential stress (on the order of 15 GPa) produced by the expanding liquid and that this creep mechanism prevents the oxide from markedly changing the melting behavior of the Al-Si particles

  6. On the role of nano-size SiC on lattice strain and grain size of Al/SiC nanocomposite

    International Nuclear Information System (INIS)

    In the present study high energy ball mill was implemented to produce aluminum (Al) matrix composite powders reinforced with silicon carbide (SiC). To clarify the role of particle size of SiC on lattice strain and grain size of Al two series of SiC with micron and nano-size were selected. Aluminum and SiC powders were mixed mechanically and milled at different times (2, 5, 10 h) to achieve Al-2.5 vol%SiC and Al-5 vol%SiC composite powders. The produced composites were investigated using X-ray diffraction pattern (XRD) to elucidate the role of particle size, secondary phase content and milling time on grain size and lattice strain of Al matrix. The results showed that an increase in milling time caused to reduce the grain size unlike the lattice strain of Al matrix. At the same condition a faster grain refinement for Al/SiC nanocomposites were observed with respect to Al/SiC composites.

  7. Eutectic morphology evolution and Sr-modification in Al-Si based alloys studied by 3D phase-field simulation coupled to Calphad data

    Science.gov (United States)

    Eiken, J.; Apel, M.

    2015-06-01

    The mechanical properties of Al-Si cast alloys are mainly controlled by the morphology of the eutectic silicon. Phase-field simulations were carried out to study the evolution of the multidimensional branched eutectic structures in 3D. Coupling to a Calphad database provided thermodynamic data for the multicomponent multiphase Al-Si-Sr-P system. A major challenge was to model the effect of the trace element Sr. Minor amounts of Sr are known to modify the silicon morphology from coarse flakes to fine coral-like fibers. However, the underlying mechanisms are still not fully understood. Two different in literature most discussed mechanisms were modelled: a) an effect of Sr on the growth kinetics of eutectic silicon and b) the formation of Al2Si2Sr on AlP particles, which consumes most potent nucleation sites and forces eutectic silicon to form with lower frequency and higher undercooling. The phase-field simulations only revealed a successful modification of the eutectic morphology when both effects acted in combination. Only in this case a clear depression of the eutectic temperature was observed. The required phase formation sequence L → fcc-(Al) → AlP → Al2Si2Sr → (Si) determines critical values for the Sr and P content.

  8. Molten pool behaviour and its physical mechanism during selective laser melting of TiC/AlSi10Mg nanocomposites: simulation and experiments

    International Nuclear Information System (INIS)

    Simulation of temperature evolution and thermal behaviour of the molten pool during selective laser melting (SLM) of TiC/AlSi10Mg nanocomposites was performed, using a finite volume method. Some important physical phenomena, such as a transition from powder to solid, nonlinearities produced by temperature-dependent material properties and fluid flow, were taken into account in the calculation. The effects of Marangoni convection and SLM processing parameters, such as laser power and scan speed, on temperature evolution behaviour, molten pool dimensions and liquid lifetime were thoroughly investigated. The simulation results showed that Marangoni convection played a crucial role in intensifying the convective heat transfer and changing the molten pool geometry. The temperature of laser–powder interaction zone, the molten pool dimensions and liquid lifetime increased with increasing laser power or decreasing scan speed. The maximum temperature gradient within the molten pool increased significantly with increasing the applied laser power, but increased slightly as a higher scan speed was applied. The experimental study on the interlayer bonding and densification behaviour and the surface morphologies and balling effect of the SLM-processed TiC/AlSi10Mg nanocomposites parts was performed. The experimental results validated the thermal behaviour and underlying physical mechanism of the molten pool obtained in the simulations. (paper)

  9. Fine-structured aluminium products with controllable texture by selective laser melting of pre-alloyed AlSi10Mg powder

    International Nuclear Information System (INIS)

    Graphical abstract: -- Abstract: This study shows that AlSi10Mg parts with an extremely fine microstructure and a controllable texture can be obtained through selective laser melting (SLM). Selective laser melting creates complex functional products by selectively melting powder particles of a powder bed layer after layer using a high-energy laser beam. The high-energy density applied to the material and the additive character of the process result in a unique material structure. To investigate this material structure, cube-shaped SLM parts were made using different scanning strategies and investigated by microscopy, X-ray diffraction and electron backscattered diffraction. The experimental results show that the high thermal gradients occurring during SLM lead to a very fine microstructure with submicron-sized cells. Consequently, the AlSi10Mg SLM products have a high hardness of 127 ± 3 Hv0.5 even without the application of a precipitation hardening treatment. Furthermore, due to the unique solidification conditions and the additive character of the process, a morphological and crystallographic texture is present in the SLM parts. Thanks to the knowledge gathered in this paper on how this texture is formed and how it depends on the process parameters, this texture can be controlled. A strong fibrous 〈1 0 0〉 texture can be altered into a weak cube texture along the building and scanning directions when a rotation of 90° of the scanning vectors within or between the layers is applied

  10. Molten pool behaviour and its physical mechanism during selective laser melting of TiC/AlSi10Mg nanocomposites: simulation and experiments

    Science.gov (United States)

    Yuan, Pengpeng; Gu, Dongdong

    2015-01-01

    Simulation of temperature evolution and thermal behaviour of the molten pool during selective laser melting (SLM) of TiC/AlSi10Mg nanocomposites was performed, using a finite volume method. Some important physical phenomena, such as a transition from powder to solid, nonlinearities produced by temperature-dependent material properties and fluid flow, were taken into account in the calculation. The effects of Marangoni convection and SLM processing parameters, such as laser power and scan speed, on temperature evolution behaviour, molten pool dimensions and liquid lifetime were thoroughly investigated. The simulation results showed that Marangoni convection played a crucial role in intensifying the convective heat transfer and changing the molten pool geometry. The temperature of laser-powder interaction zone, the molten pool dimensions and liquid lifetime increased with increasing laser power or decreasing scan speed. The maximum temperature gradient within the molten pool increased significantly with increasing the applied laser power, but increased slightly as a higher scan speed was applied. The experimental study on the interlayer bonding and densification behaviour and the surface morphologies and balling effect of the SLM-processed TiC/AlSi10Mg nanocomposites parts was performed. The experimental results validated the thermal behaviour and underlying physical mechanism of the molten pool obtained in the simulations.

  11. Modification of β-Al5FeSi Compound in Recycled Al-Si-Fe Cast Alloy by Using Sr, Mg and Cr Additions

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The effects of Sr, Mg, Cr, Sr/Mg and Sr/Cr combined additions on the Fe-containing intermetallic phase in a recycled Al-Si-Fe cast alloy are investigated. The experimental results show that the additions of Cr and Sr/Cr successfully modified the platelet and flake-like β-AlsFeSi phases (β-compound) into the fibrous α-Al8Fe2Si (α-compound). The additions of Sr and Sr/Mg were less effective to modify the β-compound into the α-compound, while the eutectic Si was fully modified into the fibrous morphology. A small secondary dendrite arm spacing (DAS) was found in the Sr-added, Cr-added and Sr/Cr-added alloys, especially in a steel mold. The Sr, Sr/Cr and Sr/Mg combined additions modify the eutectic Si simultaneously. A sludge phase was found in the addition of Cr-added, Sr/Cr-added and Mg-added alloys, especially in the graphite mold casting. The volume fraction of β-compounds was decreased by the addition of various modifying elements.The Cr and Sr/Cr combined additions are very effective to modify the β-compound for the recycled Al-Si-Fe based alloys.

  12. Heat treatment of EN AC-AlSi13Cu2Fe silumin and its effect on change of hardness of the alloy

    Directory of Open Access Journals (Sweden)

    J. Pezda

    2010-01-01

    Full Text Available Wide application of aluminum casting alloys is connected with their very good physical and technical properties. Within such group of alloys, silumins play important role in automotive and aviation industry, as well as in another branches of technique, because the silumins enable casting of complicated shapes. The most important parameters which predetermine mechanical properties of a material in aspects of suitability for castings of machinery components are: tensile strength (Rm, elongation and hardness. Alloys based on equilibrium system of Al-Si comprise additional constituents (e.g.: Mg, Cu enabling, except modification, improvement of mechanical properties, obtained in result of heat treatment. In the paper are presented results of investigations concerning effect of the heat treatment on change of hardness (HB of the EN AC-AlSi12Cu2Fe alloy. Investigated alloy was melted in an electric resistance furnace. Run of the crystallization was presented with use of the thermal-derivative method (ATD. This method was also implemented to determination of heat treatments temperature range of the alloy. Performed heat treatment gave effect in change of the hardness. Performed investigations have enabled determination of heat treatment parameters range, which conditions suitable hardness of the investigated alloy.

  13. Structure and properties of selected cemented carbides and cermets covered with TiN/(Ti,Al,SiN/TiN coatings obtained by the cathodic arc evaporation process

    Directory of Open Access Journals (Sweden)

    Leszek A. Dobrzañski

    2005-06-01

    Full Text Available This study presents the results of microstructural examinations, mechanical tests and service performance tests carried out on thin TiN/(Ti,Al,SiN/TiN wear resistance coatings obtained by the CAE process on cermet and cemented carbide substrates. Microstructural examinations of the applied coatings and the substrate were made with an OPTON DSM 940 SEM and a LEICA MEF4A light microscope. Adhesion of the coatings on cemented carbides and cermets was measured using the scratch test. The cutting properties of the materials were determined from service tests in which continuous machining of C45E steel was carried out. The hardness of the substrate and the microhardness of the coatings were determined with a DUH 202 SHIMADZU ultra microhardness tester with a load of 70 mN. Roughness tests were also carried out before applying the coatings and after the PVD process. Cutting tests confirmed the advantages of the TiN/(Ti,Al,SiN/TiN type coatings obtained using the PVD method in the CAE mode on cemented carbides and cermets, as a material that undergoes very low abrasive, thermal and adhesion wear. These coatings extend tool life compared to commercially available uncoated tools with single and multi-layer coatings deposited using PVD/CVD methods.

  14. The role of iron in the formation of porosity in Al-Si-Cu-based casting alloys. Part 3: A microstructural model

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, J.A.; Schaffer, G.B.; StJohn, D.H. [Univ. of Queensland, Brisbane, Queensland (Australia)

    1999-06-01

    Iron has been shown to have a significant effect on the formation of porosity and shrinkage defects in Al-Si-Cu-based foundry alloys. This is not simply a direct consequence of the physical presence of the {beta}-Al{sub 5}FeSi platelets in the microstructure, but is also due to the effect that these platelets have on the nucleation and growth of eutectic silicon. The alloy-dependent critical iron content determines when the {beta} phase first solidifies and, hence, when it can participate in the silicon nucleation event. At critical iron contents, the {beta} phase solidifies as the initial component of the ternary eutectic. However, at supercritical iron contents, the {beta} phase solidifies as the initial component of the ternary eutectic solidification begins, while, at subcritical iron contents, the {beta} phase forms as a component of the ternary eutectic only after the binary Al-Si eutectic is well established. Each of these paths of microstructural evolution leads to different variations in microstructural permeability and, hence, interdendritic feedability and porosity formation. The actual porosity-forming response to these alloy-induced microstructural changes is influenced by the solidification conditions in the casting.

  15. Study of an Al-Si-Cu HPDC alloy with high Zn content for the production of components requiring high ductility and tensile properties

    Energy Technology Data Exchange (ETDEWEB)

    Vicario, Iban; Egizabal, Pedro; Galarraga, Haize; Plaza, Luis Maria; Crespo, Inigo [Fundacion Tecnalia Research and Innovation, Donostia-San Sebastien (Spain). Dept. of foundry processes

    2013-04-15

    Conventional high-pressure die casting aluminium components present certain limitations in terms of mechanical properties attainable due to the intrinsic porosity of the castings as well as the presence of iron-based brittle intermetallic phases. The present work approaches the increase in ductility and tensile strength through the analysis of the effect of the alloying elements of AlSi alloys used for high-pressure die casting. The combination of alloying elements providing the best results in terms of ductility and tensile strength were eventually selected to produce a batch of components that were thoroughly tested. The final alloy had a composition of Si 8.21, Fe 0.78, Cu 1.53, Mn 0.64, Mg 0.46, Ni 0.07, Zn 3.37, Pb 0.34, Sn 0.27, Ti 0.18 and Cr 0.04wt.%. The selected alloy performance was compared to that of the commercial AlSi9Cu3 and Silafont {sup registered} 36 alloys.

  16. Effect of overheating degree of molten alloy on material reliability and performance stability of AlSi17CuNiMg silumin castings

    Directory of Open Access Journals (Sweden)

    J. Szymszal

    2010-10-01

    Full Text Available The article discusses the effect of overheating degree (above the casting temperature on material reliability of AlSi17 silumin. Theexamined alloys was poured at temperatures, 760; 870 and 980oC, holding the melt for 40 minutes and casting from the temperature of760oC. The assessment of the impact of the degree of overheating was to analysis the tensile strength. From the results of the static tensile test, the main estimators of the descriptive statistics, and coefficients of variation. Having determined the boundary value sO for Weibull distribution, the value of „m” modulus was computed along with other coefficients of material reliability, proposed formerly by the authors. Basing on the obtained results, a model of Weibull distribution function was developed for the tensile strength with respective graphic interpretation. The time-temperature parameters of the melting and casting technology have been chosen to determine the scatter of resultant parameter (Rm in function of overheating degree. The time-temperature treatment of hypereutectic AlSi17CuNiMg silumin, through its effect on the cluster structure of molten alloy, is shaping the material reliability and performance stability of castings.

  17. A comparative study on wear behavior of TiN and diamond coated WC-Co substrates against hypereutectic Al-Si alloys

    Science.gov (United States)

    Chakravarthy, G. V.; Chandran, Maneesh; Bhattacharya, S. S.; Rao, M. S. Ramachandra; Kamaraj, M.

    2012-11-01

    The demand for better tools for machining hypereutectic aluminum-silicon (Al-Si) alloys are increasing day by day since the extensive use of these alloys in internal combustion engines. In addition to the lifetime of the machining tool, surface finish of the machined piece is also equally important, as it directly affects the performance of the engine. In this paper, we compared the wear behavior of bare tungsten carbide (WC-Co), titanium nitride (TiN) coated WC-Co and diamond coated WC-Co substrates against Al-Si alloys using pin-on-disc method. Both TiN and diamond coatings were done using chemical vapor deposition technique. Diamond coated WC-Co substrates show one order less wear loss compared to the bare WC-Co substrates. Instead of weight loss, a weight gain was observed for the TiN coated WC-Co substrates. Average coefficient of friction was lowest for the diamond coated WC-Co substrates due to the different wear behavior of diamond coated tribological system, which is explained in detail.

  18. Diagrama de fases de las aleaciones (CuGaSe2)1-x(FeSe)x (0≤x≤0.5)

    OpenAIRE

    Miguel Soto; Pedro Grima-Gallardo; Miguel Quintero; Menjamin Salas; Marcos Muñoz; Sonia Durán; Luis Nieves; Ekadink Moreno; Ramos, Miguel A.; José M Briceño

    2013-01-01

    Se prepararon muestras policristalinas del sistema de aleaciones (CuGaSe2)1-x (FeSe)x en el rango de composiciones (0≤x≤0,5) por la técnica de fusión y recocido. Los productos fueron analizados usando las técnicas de Difracción de Rayos X (DRX) y Análisis Térmico Diferencial (ATD). Del análisis de los resultados experimentales se propone un diagrama de fases, T-x, en la región de composiciones cercana al CuGaSe2

  19. Profundización en los mecanismos de corrosión de las aleaciones de magnesio. Estrategias para mejorar la resistencia a la corrosión

    OpenAIRE

    Samaniego Miracle, Alejandro

    2014-01-01

    El magnesio y sus aleaciones presentan una combinación de baja densidad, alta resistencia específica y buena moldeabilidad, que los convierte en prometedores materiales estructurales. Sin embargo, dado que el magnesio es uno de los metales químicamente más activos, su resistencia frente a la corrosión es uno de los puntos clave que limitan su utilización en condiciones reales de servicio. Esta tesis se ha dividido en tres capítulos bien diferenciados. El primero de ellos se centra en el mecan...

  20. Influencia de la composición y el tratamiento térmico en las propiedades mecánicas de aleaciones de bronce al aluminio

    Directory of Open Access Journals (Sweden)

    Cenoz-Echeverría, I.

    2007-08-01

    Full Text Available Aluminium bronzes are copper-base alloys containing aluminium within the limits between 5-12 %. Additions of Fe, Ni and Mn are used as alloying elements forming a family of complex alloys noted for their exceptional strength and corrosion resistance. In present paper the Ni:Fe ratio and heat treatments have been analyzed by determining the mechanical properties for three different aluminium bronze alloys containing Cu-Al10-Fe3, Cu-Al10-Fe5-Ni5 and Cu-Al10-Fe4-Ni8. The effect of as cast, quenched and quenched and tempered structures has been investigated regarding hardness, proof and ultimate tensile strength, elongation, modulus of elasticity, Poisson ratio, fracture toughness, fatigue strength, crack propagation and Charpy impact properties. The influence of temperature has been studied by testing the elastic modulus, Poisson ratio, the proof stress, tensile strength and the Charpy impact properties at –20 °C, 24 °C and 100 °C.

    Los cuproaluminios son aleaciones de cobre con contenidos de aluminio del 5-12 % que pueden incorporar hierro, níquel, y manganeso para formar una familia de aleaciones con unas excelentes propiedades de resistencia mecánica y a la corrosión. En el presente artículo se estudia el efecto que la relación Ni:Fe y que los tratamientos térmicos ocasionan en las propiedades mecánicas como dureza, límite elástico, tensión de rotura, alargamiento, módulo de elasticidad, coeficiente de Poisson, tenacidad a la fractura estática, resiliencia, fatiga y propagación de grieta. Para ello, se analizan tres aleaciones en tres estados. Las composiciones nominales son Cu-Al10-Fe3, Cu-Al10-Fe5-Ni5 y Cu- Al10-Fe4-Ni8. Las estructuras de las aleaciones son las correspondientes a: bruto de colada, temple y temple seguido de revenido. La caracterización del módulo de elasticidad y coeficiente de Poisson, así como los ensayos de tracción y resiliencia, se realizan a –20 °C, 24 °C y 100 °C.