materials-logo

Journal Browser

Journal Browser

Alloys and Composites: Structural and Functional Applications

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Metals and Alloys".

Deadline for manuscript submissions: closed (10 January 2023) | Viewed by 17553

Special Issue Editor

School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
Interests: amorphous alloys; relaxation and rejuvenation of amorphous materials; metal matrix composites; high-entropy alloys; porous alloys; high-temperature alloys
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

According to the constituent phases in alloys and composites, materials can exhibit various performance characteristics, thus possessing great potentials in different application cases, such as aeronautics and astronautics, the automobile industry, and the electronic and electrical industry. Alloys and composites with high stiffness, high strength, and good ductility can be used as load-bearing components, those with high hardness and ductility can be used as cutting tools, and those with high corrosion resistance can be used as components in seawater or in a chemical atmosphere environment, whereas the heating furnace needs both heating components with a high heat liberation rate, as well as heat insulation components to prevent heat loss.

The aim of this SI is to understand the basic principles of property design and tailoring in alloys and composites, to be used as structural or functional materials. The materials of interest include amorphous alloys, high-entropy alloys, lightweight alloys, metal matrix composites, ceramic matrix composites, and polymer matrix composites. To design and tailor macroscopic properties as structural or functional materials, such as macroscopic stiffness and strength, the phase constituent, volume fraction, and average size of each phase, interface bonding should be well investigated. A thorough understanding of how the composition and processing parameters influence the macroscopic properties will definitely help toward new breakthroughs in the field of alloys and composites and their use in different cases.

Prof. Dr. Wei Guo
Guest Editor

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. Materials is an international peer-reviewed open access semimonthly 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

  • alloys and composites
  • mechanical properties
  • functional properties
  • phase constituent
  • design and tailoring
  • amorphous alloys
  • high-entropy alloys
  • lightweight alloys
  • metal matrix composites

Related Special Issue

Published Papers (12 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

10 pages, 2415 KiB  
Article
Platinum-Cobalt Nanowires for Efficient Alcohol Oxidation Electrocatalysis
by Wenwen Wang, Xinyi Bai, Xiaochu Yuan, Yumin Liu, Lin Yang and Fangfang Chang
Materials 2023, 16(2), 840; https://doi.org/10.3390/ma16020840 - 15 Jan 2023
Cited by 3 | Viewed by 1343
Abstract
The compositions and surface facets of platinum (Pt)-based electrocatalysts are of great significance for the development of direct alcohol fuel cells (DAFCs). We reported an approach for preparing ultrathin PtnCo100−n nanowire (NW) catalysts with high activity. The PtnCo [...] Read more.
The compositions and surface facets of platinum (Pt)-based electrocatalysts are of great significance for the development of direct alcohol fuel cells (DAFCs). We reported an approach for preparing ultrathin PtnCo100−n nanowire (NW) catalysts with high activity. The PtnCo100−n NW alloy catalysts synthesized by single-phase surfactant-free synthesis have adjustable compositions and (111) plane and strain lattices. X-ray diffraction (XRD) results indicate that the alloy composition can adjust the lattice shrinkage or expansion of PtnCo100−n NWs. X-ray photoelectron spectroscopy (XPS) results show that the electron structure of Pt is changed by the alloying effect caused by electron modulation in the d band, and the chemical adsorption strength of Pt is decreased, thus the catalytic activity of Pt is increased. The experimental results show that the activity of PtnCo100−n for the oxidation of methanol and ethanol is related to the exposed crystal surface, strain lattice and composition of catalysts. The PtnCo100−n NWs exhibit stronger electrocatalytic performance for both methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). The dominant (111) plane Pt53Co47 exhibits the highest electrocatalytic activity in MOR, which is supported by the results of XPS. This discovery provides a new pathway to design high activity, stability nanocatalysts to enhance direct alcohol fuel cells. Full article
(This article belongs to the Special Issue Alloys and Composites: Structural and Functional Applications)
Show Figures

Figure 1

10 pages, 1944 KiB  
Article
Low-Temperature Superplasticity and High Strength in the Al 2024 Alloy with Ultrafine Grains
by Elena V. Bobruk, Maxim Yu. Murashkin, Ilnar A. Ramazanov, Vil U. Kazykhanov and Ruslan Z. Valiev
Materials 2023, 16(2), 727; https://doi.org/10.3390/ma16020727 - 11 Jan 2023
Cited by 4 | Viewed by 1011
Abstract
This study aims to achieve an ultrafine-grained (UFG) Al 2024 alloy superplasticity at temperatures lower than the traditional ones for commercial Al alloys (400–500 °C). The UFG structure with a mean grain size of 100 nm produced in the alloy by high-pressure torsion [...] Read more.
This study aims to achieve an ultrafine-grained (UFG) Al 2024 alloy superplasticity at temperatures lower than the traditional ones for commercial Al alloys (400–500 °C). The UFG structure with a mean grain size of 100 nm produced in the alloy by high-pressure torsion at room temperature provided a very high strength—microhardness (HV0.1) of 286 ± 4, offset yield strength (σ0.2) of 828 ± 9 MPa, and ultimate tensile strength (σUTS) of 871 ± 6 MPa at elongation to failure (δ) of 7 ± 0.2%. Complex tensile tests were performed at temperatures from 190 to 270 °C and strain rates from 10−2 to 5 × 10−5 s−1, and the values of flow stress, total elongation and strain rate-sensitivity coefficient were determined. The UFG alloy was shown to exhibit superplastic behavior at test temperatures of 240 and 270 °C. For the first time, 400% elongation was achieved in the alloy at an unusually low temperature of 270 °C (0.56 Tm) and strain rate of 10−3 s−1. The UFG 2024 alloy after superplastic deformation was found to have higher strength (150–160 HV) than that after the standard strengthening heat treatment T6. Full article
(This article belongs to the Special Issue Alloys and Composites: Structural and Functional Applications)
Show Figures

Figure 1

14 pages, 3245 KiB  
Article
First-Principles Study on Mechanical and Optical Behavior of Plutonium Oxide under Typical Structural Phases and Vacancy Defects
by Jin-Xing Cheng, Fei Yang, Qing-Bo Wang, Yuan-Yuan He, Yi-Nuo Liu, Zi-Yu Hu, Wei-Wei Wen, You-Peng Wu, Cheng-Yin Zheng, Ai Yu, Xin Lu and Yue Zhang
Materials 2022, 15(21), 7785; https://doi.org/10.3390/ma15217785 - 04 Nov 2022
Viewed by 1066
Abstract
The chemical corrosion aging of plutonium is a very important topic. It is easy to be corroded and produces oxidation products of various valence states because of its 5f electron orbit between local and non-local. On the one hand, the phase diagram of [...] Read more.
The chemical corrosion aging of plutonium is a very important topic. It is easy to be corroded and produces oxidation products of various valence states because of its 5f electron orbit between local and non-local. On the one hand, the phase diagram of plutonium and oxygen is complex, so there is still not enough research on typical structural phases. On the other hand, most of the studies on plutonium oxide focus on PuO2 and Pu2O3 with stoichiometric ratio, while the understanding of non-stoichiometric ratio, especially for Pu2O3-x, is not deep enough. Based on this, using the DFT + U theoretical scheme of density functional theory, we have systematically studied the structural stability, lattice parameters, electronic structure, mechanical and optical properties of six typical high temperature phases of β-Pu2O3, α-Pu2O3,γ-Pu2O3, PuO, α-PuO2,γ-PuO2. Further, the mechanical properties and optical behavior of Pu2O3-x under different oxygen vacancy concentrations are analyzed and discussed in detail. The result shows that the elasticity modulus of single crystal in mechanical properties is directly related to the oxygen/plutonium ratio and crystal system. As the number of oxygen vacancies increases, the mechanical constants continue to increase. In terms of optical properties, PuO has the best optical properties, and the light absorption rate decreases with the increase of oxygen vacancy concentration. Full article
(This article belongs to the Special Issue Alloys and Composites: Structural and Functional Applications)
Show Figures

Figure 1

13 pages, 1194 KiB  
Article
Point Defects Stability, Hydrogen Diffusion, Electronic Structure, and Mechanical Properties of Defected Equiatomic γ(U,Zr) from First-Principles
by Shasha Huang, Jiang-Jiang Ma, Kan Lai, Cheng-Bin Zhang, Wen Yin, Ruizhi Qiu, Ping Zhang and Bao-Tian Wang
Materials 2022, 15(21), 7452; https://doi.org/10.3390/ma15217452 - 24 Oct 2022
Cited by 2 | Viewed by 1213
Abstract
At present, many experimental fast reactors have adopted alloy nuclear fuels, for example, U-Zr alloy fuels. During the neutron irradiation process, vacancies and hydrogen (H) impurity atoms can both exist in U-Zr alloy fuels. Here, first-principles density functional theory (DFT) is employed to [...] Read more.
At present, many experimental fast reactors have adopted alloy nuclear fuels, for example, U-Zr alloy fuels. During the neutron irradiation process, vacancies and hydrogen (H) impurity atoms can both exist in U-Zr alloy fuels. Here, first-principles density functional theory (DFT) is employed to study the behaviors of vacancies and H atoms in disordered-γ(U,Zr) as well as their impacts on the electronic structure and mechanical properties. The formation energy of vacancies and hydrogen solution energy are calculated. The effect of vacancies on the migration barrier of hydrogen atoms is revealed. The effect of vacancies and hydrogen atom on densities of states and elastic constants are also presented. The results illustrate that U vacancy is easier to be formed than Zr vacancy. The H interstitial prefers the tetrahedral site. Besides, U vacancy shows H-trap ability and can raise the H migration barrier. Almost all the defects lead to decreases in electrical conductivity and bulk modulus. It is also found that the main effect of defects is on the U-5f orbitals. This work provides a theoretical understanding of the effect of defects on the electronic and mechanical properties of U-Zr alloys, which is an essential step toward tailoring their performance. Full article
(This article belongs to the Special Issue Alloys and Composites: Structural and Functional Applications)
Show Figures

Figure 1

11 pages, 2572 KiB  
Article
In Situ Fabrication and Static Contact Resistance of CdMoO4 Reinforced Cu Matrix Composites
by Wei-Jian Li, Lu Zhang, Zi-Yao Chen, Wen-Zhu Shao and Liang Zhen
Materials 2022, 15(20), 7206; https://doi.org/10.3390/ma15207206 - 16 Oct 2022
Cited by 3 | Viewed by 1110
Abstract
Particle-reinforced Cu-based electrical contact materials prepared by traditional powder metallurgical methods suffer the same critical problem, where the agglomeration of the addition phases in the Cu matrix significantly deteriorates the performance of the composites and restricts their application. In this work, CdMoO4 [...] Read more.
Particle-reinforced Cu-based electrical contact materials prepared by traditional powder metallurgical methods suffer the same critical problem, where the agglomeration of the addition phases in the Cu matrix significantly deteriorates the performance of the composites and restricts their application. In this work, CdMoO4/Cu matrix composites were fabricated by an in situ method and followed by a powder metallurgical process. Firstly, CdMoO4/particles formed a nucleus and grew up based on the surfaces of Cu particles, realizing the controllable in situ synthesis of mixed powders with homogeneously dispersed CdMoO4 nanoparticles via a one-step reaction. Secondly, the bulk CdMoO4/Cu composites were fabricated by pressing and sintering and then densified by hot-extrusion and cold rolling processes. The microstructures and properties of the extruded and rolled specimens were characterized, respectively. The results indicated that the rolled CdMoO4/Cu composite exhibited excellent comprehensive properties of electrical conductivity and mechanical properties for electrical contact materials. Moreover, the effects of the contact force on the static contact resistance of the extruded and rolled composites were evaluated in the closed state of the contact materials. It was found that the rolled CdMoO4/Cu contact materials possessed a stable electrical contact characteristic with low and steady contact resistance. This work designed ternary CdMoO4 particles to reinforce Cu-based composites with well-balanced performances by an in situ synthesis method and this strategy can be extended to the design of ternary oxide/metal composites utilized as electrical contact materials. Full article
(This article belongs to the Special Issue Alloys and Composites: Structural and Functional Applications)
Show Figures

Graphical abstract

12 pages, 4631 KiB  
Article
Effects of Al-Ti-C Refiner and Forming Processes on the Microstructure and Properties of Al-Zn-Mg-Cu Alloys
by Qiao Liao, Jianyu Li, Jianping Liu, Shulin Lü, Lu Chen, Wei Guo and Shusen Wu
Materials 2022, 15(19), 6960; https://doi.org/10.3390/ma15196960 - 07 Oct 2022
Cited by 3 | Viewed by 1047
Abstract
In this paper, the refinement effect of Al-5Ti-0.2C refiner on Al-Zn-Mg-Cu alloys was first investigated, and then the effects of three forming processes, i.e., Gravity Casting (GC), Squeeze Casting (SC), and Squeeze Casting after Ultrasonic Treatment (UT-SC), on microstructure and properties of Al-Zn-Mg-Cu [...] Read more.
In this paper, the refinement effect of Al-5Ti-0.2C refiner on Al-Zn-Mg-Cu alloys was first investigated, and then the effects of three forming processes, i.e., Gravity Casting (GC), Squeeze Casting (SC), and Squeeze Casting after Ultrasonic Treatment (UT-SC), on microstructure and properties of Al-Zn-Mg-Cu alloys were studied. The results show that the refining effect of Al-5Ti-0.2C refiner is obvious; first, the average grain size of the alloy decreases and then increases with the increase in Ti content from 0.15 wt.% to 0.3 wt.%. The optimal amount of added Al-5Ti-0.2C is 0.2 wt.% Ti content. The good refining effect is attributed to the formation of TiC particles and Al3Ti compounds by the refiner, which can all be the nucleus of solidification. The poor refining effect when the Ti content was more than 0.2 wt.% is due to the formation of coarse Al3Ti particles. The results of three forming processes that cast Al-Zn-Mg-Cu alloys under the addition of Al-5Ti-0.2C with 0.2 wt.% Ti content show that the mechanical properties under the UT-SC process are the best; the tensile strength in the as-cast state reaches 367 MPa, and the elongation is 3.84%. The effect of tiny TiC particles in the refiner on the microstructure and properties of Al-Zn-Mg-Cu alloys is also discussed. Full article
(This article belongs to the Special Issue Alloys and Composites: Structural and Functional Applications)
Show Figures

Figure 1

11 pages, 4527 KiB  
Article
Fabrication of Copper Matrix Composites Reinforced with Carbon Nanotubes Using an Innovational Self-Reduction Molecular-Level-Mixing Method
by Bin Ya, Yang Xu, Linggang Meng, Bingwen Zhou, Junfei Zhao, Xi Chen and Xingguo Zhang
Materials 2022, 15(18), 6488; https://doi.org/10.3390/ma15186488 - 19 Sep 2022
Cited by 4 | Viewed by 1616
Abstract
An innovational self-reduction molecular-level-mixing method was proposed as a simplified manufacturing technique for the production of carbon nanotube copper matrix composites (CNT/Cu). Copper matrix composites reinforced with varying amounts of (0.1, 0.3, 0.5 and 0.7 wt%) carbon nanotubes were fabricated by using this [...] Read more.
An innovational self-reduction molecular-level-mixing method was proposed as a simplified manufacturing technique for the production of carbon nanotube copper matrix composites (CNT/Cu). Copper matrix composites reinforced with varying amounts of (0.1, 0.3, 0.5 and 0.7 wt%) carbon nanotubes were fabricated by using this method combined with hot-pressing sintering technology. The surface structure and elemental distribution during the preparation of CNT/Cu mixing powder were investigated. The microstructure and comprehensive properties of the CNT/Cu composites were examined by metallography, mechanical and electrical conductivity tests. The results revealed that the CNT/Cu could be produced by a high temperature reaction at 900 degrees under vacuum, during which the carbon atoms in the carbon nanotubes reduced the divalent copper on the surface to zero-valent copper monomers. The decrease in the ratio of D and G peaks on the Raman spectra indicated that the defective spots on the carbon nanotubes were wrapped and covered by the copper atoms after a self-reduction reaction. The prepared CNT/Cu powders were uniformly embedded in the grain boundaries of the copper matrix materials and effectively hindered the tensile fracture. The overall characteristics of the CNT/Cu composites steadily increased with increasing CNT until the maximum at 0.7 wt%. The performance was achieved with a hardness of 86.1 HV, an electrical conductivity of 81.8% IACS, and tensile strength of 227.5 MPa. Full article
(This article belongs to the Special Issue Alloys and Composites: Structural and Functional Applications)
Show Figures

Figure 1

11 pages, 3341 KiB  
Article
Tuning Microstructure and Mechanical Performance of a Co-Rich Transformation-Induced Plasticity High Entropy Alloy
by Hailong Yi, Renyi Xie, Yifan Zhang, Liqiang Wang, Min Tan, Tao Li and Daixiu Wei
Materials 2022, 15(13), 4611; https://doi.org/10.3390/ma15134611 - 30 Jun 2022
Cited by 5 | Viewed by 1586
Abstract
Multi-principal element alloys and high-entropy alloys (HEAs) are emerging metallic materials with unprecedented structures and properties for various applications. In this study, we tuned the microstructure and mechanical performance of a recently designed high-performance Co-rich TRIP-HEA via thermomechanical processing (TMP). The microstructures of [...] Read more.
Multi-principal element alloys and high-entropy alloys (HEAs) are emerging metallic materials with unprecedented structures and properties for various applications. In this study, we tuned the microstructure and mechanical performance of a recently designed high-performance Co-rich TRIP-HEA via thermomechanical processing (TMP). The microstructures of the HEA after various TMP routines were characterized, and their correlation with room-temperature tensile performance was clarified. The results showed that grain refinement is an effective strategy for enhancing strength while retaining satisfactory ductility. The formation of incoherent precipitates slightly improves the strength but inevitably sacrifices the ductility, which needs to be considered for optimizing the TMPs. The room temperature tensile yield strength and ultimate tensile strength were increased from 254.6 to 641.3 MPa and from 702.5 to 968.4 MPa, respectively, but the tensile elongation retains a satisfactory value of 68.8%. We herein provide important insights into the regulation of the microstructure and mechanical properties of TRIP-HEAs. Full article
(This article belongs to the Special Issue Alloys and Composites: Structural and Functional Applications)
Show Figures

Figure 1

14 pages, 8059 KiB  
Article
Investigation of the Structure and Corrosion Resistance of Novel High-Entropy Alloys for Potential Biomedical Applications
by Marzena Tokarewicz, Małgorzata Grądzka-Dahlke, Katarzyna Rećko, Magdalena Łępicka and Kamila Czajkowska
Materials 2022, 15(11), 3938; https://doi.org/10.3390/ma15113938 - 31 May 2022
Cited by 6 | Viewed by 1704
Abstract
High-entropy alloys are a new generation of materials that have attracted the interest of numerous scientists because of their unusual properties. It seems interesting to use these alloys in biomedical applications. However, for this purpose, the basic condition of corrosion resistance must be [...] Read more.
High-entropy alloys are a new generation of materials that have attracted the interest of numerous scientists because of their unusual properties. It seems interesting to use these alloys in biomedical applications. However, for this purpose, the basic condition of corrosion resistance must be fulfilled. In this article, selected corrosion properties of self-composed high-entropy alloys are investigated and compared with conventional biomedical alloys, that is titanium alloys and stainless steels. Corrosive parameters were determined using the potentiodynamic method. X-ray diffraction studies were performed to characterize the crystal structures. Microstructures of the prepared materials were examined using a scanning electron microscope, and surface hardness was measured by the Vickers method. The results show that investigated high-entropy alloys are characterized by simple structures. Three out of four tested high-entropy alloys had better corrosion properties than conventional implant alloys used in medicine. The Al0.7CoCrFeNi alloy was characterized by a corrosion potential of −224 mV and a corrosion current density of 0.9 μA/cm2; CoCrFeNiCu by −210 mV and 1.1 μA/cm2; TiAlFeCoNi by −435 mV and 4.6 μA/cm2; and Mn0.5TiCuAlCr by −253 mV and 1.3 μA/cm2, respectively. Therefore, the proposed high-entropy alloys can be considered as potential materials for biomedical applications, but this requires more studies to confirm their biocompatibility. Full article
(This article belongs to the Special Issue Alloys and Composites: Structural and Functional Applications)
Show Figures

Figure 1

12 pages, 3168 KiB  
Article
Effect of Heat Treatments on the Corrosion Resistance of a High Strength Mg-Gd-Y-Zn-Zr Alloy
by Hang Xu, Yuan Li, Luoyi Wu, Fulin Jiang, Dingfa Fu, Jie Teng and Hui Zhang
Materials 2022, 15(8), 2813; https://doi.org/10.3390/ma15082813 - 12 Apr 2022
Cited by 4 | Viewed by 1778
Abstract
Magnesium-rare earth (Mg-Re) alloys are very promising structural materials in lightweight industries, while the poor corrosion resistance limits their widespread application. In this work, to provide insights into the functions of precipitate characteristics on the corrosion behaviors of Mg-Re alloys, the influence of [...] Read more.
Magnesium-rare earth (Mg-Re) alloys are very promising structural materials in lightweight industries, while the poor corrosion resistance limits their widespread application. In this work, to provide insights into the functions of precipitate characteristics on the corrosion behaviors of Mg-Re alloys, the influence of heat treatments on the corrosion behavior of Mg-11.46Gd-4.08Y-2.09Zn-0.56Zr alloy was investigated via an immersion test, electrochemical experiment and scanning electron microscope (SEM). The results showed that the corrosion rate of Mg-11.46Gd-4.08Y-2.09Zn-0.56Zr alloy specimens decreased by 17.58% and 20.44% after T5 and T6 heat treatment, respectively. In the heat-treated specimens, the corrosion did not extend further into the matrix but formed fine corrosion grooves along the extrusion direction. The improved homogeneity reduced the residual stress and the β’ precipitate introduced as a corrosion barrier after T5 and T6 heat treatment reduced the corrosion rate of the studied Mg alloy. In addition, the volume fraction of the long-period stacking-ordered (LPSO) phase decreased after heat treatment, which effectively reduced galvanic corrosion and enhanced the protective effect on the Mg matrix. Full article
(This article belongs to the Special Issue Alloys and Composites: Structural and Functional Applications)
Show Figures

Figure 1

12 pages, 6729 KiB  
Article
Preparation and Electromagnetic Absorption Properties of Fe73.2Si16.2B6.6Nb3Cu1 Nanocrystalline Powder
by Bingwen Zhou, Mengnan Lv, Jiali Wu, Bin Ya, Linggang Meng, Lanqing Jianglin and Xingguo Zhang
Materials 2022, 15(7), 2558; https://doi.org/10.3390/ma15072558 - 31 Mar 2022
Cited by 4 | Viewed by 1135
Abstract
In order to decrease and control electromagnetic pollution, absorbing materials with better electromagnetic wave absorption properties should be developed. In this paper, a nanocrystalline alloy ribbon with the composition of Fe73.2Si16.2B6.6Nb3Cu1 was designed and [...] Read more.
In order to decrease and control electromagnetic pollution, absorbing materials with better electromagnetic wave absorption properties should be developed. In this paper, a nanocrystalline alloy ribbon with the composition of Fe73.2Si16.2B6.6Nb3Cu1 was designed and prepared. Nanocrystalline alloy powder was obtained by high-energy ball milling treatment. The effects of ball milling time on the soft magnetic properties, microstructure, morphology, and electromagnetic wave absorption properties of alloy powder were investigated. The results showed that, as time increased, α-(Fe, Si) gradually transformed into the amorphous phase, and the maximum saturation magnetization (Ms) reached 135.25 emu/g. The nanocrystalline alloy powder was flakelike, and the minimum average particle size of the powder reached 6.87 μm. The alloy powder obtained by ball milling for 12 h had the best electromagnetic absorption performance, and the minimum reflection loss RLmin at the frequency of 6.52 GHz reached −46.15 dB (matched thickness was 3.5 mm). As time increased, the best matched frequency moved to the high-frequency direction, and the best matched thickness decreased, while the maximum effective absorption bandwidth ΔfRL<−10 dB was 7.22 GHz (10.78–18 GHz). Full article
(This article belongs to the Special Issue Alloys and Composites: Structural and Functional Applications)
Show Figures

Figure 1

Review

Jump to: Research

19 pages, 7060 KiB  
Review
From Mo–Si–B to Mo–Ti–Si–B Alloys: A Short Review
by Mi Zhao, Wei Ye, Mengyuan Zhu, Yuteng Gui, Wei Guo, Shusen Wu and Youwei Yan
Materials 2023, 16(1), 3; https://doi.org/10.3390/ma16010003 - 20 Dec 2022
Cited by 3 | Viewed by 1714
Abstract
Mo–Si–B alloys have attracted considerable research interest during the last several decades due to their high melting points, excellent high-temperature strength and relatively good oxidation resistance. However, insufficient room-temperature fracture toughness and high-temperature oxidation resistance restrain their further application. Generally, a sufficient volume [...] Read more.
Mo–Si–B alloys have attracted considerable research interest during the last several decades due to their high melting points, excellent high-temperature strength and relatively good oxidation resistance. However, insufficient room-temperature fracture toughness and high-temperature oxidation resistance restrain their further application. Generally, a sufficient volume fraction of BCC-Mo solid-solution phase, providing the ductility, and a high Si content, responsible for the formation of passive oxide scales, is difficult to achieve simultaneously in this ternary system. Recently, macroalloying of Ti has been proposed to establish a novel phase equilibrium with a combination of enough BCC phase and intermetallic compounds that contain a large amount of Si. In this article, the development history from the ternary Mo–Si–B to the quaternary Mo–Ti–Si–B system was reviewed. It was found that the constitution phases could be easily tailored by changing the Ti content. In this regard, better performance of mechanical properties and oxidation resistance can be obtained through proper alloy design. In-depth understanding of the advantages of the quaternary alloys over their ternary ancestors may contribute to bringing about a new concept in designing novel ultra-high-temperature structural materials. Full article
(This article belongs to the Special Issue Alloys and Composites: Structural and Functional Applications)
Show Figures

Figure 1

Back to TopTop