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12 pages, 13022 KB

Open AccessArticle

Effect of Heat Treatment on Microstructure and Tensile Property of Laser-Powder-Bed-Melted Al–Mn–Mg–Sc–Zr Alloy

by Zhiqiang Cao, Hui Yin, Jin Jiang, Mingliang Cui, Hao Zhang and Sheng Cao

Materials 2025, 18(7), 1638; https://doi.org/10.3390/ma18071638 - 3 Apr 2025

Cited by 2 | Viewed by 1756

This study explored the effects of T5 and T6 heat treatments on the microstructure and tensile properties of a laser powder bed fusion (LPBF)-fabricated Al–Mn–Mg–Sc–Zr alloy. The as-built condition exhibited a bi-modal grain structure of equiaxed and columnar grains. Specimens after T5 heat [...] Read more.

This study explored the effects of T5 and T6 heat treatments on the microstructure and tensile properties of a laser powder bed fusion (LPBF)-fabricated Al–Mn–Mg–Sc–Zr alloy. The as-built condition exhibited a bi-modal grain structure of equiaxed and columnar grains. Specimens after T5 heat treatment also had a bi-modal microstructure with slight grain growth and the precipitation of secondary Al₃Sc, which enhanced the yield strength via precipitation hardening but reduced ductility. In contrast, T6 treatment triggered recrystallization, and the microstructure was only coarse equiaxed α-Al grains. This microstructure change was accompanied by coarsened primary Al₃X and Al₆(Mn, Fe) precipitates, partial Mg₂Si dissolution, and significant secondary Al₃Sc particle growth. Consequently, T6-treated specimens showed lower strength than their T5 counterparts and the poorest ductility due to brittle fracture induced by the stress concentration effect of coarse precipitates at grain boundaries. Full article

(This article belongs to the Special Issue The Additive Manufacturing of Metallic Alloys (Second Edition))

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14 pages, 4468 KB

Open AccessArticle

The Electrochemical Performance of Al-Mg-Ga-Sn-xBi Alloy Used as the Anodic Material for Al-Air Battery in KOH Electrolytes

by Yueying Wang, Hongliang Liu, Zhiming Jia, Binglin Yang and Lizi He

Crystals 2022, 12(12), 1785; https://doi.org/10.3390/cryst12121785 - 8 Dec 2022

Cited by 21 | Viewed by 3698

Abstract

The effects of Bi content (0–0.12 wt.%) on the self-corrosion properties, the open-circuit potential, the electrochemical impedance spectroscopy, the potentiodynamic polarization curves, and the battery performances of Al-0.4Mg-0.05Sn-0.015Ga alloys were investigated; meanwhile, the microstructures and the post-discharge surfaces of the alloy were also [...] Read more.

The effects of Bi content (0–0.12 wt.%) on the self-corrosion properties, the open-circuit potential, the electrochemical impedance spectroscopy, the potentiodynamic polarization curves, and the battery performances of Al-0.4Mg-0.05Sn-0.015Ga alloys were investigated; meanwhile, the microstructures and the post-discharge surfaces of the alloy were also examined by SEM. The results show that Bi can increase the amount of the precipitated phase containing Bi. The Al-0.4Mg-0.05Sn-0.015Ga-0.10Bi alloy exhibits the optimum electrochemical properties; it has the greatest negative open circuit potential of −1.780 V, the highest constant current discharge voltage of 1.287 V, and a minimum self-corrosion rate of 0.132 mL cm⁻² min⁻¹; a uniform corrosive surface is obtained after discharge. Full article

(This article belongs to the Special Issue Advances of Aluminum Alloys: Innovation and Application Potential)

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23 pages, 8524 KB

Open AccessArticle

Effect of Bi and Ca on the Solidification Parameters of Sr-Modified Al-S-Cu (Mg) Alloys

by Shimaa El-Hadad, Agnes M. Samuel, Fawzy H. Samuel, Herbert W. Doty and Victor Songmene

Materials 2022, 15(19), 6903; https://doi.org/10.3390/ma15196903 - 5 Oct 2022

Cited by 1 | Viewed by 1990

Abstract

The effect of tramp elements, mainly Bi and Ca, on the thermal characteristics of Sr-modified Al–Si–Cu and Al–Si–Cu–Mg alloys has been investigated using thermal analysis, X-ray radiography, and field emission scanning electron microscopy (FESEM) techniques. The high affinity of Bi to interact with [...] Read more.

The effect of tramp elements, mainly Bi and Ca, on the thermal characteristics of Sr-modified Al–Si–Cu and Al–Si–Cu–Mg alloys has been investigated using thermal analysis, X-ray radiography, and field emission scanning electron microscopy (FESEM) techniques. The high affinity of Bi to interact with Sr results in an increase in the Al-Si eutectic temperature, and hence an increase in the size of eutectic silicon particles. In contrast, the Ca–Sr interaction seems to have no significant effect on the alloy thermal behavior. The effect of these interactions on porosity formation has been discussed. Hot zones may be formed in thin cavities, in particular, near the bottom of the mold, leading to formation of unexpected coarse porosity, mostly shrinkage type. The study also highlights the significance of other parameters on porosity formation, such as no melt degassing, SrO, Al₂O₃ (strings or bifilms), as well as the presence of iron-based intermetallics. Full article

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26 pages, 7881 KB

Open AccessEditor’s ChoiceArticle

Cathodic Protection of Mild Steel Using Aluminium-Based Alloys

by Maria del Rosario Silva Campos, Carsten Blawert, Nico Scharnagl, Michael Störmer and Mikhail L. Zheludkevich

Materials 2022, 15(4), 1301; https://doi.org/10.3390/ma15041301 - 10 Feb 2022

Cited by 42 | Viewed by 6901

Abstract

Typically, steel is protected from corrosion by employing sacrificial anodes or coatings based on Zn, Mg, Al or Cd. However, stricter environmental regulations require new environmentally friendly alternatives to replace Cd. Traditionally, Al-based anodes have been employed to cathodically protect steel in marine [...] Read more.

Typically, steel is protected from corrosion by employing sacrificial anodes or coatings based on Zn, Mg, Al or Cd. However, stricter environmental regulations require new environmentally friendly alternatives to replace Cd. Traditionally, Al-based anodes have been employed to cathodically protect steel in marine applications or as ion vapour deposition (IVD)-Al sacrificial coatings for aerospace applications. However, Al tends to passivate, thus losing its protective effect. Therefore, it is important to identify possible alloys that can provide a constantly sufficient current. In this study, Al-X alloys (X = Ag, Bi, Ca, Cr, Cu, Ga, Gd, In, Mg, Mn, Ni, Sb, Si, Sn, V, Ti, Zn and Zr) were firstly tested for a screening of the sacrificial properties of binary systems. Al-0.5Cr, Al-1Sn, Al-0.2Ga, Al-0.1In, Al-2Si and Al-5Zn alloys were suggested as promising sacrificial Al-based alloys. Suitable heat treatments for each system were implemented to reduce the influence of the secondary phases on the corrosion properties by minimising localised attack. extensive evaluation of the corrosion properties, including galvanic coupling of these alloys to steel, was performed in the NaCl electrolyte. A comparative analysis was conducted in order to choose the most promising alloy(s) for avoiding the passivation of Al and for efficient cathodic protection to steel. Full article

(This article belongs to the Section Corrosion)

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14 pages, 23237 KB

Open AccessArticle

Influence of Electrolyte on the Electrode/Electrolyte Interface Formation on InSb Electrode in Mg-Ion Batteries

by Irshad Mohammad, Lucie Blondeau, Jocelyne Leroy, Hicham Khodja and Magali Gauthier

Molecules 2021, 26(18), 5721; https://doi.org/10.3390/molecules26185721 - 21 Sep 2021

Cited by 7 | Viewed by 4856

Abstract

Achieving the full potential of magnesium-ion batteries (MIBs) is still a challenge due to the lack of adequate electrodes or electrolytes. Grignard-based electrolytes show excellent Mg plating/stripping, but their incompatibility with oxide cathodes restricts their use. Conventional electrolytes like bis(trifluoromethanesulfonyl)imide ((Mg(TFSI)₂) [...] Read more.

Achieving the full potential of magnesium-ion batteries (MIBs) is still a challenge due to the lack of adequate electrodes or electrolytes. Grignard-based electrolytes show excellent Mg plating/stripping, but their incompatibility with oxide cathodes restricts their use. Conventional electrolytes like bis(trifluoromethanesulfonyl)imide ((Mg(TFSI)₂) solutions are incompatible with Mg metal, which hinders their application in high-energy Mg batteries. In this regard, alloys can be game changers. The insertion/extraction of Mg²⁺ in alloys is possible in conventional electrolytes, suggesting the absence of a passivation layer or the formation of a conductive surface layer. Yet, the role and influence of this layer on the alloys performance have been studied only scarcely. To evaluate the reactivity of alloys, we studied InSb as a model material. Ex situ X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy were used to investigate the surface behavior of InSb in both Grignard and conventional Mg(TFSI)₂/DME electrolytes. For the Grignard electrolyte, we discovered an intrinsic instability of both solvent and salt against InSb. XPS showed the formation of a thick surface layer consisting of hydrocarbon species and degradation products from the solvent (THF) and salt (C₂H₅MgCl−(C₂H₅)₂AlCl). On the contrary, this study highlighted the stability of InSb in Mg(TFSI)₂ electrolyte. Full article

(This article belongs to the Special Issue Electrodes, Electrolytes and Their Interfaces in Electrochemical Storage)

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17 pages, 6067 KB

Open AccessArticle

High-Performance Mg–Al–Bi Alloy Anode for Seawater Batteries and Related Mechanisms

by Changqing Wu, Xu Meng and Wei Wang

Processes 2020, 8(11), 1362; https://doi.org/10.3390/pr8111362 - 28 Oct 2020

Cited by 12 | Viewed by 5598

Abstract

Bi, a group 15 element, was added to magnesium alloys and applied to seawater batteries in marine operating machinery to improve the electrochemical performance and corrosion resistance of the battery. The electrochemical properties of as-cast pure Mg, Mg–8Al, and Mg–8Al–xBi alloy anodes in [...] Read more.

Bi, a group 15 element, was added to magnesium alloys and applied to seawater batteries in marine operating machinery to improve the electrochemical performance and corrosion resistance of the battery. The electrochemical properties of as-cast pure Mg, Mg–8Al, and Mg–8Al–xBi alloy anodes in 3.5% NaCl solution were researched. Electrochemical impedance spectroscopy and an immersion test in 3.5% NaCl solution show that the Mg–8%Al–0.4%Bi alloy provides better corrosion resistance than Mg and the Mg–8Al alloy. The galvanostatic discharge results show that the Mg–8%Al–0.4%Bi alloy revealed better electrochemical properties and utilization efficiency in 3.5% NaCl solution. The Mg₁₇Al₁₂ and BiOCl phases formed during the discharge process of the Mg–8%Al–0.4%Bi alloy play an important role in improving the electrochemical performance and utilization efficiency of the alloy. Full article

(This article belongs to the Special Issue Nano-Hybrid Composite Membranes)

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12 pages, 2300 KB

Open AccessArticle

First-Principles Study on the Cu/Fe Interface Properties of Ternary Cu-Fe-X Alloys

by Yufei Wang, Min Li, Haiyan Gao, Jun Wang and Baode Sun

Materials 2020, 13(14), 3112; https://doi.org/10.3390/ma13143112 - 13 Jul 2020

Cited by 21 | Viewed by 3972

Abstract

The supersaturated Fe in Cu is known to reduce the electrical conductivity of Cu severely. However, the precipitation kinetics of Fe from Cu are sluggish. Alloying is one of the effective ways to accelerate the aging precipitation of Cu-Fe alloys. Nucleation plays an [...] Read more.

The supersaturated Fe in Cu is known to reduce the electrical conductivity of Cu severely. However, the precipitation kinetics of Fe from Cu are sluggish. Alloying is one of the effective ways to accelerate the aging precipitation of Cu-Fe alloys. Nucleation plays an important role in the early stage of aging. The interface property of Cu/γ–Fe is a key parameter in understanding the nucleation mechanism of γ-Fe, which can be obviously affected with the addition of alloying elements. In this paper, first principles calculations were carried out to investigate the influence of alloying elements on the interface properties, including the geometric optimizations, interfacial energy, work of adhesion and electronic structure. Based on the previous research, 14 elements including B, Si, P, Al, Ge, S, Mg, Ag, Cd, Sn, In, Sb, Zr and Bi were selected for investigation. Results showed that all these alloying elements tend to concentrate in the Cu matrix with the specific substitution position of the atoms determined by the binding energy between Fe and alloy element (X). The bonding strength of the Cu/γ-Fe interface will decrease obviously after adding Ag, Mg and Cd, while a drop in interfacial energy of Cu/γ–Fe will happen when alloyed with Al, B, S, P, Si, Ge, Sn, Zr, Bi, Sb and In. Further study of the electronic structure found that Al and Zr were not effective alloying elements. Full article

(This article belongs to the Section Materials Physics)

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7 pages, 1186 KB

Open AccessArticle

Generalized Stacking Fault Energy of {10-11}<11-23> Slip System in Mg-Based Binary Alloys: A First Principles Study

by Yuchen Dou, Hong Luo, Jing Zhang and Xiaohua Tang

Materials 2019, 12(9), 1548; https://doi.org/10.3390/ma12091548 - 11 May 2019

Cited by 16 | Viewed by 4615

Abstract

In this work, the generalized stacking fault energies (GSFEs) of {10-11}<11-23> slip system in a wide range of Mg-X (X = Ag, Al, Bi, Ca, Dy, Er, Gd, Ho, Li, Lu, Mn, Nd, Pb, Sc, Sm, Sn, Y, Yb, Zn and Zr) binary [...] Read more.

In this work, the generalized stacking fault energies (GSFEs) of {10-11}<11-23> slip system in a wide range of Mg-X (X = Ag, Al, Bi, Ca, Dy, Er, Gd, Ho, Li, Lu, Mn, Nd, Pb, Sc, Sm, Sn, Y, Yb, Zn and Zr) binary alloys has been studied. The doping concentration in the doping plane and the Mg-X system is 12.5 at.% and 1.79 at.%, respectively. Two slip modes (slip mode I and II) were considered. For pure magnesium, these two slip modes are equivalent to each other. However, substituting a solute atom into the magnesium matrix will cause different effects on these two slip modes. Based on the calculated GSFEs, two design maps were constructed to predict solute effects on the behavior of the {10-11}<11-23> dislocations. The design maps suggest that the addition of Ag, Al, Ca, Dy, Er, Gd, Ho, Lu, Nd, Sm, Y, Yb and Zn could facilitate the {10-11}<11-23> dislocations. Full article

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