Research

12 pages, 4382 KiB

Open AccessArticle

Enhanced Strength–Ductility Synergy of Mg-Al-Sn-Ca Alloy via Composite Asymmetric Extrusion

by Xiwen Chen, Yuxuan Li, Zhigang Li, Chao Wang and Hai Deng

Crystals 2024, 14(4), 323; https://doi.org/10.3390/cryst14040323 - 30 Mar 2024

Viewed by 429

Fine-grain and weak-texture magnesium alloys are the long-term development targets of lightweight structural materials. In this study, a new composite asymmetric extrusion (CAE) is developed, which, coupling with an asymmetric die and an asymmetric billet, is proposed to improve the strength–ductility of the [...] Read more.

Fine-grain and weak-texture magnesium alloys are the long-term development targets of lightweight structural materials. In this study, a new composite asymmetric extrusion (CAE) is developed, which, coupling with an asymmetric die and an asymmetric billet, is proposed to improve the strength–ductility of the Mg-3.8Al-1.1Sn-0.4Ca alloy. The influence of the asymmetric billet on the microstructure and mechanical properties was investigated. The findings revealed that the asymmetric billet can induce greater plastic deformation, resulting in an increase in the cumulative strain and an improved nucleation rate. The CAE sheets exhibit fine grains (4.4 μm) and a weak tilted texture (7.57 mrd). Furthermore, the asymmetric billet results in the microstructure not forming a gradient microstructure under gradient strain along the transverse direction (TD) direction. The CAE sheets exhibited good mechanical properties, with a yield strength (YS) of 253 MPa, ultimate tensile strength (UTS) of 331 MPa, and elongation (EL) of 20%. This development shows promise in achieving high-efficiency, low-cost production of magnesium alloys. Full article

(This article belongs to the Special Issue Physical and Mechanical Properties of Magnesium Alloys and Composites (Volume II))

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14 pages, 2615 KiB

Open AccessArticle

Effect of Samarium on the Properties of Hot-Extruded Mg–Y–Gd–Zr Alloys

by Elena Lukyanova, Natalia Martynenko, Olga Rybalchenko, Tatiana Dobatkina, Irina Tarytina, Natalia Tabachkova, Georgy Rybalchenko, Nadezhda Andreeva and Sergey Dobatkin

Crystals 2023, 13(10), 1443; https://doi.org/10.3390/cryst13101443 - 28 Sep 2023

Cited by 1 | Viewed by 660

Abstract

The effect of such an additional promising alloying element as samarium on hot-extruded Mg–Y–Gd–Zr alloys is investigated. The microstructure, kinetics of aging during the decomposition of a supersaturated Mg solid solution, and the mechanical properties of the alloys are studied. The differences of [...] Read more.

The effect of such an additional promising alloying element as samarium on hot-extruded Mg–Y–Gd–Zr alloys is investigated. The microstructure, kinetics of aging during the decomposition of a supersaturated Mg solid solution, and the mechanical properties of the alloys are studied. The differences of the recrystallization processes that occur in hot-extruded alloys with various contents of samarium (0, 1.7, 2.5%) are demonstrated. After hot extrusion, Mg–Y–Gd–Zr and Mg–Y–Gd–Sm–Zr alloys are additionally hardened during aging due to the decomposition of a supersaturated Mg solid solution. At the same time, samarium changes the nature of this hardening. The alloys with samarium are hardened faster, and the maximum hardness is achieved with shorter aging exposures. The mechanical properties of hot-extruded Mg–Y–Gd–Zr alloys with samarium addition are determined at room and elevated up to 300 °C temperatures. The efficiency and expediency of using samarium both as a separate alloying element and as a partial replacement of more expensive rare-earth elements in alloys with yttrium and gadolinium are shown. Full article

(This article belongs to the Special Issue Physical and Mechanical Properties of Magnesium Alloys and Composites (Volume II))

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18 pages, 4075 KiB

Open AccessArticle

Microstructure and Corrosion Behaviour of Mg-Ca and Mg-Zn-Ag Alloys for Biodegradable Hard Tissue Implants

by Lavinia Dragomir (Nicolescu), Iulian Antoniac, Veronica Manescu (Paltanea), Aurora Antoniac, Marian Miculescu, Octavian Trante, Alexandru Streza, Cosmin Mihai Cotruț and Doriana Agop Forna

Crystals 2023, 13(8), 1213; https://doi.org/10.3390/cryst13081213 - 05 Aug 2023

Cited by 2 | Viewed by 951

Abstract

Trauma orthopaedic surgery was the first domain to use degradable metallic implants made of magnesium alloys since the early 20th century. Unfortunately, the major limitation that consists of rapid degradation and subsequent implant failure, which occur in physiological environments with a pH between [...] Read more.

Trauma orthopaedic surgery was the first domain to use degradable metallic implants made of magnesium alloys since the early 20th century. Unfortunately, the major limitation that consists of rapid degradation and subsequent implant failure, which occur in physiological environments with a pH between 7.4 and 7.6, prevents its widespread application. The biggest challenge in corrosion assay is the choice of the testing medium in order to reproduce more closely in vivo conditions. The current study was focused on two Mg-Zn-Ag alloys (Mg7Zn1Ag and Mg6Zn3Ag) and the Mg1Ca alloy. Dulbecco’s Modified Eagle Medium (DMEM) and Kokubo’s simulated body fluid solution (SBF) were selected as testing mediums and we follow the corrosion evaluation by the corrosion rate and mass loss. Also, the corrosion behaviour was interpreted in correlation with the microstructural features and alloying elements of the experimental magnesium-based alloys revealed by optical microscopy (OM), X-ray diffraction (XRD), and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDX). The experimental results highlight the more corrosive nature of the SBF environment and that a higher percentage of silver (2.5 wt.%) exhibited a better corrosion resistance. We consider that the magnesium alloy Mg6Zn3Ag showed valuable biodegradation characteristics to be considered as raw materials for manufacturing small trauma implants. Full article

(This article belongs to the Special Issue Physical and Mechanical Properties of Magnesium Alloys and Composites (Volume II))

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13 pages, 3171 KiB

Open AccessArticle

Effect of Y Alloying on Microstructure and Mechanical Properties of AZ61 Magnesium Alloy Sheets Applied as 3C Electronic Product Shells

by Jian Wang, Zheng Chang, Boyu Liu, Yongbing Li, Yan Sun and Hongxiang Li

Crystals 2022, 12(11), 1643; https://doi.org/10.3390/cryst12111643 - 16 Nov 2022

Cited by 1 | Viewed by 1256

Abstract

AZ61 magnesium alloy sheets can be applied as 3C (computer, communication, and consumer) electronic product shells. However, due to their poor plasticity and relatively low strength, the application of AZ61 alloy sheets is limited. The composition modification of AZ61, especially rare earth element [...] Read more.

AZ61 magnesium alloy sheets can be applied as 3C (computer, communication, and consumer) electronic product shells. However, due to their poor plasticity and relatively low strength, the application of AZ61 alloy sheets is limited. The composition modification of AZ61, especially rare earth element alloying, is a good choice to improve the strength and plasticity of AZ61 alloy sheets. In this paper, the strength and plasticity of AZ61 sheets with different contents of Y were studied in detail. We found that the addition of 0.9 wt.% of Y not only improved the strength, but also significantly enhanced the plasticity. As a result, the yield strength of AZ61 increased from 167 MPa to 186 MPa, and the elongation increased from 9.5% to 18%. The reasons can be explained as follows: the Al₂Y phase formed by adding Y consumed a large amount of the Al element, thus avoiding the formation of the brittle phases Al₈Mn₅ and resulting in the improved mechanical properties of the sheets. At the same time, the weakened texture and dispersed grain orientation also effectively improved the plasticity of the sheets. This study will provide a good solution to improve the strength and plasticity of AZ61 sheets without significantly increasing the production cost. Full article

(This article belongs to the Special Issue Physical and Mechanical Properties of Magnesium Alloys and Composites (Volume II))

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10 pages, 2126 KiB

Open AccessArticle

Microstructural and Mechanical Properties of a Heat-Treated EV31A Magnesium Alloy Fabricated Using the Stir-Casting Process

by M. Somasundaram and U. NarendraKumar

Crystals 2022, 12(8), 1163; https://doi.org/10.3390/cryst12081163 - 18 Aug 2022

Cited by 7 | Viewed by 1666

Abstract

This study aims to prepare a stir-cast EV31A magnesium alloy and investigate the effects of the T4 condition (solid solution strengthening) and T6 condition (solid solution strengthening cum age hardening) on the phases, microstructure, mechanical properties, and fractography. The solid solution at 520 [...] Read more.

This study aims to prepare a stir-cast EV31A magnesium alloy and investigate the effects of the T4 condition (solid solution strengthening) and T6 condition (solid solution strengthening cum age hardening) on the phases, microstructure, mechanical properties, and fractography. The solid solution at 520 °C for 8 h allows the Rare-Earth Elements (REE) to dissolve in the Mg matrix, but the solubility is limited by the presence of Zn. This phenomenon is responsible for the T4 heat-treated alloy’s strengthening, which raises the UTS to 212 MPa. The formation of new grains within the grains causes an increase in grain boundaries and dislocations during the T6 heat treatment process, increasing the strength (UTS) of the EV31A alloy to 230 MPa. In all three test conditions, the fractography of tensile samples revealed a cleavage-ductile/mixed mode fracture. As expected, the fine-grained T6 sample exhibited superior strengthening at the expense of ductility. Full article

(This article belongs to the Special Issue Physical and Mechanical Properties of Magnesium Alloys and Composites (Volume II))

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16 pages, 12271 KiB

Open AccessArticle

Microstructure, Mechanical and Thermal Properties of Mg-0.5Ca-xZr Alloys

by Ying-Long Zhou, Jie Liu and Dong-Mei Luo

Crystals 2022, 12(2), 209; https://doi.org/10.3390/cryst12020209 - 30 Jan 2022

Cited by 1 | Viewed by 2256

Abstract

To evaluate the potential values in heat dissipation applications, this study investigated the microstructure, mechanical and thermal properties of the Mg-0.5Ca-xZr alloys (x = 0.5 and 1 wt.%) under the as-cast, as-extruded and aged states. The phase constituents of the Mg alloys were [...] Read more.

To evaluate the potential values in heat dissipation applications, this study investigated the microstructure, mechanical and thermal properties of the Mg-0.5Ca-xZr alloys (x = 0.5 and 1 wt.%) under the as-cast, as-extruded and aged states. The phase constituents of the Mg alloys were examined by X-ray diffraction analysis, and the microstructure was inspected by optical microscopy and scanning electron microscopy. The thermal conductivity and mechanical properties of the Mg alloys were measured by the laser flash method and tensile tests, respectively. The results showed that the Mg alloys exhibited the equiaxed microstructure which is composed of α-Mg, Zr and compound Mg₂Ca. Both the extrusion process and increase of Zr content remarkably enhanced the mechanical strength of the Mg alloys and deteriorated the thermal performance simultaneously. It was also found that the thermal conductivity and mechanical strength of the Mg alloys increased gradually with the increase of aging time due to the higher precipitation of Zr and compound Mg₂Ca during the aging treatment. TheMg-0.5Ca-0.5Zr alloy aged at 473 K for 48 h demonstratedhigher thermal conductivity than the required values of the Mg alloys used as heat dissipation materials. Moreover, theMg-0.5Ca-0.5Zr alloy exhibited similar mechanical strength to the commonly-used Mg alloys, highlighting its potential become a potential heat dissipation material in the future due to its good combination of high thermal performance and mechanical strength. Full article

(This article belongs to the Special Issue Physical and Mechanical Properties of Magnesium Alloys and Composites (Volume II))

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Review

Jump to: Research, Other

35 pages, 9811 KiB

Open AccessReview

Manufacturing Techniques for Mg-Based Metal Matrix Composite with Different Reinforcements

by Gurmeet Singh Arora, Kuldeep Kumar Saxena, Kahtan A. Mohammed, Chander Prakash and Saurav Dixit

Crystals 2022, 12(7), 945; https://doi.org/10.3390/cryst12070945 - 05 Jul 2022

Cited by 21 | Viewed by 3798

Abstract

Magnesium is among the lightest structural metals available, with the capacity to replace traditional alloys in mass-saving applications while still providing increased stiffness and strength. The inclusion of reinforcing components into the metallic matrix has a substantial impact on stiffness, specific strength, wear [...] Read more.

Magnesium is among the lightest structural metals available, with the capacity to replace traditional alloys in mass-saving applications while still providing increased stiffness and strength. The inclusion of reinforcing components into the metallic matrix has a substantial impact on stiffness, specific strength, wear behaviour, damping behaviour, and creep properties when compared to typical engineering materials. Due to their outstanding physical and mechanical characteristics along with low density, magnesium metal matrix composites are viable materials for numerous applications. This study discusses how to choose an appropriate technique and its process parameters for synthesising magnesium-based metal matrix composites (MMCs) and gives an overview of the impacts of various reinforcements in magnesium and its alloys, emphasising their benefits and drawbacks. The essential applications of various magnesium-based MMCs are also critically examined in this article. The impact of reinforcement on the microstructure as well as mechanical characteristics are thoroughly examined. Full article

(This article belongs to the Special Issue Physical and Mechanical Properties of Magnesium Alloys and Composites (Volume II))

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Other

Jump to: Research, Review

8 pages, 1000 KiB

Open AccessPerspective

Bioinspired Strategies for Functionalization of Mg-Based Stents

by Feng Wu, Yixuan Liu, Jingan Li, Kun Zhang and Fali Chong

Crystals 2022, 12(12), 1761; https://doi.org/10.3390/cryst12121761 - 05 Dec 2022

Cited by 1 | Viewed by 1263

Abstract

Magnesium alloys have attracted considerable interest as prospective biodegradable materials in cardiovascular stents because of their metal mechanical properties and biocompatibility. However, fast degradation and slow endothelialization results in the premature disintegration of mechanical integrity and the restenosis of implanted Mg-based stents, which [...] Read more.

Magnesium alloys have attracted considerable interest as prospective biodegradable materials in cardiovascular stents because of their metal mechanical properties and biocompatibility. However, fast degradation and slow endothelialization results in the premature disintegration of mechanical integrity and the restenosis of implanted Mg-based stents, which is the primary hurdle limiting their predicted clinical applicability. The development of bioinspired strategies is a burgeoning area in cardiovascular stents’ fields of research. Inspired by the unique features of lotus leaves, pitcher plants, healthy endothelial cells (ECs), marine mussels, and extracellular matrix, various bioinspired strategies have been developed to build innovative artificial materials with tremendous promise for medicinal applications. This perspective focuses on bioinspired strategies to provide innovative ideas for reducing corrosion resistance and accelerating endothelialization. The bioinspired strategies are envisaged to serve as a significant reference for future research on Mg-based medical devices. Full article

(This article belongs to the Special Issue Physical and Mechanical Properties of Magnesium Alloys and Composites (Volume II))

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