scholarly journals Microstructural, Mechanical and Corrosion Investigations of Ship Steel-Aluminum Bimetal Composites Produced by Explosive Welding

Metals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 544 ◽  
Author(s):  
Yakup Kaya
Keyword(s):  
Explosive Welding ◽  
Energy Dispersive Spectrometry ◽  
Salt Spray ◽  
Composite Plates ◽  
Bonding Interface ◽  
Steel Plates ◽  
Neutral Salt ◽  
Aluminum Plates ◽  
Bimetal Composite

In this study, explosive welding was used in the cladding of aluminum plates to ship steel plates at different explosive ratios. Ship steel-aluminum bimetal composite plates were manufactured and the influence of the explosive ratio on the cladded bonding interface was examined. Optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS) studies were employed for the characterization of the bonding interface of the manufactured ship steel-aluminum bimetal composites. Tensile-shear, notch impact toughness, bending and twisting tests, and microhardness studies were implemented to determine the mechanical features of the bimetal composite materials. In addition, neutral salt spray (NSS) tests were performed in order to examine the corrosion behavior of the bimetal composites.

Study on Fabrication and Bonding Interface of Explosive Welded Steel/Aluminum/Steel Composite Plate

2017 ◽  
Vol 753 ◽  
pp. 188-193
Author(s):  
Nan Zhou ◽  
Jing Jiang ◽  
Kui Tang ◽  
Song Ze Tang
Keyword(s):  
Vickers Hardness ◽  
Bonding Strength ◽  
Composite Plate ◽  
Explosive Welding ◽  
Composite Plates ◽  
Bonding Interface ◽  
Dissimilar Metal ◽  
Metal Plates ◽  
Steel Composite ◽  
Layer Steel

In order to study the explosive welding experimental fabrication technology of multi-layer dissimilar metal plates and the quality of bonding interface, three-layer steel/aluminum/steel composite plates with different thickness distributions were fabricated using the method of explosive welding when their total thicknesses remained same (total 5 mm). Then the stereomicroscope was adopted to investigate the shape of bonding interface and the formed mechanism was also analyzed. In addition, the micro-hardness (Vickers hardness, Hv) distribution of the composite plate in the thickness direction was studied by a low load Vickers hardness tester. The results show that the method of explosive welding can be used to fabricate three-layer steel/aluminum/steel dissimilar metal plates successfully. Meanwhile, wave bonding interface was formed between steel fly plate and aluminum middle plate, straight bonding interface was formed between aluminum middle plate and steel base plate. The maximum Hv value of welded plate appears at the bonding interface with high bonding strength. The bonding strength of both two kinds of welded interface was considered sufficient, which offers experimental support for the explosive welding of multi-layer plates.

scholarly journals Gold hard anodized (GHA) materials with antimicrobial surface properties: mechanical, tribological, and microbiological characterization

2021 ◽  
Author(s):  
Anna Nastruzzi ◽  
Franco Cicerchia ◽  
Annalisa Fortini ◽  
Claudio Nastruzzi
Keyword(s):  
Anodic Oxidation ◽  
Salt Spray ◽  
Antimicrobial Properties ◽  
Control Measures ◽  
Nanoporous Structure ◽  
Material Surface ◽  
Oxide Surface ◽  
Neutral Salt ◽  
New Material

AbstractInfections acquired in public spaces (i.e., transports, restaurants, and bars, hospitals) present a serious burden for the entire health systems. In this respect, appropriate preventative and control measures in order to eliminate or reduce the negative effects of surface-transmitted infections appear highly desirable. Alongside recommendations for treatment and hygiene, antimicrobial material surfaces can offer indeed an important contribution to the prevention of infections. The aim of the current paper is therefore to describe the preparation and characterization of a new material obtained by an innovative anodic oxidation, defined as golden hard anodizing GHA. The anodic oxide surface thanks to the nanoporous structure acts as reservoir of silver ions (Ag+) which in turn confer antimicrobial properties to the material surface. Specifically, the manuscript presents a thorough preparation and characterization of a new material obtained by an innovative anodic oxidation treatment applied on commercially available aluminum alloys including the microscopic analysis and the description of the antimicrobial performances against a number of microorganisms, including among the others, Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. More specifically, the current article describes some of the properties of GHA materials. The tribological properties of GHA were evaluated through experimental tests performed with a pin-on-disk tribometer. The morphology of the wear surfaces was studied by means of a scanning electron microscope (SEM) analysis and profilometry investigations. Furthermore, in order to evaluate the possible anticorrosive properties of GHA, tests in neutral salt spray are in addition described.

scholarly journals Experimental Research on Hysteretic Characteristics of Steel Plates Artificially Corroded by Neutral Salt Spray

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Shan-hua Xu ◽  
Guang-chong Qin ◽  
Zong-xing Zhang
Keyword(s):  
Constitutive Model ◽  
Salt Spray ◽  
Seismic Energy ◽  
Cyclic Hardening ◽  
Steel Plates ◽  
Neutral Salt ◽  
Loading Test ◽  
Skeleton Curve ◽  
Hysteretic Characteristics ◽  
First Time

This paper aims to study the hysteretic characteristics of the steel plates artificially corroded by neutral salt spray. Salt spray was applied to accelerate the corrosion on the steel plates; specimens of varying degrees of corrosion were obtained in this manner. And each specimen was subject to cyclic loading test to get the hysteretic curve. Then the experimental results were extensively discussed, focusing on strength and ductility, hysteretic energy, the skeleton curve, and unloading and loading curve. After that, the hysteretic constitutive model of corroded steel was established based on the first time loading criterion, unloading criterion, cycle skeleton criterion, and reloading curve criterion. The result of the experiment showed that, with the increase of the degree of corrosion, the mechanical properties and seismic energy dissipation performance of seismic energy of the steel decreased; the deterioration of ductility got aggravated. On the other hand, the skeleton curve and the Ramberg-Osgood model were well matched, and the coefficient of circular enhancement showed a decreasing trend; the variation of cyclic hardening exponent did not have an obvious pattern. Meanwhile, the hysteretic constitutive model of corroded steel and the results of the experiment were well matched.

Physical Ultrasonics of Composites

2011 ◽  
Author(s):  
Dale Chimenti ◽  
Stanislav Rokhlin ◽  
Peter Nagy
Keyword(s):  
Composite Laminates ◽  
Stiffness Matrix ◽  
Composite Plates ◽  
Anisotropic Media ◽  
Anisotropic Materials ◽  
Ultrasonic Waves ◽  
Laminated Plates ◽  
Structure Characteristic ◽  
Major Advance

Physical Ultrasonics of Composites is a rigorous introduction to the characterization of composite materials by means of ultrasonic waves. Composites are treated here not simply as uniform media, but as inhomogeneous layered anisotropic media with internal structure characteristic of composite laminates. The objective here is to concentrate on exposing the singular behavior of ultrasonic waves as they interact with layered, anisotropic materials, materials which incorporate those structural elements typical of composite laminates. This book provides a synergistic description of both modeling and experimental methods in addressing wave propagation phenomena and composite property measurements. After a brief review of basic composite mechanics, a thorough treatment of ultrasonics in anisotropic media is presented, along with composite characterization methods. The interaction of ultrasonic waves at interfaces of anisotropic materials is discussed, as are guided waves in composite plates and rods. Waves in layered media are developed from the standpoint of the "Stiffness Matrix", a major advance over the conventional, potentially unstable Transfer Matrix approach. Laminated plates are treated both with the stiffness matrix and using Floquet analysis. The important influence on the received electronic signals in ultrasonic materials characterization from transducer geometry and placement are carefully exposed in a dedicated chapter. Ultrasonic wave interactions are especially susceptible to such influences because ultrasonic transducers are seldom more than a dozen or so wavelengths in diameter. The book ends with a chapter devoted to the emerging field of air-coupled ultrasonics. This new technology has come of age with the development of purpose-built transducers and electronics and is finding ever wider applications, particularly in the characterization of composite laminates.

scholarly journals Design and Multidimensional Screening of Flash-PEO Coatings for Mg in Comparison to Commercial Chromium(VI) Conversion Coating

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 337
Author(s):  
Ewa Wierzbicka ◽  
Marta Mohedano ◽  
Endzhe Matykina ◽  
Raul Arrabal
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Conversion Coating ◽  
Neutral Salt ◽  
Chromium Vi ◽  
Alkaline Electrolytes ◽  
Az31b Alloy ◽  
Plasma Electrolytic

REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulations demand for an expedient discovery of a Cr(VI)-free alternative corrosion protection for light alloys even though the green alternatives might never be as cheap as current harmful technologies. In the present work, flash- plasma electrolytic oxidation coatings (FPEO) with the process duration < 90 s are developed on AZ31B alloy in varied mixtures of silicate-, phosphate-, aluminate-, and fluoride-based alkaline electrolytes implementing current density and voltage limits. The overall evaluation of the coatings’ anticorrosion performance (electrochemical impedance spectroscopy (EIS), neutral salt spray test (NSST), paintability) shows that from nine optimized FPEO recipes, two (based on phosphate, fluoride, and aluminate or silicate mixtures) are found to be an adequate substitute for commercially used Cr(VI)-based conversion coating (CCC). The FPEO coatings with the best corrosion resistance consume a very low amount of energy (~1 kW h m−2 µm−1). It is also found that the lower the energy consumption of the FPEO process, the better the corrosion resistance of the resultant coating. The superb corrosion protection and a solid environmentally friendly outlook of PEO-based corrosion protection technology may facilitate the economic justification for industrial end-users of the current-consuming process as a replacement of the electroless CCC process.

scholarly journals Application of Commercial Surface Pretreatments on the Formation of Cerium Conversion Coating (CeCC) over High-Strength Aluminum Alloys 2024-T3 and 7075-T6

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 930
Author(s):  
Juan Jesús Alba-Galvín ◽  
Leandro González-Rovira ◽  
Francisco Javier Botana ◽  
Maria Lekka ◽  
Francesco Andreatta ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Salt Spray ◽  
Aluminum Matrix ◽  
Optical Emission ◽  
High Strength ◽  
Chemical Conversion ◽  
Conversion Coating ◽  
Neutral Salt ◽  
Corrosion Properties ◽  
Surface Pretreatment

The selection of appropriate surface pretreatments is one of the pending issues for the industrial application of cerium-based chemical conversion coatings (CeCC) as an alternative for toxic chromate conversion coating (CrCC). A two-step surface pretreatment based on commercial products has been successfully used here to obtain CeCC on AA2024-T3 and AA7075-T6. Specimens processed for 1 to 15 min in solutions containing CeCl3 and H2O2 have been studied by scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM-EDX), glow discharge optical emission spectroscopy (GDOES), potentiodynamic linear polarization (LP), electrochemical impedance spectroscopy (EIS), and neutral salt spray (NSS) tests. SEM-EDX showed that CeCC was firstly observed as deposits, followed by a general coverage of the surface with the formation of cracks where the coating was getting thicker. GDOES confirmed an increase of the CeCC thickness as the deposition proceed, the formation of CeCC over 7075 being faster than over 2024. There was a Ce-rich layer in both alloys and an aluminum oxide/hydroxide layer on 7075 between the upper Ce-rich layer and the aluminum matrix. According to LP and EIS, CeCC in all samples offered cathodic protection and comparable degradation in chloride-containing media. Finally, the NSS test corroborated the anti-corrosion properties of the CeCC obtained after the commercial pretreatments employed.

scholarly journals The Interfacial Characterization and Performance of Cu/Al-Conductive Heads Processed by Explosion Welding, Cold Pressure Welding, and Solid-Liquid Casting

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 237 ◽  
Author(s):  
Yanni Wei ◽  
Hui Li ◽  
Fu Sun ◽  
Juntao Zou
Keyword(s):  
Corrosion Resistance ◽  
Bonding Strength ◽  
Explosive Welding ◽  
Slag Inclusion ◽  
Explosion Welding ◽  
Bonding Interface ◽  
Pressure Welding ◽  
And Performance ◽  
Solid Liquid ◽  
Cold Pressure

The Cu/Al composites conductive head is widely used in hydrometallurgy as the core component of cathode plate. Its conductive properties directly affect the power consumption, and the bonding strength and corrosion resistance determine the conductive head service life. The Cu/Al conductive head prepared by explosion welding, cold pressure welding, and solid-liquid casting methods were investigated in this paper. The interface microstructure and compositions were examined by scanning electron microscope and X-ray energy dispersive spectrometry. The bonding strength, interface conductivity, and the corrosion resistance of three types of joints were characterized. The Cu/Al bonding interface produced by explosive welding presented a wavy-like morphology with typical defects and many of brittle compounds. A micro-interlocking effect was caused by the sawtooth structures on the cold pressure welding interface, and there was no typical metallurgical reaction on the interface. The Cu/Al bonding interface prepared by solid-liquid casting consisted mainly of an Al-Cu eutectic microstructure (Al2Cu+Al) and partial white slag inclusion. The thickness of the interface transition layer was about 200–250 µm, with defects such as holes, cracks, and unwelded areas. The conductivity, interfacial bonding strength, and corrosion resistance of the conductive head prepared by explosive welding were superior to the other two.

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