scholarly journals O PROCESSO DE ANODIZAÇÃO DO ALUMÍNIO E SUAS LIGAS: UMA ABORDAGEM HISTÓRICA E ELETROQUÍMICA

Química Nova ◽  
2021 ◽  
Author(s):  
João Araujo
Keyword(s):  
Low Cost ◽  
Industrial Applications ◽  
Al Alloys ◽  
Al Alloy ◽  
Duplex Structure ◽  
Acid Bath ◽  
Electrochemical Approach ◽  
Regular Arrangement ◽  
Natural Oxide ◽  
The Relationship

THE ANODIZING PROCESS OF ALUMINUM AND ITS ALLOYS: A HISTORICAL AND ELECTROCHEMICAL APPROACH. Al and its alloys are found in several industrial applications. However, like most metals, this material is not immune to corrosion, being necessary to be protected against corrosion. One of the methods most commonly employed to improve the corrosion resistance of Al alloys is the anodizing process, which consists of thickening of the natural oxide (Al2O3) presents in Al through anodic oxidation. The anodizing process is accomplished by immersion of the Al alloy into an acid bath and passing an electric current through it. This process produces two layers: a barrier layer thicker than the natural oxide and a layer with regular arrangement of nanopores (porous layer). This duplex structure forms the anodized layer with a large specific surface area. With the advent of nanotechnology, this layer has been applied in other areas due to its low cost, stability, absence of toxicity, and biocompatibility. In this context, this paper addresses a historical and electrochemical review of the anodizing process of Al and its alloys, presenting the main events that culminated in the development of the current processes and the understanding of the relationship between the chemical reactions and the mechanisms that occur during nucleation and development of the oxide layer

Microstructure and Mechanical Properties of Fe-Containing Al-Alloys Processed by a Rheo-Diecasting Process

2006 ◽  
Vol 519-521 ◽  
pp. 1251-1256
Author(s):  
X. Fang ◽  
G. Shao ◽  
Z. Fan
Keyword(s):  
Mechanical Properties ◽  
High Efficiency ◽  
Low Cost ◽  
Al Alloys ◽  
Experimental Results ◽  
Semisolid Slurry ◽  
Al Alloy ◽  
Twin Screw ◽  
Size And Morphology ◽  
Plate Morphology

Al-Fe compounds are usually present in the as-cast microstructure of Al-alloys as large needles or plates. As such, they have a detrimental effect on the mechanical properties of Al-alloys containing Fe, either as an impurity element or as an alloying addition. However, Fe-containing Al-alloys also offer attractive physical properties, such as improved stiffness, wear resistance and thermal resistance. If the needle and plate morphology of the Al-Fe compounds can be modified to a more compact morphology, with refined particle size and uniform distribution, the mechanical properties of Al-Fe based Al-alloys can be substantially improved, and therefore, they will find wider applications in many engineering sectors. A new semisolid metal processing technology, rheodiecasting (RDC), has been developed for production of Al-alloy components with high integrity. The RDC process innovatively combines the dispersive mixing power of the twin-screw mechanism, for the creation of high quality semisolid slurry, with the high efficiency, low cost nature of the high-pressure diecasting (HPDC) process for component shaping. In this paper, we present our experimental results on the effects of intensive melt shearing on the size and morphology of Al-Fe compounds in A380 alloys, with different levels of Fe additions. The experimental results have shown that intensive melt shearing during solidification can effectively change the particle shape from the usual needles and plates, to an equiaxed morphology. Samples which have undergone with melt shearing, exhibit much improved strength and ductility compared to those with the same level of Fe addition, but without exposure to melt shearing.

Influence of Machining Characteristics on Ultra-Precision Cutting of Aluminum Alloys

2014 ◽  
Vol 625 ◽  
pp. 201-206
Author(s):  
Daisuke Hirase ◽  
Yukio Maeda ◽  
Kenichi Iwatsuka ◽  
Takanori Yazawa
Keyword(s):  
Surface Roughness ◽  
Cutting Force ◽  
Edge Length ◽  
Optical Quality ◽  
Al Alloys ◽  
Cutting Edge ◽  
Al Alloy ◽  
Ultra Precision ◽  
The Relationship ◽  
Geometric Surface

In this study, we investigated ultra-precision cutting technology used in the production of Al alloy polygon mirrors. We compared characteristics of three Al alloys (Al–Mg, Al–Cu, and Al–Si) when cut with a straight diamond tool. When cutting Al alloys, it is desirable to reduce geometric surface roughness and remove tear-out marks and scratch marks. We investigated the relationship between end cutting edge length, surface roughness, and cutting force of straight diamond tools. In addition, we compared surface roughness and cutting force produced by double facet tools with microfacets at the end cutting edge and on the rake-face side. It was found that both tools have similar cutting characteristics and that Al–Mg has the best optical quality, followed by Al–Cu and Al–Si.

scholarly journals One-Step Preparation of Super-Hydrophobic Micro-Nano Dendrites on Al Alloy for Enhanced Corrosion Resistance

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 960 ◽  
Author(s):  
Xuewu Li ◽  
Tian Shi ◽  
Ben Li ◽  
Chuanwei Zhang ◽  
Bin Zhong ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Low Cost ◽  
Hydrophobic Surface ◽  
Al Alloys ◽  
Al Alloy ◽  
Ocean Engineering ◽  
Acid Modification ◽  
Sliding Angle ◽  
Corrosion Failure ◽  
One Step

Corrosion failure is a thorny issue that restricts the applications of Al alloys. As a research hotspot in functional realization, hydrophobic fabrication exactly offers an efficient method to settle metallic corrosions. This work has developed a facile and low-cost method to enhance corrosion resistance of Al alloys. The micro-nano dendrites have been firstly prepared on metallic substrate using one-step potentiostatic deposition. Then, wetting and electrochemical behaviors have been systematically investigated after stearic acid modification. Results show that the as-prepared surface possesses amplified and durable water repellence with an apparent contact angle (CA) of 154.2° and a sliding angle (SA) of 4.7°. Meanwhile, owing to the trapped air in dendrites, the newly-generated solid-air-liquid interfaces help to resist seawater penetration by reducing interfacial interactions on the super-hydrophobic surface as well as significantly enhance its corrosion resistance. This work sheds positive insights into extending the applications of Al alloys in many areas, especially for ocean engineering fields.

Friction Stir Welding of Dissimilar 5xxx to 6xxx Al Alloys: A Review

2013 ◽  
Vol 376 ◽  
pp. 42-48 ◽  
Author(s):  
S.N. Pandya ◽  
J.V. Menghani
Keyword(s):  
Friction Stir Welding ◽  
Industrial Applications ◽  
Al Alloys ◽  
Fusion Welding ◽  
Al Alloy ◽  
Pressure Welding ◽  
Roll Bonding ◽  
Friction Stir ◽  
History Of ◽  
State Nature

Many engineering applications in aerospace and automotive field require joining of dissimilar 5xxx to 6xxx Al alloys. Dissimilar Al alloy joints are used for industrial applications due to technical & economic reasons. However, due to different metallurgical behaviour & mechanical properties, joining of dissimilar Al alloys presents a number of challenges. Due to high temperature generation most of the fusion welding techniques are not suitable. In addition, other pressure welding techniques such as – Ultrasonic welding, Roll bonding, Diffusion bonding and Friction welding have some limitation. Hence, friction stir welding (FSW) can be considered to be the most suitable method to join dissimilar Al alloys due to solid-state nature of the process. Since invention, friction stir welding has been a matter of research and investigation for years. In its history of two decades, Friction Stir welding was investigated for joining dissimilar Al alloys during the last decade. Most of studies demonstrated that good quality joints between dissimilar Al alloys can be produced by the Friction Stir Welding (FSW) process. The present study is a chronological & critical review of recent studies on joining of dissimilar 5xxx to 6xxx Al alloys by friction stir welding.

scholarly journals Influence of Cumulative Plastic Deformation on Microstructure of the Fe-Al Intermetallic Phase Base Alloy

2014 ◽  
Vol 59 (3) ◽  
pp. 987-991 ◽  
Author(s):  
I. Bednarczyk ◽  
D. Kuc ◽  
G. Niewielski
Keyword(s):  
Plastic Deformation ◽  
Base Alloy ◽  
Low Cost ◽  
Intermetallic Phase ◽  
Construction Materials ◽  
Industrial Applications ◽  
Al Alloy ◽  
Deformation Method ◽  
Deformation Parameters ◽  
Feal Phase

Abstract This article is part of the research on the microstructural phenomena that take place during hot deformation of intermetallic phase-based alloy. The research aims at design an effective thermo - mechanical processing technology for the investigated intermetallic alloy. The iron aluminides FeAl have been among the most widely studied intermetallics because their low cost, low density, good wear resistance, easy of fabrication and resistance to oxidation and corrosion. There advantages create wide prospects for their industrial applications for components of machines working at a high temperature and in corrosive environment. The problem restricting their application is their low plasticity and their brittle cracking susceptibility, hampers their development as construction materials. Consequently, the research of intermetallic-phase-based alloys focuses on improvement their plasticity by hot working proceses. The study addresses the influence of deformation parameters on the structure of an Fe-38% at. Al alloy with Zr, B Mo and C microadditions, using multi – axis deformation simulator. The influence of deformation parameters on microstructure and substructure was determined. It was revealed that application of cumulative plastic deformation method causes intensive reduction of grain size in FeAl phase base alloy.

Influence of ageing treatment on microstructure, mechanical properties and adhesive wear behaviour of 6063 aluminium alloy

2014 ◽  
Vol 66 (4) ◽  
pp. 520-524 ◽  
Author(s):  
Serkan Büyükdoğan ◽  
Süleyman Gündüz ◽  
Mustafa Türkmen
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
High Speed ◽  
Al Alloys ◽  
Wear Behaviour ◽  
Al Alloy ◽  
Strain Ageing ◽  
Content Type ◽  
Static Strain ◽  
Structural Applications

Purpose – The paper aims to provide new observations about static strain ageing in aluminium (Al) alloys which are widely used in structural applications. Design/methodology/approach – The present work aims to provide theoretical and practical information to industries or researchers who may be interested in the effect of static strain ageing on mechanical properties of Al alloys. The data are sorted into the following sections: introduction, materials and experimental procedure, results and discussion and conclusions. Findings – Tensile strength, proof strength (0.2 per cent) and percentage elongation measurement were used to investigate the effect of strain ageing on the mechanical properties. Wear tests were performed by sliding the pin specimens, which were prepared from as-received, solution heat-treated, deformed and undeformed specimens after ageing, on high-speed tool steel (64 HRC). It is concluded that the variations in ageing time improved the strength and wear resistance of the 6063 Al alloy; however, a plastically deformed solution-treated alloy has higher strength and wear resistance than undeformed specimens for different ageing times at 180°C. Practical implications – A very useful source of information for industries using or planning to produce Al alloys. Originality/value – This paper fulfils an identified resource need and offers practical help to the industries.

scholarly journals Remote Reflectivity Sensor for Industrial Applications

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1301
Author(s):  
Federico Cavedo ◽  
Parisa Esmaili ◽  
Michele Norgia
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
Industrial Applications ◽  
Interference Immunity ◽  
Surface Reflection ◽  
Measurement Systems ◽  
Digital Detector ◽  
Reflected Light ◽  
Surface Optical ◽  
Diffused Light

A low-cost optical reflectivity sensor is proposed in this paper, able to detect the presence of objects or surface optical properties variations, at a distance of up to 20 m. A collimated laser beam is pulsed at 10 kHz, and a synchronous digital detector coherently measures the back-diffused light collected through a 1-inch biconvex lens. The sensor is a cost-effective solution for punctual measurement of the surface reflection at different distances. To enhance the interference immunity, an algorithm based on a double-side digital baseline restorer is proposed and implemented to accurately detect the amplitude of the reflected light. As results show, the sensor is robust against ambient light and shows a strong sensitivity on a wide reflection range. The capability of the proposed sensor was evaluated experimentally for object detection and recognition, in addition to dedicated measurement systems, like remote encoders or keyphasors, realized far from the object to be measured.

scholarly journals Deconstruction of Lignin: From Enzymes to Microorganisms

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2299
Author(s):  
Jéssica P. Silva ◽  
Alonso R. P. Ticona ◽  
Pedro R. V. Hamann ◽  
Betania F. Quirino ◽  
Eliane F. Noronha
Keyword(s):  
Microbial Communities ◽  
Metabolic Pathways ◽  
Low Cost ◽  
Direct Analysis ◽  
Industrial Applications ◽  
Natural Environments ◽  
Lignocellulosic Residues ◽  
Complementary Techniques ◽  
Plant Polymer ◽  
Powerful Strategy

Lignocellulosic residues are low-cost abundant feedstocks that can be used for industrial applications. However, their recalcitrance currently makes lignocellulose use limited. In natural environments, microbial communities can completely deconstruct lignocellulose by synergistic action of a set of enzymes and proteins. Microbial degradation of lignin by fungi, important lignin degraders in nature, has been intensively studied. More recently, bacteria have also been described as able to break down lignin, and to have a central role in recycling this plant polymer. Nevertheless, bacterial deconstruction of lignin has not been fully elucidated yet. Direct analysis of environmental samples using metagenomics, metatranscriptomics, and metaproteomics approaches is a powerful strategy to describe/discover enzymes, metabolic pathways, and microorganisms involved in lignin breakdown. Indeed, the use of these complementary techniques leads to a better understanding of the composition, function, and dynamics of microbial communities involved in lignin deconstruction. We focus on omics approaches and their contribution to the discovery of new enzymes and reactions that impact the development of lignin-based bioprocesses.

Direct Cladding from Molten Metals of Aluminum and Magnesium Alloys Using a Tandem Horizontal Twin Roll Caster

2015 ◽  
Vol 772 ◽  
pp. 250-256 ◽  
Author(s):  
Hideto Harada ◽  
Shin Ichi Nishida ◽  
Mayumi Suzuki ◽  
Hisaki Watari ◽  
T. Haga
Keyword(s):  
Surface Condition ◽  
Hardness Test ◽  
Al Alloys ◽  
Mg Alloy ◽  
Al Alloy ◽  
Molten Metals ◽  
Electron Probe Micro Analyzer ◽  
Twin Roll Caster ◽  
Aluminum And Magnesium Alloys ◽  
Twin Roll

This paper describes direct cladding of magnesium (Mg) and aluminum (Al) alloys using a tandem horizontal twin roll caster that has three pairs of upper and lower rolls. Manufacturing conditions that are appropriate for fabricating Al/Mg and Al/Mg/Al cladded material were investigated. The surface condition of the cladded cast strip was examined. An electron probe micro analyzer was used to observe the interface between Al alloy and Mg alloy. The thickness of the mixed layer of Al and Mg alloy was 15μm, and how the materials were connected was clarified. Microscopic observation and backscattered electron analysis were used to investigate the cladding mechanisms of the Al and Mg alloy layers. Average hardness was determined using the Vickers hardness test at the Al layer and at the diffused layer between Mg and Al alloys. Cladding of Al/Mg alloy and A/Mg/Al alloy was possible using a tandem twin-roll caster. In addition, Al3Mg2 and Al12Mg17 phase precipitation at the interface of the Al and Mg alloys was confirmed during direct cladding from molten metals.

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