Propiedades magnéticas y estructurales en aleaciones metamagnéticas con memoria de forma de composición Mn49Ni39Sn8Fe4 fabricadas mediante solidificación rápida.

Abstract

[ES] Los materiales con memoria de forma son materiales inteligentes, es decir, son materiales capaces de alterar su forma de manera controlada frente a un estímulo. Estas aleaciones se caracterizan por la transformación martensítica (transformación de fase sólido-sólido) que dota a los materiales con memoria de forma de las siguientes propiedades: la superelasticidad y la memoria de forma. Además, el compuesto estudiado posee efectos de deformación por campo magnético, por lo que presenta otras propiedades añadidas a las anteriores como el efecto magnetocalórico, una gran magnetorresistencia y deformación inducida por campo magnético.

En este trabajo se ha estudiado una aleación de Mn49Ni39Sn8Fe4 con estas características en colaboración con BCmaterials [1]. Se han fabricado diferentes cintas mediante la técnica de ”melt-spinning” para las velocidades de 10, 15, 20, 25 y 30 m/s. Y se han analizado sus propiedades en función de la tasa de enfriamiento o velocidad de la rueda del ”melt-spinner” mediante varias técnicas experimentales: estudio de la microestructura y composición de las cintas mediante el microscopio electrónico de barrido (SEM), análisis termodinámico mediante el calorímetro diferencial de barrido (DSC) y caracterización magnética mediante el magnetómetro de muestra vibrante (VSM).

El objetivo final de este estudio consiste en evaluar la dependencia de las propiedades físicas y mecánicas en función de la tasa de enfriamiento. En definitiva, determinar qué cintas son más resistentes y presentan mejores propiedades de memoria de forma, y en concreto, el cambio de las propiedades de deformación y transformación con el campo magnético aplicado.

Summary:

Shape memory materials are smart materials, i.e. they are materials capable of altering their shape in a controlled manner in response to a stimulus. These alloys are characterized by the martensitic transformation (solid-solid phase transformation) which endows shape memory materials with the following properties: superelasticity and shape memory. In addition, the studied composite possesses magnetic field deformation effects, so it presents other properties added to the previous ones such as magnetocaloric effect, high magnetoresistance and magnetic field induced deformation.

In this work, a Mn49Ni39Sn8Fe4 alloy with these characteristics has been studed in collaboration with BCmaterials [1]. Different ribbons have been fabricated by melt-spinning technique for the velocities of 10, 15, 20, 25 and 30 m/s. And their properties have been analyzed as a function of the cooling rate or speed of the melt-spinner wheel by means of several experimental techniques: study of the microstructure and composition of the tapes by scanning electron microscope (SEM), thermodynamic analysis by differential scanning calorimeter (DSC) and magnetic characterization by means of the vibrating sample magnetometer (VSM).

The final objective of this study is to evaluate the dependence of physical and mechanical properties as a function of cooling rate. In short, to determine which tapes are more resistant and show better shape memory properties, and in particular, the change of the deformation and transformation properties with the applied magnetic field.

[EN] Shape memory materials are smart materials, i.e. they are materials capable of altering their shape in a controlled manner in response to a stimulus. These alloys are characterized by the martensitic transformation (solid-solid phase transformation) which endows shape memory materials with the following properties: superelasticity and shape memory. In addition, the studied composite possesses magnetic field deformation effects, so it presents other properties added to the previous ones such as magnetocaloric effect, high magnetoresistance and magnetic field induced deformation.

In this work, a Mn49Ni39Sn8Fe4 alloy with these characteristics has been studed in collaboration with BCmaterials [1]. Different ribbons have been fabricated by melt-spinning technique for the velocities of 10, 15, 20, 25 and 30 m/s. And their properties have been analyzed as a function of the cooling rate or speed of the melt-spinner wheel by means of several experimental techniques: study of the microstructure and composition of the tapes by scanning electron microscope (SEM), thermodynamic analysis by differential scanning calorimeter (DSC) and magnetic characterization by means of the vibrating sample magnetometer (VSM).

The final objective of this study is to evaluate the dependence of physical and mechanical properties as a function of cooling rate. In short, to determine which tapes are more resistant and show better shape memory properties, and in particular, the change of the deformation and transformation properties with the applied magnetic field.