Submit to Special Issue Submit Abstract to Special Issue Review for Metals Propose a Special Issue

Journal Menu

Journal Browser

► Journal Browser

Microstructure and Characterization of Metal Matrix Composites

Print Special Issue Flyer
Special Issue Editors
Special Issue Information
Keywords
Benefits of Publishing in a Special Issue
Published Papers

A special issue of Metals (ISSN 2075-4701). This special issue belongs to the section "Metal Matrix Composites".

Deadline for manuscript submissions: 30 June 2026 | Viewed by 9258

Share This Special Issue

Special Issue Editors

Dr. Wislei Riuper Osório

E-Mail Website
Guest Editor

1. Faculdade de Tecnologia, FT, Universidade Estadual de Campinas/UNICAMP, Campus I, Limeira 13484-350, Brazil 2. Faculdade de Ciências Aplicadas, FCA, Centro de Manufatura de Materiais Avançados (CPMMA), UNICAMP, Campus II, Limeira 13484-332, Brazil
Interests: mechanical properties; corrosion resistance; aluminum alloys; compounds; lightweight aspects; biomaterials
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Ausdinir Danilo Bortolozo

E-Mail Website
Guest Editor

Faculdade de Ciências Aplicadas (FCA), Universidade Estadual de Campinas, Limeira 13484-350, Brazil
Interests: solder joint; soldering alloys; intermetallics

Special Issue Information

Dear Colleagues,

It is well recognized that the trade-off between the main properties and operational parameters constitutes an important challenge in engineering applications. It is known that distinct manufacturing routes, including traditional and classical routes, as well as other innovative methods, provide different microstructural arrays. Consequently, these play important roles in the final sound material’s properties. Metal alloys or metal matrix composites constituted in situ or produced from a metal alloy, or from the use of distributed particles, have widely been used in several industrial applications. Based on this, it is highly useful to concatenate at least two properties in order to prescribe and promote their potential applications. Nowadays, both economic viability and environmentally friendly aspects also need to be analyzed and associated with the proposed performance.

In this Special Issue, a wide range of manuscripts and investigations will be discussed and presented. Microstructural characterization and its effects on the resulting properties are expected. Thus, researchers are invited to propose original investigations involving a wide variety of distinctive metal alloys and composites.

Dr. Wislei Riuper Osório
Prof. Dr. Ausdinir Danilo Bortolozo
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 250 words) can be sent to the Editorial Office for assessment.

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 matrix composite
mechanical properties
microstructure
alloy
powder metallurgy
casting
blended composites
compressive strength
anisotropy properties
manufacturing route

Benefits of Publishing in a Special Issue

Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
Reprint: MDPI Books provides the opportunity to republish successful Special Issues in book format, both online and in print.

Further information on MDPI's Special Issue policies can be found here.

Published Papers (9 papers)

Download All Papers

Order results

Result details

Show export options Show export options

Select all

Export citation of selected articles as:

Research

Jump to: Review

24 pages, 6198 KB

Open AccessArticle

Structure–Property Relationships of CNT–Al₂O₃ Nano-Reinforced Al 6061 Matrix

by Beatriz Monteiro, Aida B. Moreira and Sónia Simões

Metals 2026, 16(3), 287; https://doi.org/10.3390/met16030287 - 3 Mar 2026

Viewed by 213

Abstract

Hybrid nanocomposites based on Aluminum 6061 (Al 6061) reinforced with carbon nanotubes (CNTs) and aluminum oxide (Al₂O₃) emerge as promising materials due to their ability to achieve simultaneous improvements in strength, thermal stability, and tribological performance. This study examines the structure–property relationships of CNT–Al₂O₃ nano-reinforced hybrid Al 6061, with particular emphasis on microstructural evolution and mechanical properties. The nanocomposites are fabricated via a powder metallurgy route, which enables optimized dispersion and homogeneous distribution of CNTs and Al₂O₃ within the aluminum matrix. Microstructural characteristics, interfacial bonding, and grain refinement are systematically analyzed using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). Mechanical characterization demonstrates a marked enhancement in mechanical properties compared to Al 6061. The observed property improvements are attributed to synergistic strengthening mechanisms, including effective load transfer from the matrix to Al₂O₃ particles, CNT-induced grain refinement, and increased resistance to dislocation motion. These results establish a direct correlation between microstructural features and mechanical performance, highlighting the potential of CNT–Al₂O₃ reinforced Al 6061 hybrid nanocomposites for lightweight, high-strength applications in aerospace, automotive, and structural engineering industries. Full article

(This article belongs to the Special Issue Microstructure and Characterization of Metal Matrix Composites)

► Show Figures

Figure 1

18 pages, 12661 KB

Open AccessArticle

Gradient Microstructure of Ag–Cu Metastable Metal-Matrix Composite Processed by Complex Extrusion: A Preliminary Study

by Pavel Lejček, Drahomír Dvorský, Orsolya Molnárová, Filip Průša, Stanislav Habr and Angelina Strakošová

Metals 2026, 16(1), 89; https://doi.org/10.3390/met16010089 - 13 Jan 2026

Viewed by 331

Abstract

Severe plastic deformation is an effective process to modify materials’ structures. In this work, its new modification entitled channel angular extrusion was applied to a metastable metal-matrix composite consisting of a Ag matrix and spherical Cu particulates. During this process, the rod sample deforms in an inhomogeneous way and exhibits a gradient microstructure that is characterized by ellipsoidal Cu particulates at the edge of the sample but elongated and fragmented rectangular ones in the center. In addition to the different shapes, the edge and center of the sheet also differ in preferential orientations: the ⟨110⟩ direction predominates in the center of the sheet, while the ⟨111⟩ direction dominates at the sheet edge. The changed angle of the {111} shear plane relative to the extrusion direction explains these differences. Full article

(This article belongs to the Special Issue Microstructure and Characterization of Metal Matrix Composites)

► Show Figures

Figure 1

16 pages, 7447 KB

Open AccessArticle

Effect of the Incorporation of 0.1 wt.% TiC on the Microstructure and Tensile Properties of AlSi7Mg0.3 Samples Produced by Investment Casting

by Ane Jimenez, Anna Wójcik, Wojciech Maziarz, Mikel Merchán and Maider García de Cortázar

Metals 2026, 16(1), 34; https://doi.org/10.3390/met16010034 - 27 Dec 2025

Viewed by 332

Abstract

Investment casting of aluminum alloys is widely used in the aeronautical and automotive sectors for manufacturing complex components. However, conventional alloys lack sufficient mechanical strength and high-temperature resistance, prompting the need for enhanced materials. This study investigated the addition of submicron TiC particles, introduced via stir casting process, to an AlSi7Mg0.3 alloy for investment casting. Chemical analysis confirmed the incorporation of up to 0.1 wt.% TiC, but no significant improvement in tensile properties was observed. High Resolution Scanning Electron Microscopy (HRSEM) and Transmission Electron Microscopy (TEM) revealed a complex microstructure with few TiC particles and needle-shaped intermetallic phases containing titanium, iron, silicon, or aluminum. The high mold temperature (700 °C) and slow solidification rate likely caused partial TiC dissolution and intermetallic precipitation, which may have offset strengthening mechanisms like the Hall–Petch effect. Notably, the partial dissolution of TiC particles in investment casting has not been previously reported in similar alloys. These findings highlight the challenges of using particle-reinforced alloys in this process and emphasize the need for further research into process–microstructure relationships. Full article

(This article belongs to the Special Issue Microstructure and Characterization of Metal Matrix Composites)

► Show Figures

Figure 1

21 pages, 28528 KB

Open AccessArticle

Effect of B₄C Amount on Microstructural and Mechanical Properties of Cu/h-BN/B₄C Metal Matrix Composites Fabricated via Spark Plasma Sintering

by Müslim Çelebi, Abdullah Hasan Karabacak, Serdar Özkaya, Ertuğrul Çelik, Dursun Murat Sekban, Aykut Çanakçı and Harun Yanar

Metals 2025, 15(12), 1283; https://doi.org/10.3390/met15121283 - 24 Nov 2025

Cited by 2 | Viewed by 796

Abstract

Copper (Cu) is widely used in electrical, electronic, and tribological systems owing to its excellent electrical and thermal conductivity. However, its relatively low hardness and poor wear resistance limit its use in demanding engineering applications. In this study, Cu-based hybrid metal matrix composites (MMCs) reinforced with hexagonal boron nitride (h-BN) and boron carbide (B₄C) were fabricated via spark plasma sintering (SPS) to improve their mechanical and tribological performance. The h-BN content was fixed at 1 wt.% to ensure solid lubrication, while the B₄C content was varied (0.25, 0.5, 0.75, and 1 wt.%) to examine its influence on the microstructural, mechanical, electrical, and wear properties of the composites. Microstructural analyses confirmed a homogeneous distribution of h-BN and B₄C particles in the Cu matrix at low and moderate reinforcement levels, whereas excessive B₄C resulted in partial agglomeration and reduced densification. All composites achieved relative densities above 95%, demonstrating the high densification efficiency of the SPS process. Hardness increased markedly with B₄C addition due to dispersion strengthening and grain refinement, while electrical conductivity decreased slightly because of the insulating nature of the reinforcements. Tribological tests showed that the composite containing 0.75 wt.% B₄C exhibited the best performance, with the lowest wear rate and stable friction behavior. Overall, the results indicate that co-reinforcing Cu with h-BN and B₄C through SPS is a promising strategy for developing multifunctional materials suitable for electrical contact and sliding applications. Full article

(This article belongs to the Special Issue Microstructure and Characterization of Metal Matrix Composites)

► Show Figures

Figure 1

17 pages, 4731 KB

Open AccessArticle

Effects of Ceramic Particulate Type and Porosity on the Corrosion Behavior of Open-Cell AlSn6Cu Composites Produced via Liquid-State Processing

by Mihail Kolev, Vanya Dyakova, Yoanna Kostova, Boriana Tzaneva, Hristina Spasova and Rositza Dimitrova

Metals 2025, 15(10), 1073; https://doi.org/10.3390/met15101073 - 25 Sep 2025

Viewed by 625

Abstract

The corrosion behavior of open-cell AlSn6Cu-based composites, one reinforced with SiC particles and the other with Al₂O₃ particles, was investigated. The composites were fabricated via liquid-state processing, employing both squeeze casting and the replication method, and they produced in two distinct pore size ranges (800–1000 µm and 1000–1200 µm). Corrosion performance was systematically evaluated through gravimetric (weight loss) measurements and electrochemical techniques, including open-circuit potential monitoring and potentiodynamic polarization tests. Comprehensive microstructural and phase analyses were conducted using X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. The results revealed that both reinforcement type and pore architecture have a significant impact on corrosion resistance. Al₂O₃-reinforced composites consistently outperformed their SiC-containing counterparts, and pore enlargement generally improved performance for the unreinforced alloy and the Al₂O₃ composite but not for the SiC composite. Overall, the optimal corrosion resistance is achieved by pairing a coarser-pore architecture (1000–1200 µm) with Al₂O₃ reinforcement, which minimizes both instantaneous (electrochemical) and cumulative (gravimetric) corrosion metrics. This study addresses a gap in current research by providing the first detailed assessment of corrosion in open-cell AlSn6Cu-based composites with controlled pore architectures and different ceramic reinforcements, offering valuable insights for the development of advanced lightweight materials for harsh environments. Full article

(This article belongs to the Special Issue Microstructure and Characterization of Metal Matrix Composites)

► Show Figures

Figure 1

16 pages, 7742 KB

Open AccessArticle

Study on the Effects of Cryogenic Treatment on WC-Co Cemented Carbide at Different Scales Using an Indentation Technique

by Suparoj Premjarunan, Karuna Tuchinda and Kaweewat Worasaen

Metals 2025, 15(3), 297; https://doi.org/10.3390/met15030297 - 8 Mar 2025

Cited by 3 | Viewed by 1620

Abstract

Cemented carbide (WC-Co) combines high hardness, wear resistance, and toughness, making it ideal for tooling applications. This study investigated cryogenic treatment’s effects on the mechanical properties of samples from various suppliers prepared at different scales. Indentation tests were performed to assess the mechanical properties at the microscale and nanoscale. Overall, the mean microhardness did not show a significant change after cryogenic treatment. Instead, nanoindentation testing was used to identify the improvement after cryogenic treatment. However, considering the mean nanohardness may not adequately capture improvements in the material’s resistance to deformation, the maximum nanoindentation depth and nanohardness were analyzed to elucidate the mechanisms underlying mechanical property improvements in the form of histograms of %frequency along with load–displacement curves. The results showed a decreased frequency of high maximum indentation depths from Co phase improvement. This agreed with an increased frequency of moderate and high nanohardness and a decreased frequency of low nanohardness representing different areas with different phase controls. These results indicate that an alternative interpretation of nanoindentation data, presenting nanohardness and nanoindentation depth in the form of histograms, can provide a more detailed representation of the data distribution. Full article

(This article belongs to the Special Issue Microstructure and Characterization of Metal Matrix Composites)

► Show Figures

Graphical abstract

19 pages, 6425 KB

Open AccessFeature PaperArticle

Anisotropic Tensile and Compressive Strengths of Al–4 wt.%Cu Alloy Powder: Part 1—Effects of Compaction Loads and Heat Treatments

by Rodrigo S. Bonatti, Ausdinir D. Bortolozo, Rodrigo F. G. Baldo, Erik Poloni and Wislei R. Osório

Metals 2023, 13(10), 1710; https://doi.org/10.3390/met13101710 - 7 Oct 2023

Cited by 2 | Viewed by 1961

Abstract

Powder metallurgy stands out as a preferred manufacturing method across various industries due to its advantages in design flexibility, material efficiency, and cost-effective production. In this work, we study the influence of different compaction directions on the strength characteristics of parts produced using powder metallurgy. Al–4 wt.%Cu alloys are used due to their recyclability. We use three distinctive compaction pressures. After sintering, samples are either air-cooled or water-quenched and naturally aged (T4 temper). Both the compressive and tensile strengths are characterized and thoroughly analyzed. This research highlights the significant impact of both heat treatments and compaction directions on anisotropic strengths. The novelty of this research lies in the use of powders that can be reclaimed from machining, turning, or foundry rejections. By eliminating or minimizing the melting stage and employing powder metallurgy, we achieve cost-effective and environmentally friendly processes. Furthermore, we underscore the critical role played by careful planning of compaction loads, compaction directions, and heat treatments in determining the final mechanical performance. This approach is not only economically viable but also aligns with the growing adoption of environmental, social, and governance (ESG) practices in industry. Full article

(This article belongs to the Special Issue Microstructure and Characterization of Metal Matrix Composites)

► Show Figures

Figure 1

20 pages, 6950 KB

Open AccessFeature PaperArticle

Anisotropic Tensile and Compressive Strengths of Al-4wt.%Cu Alloy Powder: Part 2—Effect of Dendritic Arm Spacings

by Rodrigo S. Bonatti, João F. Q. Rodrigues, Leandro C. Peixoto, Rodrigo F. G. Baldo, Ausdinir D. Bortolozo and Wislei R. Osório

Metals 2023, 13(7), 1282; https://doi.org/10.3390/met13071282 - 17 Jul 2023

Cited by 2 | Viewed by 1808

Abstract

This investigation focuses on the effects of the compaction directions (i.e., transversal and longitudinal) and microstructural arrays (inside the powder utilized to constitute the specimens) on the anisotropic strengths. The initial powders are obtained from the as-cast Al-4 wt.% Cu alloys solidified in two distinct cooling rates, i.e., ~0.5 and 2.5 °C/s. The powder particles are compacted by using 300, 400 and 600 MPa and sintered at 540 °C for 1 h. The compressive and tensile strengths are carried out and the anisotropic strengths are determined. It is found that transverse samples exhibit higher UCS (ultimate compressive strength) and UTS (ultimate tensile strength) than the longitudinal samples. It is also found that the powder compacted in the transversal direction and utilizing powder with finer dendritic arm spacing provides better UCS and UTS results. The novelty in the study concerns the fact that is evidenced in the role of the dendrite spacings concatenated with the compaction pressure and direction upon the mechanical behavior. It is concluded that depending on the compaction level intended or demanded mechanical behavior, the planning in the compaction direction is preprogrammed. Since recycled powder particles from conventional machining, drilling and turning can potentially be utilized to constitute parts and components, the environmentally friendly aspects are associated, and hazardous stages in a manufacturing process are substantially reduced or eliminated. Full article

(This article belongs to the Special Issue Microstructure and Characterization of Metal Matrix Composites)

► Show Figures

Figure 1

Review

Jump to: Research

47 pages, 58408 KB

Open AccessReview

Mechanical and Wear Properties of Additive Manufactured Metal Matrix Composites: A Review

by Haris Farooq Kiani, Nan Xiao, Zan Li and Shaofan Ge

Metals 2026, 16(3), 260; https://doi.org/10.3390/met16030260 - 26 Feb 2026

Viewed by 384

Abstract

In critical sectors such as energy, transportation, and high-end manufacturing, components must endure simultaneous exposure to high temperatures, heavy loads, and severe wear, necessitating materials with balanced strength, toughness, and durability. Metal matrix composites (MMCs), enhanced with ceramic reinforcements, offer a promising solution to these multifaceted demands. While conventional techniques like casting and powder metallurgy often struggle with limited design freedom and uniform reinforcement distribution, additive manufacturing (AM) enables the production of complex, graded components with tailored microstructures and unlocks new possibilities for materials operating under extreme service conditions. This review systematically examines recent advances in AM-processed MMCs—focusing on aluminum-, titanium-, nickel-, and steel-based systems—for applications in coupled extreme environments. It provides a detailed analysis of their high-temperature mechanical performance and wear resistance, emphasizing the roles of reinforcement selection, microstructural design, and AM processing parameters in governing key properties. Furthermore, the underlying strengthening and wear mechanisms are discussed, along with current challenges and future opportunities. This work aims to serve as a foundational reference for the development of next-generation AM MMCs tailored for high-performance engineering applications. Full article

(This article belongs to the Special Issue Microstructure and Characterization of Metal Matrix Composites)

► Show Figures

Journal Menu

Journal Browser

Microstructure and Characterization of Metal Matrix Composites

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (9 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI