This work is an attempt to modernise Weber's electrodynamics to make it compatible with the high-velocity regime, and with the existence of a limiting velocity, c. For this purpose, starting from the law of energy conservation and the mass–energy equivalence, new expressions for potential energy and for kinetic energy are derived jointly which...
-
December 20, 2023 (v1)PublicationUploaded on: December 25, 2023
-
February 17, 2023 (v1)Publication
Se describe y analiza una modalidad de prensado en caliente, en la que la masa de polvo sometida a compresión se calienta simultáneamente por el paso de una corriente de elevada intensidad. Las experiencias se han realizado a partir de polvo de hierro de pureza comercial. Se ha prestado especial atención a la cinética de densificación del...
Uploaded on: February 28, 2023 -
March 24, 2021 (v1)Publication
The effect of intensity and duration of the electrical resistance sintering process on the phase stability, porosity distribution and microstructural evolution of Al50Ti50 amorphous powders is studied. The phase transformations during the consolidation process were determined by X-ray diffraction. The porosity distribution was observed by...
Uploaded on: March 27, 2023 -
November 4, 2022 (v1)Publication
Esta invención propone un nuevo procedimiento de fabricación de material metálico de alta porosidad, partiendo de una masa de polvos en condiciones de imponderabilidad. La consolidación de la estructura particular se realiza preferentemente de manera cuas
Uploaded on: March 24, 2023 -
November 4, 2022 (v1)Publication
La presente patente tiene por objeto presentar un nuevo método para la fabricación pulvimetalúrgica de imanes (aplicable especialmente a la fabricación de imanes que contienen tierras raras). Lo novedoso del método reside en el empleo de alguna modalidad
Uploaded on: March 24, 2023 -
January 16, 2024 (v1)Publication
Two methods to obtain bulk nanostructured aluminium parts are compared. The first one consists on milling Al powder in an ammonia gas atmosphere. In the second method, the Al powder is milled in vacuum with the addition of solid urea. In both cases, the milled powders are consolidated to full density by a conventional press-and-sinter powder...
Uploaded on: January 19, 2024 -
January 16, 2023 (v1)Publication
Medium-frequency electrical resistance sintering (MF-ERS) is a technique that uses the application of pressure and heat, heat coming from the Joule effect, simultaneously to metallic powders. In this study, this technique consolidates commercial iron powders, and the porosity distribution and hysteresis curves of the compacts were analysed....
Uploaded on: March 3, 2023 -
December 1, 2023 (v1)Publication
Método para la fabricación pulvimetalúrgica de núcleos magnéticos que se caracteriza porque comprende (i) una primera etapa de amorfización de una mezcla de polvos magnéticamente blandos mediante molienda mecánica; y (ii) una segunda etapa de consolidación eléctrica FAST (Field Assisted Sintering Techniques) del polvo amorfizado en la primera etapa.
Uploaded on: December 3, 2023 -
January 15, 2024 (v1)Publication
In this paper, electrical-discharge-consolidation (EDC technique) experiments were carried out with an equipment based on the technology developed for the stud welding technology. The main advantage of the EDC technique is its high speed, on the order of milliseconds or less, which makes it particularly interesting when a high final porosity is...
Uploaded on: January 17, 2024 -
January 14, 2015 (v1)Publication
Polvos mezclados de aluminio y titanio ( 10 % en peso) han sido aleados mecánicamente en un molino Attritor, obteniéndose una solución metaestable de titanio en la matriz de aluminio. Se han estudiado los cambios producidos en la forma y tamaño de las partículas, estructura y microestructura, al variar el tiempo de molienda entre 2 y 10 h. El...
Uploaded on: December 4, 2022 -
July 8, 2020 (v1)Publication
A commercially pure (c.p.) nickel powder was consolidated by Medium-Frequency Electrical Resistance Sintering (MF-ERS). In this consolidation technique, a pressure and the heat released by a high-intensity and low-voltage electrical current are concurrently applied to a metal powder mass. A nickel powder with a high tap porosity (86%) and a low...
Uploaded on: March 26, 2023 -
December 1, 2023 (v1)Publication
Molienda mecánica de polvos activada por radiación ultravioleta. La presente invención tiene por objeto la molienda mecánica de polvos activada por radiación ultravioleta, lo que permite la mejora de las características de materiales en forma de polvo. Concretamente, la realización de moliendas en presencia de radiación ultravioleta (UV)...
Uploaded on: December 3, 2023 -
January 29, 2018 (v1)Publication
La fabricación de núcleos amorfos (tanto para motores eléctricos, como transformadores) es una tarea compleja que hasta ahora ha requerido la fabricación del material amorfo en forma de cintas de fino espesor (mediante enfriamiento muy severo, melt spinning) y su posterior apilado y/o plegado para la formación de la pieza final. El proceso...
Uploaded on: March 27, 2023 -
June 21, 2021 (v1)Publication
Porosity is a characteristic present in most sintered materials, full densification only being achieved in special cases. For some sintered materials, porosity is indeed a desired characteristic, serving for the intended application of the material. In any case, the porosity present in materials can have a strong effect on some of their...
Uploaded on: March 25, 2023 -
January 15, 2024 (v1)Publication
This research is focused on the production of aluminum matrix composites (AMCs) reinforced with various percentages of aluminum nitride (AlN). For this purpose, aluminum powder was milled at room temperature for a total time of 5 hours. The percentage of reinforcement is varied by milling under different periods of vacuum followed by ammonia...
Uploaded on: January 17, 2024 -
March 23, 2021 (v1)Publication
Aluminium powder was mechanically alloyed under ammonia gas flow for different times (1-5 h) in order to produce a second-phase reinforcement, mainly by aluminium nitride (AlN). After milling, powders were consolidated by cold uniaxial pressing and vacuum sintering. A small amount of copper powder was added to the Al milled powder to improve...
Uploaded on: December 4, 2022 -
October 5, 2016 (v1)Publication
Properties of compacts made from aluminium powder, milled under different atmospheres, were evaluated. The duration of all the milling processes was 10 h, although different atmospheres were tested: vacuum, confined ammonia, and vacuum combined with a short-time ammonia gas flow (5 min). Milled powders were consolidated by cold uniaxial...
Uploaded on: December 4, 2022