Microstructural Evolution and Mechanical Properties of Aluminum Alloys

A special issue of Metals (ISSN 2075-4701). This special issue belongs to the section "Metal Casting, Forming and Heat Treatment".

Deadline for manuscript submissions: closed (30 November 2023) | Viewed by 7017

Special Issue Editors

College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China
Interests: integrated manufacturing technology; high-performance and high-precision collaborative manufacturing of light materials and components
Special Issues, Collections and Topics in MDPI journals
Dr. Yongqian Xu
E-Mail Website
Guest Editor
School of Mechanical and Electrical Engineering, Central South University, Changsha, China
Interests: advanced thermoforming; smart equipment
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Over the years, research enthusiasm in the field of metal alloy materials has continued to grow. Among such materials, aluminum alloy has become one of the most widely used in many industries due to its low density, corrosion resistance, good thermal conductivity, and suitable mechanical properties. Its output is increasing every year, and it is being widely used in aerospace fields. This Special Issue of Metals will focus on the following:

  1. Strengthening of mechanisms of aluminum alloys, including dislocation strengthening, grain refinement strengthening, and precipitation strengthening, to improve the properties of aluminum alloys;
  2. Formation of manufacturing technology;
  3. Characterization and analysis of the microstructure of aluminum alloy materials, such as grain morphology, texture, dislocation, and precipitation;
  4. Simulation of the forming process;
  5. Design of high-performance aerospace materials.

It is our pleasure to invite you to submit manuscripts to this Special Issue and share your research results.

Prof. Dr. Lihua Zhan
Dr. Yongqian Xu
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Metals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • aluminum alloys
  • microstructure
  • phase composition
  • mechanical properties
  • heat treatment
  • manufacturing technology

Related Special Issue

Published Papers (6 papers)

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Research

16 pages, 9650 KiB  
Article
Coupling Effect of Mn Addition and Deformation on Mechanical and Electrical Properties of Al-Zr Alloys
Metals 2024, 14(1), 63; https://doi.org/10.3390/met14010063 - 04 Jan 2024
Viewed by 655
Abstract
In order to increase the strength of Al-Zr alloys, which are promisingly used for heat-resistant conductors, the coupling effect of Mn addition (0.16 wt.% and 0.88 wt.%) and deformation on the precipitation, mechanical, and electrical properties of an Al-0.18wt.% Zr alloy was studied [...] Read more.
In order to increase the strength of Al-Zr alloys, which are promisingly used for heat-resistant conductors, the coupling effect of Mn addition (0.16 wt.% and 0.88 wt.%) and deformation on the precipitation, mechanical, and electrical properties of an Al-0.18wt.% Zr alloy was studied using transmission electron microscopy (TEM), atom probe tomography (APT), hardness testing, and electrical conductivity measurement, respectively. Results showed that the Mn addition fully suppresses the Al3Zr precipitation in both hot-deformed and undeformed cases, which is mainly due to a strong Mn-vacancy bonding, in which Mn atoms seize vacancies and hence reduce the available vacancies for Al3Zr nucleation. Minor 0.16 wt.% Mn addition causes a simultaneous decrease in hardness and electrical conductivity, regardless of whether there is deformation. The higher 0.88 wt.% Mn addition, however, significantly increases the hardness by over 40%, especially in combination with deformation. Possible influencing factors such as grain size, dislocations, intergranular/intragranular precipitation, and solute clusters are comparatively discussed in terms of microstructural features and mechanical/electrical properties that are tuned by Mn addition and/or deformation. It is found that the Mn addition can make remarkable contributions to the hardness and thermal stability of the Al-Zr alloys when coupled with deformation. Full article
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9 pages, 2862 KiB  
Communication
Effects of Sc and Be Microalloying Elements on Mechanical Properties of Al-Zn-Mg-Cu (Al7xxx) Alloy
Metals 2023, 13(2), 340; https://doi.org/10.3390/met13020340 - 08 Feb 2023
Cited by 1 | Viewed by 1126
Abstract
We demonstrate via comprehensive microstructural investigation the effects of Sc and Be microalloying on the mechanical properties of Al-Zn-Mg-Cu-based alloys, where Sc microalloying enhances the tensile properties of an Al-9.0Zn-3.0Mg-3.0Cu alloy from 645 MPa (εf = ~6%) to 672 MPa (εf [...] Read more.
We demonstrate via comprehensive microstructural investigation the effects of Sc and Be microalloying on the mechanical properties of Al-Zn-Mg-Cu-based alloys, where Sc microalloying enhances the tensile properties of an Al-9.0Zn-3.0Mg-3.0Cu alloy from 645 MPa (εf = ~6%) to 672 MPa (εf = ~8%). In contrast, simultaneous microalloying with Sc and Be reduces the mechanical strength of a synthesized Al alloy to 654 MPa (εf = ~8%). Comprehensive microstructural investigation revealed that Sc microalloying leads to Al grain refinement, the formation of hardening (MgZn2, Al3M) phases, and an increase in the solid solution of Al. Additional Be microalloying also enhances the formation of MgZn2 phase, while Al3M (M: Zr, Sc) type phases are restrained from forming in Al grains. Furthermore, solid solution in Al grains is reduced by the trace addition of Be microalloying, resulting in an increase in large intermetallic compounds at Al grain boundaries. Full article
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21 pages, 14990 KiB  
Article
Creep Aging Behavior of a Thermo-Mechanical Treated 7B04 Aluminum Alloy
Metals 2023, 13(2), 182; https://doi.org/10.3390/met13020182 - 17 Jan 2023
Cited by 1 | Viewed by 995
Abstract
Creep aging behavior of a pre-strain and under-age treated 7B04 aluminum alloy (7B04-P for short) was systematically investigated under different temperatures and applied stresses. A lot of dislocation tangles and η’/GPzs were formed in the Al matrix of the 7B04-P al alloy. With [...] Read more.
Creep aging behavior of a pre-strain and under-age treated 7B04 aluminum alloy (7B04-P for short) was systematically investigated under different temperatures and applied stresses. A lot of dislocation tangles and η’/GPzs were formed in the Al matrix of the 7B04-P al alloy. With the increase in temperature and applied stress, the total creep strain and steady-state creep rate increased significantly. However, the mechanical properties of creep-aged 7B04-P al alloy are sensitive to temperature rather than applied stress. The age-hardening precipitates and grain boundaries change obviously when the temperature rises to 160 °C. Compare to the low temperature (less than 160 °C) creep-aged samples, the size of precipitates is much larger, the width of PFZ is broader, and the grain boundary precipitates are more discontinuous and coarsen. As expected, the electrical conductivity is improved after the high-temperature creep aging process at 160 °C. Last but not least, the creep deformation of 7B04-P al alloy almost retains that of AA7B04-T7451. Meanwhile, the mechanical properties after the creep aging process of 7B04-P al alloy are better than that of AA7B04-T7451. It can be suggested that the novel high-temperature creep age forming of the thermo-mechanical treated 7B04 aluminum alloy can enhance the forming efficiency and comprehensive properties for aerospace industries. Full article
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14 pages, 4334 KiB  
Article
Effect of Deep Cryogenic Treatment on the Artificial Ageing Behavior of SiCp–AA2009 Composite
Metals 2022, 12(10), 1767; https://doi.org/10.3390/met12101767 - 20 Oct 2022
Cited by 2 | Viewed by 1177
Abstract
The effect of deep cryogenic treatment (DCT) on the artificial ageing kinetics of a SiC particles reinforced aluminum alloy composite (SiCp-Al) is experimentally studied in this paper. The evolutions of both macro-properties (i.e., yield strength and ultimate tensile strength) and microstructures (precipitates) have [...] Read more.
The effect of deep cryogenic treatment (DCT) on the artificial ageing kinetics of a SiC particles reinforced aluminum alloy composite (SiCp-Al) is experimentally studied in this paper. The evolutions of both macro-properties (i.e., yield strength and ultimate tensile strength) and microstructures (precipitates) have been investigated by a set of hardness tests, tensile tests, and microstructural observations (scanning electron microscope, SEM and transmission electron microscope, TEM) for a SiCp-Al composite material with conventional heat treatment (solution heat treatment + quenching + artificial ageing, CHT) or DCT (solution heat treatment + quenching + deep cryogenic + artificial ageing). The results show that SiCp could significantly accelerate the ageing kinetics of the composites. Meanwhile, compared with CHT conditions, DCT can further improve the yield strength (YS) and ultimate tensile strength (UTS) of the composite materials after artificial ageing. The microstructures show that DCT induces the generation of more thinner θ′ precipitates homogeneously distributed in the grains during artificial ageing compared with corresponding CHT conditions. A quantified analysis has been performed based on the microstructural data, and the calculated results further support the indication that the strengthening effect in DCT compared with CHT is mainly contributed by corresponding precipitation behavior. Full article
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14 pages, 11230 KiB  
Article
Effect of Microstructure on Mechanical Properties of 2519A Aluminum Alloy in Thickness Direction
Metals 2022, 12(7), 1218; https://doi.org/10.3390/met12071218 - 19 Jul 2022
Cited by 1 | Viewed by 1131
Abstract
2519A aluminum alloy thick plate is a promising structural material in the field of military industries, owing to its low density, high tensile strength and excellent ballistic performance. However, the nonuniformly distributed microstructure along the thickness direction of this alloy leads to delamination [...] Read more.
2519A aluminum alloy thick plate is a promising structural material in the field of military industries, owing to its low density, high tensile strength and excellent ballistic performance. However, the nonuniformly distributed microstructure along the thickness direction of this alloy leads to delamination cracks, which restrict its further application in light armor fields. In order to understand the mechanism of delamination cracking along the thickness direction, the effect of the microstructure on the mechanical properties of 2519A aluminum alloy in the thickness direction was investigated. The results show that the elongation and critical stress intensity factor values (ΔKcr) of the alloy in the thickness direction are 45.8% and 44.1% lower than the values in the rolling direction, respectively. The low mechanical properties of the alloy may be due to the short distance between the second phase, the weak binding force of grain boundaries and the disharmonious deformation caused by the inhomogeneous distribution of the microstructure. This study provides a basis for improving the mechanical properties and delamination cracking of the alloy along the thickness direction. Full article
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13 pages, 2751 KiB  
Article
Pre-Aging Effect on the Formation of Ω Phase and Mechanical Properties of the Al-Cu-Mg-Ag Alloy
Metals 2022, 12(7), 1208; https://doi.org/10.3390/met12071208 - 16 Jul 2022
Cited by 4 | Viewed by 1331
Abstract
In the present work, different aging treatments were performed to investigate the pre-aging effect on the formation of Ω phase and mechanical properties in Al-Cu-Mg-Ag alloy. The results showed that pre-strain could inhibit the formation of Ω phases, which was detrimental to the [...] Read more.
In the present work, different aging treatments were performed to investigate the pre-aging effect on the formation of Ω phase and mechanical properties in Al-Cu-Mg-Ag alloy. The results showed that pre-strain could inhibit the formation of Ω phases, which was detrimental to the alloy strength. Due to the introduction of pre-aging treatment before pre-strain, the adverse effect of pre-strain on the precipitation of the Ω phase was reduced, and the alloy strength was increased by at least 15 MPa. Besides this, increasing the pre-aging temperature promoted the precipitation of Ω phases, inhibited the formation of θ′ phases, and improved the alloy strength. This was because the higher pre-aging temperature promoted more pre-precipitated Ω phases in the pre-aging process, and most of the pre-precipitated Ω phases could be retained and grew in the subsequent aging process. As a result, the tensile strength of the alloy increased from 523 MPa to 540 MPa. In addition, pre-aging with a higher temperature consumed more solute atoms, leading to less residual solute atoms in the matrix. Thus, the adverse effects of pre-strain, which inhibit the formation of clusters by the segregation of solute atoms, were reduced. Full article
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