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Article

Harun Mindivan

This paper aims to investigate the structural, corrosion and the study of tribocorrosion features of the AA7075 aluminum alloy with and without the application of…

Abstract

Purpose

This paper aims to investigate the structural, corrosion and the study of tribocorrosion features of the AA7075 aluminum alloy with and without the application of electroless Ni-P/Ni-B duplex coating with a thickness of approximately 40 microns.

Design/methodology/approach

Surface characterization of the samples was made by structural surveys (light optic microscope, scanning electron microscopic examinations and X-ray diffraction analyses), hardness measurements, corrosion and tribocorrosion tests.

Findings

Results of the experiments showed that upper Ni-B coating deposited on the surface of first Ni-P layer by duplex treatment caused remarkable increment in the hardness, corrosion resistance and tribocorrosion performance as compared to the AA7075 aluminum alloy.

Originality/value

This study can be a practical reference and offers insight into the effects of duplex treating on the increase of hardness, corrosion and tribocorrosion performance.

Details

Industrial Lubrication and Tribology, vol. 71 no. 5
Type: Research Article
ISSN: 0036-8792

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Article

Isam Tareq Abdullah and Sabah Khammass Hussein

The purpose of this paper is to join a sheet of the AA7075 with the high-density polyethylene (HDPE) by a lap joint using friction spot processing and investigate the…

Abstract

Purpose

The purpose of this paper is to join a sheet of the AA7075 with the high-density polyethylene (HDPE) by a lap joint using friction spot processing and investigate the temperature distribution of joint during this process using the finite element method (FEM).

Design/methodology/approach

A semi-conical hole was manufactured in the AA7075 specimen and a lap joint configuration was prepared with the HDPE specimen. A rotating tool was used to generate the required heat to melt the polymer by the friction with the AA7075 specimen. The applied tool force moved the molten polymer through the hole. Four parameters were used: lower diameter of hole, rotating speed, plunging depth and time. The results of shear test were analyzed using the Taguchi method. A FEM was presented to estimate the temperature distribution of joint during the process.

Findings

All specimens failed by shearing the polymer at the lap joint region without dislocation. The specimens of the smallest diameter exhibited the highest shear strength at the lap joint. The maximum ranges of temperature were recorded at the contact region between the rotating tool and the AA7075 specimen. The tool plunging depth recorded the highest effect on the generated heat compared with the rotating speed and plunging time.

Originality/value

For the first time, the AA7075 sheet was joined with the HDPE sheet by friction spot processing. The temperature distribution of this joint was simulated using the FEM.

Details

International Journal of Structural Integrity, vol. 10 no. 4
Type: Research Article
ISSN: 1757-9864

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Article

Suganeswaran Kandasamy, Parameshwaran Rathinasamy, Nithyavathy Nagarajan, Karthik Arumugam, Rajasekar Rathanasamy and Gobinath Velu Kaliyannan

This paper aims to overcome the corrosion in AA7075 by incorporating the dual-reinforcements like Al2O3 and SiC through friction stir processing (FSP). In recent days, an…

Abstract

Purpose

This paper aims to overcome the corrosion in AA7075 by incorporating the dual-reinforcements like Al2O3 and SiC through friction stir processing (FSP). In recent days, an automotive monocoque structure undergoes corrosion because of changes in environmental conditions.

Design/methodology/approach

Surface hybrid composites (SHCs) of AA7075 with different weight ratios of Al2O3 and SiC were fabricated at a rotating speed of 1000 rpm, traveling speed of 56 mm/min and tool tilt angle of 2º with two passes. Surface regions were observed using optical microscopy, and the potentiodynamic corrosion test was performed under a 3.5 per cent NaCl environment at room temperature. Then, the surface morphology analysis of corroded samples and their structural properties were also investigated through scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron dispersive spectroscopy (EDS).

Findings

Through FSP, an improved interface between the reinforced particles and the AA7075 base matrix was observed because of the severe plastic deformation. Potentiodynamic polarization tests confirmed that the AA7075 matrix with a higher concentration of Al2O3 and a lower concentration of SiC (Al2O3 – 75 per cent and SiC – 25 per cent) possesses a lower corrosion rate than other specimens. This result is because of the combined effect of stable passive film formation and the resistance produced by hard SiC particles. In addition, the formation of a stronger interface between the reinforcements and the base matrix impedes the NaCl solution attack. The SEM micrograph depicts the film crystallinity variations with an increase in Al2O3 content. Debonding between the layers was observed on increasing the SiC content in the base matrix. XRD shows the peaks of reinforcing elements that influence the corrosion behavior. These observations suggest that the AA7075 reinforced with a higher concentration of Al2O3 and a lower concentration of SiC through FSP affords a suitable solution for automotive monocoque applications.

Originality/value

The corrosion rate has been identified for AA7075 SHCs with various concentrations of Al2O3 and SiC and has been compared with that of the base metal and the friction stir processed specimen without reinforcement.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 4
Type: Research Article
ISSN: 0003-5599

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Article

Ijlal Şimşek

This paper aims to investigate the effects of second phase precipitate size on microstructure, hardness, density, corrosion and electrical conductivity of 7075 aluminum

Abstract

Purpose

This paper aims to investigate the effects of second phase precipitate size on microstructure, hardness, density, corrosion and electrical conductivity of 7075 aluminum alloy fabricated by the powder metallurgy method and aged at 120°C for various aging periods.

Design/methodology/approach

For the aging process (T6), these alloys were solution-treated at 485°C for 2 h, quenched, aged at 120°C for four various periods and finally air cooled. After the aging process, these alloys were examined with scanning electron microscope, X-ray diffraction, density and hardness measurements. The corrosion tests were carried out using the potentiodynamic polarization technique; electrical conductivity values were measured as IACS%.

Findings

Results showed that the precipitate size increased with increasing aging period and the maximum precipitate size was achieved for the sample aged for 28 h. The maximum hardness was attained for the sample aged for 24 h, while the same specimen obtained the lowest electrical conductivity and corrosion resistance.

Originality/value

In this research, second phase precipitates of heat treatment processing affected the electrical conductivity and corrosion behavior of the 7075 aluminum alloy. Also it is understood that the heat treatment period is an effective parameter on these properties.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 5
Type: Research Article
ISSN: 0003-5599

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Article

Reham Reda, Mohamed Saad, Mohamed Zaky Ahmed and Hoda Abd-Elkader

This paper aims to monitor, evaluate and adjust the joint quality of dissimilar friction stir welded AA2024-T3 and AA7075-T6 Al alloys.

Abstract

Purpose

This paper aims to monitor, evaluate and adjust the joint quality of dissimilar friction stir welded AA2024-T3 and AA7075-T6 Al alloys.

Design/methodology/approach

Taguchi analysis for design of experiments and ANOVA analysis were applied. Tensile test, visual inspection and macro and microstructure investigations were carried out at each welding condition. In addition, the grain size of stir zone and the value of heat input were measured.

Findings

Using Taguchi analysis, the optimum values of tool rotary speed, welding speed and axial load were 1,200 rpm, 100 mm/min and 1,300 kg, respectively, yielding the maximum tensile strength of the joints of 427 MPa. ANOVA analysis indicated that the most significant parameter on the joint strength is the tool rotary speed, followed by welding speed and axial load, with contributions of 67, 27 and 2 per cent, respectively. Best mixing between Al alloys in the stir zone with no defects was observed at moderate speeds because of proper heat input and grain size, resulting in high strength.

Originality/value

A relation between structure characteristics of the joint, the process parameters and the joint strength was established to control the joint quality.

Details

Journal of Engineering, Design and Technology, vol. 16 no. 2
Type: Research Article
ISSN: 1726-0531

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Article

Yong Zhou, Pei Zhang, Jinping Xiong and Fuan Yan

A chromate conversion coating was prepared on the surface of bare AA2024 aluminum alloy by direct immersion in the chromating treatment bath, and the corrosion behavior of…

Abstract

Purpose

A chromate conversion coating was prepared on the surface of bare AA2024 aluminum alloy by direct immersion in the chromating treatment bath, and the corrosion behavior of chromated AA2024 aluminum alloy in 3.5 per cent NaCl solution was studied by electrochemical measurement and microstructural observation.

Design/methodology/approach

According to the polarization curve test and the scanning electron microscope observation, the corrosion evolution of chromated AA2024 in 3.5 per cent NaCl solution was divided into the following three stages: coating failure, pitting corrosion and intergranular corrosion (IGC).

Findings

In the first stage, the chromate coating degraded gradually due to the combined action of chloride anions and water molecules, resulting in the complete exposure of AA2024 substrate to 3.5 per cent NaCl solution. Subsequently, in the second stage, chloride anions adsorbed at the sites of θ phase (Al2Cu) and S phase (Al2CuMg) on the AA2024 surface preferentially, and some corrosion pits initiated at the above two sites and propagated towards the deep of crystal grains. However, the propagation of a pit terminated when the pit front arrived at the adjacent grain boundary, where the initiation of IGC occurred.

Originality/value

Finally, in the third stage, the corrosion proceeded along the continuous grain boundary net and penetrated the internal of AA2024 substrate, resulting in the propagation of IGC. The related corrosion mechanisms for the bare and the chromated AA2024 were also discussed.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 6
Type: Research Article
ISSN: 0003-5599

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Article

Qi Zheng Li, Yu Zuo, Jing Mao Zhao, Yu Ming Tang, Xu Hui Zhao and Jin Ping Xiong

By adding a Ce salt and an Nd salt to an anodizing electrolyte, modified anodic films are obtained on aluminum surfaces. This paper aims to study the effects of rare‐earth…

Abstract

Purpose

By adding a Ce salt and an Nd salt to an anodizing electrolyte, modified anodic films are obtained on aluminum surfaces. This paper aims to study the effects of rare‐earth elements on the corrosion resistance of the anode film.

Design/methodology/approach

The crystalline film was studied by X‐ray diffraction. The methods of scanning electron microscope, energy dispersive X‐ray analysis, electrochemical polarization, and electrochemical impedance spectroscopy (EIS) were used to characterize the properties of the films.

Findings

After rare‐earth element modification, the pores of the porous layer were very evidently smaller, the anodic film was more compact, and the thickness and hardness of the films had increased. The corrosion resistance of the anodic films modified with rare‐earth elements clearly was improved in neutral, acidic, and basic NaCl solutions. Ce showed a better effect than Nd in increasing the corrosion resistance of the films, and the film modified with Ce+Nd showed the highest corrosion resistance. EIS analysis showed that the impedances of both the barrier layer and porous layer of the anodic films increased after modification with the rare‐earth elements, indicating that the anodizing process was affected by the presence of the rare‐earth elements.

Originality/value

The results presented in this paper offer a foundation for further research and application of rare‐earth elements in aluminum anodic oxide films.

Details

Anti-Corrosion Methods and Materials, vol. 57 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

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Article

Girish G. and Anandakrishnan V.

This study aims to investigate and present the tribological behaviour of recursively friction stir processed 7075 aluminium alloy.

Abstract

Purpose

This study aims to investigate and present the tribological behaviour of recursively friction stir processed 7075 aluminium alloy.

Design/methodology/approach

In this work, aluminium 7075 alloy is friction stir processed recursively by varying the tool rotational speed, traverse speed and the number of passes. Wear pins for testing were extracted from the processed zone and the surfaces were prepared. Wear tests were conducted as per the standard on a pin-on-disc wear testing machine at constant testing conditions and the corresponding tribological properties were analysed. The worn surface and the debris were analysed using a field-emission scanning electron microscope with energy dispersive spectroscopy analysis and elemental mapping to identify the mode of wear mechanism.

Findings

The experimental results indicate that the specimen fabricated at 1,150 rpm of tool rotation speed and 60 mm/min of traverse speed with 4 passes had the highest wear resistance and the minimum friction coefficient.

Originality/value

This paper details the effect of recursive friction stir processing on the surface of AA 7075 to improve the tribological properties.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2020-0070/

Details

Industrial Lubrication and Tribology, vol. 72 no. 7
Type: Research Article
ISSN: 0036-8792

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Article

Ayşe Nur Acar, Rasiha Nefise Mutlu, Abdul Kadir Ekşi, Ahmet Ekicibil and Birgül Yazıcı

The purpose of this paper is to examine new alloys created from Alumix 431 powder and investigate their mechanical and electrochemical properties.

Abstract

Purpose

The purpose of this paper is to examine new alloys created from Alumix 431 powder and investigate their mechanical and electrochemical properties.

Design/methodology/approach

In this study; Alumix-431 alloy samples were prepared using the powder metallurgy (P/M) method applying cold (RT) and warm (50°C and 80°C) compaction methods under pressures of 200 and 250 MPa and were sintered at 600°C in N2(g) atmosphere. Hardness and density of the samples were measured, and corrosion properties were determined by electrochemical impedance spectroscopy charting polarization curves. Surface characterization was determined by contact angle, scanning electron microscopy/mapping, energy dispersive X-ray spectrometry and X-ray diffractometry images.

Findings

Alumix-431 alloys obtained upon compaction at 250 MPa/50 °C had the highest mechanical properties and corrosion resistance and good surface properties. On the surfaces of Alumix-431 alloys, α-Al, MgZn2, Al2,CuMg, Al2,O3, Al2MgO4 phases were recorded.

Originality/value

This study aimed to construct a correlation between mechanical and electrochemical properties of the newly created alloys (prepared under special conditions).

Details

Anti-Corrosion Methods and Materials, vol. 65 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

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Article

Rahul S.G. and Sharmila A.

The purpose of this study is to present a comprehensive review of the fundamental concepts and terminologies pertaining to different types of aluminium metal matrix…

Abstract

Purpose

The purpose of this study is to present a comprehensive review of the fundamental concepts and terminologies pertaining to different types of aluminium metal matrix composites, their joining techniques and challenges, friction stir welding (FSW) process, post-welding characterizations and basic control theory of FSW, followed by the discussions on the research reports in these areas.

Design/methodology/approach

Joining of aluminium metal matrix composites (Al-MMC) poses many challenges. These materials have their demanding applications in versatile domains, and hence it is essential to understand their weldability and material characteristics. FSW is a feasible choice for joining of Al-MMC over the fusion welding because of the formation of narrow heat affected zone and minimizing the formation of intermetallic compounds at weld interface. The goal in FSW is to generate enough thermal energy by friction between the workpiece and rotating tool. Heat energy is generated by mechanical interaction because of the difference in velocity between the workpiece and rotating tool. In the present work, a detailed survey is done on the above topics and an organised conceptual context is presented. A complete discussion on significance of FSW process parameters, control schemes, parameter optimization and weld quality monitoring are presented, along with the analysis on relation between the interdependent parameters.

Findings

Results from the study present the research gaps in the FSW studies for joining of the aluminium-based metal matrix composites, and they highlight further scope of studies pertaining to this domain.

Originality/value

It is observed that the survey done on FSW of Al-MMCs and their control theory give an insight into the fundamental concepts pertaining to this research area to enhance interdisciplinary technology exploration.

Details

World Journal of Engineering, vol. 16 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

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