Name: indirect fabrication of lattice metals with thin sections using centrifugal casting
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Description: Watch this Scientific Journal Video about Indirect Fabrication of Lattice Metals with Thin Sections Using Centrifugal Casting at JoVE.com

Este estudio recibió el apoyo de la Investigación Iniciación Grant (RIG) del Vicerrectorado de Investigación y Desarrollo Económico de la Universidad del Norte de Texas (UNT). Los autores también agradecen a KCI Co. Ltd para apoyar parcialmente este estudio. El apoyo del Instituto de Tecnología de PACCAR en UNT para el éxito de esta publicación es muy apreciada.

1. Planificación del Experimento <ol><li> Dibujar un patrón de sacrificio (una estructura de celosía octeto con un sistema de bebedero) utilizando software de diseño asistido por ordenador (CAD) como se muestra en la Figura 1 y guardar el modelo CAD como un formato de archivo STL. Nota: El patrón de sacrificio es un patrón integrado de la estructura de celosía octeto con un sistema de bebedero que serán finalmente se fundió para la fundición. Debido a que el patrón de sacrificio incluye tanto la estructura de armadura octeto y el sistema de bebedero, que no representa exactamente la propia armadura octeto. Se proporciona un archivo STL del patrón de sacrificio. Registrar el volumen del patrón de sacrificio proporcionada por software CAD, que se utilizará para calcular la masa metales. </li><li> Abra el dibujo CAD del patrón de sacrificio en el software de impresión 3D conectado a una impresora 3D para imprimir el patrón. </li><li> Asegúrese de que la impresora 3D tiene suficiente UV curables plástico / moldeable acrílico y un material de soporte hecha de una ceraen los cartuchos de impresora. </li></ol> 2. La fabricación de patrón de sacrificio <ol><li> Fabricación el patrón de sacrificio que consiste en la estructura de octetos celosía y el sistema de canal de colada usando una impresora 3D (Figura 2A - C). Nota: Los procesos en 2.1.3 - 2.1.7 no son necesarios si se utiliza una impresora 3D que no genera materiales de apoyo. <ol><li> Enviar un archivo STL del patrón de sacrificio a la impresora 3D para imprimir un patrón de sacrificio (Figura 2A). </li><li> Derretir a cabo un material de soporte del patrón de sacrificio en un horno a por encima de la temperatura de fusión del material de soporte (60 a 70 C) durante 2 horas (Figura 2B). Nota: La temperatura para eliminar el material de soporte no debe ser demasiado alta. De lo contrario, puede provocar daños en el patrón de sacrificio. El patrón de sacrificio empieza a ser dañado en alrededor de 80 C en este estudio. Nota: La temperatura de fusión de apomateriales t varía con las impresoras 3D en donde se utilicen diferentes materiales de apoyo. </li><li> Llenar un limpiador ultrasónico digital con aceite para bebés de hasta 2,5 L, el volumen máximo que el limpiador puede contener (Figura 2C). Nota: Se recomienda el proveedor de la impresora 3D de usar aceite de bebé para disolver los residuos del material de soporte similar a la cera. </li><li> Ponga el patrón de sacrificio en el limpiador ultrasónico digital y conectar la alimentación de la aspiradora (Figura 2C). Asegúrese de que el patrón de sacrificio está totalmente sumergida en el aceite. </li><li> Eliminar el residuo del material de soporte sumergiendo el patrón de sacrificio en el aceite a 65ºC durante 40 minutos (Figura 2C). </li><li> Sacar el patrón de sacrificio de la aspiradora si el material de soporte se elimina por completo. </li><li> Tener el patrón de sacrificio seca con un ventilador a temperatura ambiente (~ 20 ° C) (Figura 2C). Nota: Se tarda aproximadamente 2 horashasta que el aceite en la superficie del patrón de sacrificio está totalmente seca. Considere el patrón de sacrificio a secar completamente si la superficie no es pegajosa. </li></ol></li></ol> 3. Fabricación de Mold <ol><li> Asamblea patrón <ol><li> Adjuntar una junta de goma para el patrón de sacrificio (la armadura octeto con el sistema de bebedero) y colocarlos en el fondo de un matraz en forma de cilindro con una altura de 6,35 cm y un diámetro de 6,35 cm (Figura 2D). Nota: Preparar dos matraces para la colada de cada metal; Al y Cu aleaciones. </li><li> verificación doble la junta de goma con el patrón de sacrificio está completamente unido a la parte inferior del matraz. </li><li> Envolver el matraz con una cinta adhesiva de manera que la inversión en polvo mezcla de agua, cuyo procedimiento se describe en la siguiente sección, no puede salirse del matraz. </li></ol></li><li> Preparación del molde de revestimiento <ol><li> Preparar la inversión en polvo (CaSO4 </sub&gt;, ρ = 1019 kg / m 3) de 89 g, que es 87.16 ml. Utilice una balanza para pesar el polvo de la inversión. Nota: Las propiedades físicas del polvo de revestimiento se muestran en la Tabla 1. </li><li> Verter el polvo de la inversión en un recipiente de mezcla (1 l). </li><li> Verter agua (114 ml) en el tazón. Use un vaso de precipitados para medir el volumen de agua. </li><li> Mezclar el polvo de revestimiento con agua en el recipiente durante 3 min. Mezclar bien hasta que no queden grumos en la mezcla de polvo de la inversión en agua. De lo contrario, puede causar una mala calidad de la superficie del molde de revestimiento. Siga el flujo de trabajo, como se muestra en la Figura 3. </li><li> Con el fin de eliminar las burbujas de aire en la mezcla, colocar el recipiente en una cámara de vacío durante 90 segundos hasta que las burbujas de aire no se pueden ver en la mezcla con los ojos desnudos (Figura 3). </li><li> Verter la mezcla en un matraz de incrustar el patrón de sacrificio y la junta de goma (Figura 2E). </li><li> Coloque los flask en la cámara de vacío de nuevo durante 90 segundos para eliminar el residuo de burbujas de aire dentro de la mezcla (Figura 3). </li><li> Secar la mezcla en el interior del matraz hasta que se endurece a temperatura ambiente (Figura 3). Nota: Por lo general, se tarda unos 10 - 15 minutos para que la mezcla se endurezca a temperatura ambiente. </li><li> Retirar el matraz y la junta de goma en la parte inferior de la mezcla en el matraz una vez que la mezcla se endurece (Figura 3). Este producto puede ser llamado un molde de yeso. </li></ol></li><li> Burn-out <ol><li> Establecer un tiempo de quemado en un horno mientras se sigue el horario de calefacción y refrigeración (Figura 4) de calentamiento desde 23 de hasta 150 ° C en el 2,1 C / min; 150-370 C a 3,7 C / min; 370-480 C a 1,85 c / min; 480-730 C a 4,17 c / min; 730 C durante 1 hora; enfriamiento 730-480 C a -4,17 C / min. Nota: El tiempo de burn-out varIES con tamaño de un matraz. En este estudio, establecer el tiempo de quemado a 6 horas. </li><li> Coloque el molde de yeso en un horno (Figura 2F). </li><li> Encienda el horno y aumentar la temperatura en el horno para eliminar el patrón de sacrificio en el interior del molde de yeso. Siga la condición de temperatura en la Figura 4. Nota: Debido a que el plástico acrílico UV curable / moldeable, los materiales del patrón de sacrificio, es un plástico termoendurecible acrílico-polímero, no fluye pero se disocia a una fase de gas en el horno. </li></ol></li><li> Fundición centrífuga (Figura 2G) <ol><li> Compruebe que el brazo de la máquina de fundición centrífuga gira con una velocidad angular de 425 rpm usando un tacómetro después de conectar la alimentación de una máquina de fundición centrífuga. </li><li> Preparar dos crisoles de cerámica que pueden contener una aleación de 150 g se derrita. Usar crisoles separados para aleaciones de Al y Cu para evitar que se contaminen con el correoACH otro. </li><li> Conecte la alimentación de la máquina de fundición centrífuga. </li><li> Usando un cortador de metal, picar las aleaciones en pedazos con 10 - 20 mm de longitud. Prepararlos suficiente para llenar completamente la cavidad del molde cuyo volumen debe ser el mismo que el patrón de sacrificio. Nota: La masa de los metales necesarios para llenar el mismo volumen de la cavidad del molde varía teniendo en cuenta la variación de densidad para cada metal. </li><li> Use telas retardantes de llama y guantes y gafas de seguridad. Preparar un cubo de agua (30 l) a temperatura ambiente. </li><li> Tome el molde de yeso temporalmente fuera del horno en la Sección 3.3, instalarlo en el soporte de frasco y equilibrar el brazo de la máquina de fundición centrífuga (Figura 5). </li><li> Coloque el molde de yeso de nuevo al horno y pre-calentamiento hasta 482 ° C antes de la colada. </li><li> Colocar el crisol en el soporte crisol (Figura 5). </li><li> Ponga la aleación picado en el crisol. </li><li> Abra la válvula de un oxígenotanque conectado con un soplete de acetileno-oxígeno y mantener un nivel de presión en el depósito de 96,5 kPa (14 psi). </li><li> Encender el soplete de acetileno-oxígeno con un encendedor y controlar la intensidad de la llama mediante el ajuste de la mezcla de gases. Nota: Es necesario tener precaución cuando se utiliza el soplete de acetileno-oxígeno. Su temperatura máxima de la antorcha es de alrededor de 1200 ° C. </li><li> Fundir la aleación de picado (aleación de Al o de aleación de Cu) con la antorcha en el crisol hasta que la aleación se vuelve completamente líquida. </li><li> Se agita la aleación en el crisol con una varilla de carbono hasta que la aleación de picado se derrita por completo. </li><li> Coloque el molde de yeso en la cuna petaca al lado del crisol que contiene la aleación fundida (Figura 5). </li><li> Cierre la cubierta de la máquina de fundición centrífuga, dejar que la rotación del brazo centrífugo y esperar por lo menos durante 3 min. Nota: La máquina de colada centrífuga comienza a funcionar tan pronto como la cubierta de la máquina de colada se cierra. El brazo centrífugogira a una velocidad de 425 rpm que corresponde a la velocidad de entrada en la cavidad del molde del patrón de sacrificio, v r = 8,03 m / s 28, 29 en la Figura 5, donde la entrada de velocidad se calcula utilizando la dinámica de partículas macroscópicas de un angular velocidad de la fundición centrífuga brazo 28, 29. </li><li> Desactive la alimentación de la máquina de fundición centrífuga después de la rotación 3 min del brazo. </li><li> Abra la tapa de la máquina de colada. </li><li> Tome el molde de yeso del soporte de frasco con unas pinzas. </li><li> Mantener el molde a temperatura ambiente durante 15 - 20 min hasta que el color de la aleación fundida se convierte en su original en la fase sólida. </li><li> Con unas pinzas, apagar el molde de yeso en agua colocada en un cubo (30 L) a ta durante aproximadamente 5 min. Asegúrese de que la temperatura del molde de yeso está cerca de RT después del temple. </li><li> Con el fin de obtener el metal de celosía en el interior del molde, se disuelve elmoho en el agua. El molde de yeso se disuelve fácilmente en agua. </li></ol></li></ol> 4. Tratamiento posterior de los productos finales del octeto Truss Metales <ol><li> Conecte la alimentación de un chorro de arena. </li><li> Coloque los metales octeto de celosía en la plataforma dentro del chorro de arena y cerrar la puerta de la máquina. </li><li> Póngase los guantes y agarrar la pistola de chorro de arena. </li><li> Agarrar la parte del bebedero del producto metálico y soplar el yeso residual de la rejilla metálica con el chorro de arena durante 2 horas. Nota: La intensidad del chorro de arena se fija automáticamente aproximadamente a 550 kPa. Una vez que se acciona el chorro de arena, a continuación, el aire sale automáticamente de la pistola. </li><li> Mantenga el chorro de arena en marcha hasta que el residuo de yeso de inversión dentro del metal octeto cercha se elimina por completo mientras se comprueba a simple vista. Nota: No hay un criterio microscópica en la eliminación de los residuos de yeso. Esto está más allá del alcance de este estudio. Tque la eliminación del residuo de yeso se determina fácilmente con el ojo desnudo. Debido a que la armadura octeto es una estructura de células abiertas, es posible ver a través y comprobar si o no el residuo de yeso se elimina por completo. La precaución es necesaria para el chorro de arena para no dañar el metal octeto de celosía con un espesor de pared delgada (0,5 mm) a la alta presión (550 kPa): Nota. </li><li> Si el residuo de yeso inversión dentro del metal octeto armadura no se elimina totalmente con el chorro de arena, usar métodos de procesamiento de mensaje adicionales, por ejemplo, una limpieza por ultrasonidos o dejando el producto en agua durante un día. </li><li> En caso de utilizar un limpiador ultrasónico, llenar 0,7 L de agua en el limpiador ultrasónico y colocar el metal octeto cercha con residuos de yeso en el limpiador ultrasónico. <ol><li> Conecte la alimentación del limpiador ultrasónico. </li><li> Establecer una condición de operación, por ejemplo, 3 horas a 70 ° C. </li><li> Tome el metal octeto cercha fuera del limpiador ultrasónico vez THoperación e termina. </li><li> Secar el metal octeto cercha a TA hasta que el agua sobre la superficie metálica se elimina por completo. </li></ol></li><li> Como método alternativo post-procesamiento, deje el metal octeto cercha en agua. Esto hace que el residuo de yeso para ser disuelto en agua. <ol><li> Coloque el metal octeto cercha con el residuo de yeso en el agua y se deja durante un día, así que la fuerza de unión entre el yeso inversión y la superficie metálica se convierte en agua debilitan. </li><li> Tome el metal octeto cercha fuera del agua. </li><li> Secar el metal octeto cercha a TA hasta que el agua sobre la superficie metálica se elimina por completo. </li></ol></li><li> Con una sierra u otras herramientas apropiadas, cortar el metal llena la cavidad de la parte del sistema de bebedero fuera del producto metálico y obtener el metal octeto cercha final con un tamaño de 25 mm x 25 mm x 25 mm, como se muestra en la Figura 1B. </li></ol>

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Process. 17, 28-40 (2015).</li><li>Challapalli, A., Ju, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuum+Model+for+Effective+Properties+of+Orthotropic+Octet-Truss+Lattice+Materials.">Continuum Model for Effective Properties of Orthotropic Octet-Truss Lattice Materials.</a> Proceedings of the ASME International Mechanical Engineering Congress and Exposition. , (2014).</li><li>Taylor, H. F., Flemings, M. C., Wulff, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Foundry Engineering. , (1959).</li><li>Mun, J., Ju, J., Thurman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Indirect+Additive+Manufacturing+Based+Casting+(I+AM+Casting)+of+a+Lattice+Structure.">Indirect Additive Manufacturing Based Casting (I AM Casting) of a Lattice Structure.</a> Proceedings of the ASME International Mechanical Engineering Congress and Exposition. , (2014).</li><li>Mun, J., Ju, J., Thurman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Indirect+Additive+Manufacturing+of+a+Copper+Alloy+Cubic+Lattice+Structure.">Indirect Additive Manufacturing of a Copper Alloy Cubic Lattice Structure.</a> Proceedings of the 25th Annual International Solid Freeform Fabrication Symposium. , (2014).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Volume+2+Properties+and+Selection:+Nonferrous+Alloys+and+Pure+Metals.">Volume 2 Properties and Selection: Nonferrous Alloys and Pure Metals.</a> Metals Handbook Ninth Edition. , (1979).</li><li>Romano, J., Ladani, L., Razmi, J., Sadowski, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temperature+Distribution+and+Melt+Geometry+in+Laser+and+Electron-beam+Melting+Processes+-+A+Comparison+Among+Common+Materials.">Temperature Distribution and Melt Geometry in Laser and Electron-beam Melting Processes - A Comparison Among Common Materials.</a> J. of Additive Manuf. 8, 1-11 (2015).</li></ol>

The authors have nothing to disclose.

Para la fundición de metal convencional, es importante para mantener el flujo del metal fundido suave y racionalizado en &#39;laminar&#39; en la cavidad del molde y más bien evitar el flujo irregular y agitado observado generalmente en flujo turbulento 27. En consecuencia, es importante diseñar correctamente la entrada del sistema de bebedero asociada con la velocidad de rotación de un brazo de centrífuga para mantener el flujo de metal fundido dentro de la cavidad del molde de celosía &#39;laminar&#39;...

Metales celulares son los metales formados por una red interconectada de puntales sólidos o placas complejas y tienen micro-arquitecturas con huecos 1. Los ejemplos incluyen tanto i) espumas estructuradas estocásticos azar y ii) ordenados periódicamente) panales de dos dimensiones (2D y (estructuras de celosía tridimensional 3D) de celosía. Ellos han recibido atención debido a su alta rigidez específica y la fuerza 1-3 y alta resistencia específica de 4-5, una excelente absorción de energía para la carga de impacto 6, aislamiento acústico 7, posible diseño de disipadores de calor e intercambiadores de calor 8. Especialmente, estructuras de celosía ordenados periódicamente tienen el potencial para diseñar las propiedades superiores con una capacidad para controlar la geometría de la red porosa interna. Debido a su geometría de la red porosa interna compleja, es difícil para la fabricación de metales celulares usando el machinin sustractivo convencionalgramo. Como tal, los investigadores han empezado a buscar métodos alternativos para fabricar metales celulares: gas de formación en el metal líquido o mezcla de polvo de metal con agentes de expansión fueron exploradas para la fabricación de formas de metal estocásticos 9. Debido a la falta de control sobre la topología de la célula, es difícil de adaptar las propiedades mecánicas. Como alternativa, se exploraron métodos de fabricación de metales celulares ordenados periódicamente: estampado de hojas delgadas de metal en una forma ondulada seguido de unirse a ellos para crear estructuras periódicas 10, la unión ranurada chapas metálicas 11, extrusión 12, el tejido y resplandecientes filamentos de metal para fabricar textiles 13. A pesar de que estos métodos de fabricación ofrecen patrones repetibles, los patrones son todavía limitados en la dirección planar. En un esfuerzo para generar la repetición patrón 3D, los investigadores empezaron a utilizar la fabricación aditiva (AM); por ejemplo, fusión selectiva por láser (SLM) 14, haz de electrones de fusión (MBE) <sup&gt; 15, y Direct-metal sinterización láser (LMD) 16. A pesar de su capacidad para fabricar 3D ordenó geometrías de celosía complejos, todavía existen algunas limitaciones: dificultad para usar metales con alta conductividad térmica y alta reflectividad óptica 17, de alta tensión residual térmica 18, mal acabado de la superficie con el fenómeno &#39;bolas&#39; durante láser o de electrones de fusión 19, 20-21 propiedades anisótropas de partes causado por un efecto combinado de la fabricación por capas, la formación anisotrópica de granos, tamaño del polvo, el poder y la velocidad de escaneo de láser o por haz de electrones 15, alto consumo de energía, etc. La combinación de AM a base de polímero con la fundición de metal puede proporcionar un método alternativo para la fabricación de metales de celosía. Uno puede llamar a este &quot;AM indirecta&quot;. Indirecta AM puede proporcionar una solución para superar los problemas técnicos de AM directa de los metales mencionados anteriormente. Varios esfuerzos han sido made metales para la fabricación de celosía utilizando indirecta Estoy combinando la impresión en 3D de polímeros con la fundición por gravedad basado 22-25; por ejemplo, un bastidor de inversión combinada con el modelado por deposición fundida (FDM) para fabricar una aleación de celosía 22-25 o arena de fundición combinada con un polvo de arena basado AM 23. El casting basado gravedad parece seguir siendo un desafío técnico para superar - misrun y la porosidad causada por la solidificación repentina de metales fundidos, cuando se reúnan las estructuras de red con esquinas puntiagudas de los moldes estructurales de celosía 25-26. Área superficial relativamente grande de moldes estructurales de celosía también parece contribuir a un enfriamiento brusco, lo que resulta en la solidificación prematura 25-26. En este estudio, se propone un AM indirecta alternativa que puede superar la misrun durante la fabricación de los metales de celosía - fundición centrífuga a una cavidad de molde de celosía hecha por un patrón de polímero sacrificial celosía 3D impreso. Utilizamos una cámara digitalLight Processing (DLP) método de impresión en 3D basado construir un modelo estructural de sacrificio celosía seguido de fundición centrífuga de aleaciones de Al y Cu. El objetivo de este estudio es proporcionar un protocolo detallado en la fabricación de metales de celosía en 3D que tienen una forma compleja y un espesor de pared delgada. La principal contribución de este proceso es proporcionar una oportunidad para extender la selección de materiales con bajo coste de fabricación para la fabricación de metales de celosía.

<table><tbody><tr><td>Motorized centrifugal casting machine</td><td>Rey Motorized Centrifugal Casting Machine, Rey Industries Inc.</td><td></td><td>Made in U.S.A. by Rey industries, Inc. Dallas, TX 75220</td></tr><tr><td>Gypsum powder</td><td>Satin Cast 20, FindingKing Kerr</td><td>7960</td><td>Gypsum powder is used to make the investment mixture</td></tr><tr><td>Ployjet 3D printer</td><td>Projet HD3500 Plus, 3D Systems</td><td></td><td>This polymer based 3D printer to print out sacrificial pattern for casting.</td></tr><tr><td>Cartridge materials - UV curable and castable acrylic plastic</td><td>VisiJet Procast, 3D Systems</td><td></td><td>This is castable material that is going to be burn out before casting</td></tr><tr><td>Cartridge materials- support material</td><td>VijiJet S300, 3D Systems</td><td></td><td>This is support material that is going to be removed before pattern assemble</td></tr><tr><td>Ancient Bronze Casting Grain</td><td>Rio Grande</td><td>706051</td><td>This true bronze grain contains no zinc. Highly fluid, it melts quickly, casts cleanly and provides a good balance between strength and durability. The warm, deep-bronze color has rich red undertones, and the alloy takes a good patina.&lt;br/&gt; Composition is 90% copper with an amount of tin; fits into the CDA#90700 category. This grain is sold in 1 lb. packages.</td></tr><tr><td>Aluminum Round Wire, 1/8&quot;, 1-Lb. Spool, Dead Soft</td><td>Rio Grande</td><td>134700</td><td>Lightweight and strong, aluminum wire is an economical and versatile choice. Not as bright-white as silver, aluminum offers a warmer tone much like that of platinum. Solder ONLY with low-temp solders such as Stay-Brite; suitable for both pulse-arc and laser welding. This quality aluminum wire is packaged on 1 lb. spools.</td></tr><tr><td>Computer aided design software (Pro-e)</td><td></td><td></td><td>This software can be replaced with the others such as Auto CAD, Catia, and so on.</td></tr><tr><td>ProJet Finisher 1-A</td><td>3D Systems</td><td></td><td>This machine is used to melt the support material.</td></tr><tr><td>160 Watt 2.5 Liters Digital Ultrasonic Cleaner with Timer Heater Rings Tools</td><td>Chicago, Electric, Power Tools</td><td></td><td>85 oz. capacity, Five cleaning cycles: 90, 180, 280, 380 and 480 seconds, Clean with or without heat, Easy-to-read LED digital timer, Clear-view window</td></tr><tr><td>Fan&amp;nbsp;</td><td>Honeywell Inc.&amp;nbsp;</td><td>HT-800</td><td>120 V A.C., 60 Hz., 0.85 A. TP</td></tr><tr><td>Paraffin wax for wax sheet - Modeler&#039;s Pink Wax Sheet, 3&quot; by 6&quot;, 24-Ga.</td><td>Rio Grande</td><td>700075</td><td>Sheet wax is flexible and can be cut or formed into any shape. It&amp;rsquo;s ideal for designing since you can draw or trace directly onto the sheet; choose green or pink depending on which will best show your designs. High manufacturing standards ensure exceptional consistency and significant price savings. Value is enhanced by larger package quantities at the same price as the smaller packages available elsewhere. Each 8-oz. package contains approximately 30 sheets.</td></tr><tr><td>Paraffin wax for wax stick - Modeler&#039;s Medium Red Sprue Wax, 8-Ga</td><td>Rio Grande</td><td>700741</td><td>A pliable, softer sprue wax than the firm blue. Good for forming gates and sprues and burns out cleanly with no residue.</td></tr><tr><td>Alcohol Lamp</td><td>Rio Grande</td><td>700008</td><td>Use this lamp to heat wax-working tools or as a flame polisher. The heavy glass reservoir has faceted sides to allow it to be tipped for angling the flame. A screw adjustment for the 7&quot; x 3/16&quot; wick controls the height of the flame. A safety cap snuffs the flame and prevents fuel evaporation. For the best flame, use methyl alcohol fuel. Replacement wicks available. Reservoir holds 5 oz. (150 ml) of fuel.</td></tr><tr><td>Wax carving tool set - Soft Grip Wax Carvers, Set of 10</td><td>Rio Grande</td><td>700329</td><td>This boxed set offers the best in cutting and shaping technology. Each of these ten high-quality steel wax-carving tools features a 5/16&quot; PVC covered handle that ensures a sure, comfortable grip through hours of work and all have sharp edges for shaping and fine detailing. Sharpen or custom-shape each tool to fit your needs. These tools provide exceptional tool strength and deliver excellent results. This set comes in a hinged, foam-lined wood box.</td></tr><tr><td>Rubber Mixing Bowl, 1 - 1/2 Qt.</td><td>Rio Grande</td><td>702131</td><td>This highly-flexible vulcanized rubber bowl is easy to grip, will not be marred by a spatula and cleans with ease.</td></tr><tr><td>Pyrex Beaker, 1,000ml</td><td>Rio Grande</td><td>335040</td><td>Ideal for holding and heating bath plating solutions, this genuine Pyrex glass beaker is sturdy and durable.</td></tr><tr><td>Rio Premium Stainless Steel Flask, 2 - 1/2&quot; dia.</td><td>Rio Grande</td><td>70201514</td><td>This solid, #304-quality stainless steel flask is corrosion-resistant, durable for a long service life and performs under extreme temperature without distortion.</td></tr><tr><td>CAST/T Ceramic Casting Crucible, 450 g</td><td>Rio Grande</td><td>705047</td><td>Made exclusively for the CAST/T centrifugal casting machine, this crucible is designed with an angled base that slides into the hinged bracket on top of the casting machine. This brings the crucible into perfect alignment with the center of the flask ring to ensure an error-free pour.</td></tr><tr><td>MyWeigh iBalance 300 Digital Scale</td><td>Rio Grande</td><td>116850</td><td>This scale is used to measure the weight of the sacrificial and sprue system for metal which is going to be used for centrifugal casting.</td></tr><tr><td>Rubber bottom - CAST/T Flask Ring Base</td><td>Rio Grande</td><td>705025</td><td>Specially made for the CAST/T centrifugal casting machine, this rubber base accommodates all Table King flask ring styles, creating a secure, airtight seal throughout the investment process. The center post fits either of the wax disc styles for complete versatility.</td></tr><tr><td>Scotch&amp;reg; Colored Duct Tape, 1 7/8&quot; x 20 Yd., Blue</td><td>OfficeMax&amp;nbsp;</td><td>22353766</td><td>This scotch tape is used to make sure that the gypsum-water mixture fully covers the assembled sacrificial pattern inside the flask by allowing for extra material above the flask height</td></tr><tr><td>Vacuum casting machine - V.I.C. 12 Tabletop Solid- and Perforated-Flask Casting Machine with The Rio Assistant, 110-Volt</td><td>Rio Grande</td><td>70511814</td><td>The V.I.C. 12 casting machine offers all the latest technical innovations for efficient, productive vacuum investing and casting. Designed to meet the demands of medium-sized casting operations, this machine includes a powerful 1/2 hp, 5cfm vacuum pump for effective vacuuming and outstanding casting results. The V.I.C. 12 casts small or large flasks. Includes an adapter table that accepts standard solid flasks up to 5&quot; x 7&quot; high and is mounted on rubber feet for stability.</td></tr><tr><td>Furnace for burn out sacrificial pattern -Rio Model 1000 Enameling Kiln with Nine Program Controller</td><td>Rio Grande</td><td>703121</td><td>The Rio enameling kiln features three pre-set firing temperatures for enamels and six that you can define. Use the exclusive Rio controller to set and maintain firing temperatures. Perfect for all types of enameling, including tall pieces. Includes ample space for firing and an easy-latch door that will not jar your enamels when opening and closing. Also suitable for metal clay, glass and ceramics. Galvanized steel case with high-temperature insulating firebrick keeps them cool. Element protected in recessed groove. Includes user instructions.</td></tr><tr><td>Smith Complete Little Torch Acetylene and Oxygen System</td><td>Rio Grande</td><td>500030</td><td>Get everything you need to equip your shop for soldering and brazing. Use Little Torch systems for gold&lt;br/&gt; or silver soldering, brazing and casting applications. Complete every soldering and melting job with confidence and ease! This system accepts all Little Torch accessory tips for melting, brazing and large soldering jobs and is a staple for every jeweler.</td></tr><tr><td>Heat-Resistant Safety Apron</td><td>Rio Grande</td><td>750160</td><td>The specially designed apron has an 800 &amp;deg;F (427 &amp;deg;C) temperature resistance. Its reflective finish repels hot metal splashes and helps insulate the wearer from heat.</td></tr><tr><td>Radnor Heat-Resistant Gloves</td><td>Rio Grande</td><td>350050</td><td>These flexible, heat-resistant gloves are ideal for enameling projects, allowing you to grip even small tongs securely. Blue, shoulder-split leather gloves are made of tough cowhide and lined with cotton and foam, and have reinforced thumb wings.</td></tr><tr><td>Platinum Soldering Glasses, #7</td><td>Rio Grande</td><td>113914</td><td>Protect yourself and your employees when soldering platinum. Comfortable glasses feature adjustable earpieces and 52mm IR green polycarbonate #7 lenses. The #7 lens is approved by The Platinum Guild.</td></tr><tr><td>Economy Light-Duty Flask Tongs</td><td>Rio Grande</td><td>704026</td><td>Constructed of bent steel, these tongs are designed to handle flasks 3-1/2&quot; or less in diameter. The small-angle notches grip smaller flask sizes and the larger, rounded contour area securely holds larger flasks.</td></tr><tr><td>Separating Screen Bucket</td><td>Rio Grande</td><td>201360</td><td>15&quot;-diameter, 11-1/2&quot;-deep</td></tr><tr><td>Sand blaster - Econoline - 101701CB-A - Free-Standing Cabinets Workspace Width (Inch): 60 Workspace Depth (Inch): 48</td><td>MSC industrial supply Co.&amp;nbsp;</td><td>223818</td><td>Ree-Standing Cabinets; Workspace Width (Inch): 60; Workspace Depth (Inch): 48; Workspace Height (Inch): 40; Air Requirement: 12 CFM @ 80 psi; Overall Cabinet Width (Inch): 65; Maximum Cabinet Depth (Inch): 86</td></tr><tr><td>Johnson&#039;s Baby Oil Shea &amp;amp; Cocoa Butter&amp;nbsp;</td><td>Wal-Mart</td><td>260074132</td><td>This baby&amp;nbsp; oil is used for removing the residue of the support material for the castable sacrificial pattern using Digital Ultrasonic Cleaner.</td></tr><tr><td>German 4&quot; Saw Frame and Saw Blade Kit</td><td>Rio Grande</td><td>110112</td><td>Quality, German-made frames are our most popular saw frames, and this frame includes a sampler pack of Rio German saw blades! The adjustable saw frame allows you to achieve the blade tension you want. Throat depth is 102mm (4&quot;). Saw blades have rounded backs that make cutting curves and corners easy and are made from hardened, tempered steel.</td></tr></tbody></table>

indirect fabrication of lattice metals with thin sections using centrifugal casting

Uno de los métodos típicos para la fabricación de metales de celosía en 3D es el proceso directo de metal fabricación aditiva (AM) como fusión selectiva por láser (SLM) y el haz de electrones de fusión (MBE). A pesar de su capacidad de procesamiento potencial, el método AM directo tiene varias desventajas tales como el alto costo, pobre acabado superficial de los productos finales, limitación en la selección de materiales, de alta tensión térmica, y las propiedades anisotrópicas de piezas. Proponemos un método rentable para la fabricación de metales de celosía en 3D. El objetivo de este estudio es proporcionar un protocolo detallado en la fabricación de metales de celosía en 3D que tienen una forma compleja y un espesor de pared delgada, por ejemplo, braguero octeto hechos de aleaciones de Al y Cu con una longitud de celda unitaria de 5 mm y un espesor de pared de la célula de 0,5 mm. Un procedimiento experimental general se divide en ocho secciones: (a) la impresión en 3D de los patrones de sacrificio (b) por fusión de materiales de apoyo (c) la eliminación de los residuos de materiales de apoyo (d) assembl de patróny (e) la inversión (f) agotamiento de los patrones de sacrificio (g) de fundición centrífuga (h) después de la transformación de los productos finales. La técnica indirecta AM sugerido proporciona el potencial para la fabricación de metales de celosía ultra-ligeros;. Por ejemplo, estructuras de celosía con aleaciones de Al. Parece ser que los parámetros de proceso deben ser controlados adecuadamente dependiendo de los materiales y la geometría del enrejado, la observación de los productos finales de metales octeto de celosía por la técnica de AM indirecta.

Uso de la fabricación de aditivos indirecto descrito en la sección de protocolo, se utilizaron Al y Cu aleaciones de metales octeto de fabricación entramados, como se muestra en la Figura 1 El procedimiento de colada conjunto se resume en la Figura 2 El procedimiento consiste en ocho secciones:.. (A) sacrificial patrón de impresión (b) fusión de material de apoyo (c) la eliminación de los residuos de material de apoyo (d) conjunto de patrones (e) ...

Watch this Scientific Journal Video about Indirect Fabrication of Lattice Metals with Thin Sections Using Centrifugal Casting at JoVE.com

Indirect Fabrication of Lattice Metals with Thin Sections Using Centrifugal Casting

Un método de fabricación de aditivos indirecta la combinación de una impresión en 3D de polímeros con una fundición centrífuga se describe para la fabricación de metales para entramados de octetos 3D (Al y Cu aleaciones) con una longitud de celda unitaria de 5 mm con un espesor de pared de 0,5 mm.

La fabricación indirecta de celosía Los metales con secciones delgadas Uso de fundición centrífuga

One of the typical methods to manufacture 3D lattice metals is the direct-metal additive manufacturing (AM) process such as Selective Laser Melting (SLM) ...

indirect-fabrication-lattice-metals-with-thin-sections-using

Universidad San Sebastian

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JoVE Journal

Mechanical Engineering

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SCIENTISTS IN ACTION

12.4K vistas.  University of North Texas.  Un método de fabricación de aditivos indirecta la combinación de una impresión en 3D de polímeros con una fundición centrífuga se describe para la fabricación de metales para entramados de octetos 3D (Al y Cu aleaciones) con una longitud de celda unitaria de 5 mm con un espesor de pared de 0,5 mm. 

Video: Indirect Fabrication of Lattice Metals with Thin Sections Using Centrifugal Casting

Fabricating Metamaterials Using the Fiber Drawing Method

Metamaterials are man-made composite materials, fabricated by assembling components much smaller than the wavelength at which they operate 1. They owe their electromagnetic properties to the structure of their constituents, instead of the atoms that compose them. For example, sub-wavelength metal wires can be arranged to possess an effective electric permittivity that is either positive or negative at a given frequency, in contrast to the metals themselves 2. This unprecedented control over the behaviour of light can potentially lead to a number of novel devices, such as invisibility cloaks 3, negative refractive index materials 4, and lenses that resolve objects below the diffraction limit 5. However, metamaterials operating at optical, mid-infrared and terahertz frequencies are conventionally made using nano- and micro-fabrication techniques that are expensive and produce samples that are at most a few centimetres in size 6-7. Here we present a fabrication method to produce hundreds of meters of metal wire metamaterials in fiber form, which exhibit a terahertz plasmonic response 8. We combine the stack-and-draw technique used to produce microstructured polymer optical fiber 9 with the Taylor-wire process 10, using indium wires inside polymethylmethacrylate (PMMA) tubes. PMMA is chosen because it is an easy to handle, drawable dielectric with suitable optical properties in the terahertz region; indium because it has a melting temperature of 156.6 &deg;C which is appropriate for codrawing with PMMA. We include an indium wire of 1 mm diameter and 99.99% purity in a PMMA tube with 1 mm inner diameter (ID) and 12 mm outside diameter (OD) which is sealed at one end. The tube is evacuated and drawn down to an outer diameter of 1.2 mm. The resulting fiber is then cut into smaller pieces, and stacked into a larger PMMA tube. This stack is sealed at one end and fed into a furnace while being rapidly drawn, reducing the diameter of the structure by a factor of 10, and increasing the length by a factor of 100. Such fibers possess features on the micro- and nano- scale, are inherently flexible, mass-producible, and can be woven to exhibit electromagnetic properties that are not found in nature. They represent a promising platform for a number of novel devices from terahertz to optical frequencies, such as invisible fibers, woven negative refractive index cloths, and super-resolving lenses.

Metamaterials at terahertz frequencies offer unique opportunities, but are challenging to fabricate in bulk. We adapt the fabrication procedure for microstructured polymer optical fibers to inexpensively fabricate metamaterials potentially on an industrial scale. We produce polymethylmethacrylate fibers containing ~10 &mu;m diameter indium wires separated by ~100 &mu;m, which exhibit a terahertz plasmonic response.

Los metamateriales Fabricacion mediante el método de dibujo de fibra

Metamaterials are man-made composite materials, fabricated by assembling components much smaller than the wavelength at which they operate 1. They owe ...

Investigación

Ingeniería

A Method to Fabricate Disconnected Silver Nanostructures in 3D

The standard nanofabrication toolkit includes techniques primarily aimed at creating 2D patterns in dielectric media. Creating metal patterns on a submicron scale requires a combination of nanofabrication tools and several material processing steps. For example, steps to create planar metal structures using ultraviolet photolithography and electron-beam lithography can include sample exposure, sample development, metal deposition, and metal liftoff. To create 3D metal structures, the sequence is repeated multiple times. The complexity and difficulty of stacking and aligning multiple layers limits practical implementations of 3D metal structuring using standard nanofabrication tools. Femtosecond-laser direct-writing has emerged as a pre-eminent technique for 3D nanofabrication.1,2 Femtosecond lasers are frequently used to create 3D patterns in polymers and glasses.3-7 However, 3D metal direct-writing remains a challenge. Here, we describe a method to fabricate silver nanostructures embedded inside a polymer matrix using a femtosecond laser centered at 800 nm. The method enables the fabrication of patterns not feasible using other techniques, such as 3D arrays of disconnected silver voxels.8 Disconnected 3D metal patterns are useful for metamaterials where unit cells are not in contact with each other,9 such as coupled metal dot10,11or coupled metal rod12,13 resonators. Potential applications include negative index metamaterials, invisibility cloaks, and perfect lenses.
In femtosecond-laser direct-writing, the laser wavelength is chosen such that photons are not linearly absorbed in the target medium. When the laser pulse duration is compressed to the femtosecond time scale and the radiation is tightly focused inside the target, the extremely high intensity induces nonlinear absorption. Multiple photons are absorbed simultaneously to cause electronic transitions that lead to material modification within the focused region. Using this approach, one can form structures in the bulk of a material rather than on its surface.
Most work on 3D direct metal writing has focused on creating self-supported metal structures.14-16 The method described here yields sub-micrometer silver structures that do not need to be self-supported because they are embedded inside a matrix. A doped polymer matrix is prepared using a mixture of silver nitrate (AgNO3), polyvinylpyrrolidone (PVP) and water (H2O). Samples are then patterned by irradiation with an 11-MHz femtosecond laser producing 50-fs pulses. During irradiation, photoreduction of silver ions is induced through nonlinear absorption, creating an aggregate of silver nanoparticles in the focal region. Using this approach we create silver patterns embedded in a doped PVP matrix. Adding 3D translation of the sample extends the patterning to three dimensions.

Femtosecond-laser direct-writing is frequently used to create three-dimensional (3D) patterns in polymers and glasses. However, patterning metals in 3D remains a challenge. We describe a method for fabricating silver nanostructures embedded inside a polymer matrix using a femtosecond laser centered at 800 nm.

Un método para fabricar nanoestructuras desconectados de plata en 3D

The standard nanofabrication toolkit includes  techniques primarily aimed at creating 2D patterns in dielectric media. Creating  metal patterns on a ...

Process of Making Three-dimensional Microstructures using Vaporization of a Sacrificial Component

Vascular structures in natural systems are able to provide high mass transport through high surface areas and optimized structure. Few synthetic material fabrication techniques are able to mimic the complexity of these structures while maintaining scalability. The Vaporization of a Sacrificial Component (VaSC) process is able to do so. This process uses sacrificial fibers as a template to form hollow, cylindrical microchannels embedded within a matrix. Tin (II) oxalate (SnOx) is embedded within poly(lactic) acid (PLA) fibers which facilitates the use of this process. The SnOx catalyzes the depolymerization of the PLA fibers at lower temperatures. The lactic acid monomers are gaseous at these temperatures and can be removed from the embedded matrix at temperatures that do not damage the matrix. Here we show a method for aligning these fibers using micromachined plates and a tensioning device to create complex patterns of three-dimensionally arrayed microchannels. The process allows the exploration of virtually any arrangement of fiber topologies and structures.

The Vaporization of a Sacrificial Component (VaSC) process is used to fabricate microvascular structures. This procedure uses sacrificial poly(lactic) acid fibers to form hollow microchannels with precise 3D geometric positioning provided by laser micromachined guide plates.

Proceso de fabricación microestructuras tridimensionales mediante vaporización de un componente de sacrificio

Vascular structures in natural systems are able to provide high mass transport through high surface areas and optimized structure. Few synthetic material ...

Fabrication of Spatially Confined Complex Oxides

Complex materials such as high Tc superconductors, multiferroics, and colossal magnetoresistors have electronic and magnetic properties that arise from the inherent strong electron correlations that reside within them. These materials can also possess electronic phase separation in which regions of vastly different resistive and magnetic behavior can coexist within a single crystal alloy material. By reducing the scale of these materials to length scales at and below the inherent size of the electronic domains, novel behaviors can be exposed. Because of this and the fact that spin-charge-lattice-orbital order parameters each involve correlation lengths, spatially reducing these materials for transport measurements is a critical step in understanding the fundamental physics that drives complex behaviors. These materials also offer great potential to become the next generation of electronic devices 1-3. Thus, the fabrication of low dimensional nano- or micro-structures is extremely important to achieve new functionality. This involves multiple controllable processes from high quality thin film growth to accurate electronic property characterization. Here, we present fabrication protocols of high quality microstructures for complex oxide manganite devices. Detailed descriptions and required equipment of thin film growth, photo-lithography, and wire-bonding are presented.

We describe the use of pulsed laser deposition (PLD), photolithography and wire-bonding techniques to create micrometer scale complex oxides devices. The PLD is utilized to grow epitaxial thin films. Photolithography and wire-bonding techniques are introduced to create practical devices for measurement purposes.

La fabricación de óxidos complejos espacialmente confinados

Complex materials such as high Tc superconductors, multiferroics, and colossal magnetoresistors have electronic and magnetic properties that arise from ...

Fabrication of Uniform Nanoscale Cavities via Silicon Direct Wafer Bonding

Measurements of the heat capacity and superfluid fraction of confined 4He have been performed near the lambda transition using lithographically patterned and bonded silicon wafers. Unlike confinements in porous materials often used for these types of experiments3, bonded wafers provide predesigned uniform spaces for confinement. The geometry of each cell is well known, which removes a large source of ambiguity in the interpretation of data.
Exceptionally flat, 5 cm diameter, 375 &#181;m thick Si wafers with about 1 &#181;m variation over the entire wafer can be obtained commercially (from Semiconductor Processing Company, for example). Thermal oxide is grown on the wafers to define the confinement dimension in the z-direction. A pattern is then etched in the oxide using lithographic techniques so as to create a desired enclosure upon bonding. A hole is drilled in one of the wafers (the top) to allow for the introduction of the liquid to be measured. The wafers are cleaned2 in RCA solutions and then put in a microclean chamber where they are rinsed with deionized water4. The wafers are bonded at RT and then annealed at ~1,100 &#176;C. This forms a strong and permanent bond. This process can be used to make uniform enclosures for measuring thermal and hydrodynamic properties of confined liquids from the nanometer to the micrometer scale.

A method for permanently bonding two silicon wafers so as to realize a uniform enclosure is described. This includes wafer preparation, cleaning, RT bonding, and annealing processes. The resulting bonded wafers (cells) have uniformity of enclosure ~1%1,2. The resulting geometry allows for measurements of confined liquids and gasses.

Fabricación De Cavidades Uniformes A Nanoescala A Través De La Unión Directa De Obleas De Silicio

Measurements of the heat capacity and superfluid fraction of confined 4He have been performed near the lambda transition using lithographically patterned ...

Preparation of Liquid-exfoliated Transition Metal Dichalcogenide Nanosheets with Controlled Size and Thickness: A State of the Art Protocol

We summarize recent advances in the production of liquid-exfoliated transition metal dichalcogenide (TMD) nanosheets with controlled size and thickness. Layered crystals of molybdenum disulphide (MoS2) and tungsten disulphide (WS2) are exfoliated in aqueous surfactant solution by sonication. This yields highly polydisperse mixtures containing nanosheets with broad size and thickness distributions. However, for most purposes, specific sizes (in terms of both lateral dimension and thickness) are required. For example, large and thin nanosheets are desired for (opto) electronic applications, while laterally small nanosheets are interesting for catalytic applications. Therefore, post-exfoliation size selection is an important step that we address here. We provide a detailed protocol on the efficient size selection in large quantities by liquid cascade centrifugation and the size and thickness quantification by statistical microscopic analysis (atomic force microscopy and transmission electron microscopy). The comparison of MoS2 and WS2 shows that both materials are size-selected in a similar way by the same procedure. Importantly, the dispersions of size-selected nanosheets show systematic changes in their optical extinction spectra with size due to edge and confinement effects. We show how these optical changes are related quantitatively to the nanosheets dimensions and describe how mean nanosheets length and layer number can be extracted reliably from the extinction spectra. The exfoliation and size selection protocol can be applied to a broad range of layered crystals as we have previously demonstrated for graphene, gallium sulphide (GaS) and black phosphorus.

A protocol for the liquid exfoliation of layered materials to nanosheets, their size selection and size measurement by microscopic and spectroscopic techniques is presented.

Preparación de exfoliadas-Liquid Metal transición Dichalcogenide nanoláminas con Controlled tamaño y grosor: Un Estado del Protocolo de Arte

We summarize recent advances in the production of liquid-exfoliated transition metal dichalcogenide (TMD) nanosheets with controlled size and thickness. ...

Fabrication of Periodic Gold Nanocup Arrays Using Colloidal Lithography

Within recent years, the field of plasmonics has exploded as researchers have demonstrated exciting applications related to chemical and optical sensing in combination with new nanofabrication techniques. A plasmon is a quantum of charge density oscillation that lends nanoscale metals such as gold and silver unique optical properties. In particular, gold and silver nanoparticles exhibit localized surface plasmon resonances-collective charge density oscillations on the surface of the nanoparticle-in the visible spectrum. Here, we focus on the fabrication of periodic arrays of anisotropic plasmonic nanostructures. These half-shell (or nanocup) structures can exhibit additional unique light-bending and polarization-dependent optical properties that simple isotropic nanostructures cannot. Researchers are interested in the fabrication of periodic arrays of nanocups for a wide variety of applications such as low-cost optical devices, surface-enhanced Raman scattering, and tamper indication. We present a scalable technique based on colloidal lithography in which it is possible to easily fabricate large periodic arrays of nanocups using spin-coating and self-assembled commercially available polymeric nanospheres. Electron microscopy and optical spectroscopy from the visible to near-infrared (near-IR) was performed to confirm successful nanocup fabrication. We conclude with a demonstration of the transfer of nanocups to a flexible, conformal adhesive film.

We demonstrate the fabrication of periodic gold nanocup arrays using colloidal lithographic techniques and discuss the importance of nanoplasmonic films.

Fabricación de matrices Nanocup oro periódicas usando litografía coloidal

Within recent years, the field of plasmonics has exploded as researchers have demonstrated exciting applications related to chemical and optical sensing ...

Processing of Bulk Nanocrystalline Metals at the US Army Research Laboratory

Given their potential for significant property improvements relative to their large grained counterparts, much work has been devoted to the continued development of nanocrystalline metals. Despite these efforts, the transition of these materials from the lab bench to actual applications has been blocked by the inability to produce large scale parts that retain the desired nanocrystalline microstructures. Following the development of a method proven to stabilize the nanosized grain structure to temperatures approaching that of the melting point for the given metal, the US Army Research Laboratory (ARL) has progressed to the next stage in the development of these materials - namely the production of large scale parts suitable for testing and evaluation in a range of relevant test environments. This report provides a broad overview of the ongoing efforts in the processing, characterization, and consolidation of these materials at ARL. In particular, focus is placed on the methodology used for producing the nanocrystalline metal powders, in both small and large-scale amounts, that are at the center of ongoing research efforts.

This paper provides a brief overview of the ongoing efforts at the Army Research Laboratory on the processing of bulk nanocrystalline metals with an emphasis on the methodologies used for the production of the novel metal powders.

Tratamiento de metales nanocristalinos de bulto en el laboratorio de investigación del ejército de Estados Unidos

Given their potential for significant property improvements relative to their large grained counterparts, much work has been devoted to the continued ...

Fused Filament Fabrication (FFF) of Metal-Ceramic Components

Technical ceramics are widely used for industrial and research applications, as well as for consumer goods. Today, the demand for complex geometries with diverse customization options and favorable production methods is increasing continuously. With fused filament fabrication (FFF), it is possible to produce large and complex components quickly with high material efficiency. In FFF, a continuous thermoplastic filament is melted in a heated nozzle and deposited below. The computer-controlled print head is moved in order to build up the desired shape layer by layer. Investigations regarding printing of metals or ceramics are increasing more and more in research and industry. This study focuses on additive manufacturing (AM) with a multi-material approach to combine a metal (stainless steel) with a technical ceramic (zirconia: ZrO2). Combining these materials offers a broad variety of applications due to their different electrical and mechanical properties. The paper shows the main issues in preparation of the material and feedstock, device development, and printing of these composites.

Fused Filament Fabrication FFF of Metal-Ceramic Components

This study shows multi-material additive manufacturing (AM) using fused filament fabrication (FFF) of stainless steel and zirconia.

Fabricación de filamento fundido (FFF) de componentes de Metal-cerámica

Technical ceramics are widely used for industrial and research applications, as well as for consumer goods. Today, the demand for complex geometries with ...

Fabrication of Magnetic Nanostructures on Silicon Nitride Membranes for Magnetic Vortex Studies Using Transmission Microscopy Techniques

Electron and x-ray magnetic microscopies allow for high-resolution magnetic imaging down to tens of nanometers. However, the samples need to be prepared on transparent membranes which are very fragile and difficult to manipulate. We present processes for the fabrication of samples with magnetic micro- and nanostructures with spin configurations forming magnetic vortices suitable for Lorentz transmission electron microscopy and magnetic transmission x-ray microscopy studies. The samples are prepared on silicon nitride membranes and the fabrication consists of a spin coating, UV and electron-beam lithography, the chemical development of the resist, and the evaporation of the magnetic material followed by a lift-off process forming the final magnetic structures. The samples for the Lorentz transmission electron microscopy consist of magnetic nanodiscs prepared in a single lithography step. The samples for the magnetic x-ray transmission microscopy are used for time-resolved magnetization dynamic experiments, and magnetic nanodiscs are placed on a waveguide which is used for the generation of repeatable magnetic field pulses by passing an electric current through the waveguide. The waveguide is created in an extra lithography step.

A protocol for the fabrication of magnetic micro- and nanostructures with spin configurations forming magnetic vortices suitable for transmission electron microscopy (TEM) and magnetic transmission x-ray microscopy (MTXM) studies is presented.

Fabricación de nanoestructuras magnéticas en membranas de nitruro de silicio para estudios de vórtice magnético usando técnicas de microscopía de transmisión

Electron and x-ray magnetic microscopies allow for high-resolution magnetic imaging down to tens of nanometers. However, the samples need to be prepared ...