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5 results on '"Aluminum -- Thermal properties"'

1. Investigations of thermal properties of aluminum treated by plasma electrolytic oxidation

Author

Araujo, Tamires do Espirito Santo, Universidade Estadual Paulista (Unesp), and Cruz, Nilson Cristino da [UNESP]

Subjects
Oxidação eletrolítica por plasma, Plasma electrolytic oxidation, Aluminum thermal properties, Propriedades térmicas de alumínio, Espectroscopia fotoacústica, Photoacoustic spectroscopy
Abstract

Submitted by TAMIRES DO ESPIRITO SANTO ARAUJO (ft.tamires@gmail.com) on 2019-03-20T20:55:19Z No. of bitstreams: 1 V. Final 20.03.19 - Dissertação Tamires Araujo.pdf: 3357720 bytes, checksum: cd608523bf9b720ae2444644a103823f (MD5) Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2019-03-21T14:10:26Z (GMT) No. of bitstreams: 1 araujo_tes_me_bauru_par.pdf: 405154 bytes, checksum: ddd25a28b12930ea7e3ff1b9f0f25a97 (MD5) Made available in DSpace on 2019-03-21T14:10:26Z (GMT). No. of bitstreams: 1 araujo_tes_me_bauru_par.pdf: 405154 bytes, checksum: ddd25a28b12930ea7e3ff1b9f0f25a97 (MD5) Previous issue date: 2019-02-25 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) O alumínio é um dos materiais mais utilizados em vários setores da indústria. Devido ao baixo custo, se comparado ao cobre, e considerando sua abundância de oferta, o interesse nas propriedades térmicas do alumínio tem aumentado. Neste contexto, a proposta desta pesquisa é avaliar as propriedades térmicas de amostras de alumínio tratadas por oxidação eletrolítica plasmática (PEO), em eletrólitos de silicato de sódio, utilizando espectroscopia fotoacústica. A rugosidade, morfologia e a composição química dos revestimentos foram analisados, respectivamente, por perfilometria, Microscopia Eletrônica de Varredura (MEV) e Espectroscopia de Energia Dispersiva (EDS). A porosidade da camada superficial do revestimento foi estimada pelo software de processamento de imagem digital, utilizando imagens da análise de MEV, enquanto difração de Raios X (DRX) foi utilizada para determinar a estrutura cristalina das superfícies tratadas. Os resultados das análises demonstraram que os revestimentos, predominantemente constituídos por γ-Al2O3, são rugosos, com superfícies porosas e apresentam boa resistência mecânica. A espectroscopia de absorção de UV-VIS demonstrou que a amostra tratada absorveu em média 18% mais radiação na região infravermelha quando comparada com amostras sem tratamento. Em consequência, como revelado pela espectroscopia fotoacústica a difusividade térmica das amostras tratadas é pelo menos 30% maior se comparada ao alumínio não tratado e 700% maior do que a alumina convencional. Aluminum is one of the most widely used materials in several areas of the industry. Owing to lower cost, if compared to copper, and considering its abundance, the interest on the thermal properties of aluminum has increased. In this context, the proposal of this research is to evaluate the thermal properties of aluminum samples treated by Plasma electrolytic oxidation (PEO), in sodium silicate electrolytes, using photoacoustic spectroscopy. Roughness, morphology and chemical composition of the coatings have been analyzed, respectively, by profilometry, scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS). The porosity of the surface layer was estimated by digital image processing using SEM micrographs while X-ray diffraction (XRD) was used for determining the crystalline structure of the treated surfaces. The results of the analyses have shown that the coatings, predominantly constituted by γ-Al2O3, are rough, with porous surfaces and present good mechanical resistance. UV-Vis absorption spectroscopy has shown that the treated sample absorbed on average 18% more radiation in the infrared region than the pristine samples. In consequence, as revealed by photoacoustic spectroscopy the thermal diffusivity of the treated samples is at least 30% larger if compared to untreated aluminum and 700% larger than that of conventional Alumina FAPESP 2015031596 CNPQ 302992/2017-0 CAPES 1766895

Published
2019

2. Development and Testing of an Energy Storage Material/Phase Change Material Enhanced Heat Sink.

Author

Tu, Jianping, Shih, Wei, Mak, Henry, and Yuen, Walter W.

Subjects
ENERGY storage, PHASE change materials, HEAT sinks (Electronics), ALUMINUM, HEAT transfer
Abstract

A concept of using energy storage material (ESM) or phase change material (PCM) to enhance the heat transfer dissipation by a conventional compact fin-based heat sink is demonstrated. An actual design is developed, fabricated, and tested to demonstrate the heat transfer enhancement. The heat sink is light weight (made with Aluminum) and miniature in size with a total fin length of 26 mm. Test results demonstrated that under a high peak load (4.4 W/cm2) and low duty power cycle (30/55 on/off ratio with a period of 85 sec), the peak temperature at the heating surface with the ESM/PCM heat sink is 5°C lower than that of a conventional heat sink. At the tip of the fin, the peak temperature with the ESM/PCM heat sink is 3°C lower than that of a conventional heat sink. When the external heat transfer coefficient increases (with increase air velocity), the impact of the PCM/ESM on the heat transfer performance is less. A numerical model, based on COMSOL, is developed to provide a theoretical understanding of the experimental observation. [ABSTRACT FROM PUBLISHER]

Published
2017
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3. The influence of Sintering Temperature and Silicon Carbide Percent on The Compression Properties.

Author

Ahmed, Y. and Alaalam, M.

Subjects
SILICON carbide, SINTERING, TEMPERATURE effect, COMPRESSIVE strength, POWDER metallurgy, COMPOSITE materials
Abstract

Powder metallurgy (P/M) is the processing of parts from metal powders. In (P/M) technology can be produce homogenous and net shape products, to generate properties not attainable through conventional metal working processes or to manufacture parts to net shape, this reason has motivated the need to find a cost effective technological production method for these composites. In this study the effect of Sintering Temperature and Silicon Carbide Percent on the Compression Properties of the aluminum silicon carbide produced by powder metallurgy is investigated by using the heat treatment of the composite. This method produce a local fusing and welding of the aluminum particles while using aluminum powder with thick oxide layer surrounding the particles prevents the all melting of the composite. Sintering temperatures between 500 and 850 °C were applied after cold compaction on samples containing (0%, 5%, 10%, 15%, 20%, 25% 30% and 35%) of silicon carbide powder then the specimens examined to study the compression properties. The results show that the compression properties of the samples increases with increasing the silicon carbide percent and sintering temperature. Also, to obtain good compression properties the sintering temperature are found to be 600°C for the aluminum with no silicon carbide content, 700 °C for composite containing both 5% and 10% SiC, 750°C for composite containing 15% SiC, 800 °C for composite containing 20%, 25% SiC, 850°C for composite containing 30%, 35% SiC. [ABSTRACT FROM AUTHOR]

Published
2015
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4. Workholder Devices : Design and Calculations

Author

Vukota Boljanovic and Vukota Boljanovic

Abstract

Advancements in the fields of mechanization and automation have led to large strides forward for the entire manufacturing industry. Various products, ranging in size from cars to small circuit components, are made through automated procedures in manufacturing facilities. These processes help improve efficiency, save on labor costs, and reduce the occurrences of defective products, improving company growth and product quality. A common feature of automated processes is the need for the item being worked on to be held firmly in place while work is being done on it—“workholding.” Workholders help improve the economy of production by creating smooth operational processes and helping to facilitate quick transitions from one work station to another. This simplifies and streamlines the entire mounting parts operation. Manufacturing workholders use many different methods to hold the parts securely, including hydraulic, electric, pneumatic, and mechanical holders, depending on the application. Workholding devices are regularly referred to as “jigs” and “fixtures,” and are often used interchangeably. A fixture secures the workpiece and allows the tool (but does not guide it) to move relative to the workpiece, while a jig holds and locates the workpiece and actually guides the tool.Workholder Devices presents the fundamentals of workholders design for machining and welding operations with their relevant applications, so readers can clearly assess the capabilities, limitations, potentials, and competitive aspects of each of these devices. The author shows how dynamic workholders are subject to constant change, improvement, and innovation. Unique Features Contains more than 180 illustrations, numerous calculations, tables, and essential appendices. Special attention is paid to modular systems, clamping devices, and clamping force calculation. Perfect for students of manufacturing engineering, process engineers, design engineers and drafters, as well as quality control and maintenance and reliability managers and technicians.

Published
2024

5. Engineering Properties of Magnesium Alloys

Author

Moosbrugger, Charles, Marquard, Liz, Moosbrugger, Charles, and Marquard, Liz

Subjects
Magnesium alloys
Abstract

Magnesium and magnesium alloys provide unique properties for engineering applications. Magnesium alloys are popular as a structural material because of their combination of light weight and strength. They are desirable for portable tools, appliances, electronic devices, airplanes, space vehicles, and land transportation. This book is written for engineers, scientists, teachers, and students engaged in the design process of material selection and material elimination. While focused on mechanical properties for structural design, the physical properties that are germane to corrosion behavior and electrical applications are represented. Two-thirds of the book is devoted to datasheets for individual alloys which provide a handy quick reference to specific properties and performance. The remainder of the book addresses topics common to all magnesium alloys such as the alloy designation system and product forms. Casting alloys and wrought alloys are compared. The alloy performance at elevated temperature is presented, as are fatigue properties. Finally, a summary of the corrosion behavior of selected alloys is discussed along with how these corrosion mechanisms can be applied for beneficial results.

Published
2017

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