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15 pages, 10628 KiB

Open AccessArticle

High Strain Rate Deformation Behavior of Gradient Rolling AZ31 Alloys

by Yingjie Li, Hui Yu, Chao Liu, Yu Liu, Wei Yu, Yuling Xu, Binan Jiang, Kwangseon Shin and Fuxing Yin

Metals 2024, 14(7), 788; https://doi.org/10.3390/met14070788 - 5 Jul 2024

Cited by 1 | Viewed by 651

Abstract

A dynamic impact test was performed on as-rolled AZ31 alloys with gradient microstructure under various strains. The microstructural evolution and mechanical properties were systematically investigated. As the strain rate gradually increased, an increasing number of twins were formed, facilitating dynamic recrystallization (DRX), and [...] Read more.

A dynamic impact test was performed on as-rolled AZ31 alloys with gradient microstructure under various strains. The microstructural evolution and mechanical properties were systematically investigated. As the strain rate gradually increased, an increasing number of twins were formed, facilitating dynamic recrystallization (DRX), and the mechanical properties were also gradually improved. The microstructure became heterogeneous at higher strain rates, but the peak stress decreased. The impact process resulted in a significantly higher performance due to microstructural refinement, work hardening by dislocations, and precipitates. In addition, both the adiabatic shear band and the adjacent crack experienced a temperature rise that exceeded the recrystallization temperature of the alloys. This observation also explains the presence of ultrafine recrystallized grains within the adiabatic shear band and the appearance of molten metal around the crack. Full article

(This article belongs to the Special Issue Preparation and Processing Technology of Advanced Magnesium Alloys)

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12 pages, 3660 KiB

Open AccessArticle

Study on the Optimization of the Preparation Process of ZM5 Magnesium Alloy Micro-Arc Oxidation Hard Ceramic Coatings and Coatings Properties

by Bingchun Jiang, Zejun Wen, Peiwen Wang, Xinting Huang, Xin Yang, Minghua Yuan and Jianjun Xi

Metals 2024, 14(5), 594; https://doi.org/10.3390/met14050594 - 19 May 2024

Cited by 1 | Viewed by 1095

Abstract

Hard ceramic coatings were successfully prepared on the surface of ZM5 magnesium alloy by micro-arc oxidation (MAO) technology in silicate and aluminate electrolytes, respectively. The optimization of hard ceramic coatings prepared in these electrolyte systems was investigated through an orthogonal experimental design. The [...] Read more.

Hard ceramic coatings were successfully prepared on the surface of ZM5 magnesium alloy by micro-arc oxidation (MAO) technology in silicate and aluminate electrolytes, respectively. The optimization of hard ceramic coatings prepared in these electrolyte systems was investigated through an orthogonal experimental design. The microstructure, elemental composition, phase composition, and tribological properties of the coatings were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and tribological testing equipment. The results show that the growth of the hard ceramic coatings is significantly influenced by the different electrolyte systems. Coatings prepared from both systems have shown good wear resistance, with the aluminate electrolyte system being superior to the silicate system in performance. The optimized formulation for the silicate electrolyte solution has been determined to be sodium silicate at 8 g/L, sodium dihydrogen phosphate at 0.2 g/L, sodium tetraborate at 2 g/L, and potassium hydroxide at 1 g/L. The optimized formulation for the aluminate electrolyte solution consists of sodium aluminate at 5 g/L, sodium fluoride at 3 g/L, sodium citrate at 3 g/L, and sodium hydroxide at 0.5 g/L. Full article

(This article belongs to the Special Issue Preparation and Processing Technology of Advanced Magnesium Alloys)

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14 pages, 10752 KiB

Open AccessArticle

Improving the Corrosion Resistance of Micro-Arc Oxidization Film on AZ91D Mg Alloy through Silanization

by Junchi Liu, Hang Yin, Zhengyi Xu, Yawei Shao and Yanqiu Wang

Metals 2024, 14(5), 569; https://doi.org/10.3390/met14050569 - 12 May 2024

Viewed by 1446

Abstract

The presence of inherent micro-pores and micro-cracks in the micro-arc oxidation (MAO) film of Mg alloys is a key factor contributing to substrate corrosion. A composite film layer with high corrosion resistance was achieved through silanizing the micro-arc oxidation film. The corrosion performance [...] Read more.

The presence of inherent micro-pores and micro-cracks in the micro-arc oxidation (MAO) film of Mg alloys is a key factor contributing to substrate corrosion. A composite film layer with high corrosion resistance was achieved through silanizing the micro-arc oxidation film. The corrosion performance of the MAO films treated with various silane coupling agents was assessed through morphological characterization and electrochemical tests. SEM graphs depicted that the silane film can effectively seal the defects existing in micro-arc oxidation film, and electrochemical tests indicated the significant corrosion resistance improvement of MAO film after silanization treatment. Full article

(This article belongs to the Special Issue Preparation and Processing Technology of Advanced Magnesium Alloys)

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10 pages, 4412 KiB

Open AccessArticle

Cold Formability of Twin-Roll Cast, Rolled and Annealed Mg Strips

by Madlen Ullmann, Kristina Kittner and Ulrich Prahl

Metals 2024, 14(1), 121; https://doi.org/10.3390/met14010121 - 19 Jan 2024

Viewed by 1350

Abstract

This study investigates the cold formability of twin-roll cast and rolled magnesium strips, specifically focusing on AZ31 and ZAX210 alloys. The aim is to assess the suitability of these alloys for various forming processes. The mechanical properties and formability characteristics of the strips [...] Read more.

This study investigates the cold formability of twin-roll cast and rolled magnesium strips, specifically focusing on AZ31 and ZAX210 alloys. The aim is to assess the suitability of these alloys for various forming processes. The mechanical properties and formability characteristics of the strips were thoroughly examined to provide insights into their potential applications in transportation industries such as automotive and aerospace. The AZ31 and ZAX210 alloys were subjected to twin-roll casting and rolling processes to produce thin strips. The resulting strips were then evaluated for their cold formability. The results indicate that both alloys exhibit favourable cold formability. The ZAX210 alloy, in particular, demonstrates medium strengths with an average tensile strength of approximately 240 MPa at room temperature. The 0.2% proof stress values range between 136 MPa and 159 MPa, depending on the sampling direction. The total elongation values vary from 28% in the transverse direction to 32% at a 45° angle, indicating excellent ductility. Comparing the two alloys, the AZ31 alloy shows higher strengths due to its higher aluminium content. However, it also exhibits a more pronounced directional dependence of mechanical properties due to the formation of a strong basal texture during hot rolling. The transverse direction experiences reduced total elongation compared to the rolling direction, achieving only about 50% of the total elongation. The average Erichsen Index recorded for AZ31 and ZAX210 strips were 4.9 mm and 7.1 mm, respectively. The ZAX210 strip displays superior formability, which can be attributed to the fine-grained microstructure and the texture softening resulting from the weakening of the basal texture intensity and the splitting of the basal pole towards the rolling direction. In conclusion, the investigated twin-roll cast, rolled and annealed AZ31 and ZAX210 magnesium strips exhibit promising cold formability characteristics. The findings of this study contribute to the understanding of their mechanical behaviour and can guide the selection and optimisation of these alloys for various forming applications. Full article

(This article belongs to the Special Issue Preparation and Processing Technology of Advanced Magnesium Alloys)

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17 pages, 10993 KiB

Open AccessArticle

Structure, Phase Composition, and Mechanical Properties of ZK51A Alloy with AlN Nanoparticles after Heat Treatment

by Anastasia A. Akhmadieva, Anton P. Khrustalev, Mikhail V. Grigoriev, Ilya A. Zhukov and Alexander B. Vorozhtsov

Metals 2024, 14(1), 71; https://doi.org/10.3390/met14010071 - 8 Jan 2024

Cited by 1 | Viewed by 1106

Abstract

The paper studies the influence of the content of aluminum nitride nanoparticles on the structure and mechanical properties of the ZK51A magnesium alloy. The microstructure investigations with optical and electron microscopy show that 1 wt.% AlN promotes the best grain refinement and size [...] Read more.

The paper studies the influence of the content of aluminum nitride nanoparticles on the structure and mechanical properties of the ZK51A magnesium alloy. The microstructure investigations with optical and electron microscopy show that 1 wt.% AlN promotes the best grain refinement and size distribution. According to tensile strength testing of the ZK51A alloy, grain refinement is not a dominating mechanism in the property improvement of the alloy after heat treatment. The maximum values of mechanical parameters are achieved at the lowest (0.1 wt.%) content of aluminum nitride. The main mechanism of mechanical characteristics increase with the addition of AlN nanoparticles is dispersion hardening. Full article

(This article belongs to the Special Issue Preparation and Processing Technology of Advanced Magnesium Alloys)

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23 pages, 11305 KiB

Open AccessArticle

Influence of Aluminum Content on the Microstructure, Mechanical Properties, and Hot Deformation Behavior of Mg-Al-Zn Alloys

by Marie Moses, Madlen Ullmann and Ulrich Prahl

Metals 2023, 13(9), 1599; https://doi.org/10.3390/met13091599 - 15 Sep 2023

Cited by 3 | Viewed by 1451

Abstract

This study compares AZ91 with AZ31 to investigate the influence of a higher Al content on the resulting microstructure, mechanical properties, and hot deformation behavior. While AZ31 exhibits a globular structure after casting, AZ91 shows a fully developed dendritic structure due to the [...] Read more.

This study compares AZ91 with AZ31 to investigate the influence of a higher Al content on the resulting microstructure, mechanical properties, and hot deformation behavior. While AZ31 exhibits a globular structure after casting, AZ91 shows a fully developed dendritic structure due to the promotion of dendrites. A heat treatment helped to homogenize AZ31, dissolved a large part of the Mg-Al precipitations in AZ91, and formed globular grains in AZ91. Due to the impact of Al on constitutional supercooling, AZ91 exhibits smaller grains than AZ31. Because of the strengthening of the solid solution, AZ91 also exhibits higher strength and hardness compared to AZ31. Cylindric compression tests of the heat-treated samples were conducted at different temperatures (300–400 °C) and strain rates (0.1 × 10 s⁻¹). The main dynamic recrystallization (DRX) mechanisms in AZ31 and AZ91 are twinning-induced DRX and discontinuous DRX. It was detected that Mg₁₇Al₁₂ precipitates at the grain boundaries in AZ91, which influences the grain size through pinning. Similar results could be conducted in rolling trials. Although both alloys have similar grain sizes after rolling, AZ91 exhibits higher strengths, while AZ31 shows higher ductility. This can be explained by the solid solution strengthening in AZ91 and less brittle Mg₁₇Al₁₂ precipitations in AZ31. Full article

(This article belongs to the Special Issue Preparation and Processing Technology of Advanced Magnesium Alloys)

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13 pages, 7793 KiB

Open AccessArticle

Simultaneous Improvement of Strength, Ductility and Damping Capacity of Single β-Phase Mg–Li–Al–Zn Alloys

by Xinhe Yang, Yang Jin, Ruizhi Wu, Jiahao Wang, Dan Wang, Xiaochun Ma, Legan Hou, Vladimir Serebryany, Iya I. Tashlykova-Bushkevich and Sergey Ya. Betsofen

Metals 2023, 13(1), 159; https://doi.org/10.3390/met13010159 - 12 Jan 2023

Cited by 7 | Viewed by 1916

Abstract

Body-centered cubic (BCC) Mg–Li alloy can be effectively strengthened by with the addition of Al and Zn. However, adding excessive amounts result in reduced mechanical properties and damping capacity of the alloy during subsequent heat treatment and deformation. The effects of solution-hot rolling-aging [...] Read more.

Body-centered cubic (BCC) Mg–Li alloy can be effectively strengthened by with the addition of Al and Zn. However, adding excessive amounts result in reduced mechanical properties and damping capacity of the alloy during subsequent heat treatment and deformation. The effects of solution-hot rolling-aging on the mechanical properties and damping capacity of LAZ1333 alloy and LAZ1366 alloy were studied. The solid solution strengthening greatly increases the hardness of the alloy, but the ductility is extremely poor. The AlLi softening phase precipitated during the subsequent hot rolling and aging process greatly improves the ductility of the alloy, but the excess precipitation of in the AlLi softening phase and the solid solution of excess Zn element are not conducive to the substantial improvement of the strength and ductility of the alloy. Excessive addition of alloying elements is detrimental to the damping capacity of the alloy, but the damping capacity of the alloy can be significantly improved by depleting the number of solute atoms through subsequent ageing treatments. The UTS and FE of as-cast LAZ 1333 alloy are 111 MPa and 16.9%, respectively. The as-aged LAZ1333 alloy has the best mechanical properties and damping capacity, and the UTS and FE are increased by 65.8% and 89.3%, respectively, compared to the as-cast alloy, and the damping capacity increased from 0.011 to 0.015. Full article

(This article belongs to the Special Issue Preparation and Processing Technology of Advanced Magnesium Alloys)

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12 pages, 5481 KiB

Open AccessArticle

BCC-Based Mg–Li Alloy with Nano-Precipitated MgZn₂ Phase Prepared by Multidirectional Cryogenic Rolling

by Qing Ji, Xiaochun Ma, Ruizhi Wu, Siyuan Jin, Jinghuai Zhang and Legan Hou

Metals 2022, 12(12), 2114; https://doi.org/10.3390/met12122114 - 8 Dec 2022

Cited by 1 | Viewed by 1353

Abstract

In this study, we deformed the single β phase Mg–Li alloy, Mg–16Li–4Zn–1Er (LZE1641), with conventional rolling (R) and multi-directional rolling (MDR), both at cryogenic temperature. Results showed that the nano-precipitation phase MgZn₂ appeared in the alloy after MDR, but this phenomenon was [...] Read more.

In this study, we deformed the single β phase Mg–Li alloy, Mg–16Li–4Zn–1Er (LZE1641), with conventional rolling (R) and multi-directional rolling (MDR), both at cryogenic temperature. Results showed that the nano-precipitation phase MgZn₂ appeared in the alloy after MDR, but this phenomenon was not present in the alloy after R. The finite element simulation result showed that the different deformation modes changed the stress distribution inside the alloy, which affected the microstructures and the motion law of the solute atoms. The high-density and dispersively distributed MgZn₂ particles with a size of about 35 nm were able to significantly inhibit the grain boundary migration. They further hindered the dislocation movement and consolidated the dislocation strengthening and fine-grain strengthening effects. Compared with the compressive strength after R (273 MPa), the alloy compressive strength was improved by 21% after MDR (331 MPa). After 100 °C compression, the MgZn₂ remained stable. Full article

(This article belongs to the Special Issue Preparation and Processing Technology of Advanced Magnesium Alloys)

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16 pages, 8582 KiB

Open AccessArticle

Research on Dynamic Marine Atmospheric Corrosion Behavior of AZ31 Magnesium Alloy

by Ying Wang, Weichen Xu, Xiutong Wang, Quantong Jiang, Yantao Li, Yanliang Huang and Lihui Yang

Metals 2022, 12(11), 1886; https://doi.org/10.3390/met12111886 - 4 Nov 2022

Cited by 10 | Viewed by 1837

Abstract

The dynamic marine atmospheric corrosion behavior of AZ31 magnesium alloy was investigated in situ exposed on the deck of marine scientific research vessel for 1 year. The marine scientific research vessel carried out five voyages from the coast of China to the western [...] Read more.

The dynamic marine atmospheric corrosion behavior of AZ31 magnesium alloy was investigated in situ exposed on the deck of marine scientific research vessel for 1 year. The marine scientific research vessel carried out five voyages from the coast of China to the western Pacific Ocean, while the navigation track and environmental data were collected and analyzed. The corrosion rate and characteristics were evaluated by using weight loss tests, scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and electrochemical measurements. The corrosion rate from weight loss values was 52.23 μm∙y⁻¹ after exposure for 1 year, which was several times higher than that of the static field exposure test in marine atmospheric environment of other reported literature. The main corrosion products were Mg₅(CO₃)₄(OH)₂·4H₂O, MgCO₃·3H₂O and Mg₂(OH)₃Cl·4H₂O. The corrosion was initiated from pitting corrosion and evolved into general corrosion gradually. The serious corrosion maybe due to the harsh corrosive environment with alternating changes in temperature and relative humidity caused by multiple longitude and latitude changes, and particularly high deposition rate of chloride during voyage, which was nearly twenty times that on the coast of China. This study provides effective data for the application of magnesium alloy in shipboard aircraft and other equipment, and provides a reference for indoor simulation experiments. Full article

(This article belongs to the Special Issue Preparation and Processing Technology of Advanced Magnesium Alloys)

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14 pages, 27928 KiB

Open AccessArticle

Evolution of the Microstructure and Mechanical Properties of AZ31 Magnesium Alloy Sheets during Multi-Pass Lowered-Temperature Rolling

by Qing Miao, Lantao Zhu, Wenke Wang, Zhihao Wang, Bin Shao, Wenzhen Chen, Yang Yu and Wencong Zhang

Metals 2022, 12(11), 1811; https://doi.org/10.3390/met12111811 - 26 Oct 2022

Cited by 3 | Viewed by 1989

Abstract

AZ31 magnesium alloy sheets with 2 mm thickness were successfully fabricated by multi-pass lowered-temperature rolling. The evolution of the microstructure, texture, and mechanical properties during the rolling process was investigated. Based on the effect of multiple dynamic recrystallization, multi-pass lowered-temperature rolling not only [...] Read more.

AZ31 magnesium alloy sheets with 2 mm thickness were successfully fabricated by multi-pass lowered-temperature rolling. The evolution of the microstructure, texture, and mechanical properties during the rolling process was investigated. Based on the effect of multiple dynamic recrystallization, multi-pass lowered-temperature rolling not only refined the grain size obviously but also markedly improved the microstructure homogeneity. The resulting sheets had the optimal microstructure morphology with an average grain size of 4.38 μm. For the texture evolution, the stress state of the rolling process made the (0002) basal plane gradually rotate toward the rolling plane. However, the activation of non-basal slips due to the higher rolling temperature slightly rotated the (0002) basal plane point to the rolling direction (RD). As a result, the grain refinement strengthening and the texture strengthening together increased the yield stress to 202 MPa in the transverse direction (TD) and 189.8 MPa in the RD. Importantly, the resulting sheet concurrently exhibited excellent fracture elongation, about 38% in the TD and 39.2% in the RD. This was mainly ascribed to the finer grain size, giving rise to a significant effect of grain boundary sliding and the activation amount of non-basal slips. Full article

(This article belongs to the Special Issue Preparation and Processing Technology of Advanced Magnesium Alloys)

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