Special Issue "Mechanical Behaviour of Aluminium Alloys"

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Mechanical Engineering".

Deadline for manuscript submissions: closed (31 July 2018)

Special Issue Editors

Guest Editor
Prof. Dr. Ricardo Branco

Department of Mechanical Engineering, University of Coimbra, Coimbra 3004-531, Portugal
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Interests: mechanical behavior of materials; fatigue and fracture; multiaxial fatigue life prediction; low-cycle fatigue; fatigue crack initiation; numerical modelling of fatigue crack growth
Guest Editor
Prof. Filippo Berto

Department of Industrial and Mechanical Engineering, Norwegian University of Science and Technology, 7491 Trondheim, Norway
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Interests: fatigue of advanced and traditional materials; fracture mechanics; solid mechanics; structural integrity; additive materials
Guest Editor
Prof. Dr. Andrei Kotousov

School of Mechanical Engineering, University of Adelaide, South Australia 5005, Australia
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Interests: solid mechanics; fracture mechanics

Special Issue Information

Dear Colleagues,

Aluminum is the leading non-ferrous metal in use. This is due to its unique properties, such as lightness, strength, corrosion resistance, toughness, electrical and thermal conductivity, recyclability, and formability. The combination of these specific features makes aluminum alloys attractive for a broad spectrum of applications in different strategic sectors, namely automotive, aerospace, mold and structural industries, among others. Despite the knowledge accumulated over time, recent advances in the production and processing techniques, combined with the development of new and more ingenious products, require a profound understanding of the mechanical behavior of aluminum alloys.

The goal of this Special Issue is to foster the dissemination of the latest research devoted to the structural integrity of aluminium alloys. Original contributions dealing with the effects of manufacturing strategies, chemical composition, microstructure, environmental conditions, and loading history on mechanical behavior of aluminum alloys are encouraged. Both experimental and numerical approaches are accepted.  

Prof.Ricardo Branco
Prof. Filippo Berto
Prof. Andrei Kotousov
Guest Editors

Manuscript Submission Information

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Keywords

  • Aluminium alloys

  • Structural integrity

  • Manufacturing and processing techniques

  • Alloy design

  • Microstructure and texture

  • Mechanical properties

  • Loading history

  • Environmental conditions

  • Applications

Published Papers (11 papers)

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Research

Open AccessArticle Improving Stability Prediction in Peripheral Milling of Al7075T6
Appl. Sci. 2018, 8(8), 1316; https://doi.org/10.3390/app8081316
Received: 11 July 2018 / Revised: 1 August 2018 / Accepted: 1 August 2018 / Published: 7 August 2018
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Abstract
Chatter is an old enemy to machinists but, even today, is far from being defeated. Current requirements around aerospace components call for stronger and thinner workpieces which are more prone to vibrations. This study presents the stability analysis for a single degree of
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Chatter is an old enemy to machinists but, even today, is far from being defeated. Current requirements around aerospace components call for stronger and thinner workpieces which are more prone to vibrations. This study presents the stability analysis for a single degree of freedom down-milling operation in a thin-walled workpiece. The stability charts were computed by means of the enhanced multistage homotopy perturbation (EMHP) method, which includes the helix angle but also, most importantly, the runout and cutting speed effects. Our experimental validation shows the importance of this kind of analysis through a comparison with a common analysis without them, especially when machining aluminum alloys. The proposed analysis demands more computation time, since it includes the calculation of cutting forces for each combination of axial depth of cut and spindle speed. This EMHP algorithm is compared with the semi-discretization, Chebyshev collocation, and full-discretization methods in terms of convergence and computation efficiency, and ultimately proves to be the most efficient method among the ones studied. Full article
(This article belongs to the Special Issue Mechanical Behaviour of Aluminium Alloys)
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Open AccessArticle The Determination of Dendrite Coherency Point Characteristics Using Three New Methods for Aluminum Alloys
Appl. Sci. 2018, 8(8), 1236; https://doi.org/10.3390/app8081236
Received: 24 May 2018 / Revised: 21 July 2018 / Accepted: 23 July 2018 / Published: 26 July 2018
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Abstract
The aim of this work is to give an overview of existing methods and to introduce three new methods for the determination of the Dendrite Coherency Point (DCP) for AlSi10Mg alloys, as well as to compare the acquired values of DCP
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The aim of this work is to give an overview of existing methods and to introduce three new methods for the determination of the Dendrite Coherency Point (DCP) for AlSi10Mg alloys, as well as to compare the acquired values of DCP based on a thermal analysis and on the analysis of cooling curves working with only one thermocouple. Additionally, the impact of alloying and contaminant elements on the DCP will be also studied. The first two proposed methods employ the higher order derivatives of the cooling curves. The DCP was determined as the crossing point of the second and third derivative curves plotted versus time (method 1) or that of the temperature (method 2) with the zero line just after the maximum liquidus temperature. The third proposed method is based on the determination of the crossing point of the third solid fraction derivative curve with the zero line, corresponding to a minimum of the second derivative. A Taguchi design for the experiments was developed to study the DCP values in the AlSi10Mg alloy. The DCP temperature values of the test alloys were compared with the DCP temperatures predicted by the previous methods and the influence of the major and minor alloying elements and contaminants over the DCP. The new processes obtained a correlation factor r2 from 0.954 and 0.979 and a standard deviation from 1.84 to 2.6 °C. The obtained correlation values are higher or similar than those obtained using previous methods with an easier way to define the DCP, allowing for a better automation of the accuracy of DCP determination. The use of derivative curves plotted versus temperature employed in the last two proposed methods, where the test samples did not have an influence over the registration curves, is proposed to have a better accuracy than those of the previously described methods. Full article
(This article belongs to the Special Issue Mechanical Behaviour of Aluminium Alloys)
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Open AccessArticle Effect of Droplet Impingement on the Weld Profile and Grain Morphology in the Welding of Aluminum Alloys
Appl. Sci. 2018, 8(7), 1203; https://doi.org/10.3390/app8071203
Received: 3 July 2018 / Revised: 17 July 2018 / Accepted: 19 July 2018 / Published: 23 July 2018
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Abstract
To achieve a better understanding of the effect of droplet impingement on the weld profile and grain morphology, welding with vertical and inclined torches in the double pulsed-gas metal arc welding of aluminum alloy were compared. When using vertical welding, the grains along
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To achieve a better understanding of the effect of droplet impingement on the weld profile and grain morphology, welding with vertical and inclined torches in the double pulsed-gas metal arc welding of aluminum alloy were compared. When using vertical welding, the grains along the wall of the finger-like penetration (FLP) were refined by a more violent flow driven by droplet impingement running in the confined space created by FLP. When using inclined welding, the sharp inflection point disappeared and the curved columnar grains emerged on the non-impact action side, which was attributed to the gradually weakened impingement at that location. Moreover, when the penetration became shallower due to a low mean current, the droplets impinged alternately along split trajectories, causing significant changes in the grain morphology, such as creating grains which were sharply shortened by the direct impact of droplet impingement at impact point. The change of trajectory was ascribed to the variation of the width/depth ratio of FLP, which changed the magnitude of the contradiction between the room required by the fluid flow driven by droplet impingement and the space supplied for that by FLP. Full article
(This article belongs to the Special Issue Mechanical Behaviour of Aluminium Alloys)
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Open AccessArticle Case Study of a Functionally Graded Aluminum Part
Appl. Sci. 2018, 8(7), 1113; https://doi.org/10.3390/app8071113
Received: 31 May 2018 / Revised: 28 June 2018 / Accepted: 5 July 2018 / Published: 10 July 2018
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Abstract
The growing interest in aluminum alloys is due to the excellent ductility and mechanical strength, especially in relation with their lightness. These properties make aluminum alloys one of the most used and competitive materials in the automotive sectors. In fact, at the present
[...] Read more.
The growing interest in aluminum alloys is due to the excellent ductility and mechanical strength, especially in relation with their lightness. These properties make aluminum alloys one of the most used and competitive materials in the automotive sectors. In fact, at the present day, automotive components must guarantee high mechanical and thermal properties in order to ensure low emissions of the vehicle. Despite that, harsh operating conditions can lead to a rupture in aluminum components, especially if subjected to both thermal and mechanical loads. In this panorama, aluminum functionally graded materials (FGMs) could be introduced, in order to produce a single piece with different properties that fulfill all the piece requirements. In this work, considering the typical application of the aluminum alloys as engine pistons, FGMs are realized by sequential gravity casting with the piston alloy EN AB 48000 and the alloy EN AB 42100. Tensile tests on these bi-metal parts give good results in terms of mechanical strength, elongation rates and alloys bonding. Full article
(This article belongs to the Special Issue Mechanical Behaviour of Aluminium Alloys)
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Open AccessArticle A New Technique for Batch Production of Tubular Anodic Aluminum Oxide Films for Filtering Applications
Appl. Sci. 2018, 8(7), 1055; https://doi.org/10.3390/app8071055
Received: 1 May 2018 / Revised: 31 May 2018 / Accepted: 26 June 2018 / Published: 28 June 2018
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Abstract
With larger surface areas and nanochannels for mass delivery and gas diffusion, three-dimensional tubular anodic aluminum oxide (AAO) films have practical advantages over two-dimensional AAO films for medical and energy applications. In this research, we have developed a process for batch production of
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With larger surface areas and nanochannels for mass delivery and gas diffusion, three-dimensional tubular anodic aluminum oxide (AAO) films have practical advantages over two-dimensional AAO films for medical and energy applications. In this research, we have developed a process for batch production of tubular AAO films using a 6061 Al tube. The tubular AAO films have open nano-channels on both sides, with average pore dimensions of about 60 nm and pore densities of about 108 to 109 pore/cm2. It was found that the porous AAO material with nano-channel structure exhibited dialysis behavior, allowing for liquid/gas exudation through diffusion between the inner and outer surfaces of the tubular AAO films. Ar gas bearing test and aeration test were conducted to find the pressure bearing capacity of tubular AAO films. It was demonstrated that the AAO film with a thickness of 100 μm can resist an argon pressure up to 8 atm; however, 30 μm AAO film can only withstand 3 atm of Ar gas. The tubular AAO films with exudation characteristics have the potential for applications in advanced technologies, such as liquid or gas filters, drug delivery, and energy applications. Full article
(This article belongs to the Special Issue Mechanical Behaviour of Aluminium Alloys)
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Open AccessArticle Stability of Cu-Precipitates in Al-Cu Alloys
Appl. Sci. 2018, 8(6), 1003; https://doi.org/10.3390/app8061003
Received: 30 May 2018 / Revised: 9 June 2018 / Accepted: 9 June 2018 / Published: 20 June 2018
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Abstract
We present first principle calculations on formation and binding energies for Cu and Zn as solute atoms forming small clusters up to nine atoms in Al-Cu and Al-Zn alloys. We employ a density-functional approach implemented using projector-augmented waves and plane wave expansions. We
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We present first principle calculations on formation and binding energies for Cu and Zn as solute atoms forming small clusters up to nine atoms in Al-Cu and Al-Zn alloys. We employ a density-functional approach implemented using projector-augmented waves and plane wave expansions. We find that some structures, in which Cu atoms are closely packed on {100}-planes, turn out to be extraordinary stable. We compare the results with existing numerical or experimental data when possible. We find that Cu atoms precipitating in the form of two-dimensional platelets on {100}-planes in the fcc aluminum are more stable than three-dimensional structures consisting of the same number of Cu-atoms. The preference turns out to be opposite for Zn in Al. Both observations are in agreement with experimental observations. Full article
(This article belongs to the Special Issue Mechanical Behaviour of Aluminium Alloys)
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Open AccessArticle Manufacturing of Non-Stick Molds from Pre-Painted Aluminum Sheets via Single Point Incremental Forming
Appl. Sci. 2018, 8(6), 1002; https://doi.org/10.3390/app8061002
Received: 29 May 2018 / Revised: 17 June 2018 / Accepted: 18 June 2018 / Published: 20 June 2018
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Abstract
The process of single point incremental formation (SPIF) awakens interest in the industry of mold manufacturing for the food industry. By means of SPIF, it is possible to generate short series of molds or mold prototypes at low cost. However, these industries require
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The process of single point incremental formation (SPIF) awakens interest in the industry of mold manufacturing for the food industry. By means of SPIF, it is possible to generate short series of molds or mold prototypes at low cost. However, these industries require such molds to be functional (non-sticky) and to have an adequate geometry accuracy. This study presents a technique that enables direct manufacturing of molds from pre-coated sheets with non-stick resins. It has also studied the influence of two technological variables in the process (feed-rate and pitch) for different geometrical parameters of the mold. Low values of these variables result in a lower overall error in the profile obtained. However, in order to obtain greater detail in particular parameters (angles, depth), it is necessary to use higher values of feed-rate and pitch. Full article
(This article belongs to the Special Issue Mechanical Behaviour of Aluminium Alloys)
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Open AccessArticle Effects of Shot-Peening and Stress Ratio on the Fatigue Crack Propagation of AL 7475-T7351 Specimens
Appl. Sci. 2018, 8(3), 375; https://doi.org/10.3390/app8030375
Received: 23 January 2018 / Revised: 24 February 2018 / Accepted: 28 February 2018 / Published: 5 March 2018
Cited by 1 | PDF Full-text (5368 KB) | HTML Full-text | XML Full-text
Abstract
Shot peening is an attractive technique for fatigue enhanced performance of metallic components, because it increases fatigue crack initiation life prevention and retards early crack growth. Engineering design based on fatigue crack propagation predictions applying the principles of fracture mechanics is commonly used
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Shot peening is an attractive technique for fatigue enhanced performance of metallic components, because it increases fatigue crack initiation life prevention and retards early crack growth. Engineering design based on fatigue crack propagation predictions applying the principles of fracture mechanics is commonly used in aluminum structures for aerospace engineering. The main purpose of present work was to analyze the effect of shot peening on the fatigue crack propagation of the 7475 aluminum alloy, under both constant amplitude loading and periodical overload blocks. The tests were performed on 4 and 8 mm thickness specimens with stress ratios of 0.05 and 0.4. The analysis of the shot-peened surface showed a small increase of the micro-hardness values due to the plastic deformations imposed by shot peening. The surface peening beneficial effect on fatigue crack growth is very limited; its main effect is more noticeable near the threshold. The specimen’s thickness only has marginal influence on the crack propagation, in opposite to the stress ratio. Periodic overload blocks of 300 cycles promotes a reduction of the fatigue crack growth rate for both intervals of 7500 and 15,000 cycles. Full article
(This article belongs to the Special Issue Mechanical Behaviour of Aluminium Alloys)
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Open AccessArticle Effects of Heat Treatment on the Tribological Properties of Sicp/Al-5Si-1Cu-0.5Mg Composite Processed by Electromagnetic Stirring Method
Appl. Sci. 2018, 8(3), 372; https://doi.org/10.3390/app8030372
Received: 29 January 2018 / Revised: 26 February 2018 / Accepted: 1 March 2018 / Published: 4 March 2018
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Abstract
This paper investigated the influence of heat treatment (T6) on the dry sliding wear behavior of SiCp/Al-5Si-1Cu-0.5Mg composite that was fabricated by electromagnetic stirring method. The wear rates and friction coefficients were measured using a pin-on-disc tribometer under loads of 15–90 N at
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This paper investigated the influence of heat treatment (T6) on the dry sliding wear behavior of SiCp/Al-5Si-1Cu-0.5Mg composite that was fabricated by electromagnetic stirring method. The wear rates and friction coefficients were measured using a pin-on-disc tribometer under loads of 15–90 N at dry sliding speeds of 100 r/min, 200 r/min, and 300 r/min, over a sliding time of 15 min. The worn surfaces and debris were examined using a scanning electron microscope and was analyzed with an energy dispersive spectrometer. The experimental results revealed that SiCp/Al-5Si-1Cu-0.5Mg alloy treated with T6 exhibited lower wear rate and friction coefficient than the other investigated alloys. As the applied load increased, the wear rate and friction coefficient increased. While, the wear rate and friction coefficient decreased with the sliding speed increasing. The morphology of the eutectic silicon was spheroidal after the T6 heat treatment. SiCp particles and Al2Cu phase can be considered as the main raisons for improving the wear behavior. Abrasion and oxidation were the wear mechanisms at low load levels. However, the wear mechanisms at high load levels were plastic deformation and delamination. Full article
(This article belongs to the Special Issue Mechanical Behaviour of Aluminium Alloys)
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Open AccessArticle Impact of Alloying on Stacking Fault Energies in γ-TiAl
Appl. Sci. 2017, 7(11), 1193; https://doi.org/10.3390/app7111193
Received: 21 October 2017 / Revised: 13 November 2017 / Accepted: 15 November 2017 / Published: 21 November 2017
Cited by 2 | PDF Full-text (1055 KB) | HTML Full-text | XML Full-text
Abstract
Microstructure and mechanical properties are key parameters influencing the performance of structural multi-phase alloys such as those based on intermetallic TiAl compounds. There, the main constituent, a γ-TiAl phase, is derived from a face-centered cubic structure. Consequently, the dissociation of dislocations and
[...] Read more.
Microstructure and mechanical properties are key parameters influencing the performance of structural multi-phase alloys such as those based on intermetallic TiAl compounds. There, the main constituent, a γ -TiAl phase, is derived from a face-centered cubic structure. Consequently, the dissociation of dislocations and generation of stacking faults (SFs) are important factors contributing to the overall deformation behavior, as well as mechanical properties, such as tensile/creep strength and, most importantly, fracture elongation below the brittle-to-ductile transition temperature. In this work, SFs on the { 111 ) plane in γ -TiAl are revisited by means of ab initio calculations, finding their energies in agreement with previous reports. Subsequently, stacking fault energies are evaluated for eight ternary additions, namely group IVB–VIB elements, together with Ti off-stoichiometry. It is found that the energies of superlattice intrinsic SFs, anti-phase boundaries (APBs), as well as complex SFs decrease by 20–40% with respect to values in stoichiometric γ -TiAl once an alloying element X is present in the fault plane having thus a composition of Ti-50Al-12.5X. In addition, Mo, Ti and V stabilize the APB on the (111) plane, which is intrinsically unstable at 0 K in stoichiometric γ -TiAl. Full article
(This article belongs to the Special Issue Mechanical Behaviour of Aluminium Alloys)
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Open AccessArticle The Stability of New Single-Layer Combined Lattice Shell Based on Aluminum Alloy Honeycomb Panels
Appl. Sci. 2017, 7(11), 1150; https://doi.org/10.3390/app7111150
Received: 16 October 2017 / Revised: 31 October 2017 / Accepted: 6 November 2017 / Published: 9 November 2017
Cited by 2 | PDF Full-text (6735 KB) | HTML Full-text | XML Full-text
Abstract
This article proposes a new type of single-layer combined lattice shell (NSCLS); which is based on aluminum alloy honeycomb panels. Six models with initial geometric defect were designed and precision made using numerical control equipment. The stability of these models was tested. The
[...] Read more.
This article proposes a new type of single-layer combined lattice shell (NSCLS); which is based on aluminum alloy honeycomb panels. Six models with initial geometric defect were designed and precision made using numerical control equipment. The stability of these models was tested. The results showed that the stable bearing capacity of NSCLS was approximately 16% higher than that of a lattice shell with the same span without a reinforcing plate. At the same time; the properties of the NSCLS were sensitive to defects. When defects were present; its stable bearing capacity was decreased by 12.3% when compared with the defect-free model. The model with random defects following a truncated Gaussian distribution could be used to simulate the distribution of defects in the NSCLS. The average difference between the results of the nonlinear analysis and the experimental results was 5.7%. By calculating and analyzing nearly 20,000 NSCLS; the suggested values of initial geometric defect were presented. The results of this paper could provide a theoretical basis for making and revising the design codes for this new combined lattice shell structure. Full article
(This article belongs to the Special Issue Mechanical Behaviour of Aluminium Alloys)
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