Publication: Cambios microestructurales en una aleación Mg-Zn-Y reforzada con fase cuasicristalina inducidos por la adición de 0,5%at. de Ca, Mn o CeMM y su influencia en las propiedades mecánicas
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2017-02-23
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Universidad Complutense de Madrid
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Abstract
La reducción del peso de los vehículos para disminuir el consumo de combustible y las emisiones de CO2 es una de las principales razones que ha impulsado la investigación y el desarrollo de aleaciones de magnesio en las últimas décadas. La combinación de propiedades como ligereza, elevada tenacidad específica, buena colabilidad y conformabilidad son razones por las que las aleaciones de magnesio son muy adecuadas para su empleo en aplicaciones estructurales. Sin embargo, su empleo ha quedado restringido a aplicaciones muy específicas ya que para otras es necesario superar los problemas que plantea su uso como son su escasa resistencia frente a la corrosión y la pérdida de resistencia mecánica que experimenta, principalmente, a temperaturas intermedias y altas. La presente memoria tiene como objetivo el diseño de nuevas aleaciones de magnesio con elevada resistencia mecánica en el intervalo 25 °C-200 °C y con buen comportamiento a fluencia, para su posible empleo en la fabricación de componentes estructurales, principalmente en el sector del transporte. Las composiciones de las aleaciones elegidas en el estudio pertenecen a la familia Mg-Zn-Y reforzada con la fase cuasicristalina I, modificadas mediante la adición de pequeñas cantidades de calcio, manganeso y cerio mischmetal. La investigación llevada a cabo ha consistido en determinar los cambios microestructurales que producen las adiciones de los elementos citados tanto en las aleaciones en el estado de colada como tras su procesado por extrusión a diferentes temperaturas y su efecto sobre las propiedades mecánicas en un intervalo amplio de temperaturas y velocidades de deformación...
Vehicle-weight reduction to decrease the fuel consumption and CO2 emissions from engines is one of the main reasons that has driven the research and development of magnesium alloys over the last few decades. The combination of properties such as lightness, high specific stiffness and excellent castability and workability makes magnesium alloys to be suitable candidates as structural materials in the transportation industry. However their use is still limited because of their poor corrosion resistance and low mechanical strength, mainly, at intermediate and high temperatures. The main goal in the present work is to design new magnesium alloys with high mechanical strength in the range of 25-200 °C and good creep behavior for their application as structural components mainly in the automotive industry. Chemical compositions of the alloys that are chosen in this study belong to the Mg-Zn-Y system reinforced by quasicrystalline I-phase. These alloys were modified by calcium, manganese and cerium mischmetal additions. The research work has been done to identify the microstructural changes produced by the addition of mentioned elements in both, the as-cast state and after extrusion process at different temperatures, as well as their effect on the mechanical properties in a wide range of temperatures at different strain rates...
Vehicle-weight reduction to decrease the fuel consumption and CO2 emissions from engines is one of the main reasons that has driven the research and development of magnesium alloys over the last few decades. The combination of properties such as lightness, high specific stiffness and excellent castability and workability makes magnesium alloys to be suitable candidates as structural materials in the transportation industry. However their use is still limited because of their poor corrosion resistance and low mechanical strength, mainly, at intermediate and high temperatures. The main goal in the present work is to design new magnesium alloys with high mechanical strength in the range of 25-200 °C and good creep behavior for their application as structural components mainly in the automotive industry. Chemical compositions of the alloys that are chosen in this study belong to the Mg-Zn-Y system reinforced by quasicrystalline I-phase. These alloys were modified by calcium, manganese and cerium mischmetal additions. The research work has been done to identify the microstructural changes produced by the addition of mentioned elements in both, the as-cast state and after extrusion process at different temperatures, as well as their effect on the mechanical properties in a wide range of temperatures at different strain rates...
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Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Físicas, Departamento de Física de Materiales, leída el 14-07-2016