Materials

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18 pages, 7220 KiB

Open AccessArticle

Characterization of Al₂O₃ Matrix Composites Fabricated via the Slip Casting Method Using NiAl-Al₂O₃ Composite Powder

by Justyna Zygmuntowicz, Katarzyna Konopka, Marek Krasnowski, Paulina Piotrkiewicz, Jan Bolek, Marcin Wachowski, Radosław Żurowski and Mikołaj Szafran

Materials 2022, 15(8), 2920; https://doi.org/10.3390/ma15082920 - 16 Apr 2022

Cited by 5 | Viewed by 2116

Abstract

This work aimed to characterize Al₂O₃ matrix composites fabricated by the slip casting method using NiAl-Al₂O₃ composite powder as the initial powder. The composite powder, consisting of NiAl + 30 wt.% Al₂O₃, was [...] Read more.

This work aimed to characterize Al₂O₃ matrix composites fabricated by the slip casting method using NiAl-Al₂O₃ composite powder as the initial powder. The composite powder, consisting of NiAl + 30 wt.% Al₂O₃, was obtained by mechanical alloying of Al₂O₃, Al, and Ni powders. The composite powder was added to the Al₂O₃ powder to prepare the final powder for the slip casting method. The stained composite samples presented high density. EDX and XRD analyses showed that the sintering process of the samples in an air atmosphere caused the formation of the NiAl₂O₄ spinel phase. Finally, the phase composition of the composites changed from the initial phases of Al₂O₃ and NiAl to Al₂O₃, Ni, and NiAl₂O₄. However, in the area of Ni, fine Al₂O₃ particles remaining from the initial composite powder were visible. It can be concluded that after slip casting, after starting with Al₂O₃ and the composite powder (NiAl-Al₂O₃) and upon sintering in air, ceramic matrix composites with Ni and NiAl₂O₄ phases, complex structures, high-quality sintered samples, and favorable mechanical properties were obtained. Full article

(This article belongs to the Special Issue Advances in Metal and Ceramic Matrix Composites)

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16 pages, 2014 KiB

Open AccessArticle

Al₂O₃-Cu-Ni Composites Manufactured via Uniaxial Pressing: Microstructure, Magnetic, and Mechanical Properties

by Paulina Piotrkiewicz, Justyna Zygmuntowicz, Marcin Wachowski, Konrad Cymerman, Waldemar Kaszuwara and Anna Więcław Midor

Materials 2022, 15(5), 1848; https://doi.org/10.3390/ma15051848 - 1 Mar 2022

Cited by 4 | Viewed by 1902

Abstract

This study’s main goal was to obtain and characterize Al₂O₃-Cu-Ni composites with different metallic phase content. The study analyzed the three series of samples differing in the metallic phase 5, 10, 15 vol.% volume contents. An identical volume share [...] Read more.

This study’s main goal was to obtain and characterize Al₂O₃-Cu-Ni composites with different metallic phase content. The study analyzed the three series of samples differing in the metallic phase 5, 10, 15 vol.% volume contents. An identical volume share of the metallic components in the metallic phase was used. Ceramic–metal composites were formed using uniaxial pressing and sintered at a temperature of 1400 °C. The microstructural investigation of the Al₂O₃-Cu-Ni composite and its properties involved scanning electron microscopes observations and X-ray diffraction. The size of the metallic phase in the ceramic matrix was performed using a stereological analysis. Microhardness analysis with fracture toughness measures was applied to estimate the mechanical properties of the prepared materials. Additionally, magnetic measurements were carried out, and the saturation magnetization was determined on the obtained magnetic hysteresis loops. The prepared samples, regardless of the content of the metallic phase in each series, were characterized by a density exceeding 95% of the theoretical density. The magnetic measurements exhibited that the fabricated composites had ferromagnetic properties due to nickel and nickel-rich phases. The hardness of the samples containing 5, 10, 15 vol.% metallic phases decreased with an increase in the metallic phase content, equal to 17.60 ± 0.96 GPa, 15.40 ± 0.81 GPa, 12.6 ± 0.36 GPa, respectively. Full article

(This article belongs to the Special Issue Advances in Metal and Ceramic Matrix Composites)

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19 pages, 9962 KiB

Open AccessArticle

Pulse Plasma Sintering of NiAl-Al₂O₃ Composite Powder Produced by Mechanical Alloying with Contribution of Nanometric Al₂O₃ Powder

by Katarzyna Konopka, Justyna Zygmuntowicz, Marek Krasnowski, Konrad Cymerman, Marcin Wachowski and Paulina Piotrkiewicz

Materials 2022, 15(2), 407; https://doi.org/10.3390/ma15020407 - 6 Jan 2022

Cited by 5 | Viewed by 1675

Abstract

NiAl-Al₂O₃ composites, fabricated from the prepared composite powders by mechanical alloying and then consolidated by pulse plasma sintering, were presented. The use of nanometric alumina powder for reinforcement of a synthetized intermetallic matrix was the innovative concept of this work. [...] Read more.

NiAl-Al₂O₃ composites, fabricated from the prepared composite powders by mechanical alloying and then consolidated by pulse plasma sintering, were presented. The use of nanometric alumina powder for reinforcement of a synthetized intermetallic matrix was the innovative concept of this work. Moreover, this is the first reported attempt to use the Pulse Plasma Sintering (PPS) method to consolidate composite powder with the contribution of nanometric alumina powder. The composite powders consisting of the intermetallic phase NiAl and Al₂O₃ were prepared by mechanical alloying from powder mixtures containing Ni-50at.%Al with the contribution of 10 wt.% or 20 wt.% nanometric aluminum oxide. A nanocrystalline NiAl matrix was formed, with uniformly distributed Al₂O₃ inclusions as reinforcement. The PPS method successfully consolidated NiAl-Al₂O₃ composite powders with limited grain growth in the NiAl matrix. The appropriate sintering temperature for composite powder was selected based on analysis of the grain growth and hardness of Al₂O₃ subjected to PPS consolidation at various temperatures. As a result of these tests, sintering of the NiAl-Al₂O₃ powders was carried out at temperatures of 1200 °C, 1300 °C, and 1400 °C. The microstructure and properties of the initial powders, composite powders, and consolidated bulk composite materials were characterized by SEM, EDS, XRD, density, and hardness measurements. The hardness of the ultrafine-grained NiAl-Al₂O₃ composites obtained via PPS depends on the Al₂O₃ content in the composite, as well as the sintering temperature applied. The highest values of the hardness of the composites were obtained after sintering at the lowest temperature (1200 °C), reaching 7.2 ± 0.29 GPa and 8.4 ± 0.07 GPa for 10 wt.% Al₂O₃ and 20 wt.% Al₂O₃, respectively, and exceeding the hardness values reported in the literature. From a technological point of view, the possibility to use sintering temperatures as low as 1200 °C is crucial for the production of fully dense, ultrafine-grained composites with high hardness. Full article

(This article belongs to the Special Issue Advances in Metal and Ceramic Matrix Composites)

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15 pages, 4291 KiB

Open AccessArticle

Effect of Gd₂O₃ Addition on the Microstructure and Properties of Gd₂O₃-Yb₂O₃-Y₂O₃-ZrO₂ (GYYZO) Ceramics

by Pei-Hu Gao, Sheng-Cong Zeng, Can Jin, Bo Zhang, Bai-Yang Chen, Zhong Yang, Yong-Chun Guo, Min-Xian Liang, Jian-Ping Li, Quan-Ping Li, Yong-Qing Lu, Lu Jia and Dan Zhao

Materials 2021, 14(23), 7470; https://doi.org/10.3390/ma14237470 - 6 Dec 2021

Cited by 9 | Viewed by 2608

Abstract

Gd and Yb elements have high chemical stability, which can stabilize the solid solution in ZrO₂. Gd₂O₃ and Yb₂O₃ have high melting points, and good oxidation resistance in extreme environments, stable chemical properties. Therefore, Gd [...] Read more.

Gd and Yb elements have high chemical stability, which can stabilize the solid solution in ZrO₂. Gd₂O₃ and Yb₂O₃ have high melting points, and good oxidation resistance in extreme environments, stable chemical properties. Therefore, Gd₂O₃ and Yb₂O₃ were added to ZrO₂ to stabilize oxides, improve the high temperature stability, and effectively decrease the thermal conductivity at high temperature. In this work, 5 wt% Yb₂O₃ and 5 wt%, 10 wt%, 15 wt% Gd₂O₃ were doped into 8 wt% Y₂O₃ stabilized ZrO₂ (8YSZ) powders as thermal barrier coating materials, and sintered at 1650 °C for 6 h, 12 h, 24 h. The effects of Gd₂O₃ addition on the microstructure, density, thermal conductivity, hardness, and fracture toughness of Gd₂O₃-Yb₂O₃-Y₂O₃-ZrO₂ (GYYZO) bulk composite ceramics were investigated. It was found that the densification of the 8YSZ bulk and GYYZO bulk with 15 wt% Gd₂O₃ reached 96.89% and 96.22% sintered at 1650 °C for 24 h. With the increase of Gd₂O₃ addition, the hardness, elastic modulus and fracture toughness of the GYYZO bulk increased and the thermal conductivity and thermal expansion coefficient of the GYYZO bulk decreased. GYYZO bulk with 15 wt% Gd₂O₃ sintered at 1650 °C for 24h had the highest hardness, elastic modulus and fracture toughness of 15.61 GPa, 306.88 GPa, 7.822 MPa·m^0.5, and the lowest thermal conductivity and thermal expansion coefficient of 1.04 W/(m·k) and 7.89 × 10⁻⁶/°C at 1100 °C, respectively. The addition of Gd₂O₃ into YSZ could not only effectively reduce the thermal conductivity but also improve the mechanical properties, which would improve the thermal barrier coatings’ performances further. Full article

(This article belongs to the Special Issue Advances in Metal and Ceramic Matrix Composites)

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21 pages, 7024 KiB

Open AccessArticle

ZTA Pipes with a Gradient Structure-Effect of the Rheological the Behavior of Ceramic Suspensions on the Gradient Structure and Characterized of the Obtained Products

by Radosław Żurowski, Justyna Zygmuntowicz, Paulina Piotrkiewicz, Marcin Wachowski and Michał M. Szczypiński

Materials 2021, 14(23), 7348; https://doi.org/10.3390/ma14237348 - 30 Nov 2021

Cited by 8 | Viewed by 1544

Abstract

This paper focuses on the verifying the possibility of producing Al₂O₃-ZrO₂ composite pipes with a gradient structure using centrifugal slip casting method. The aim of the research is to define the correlation between the rheological properties of aqueous [...] Read more.

This paper focuses on the verifying the possibility of producing Al₂O₃-ZrO₂ composite pipes with a gradient structure using centrifugal slip casting method. The aim of the research is to define the correlation between the rheological properties of aqueous suspensions of ceramic powders with different solid loading and obtaining the ZrO₂ phase gradient in the Al₂O₃ matrix. Such products, due to their unique properties, can be utilized in the transport of aggressive substances, even in extreme temperature or corrosive conditions. The suspensions and the sintered samples were characterized by: broad rheological analysis, scanning electron microscopy, X-ray diffraction, stereological analysis and Vickers hardness tests. The study reports on a series of samples produced of ceramic suspensions (70 vol.% Al₂O₃–30 vol.% ZrO₂) differing in the total solid loading in the range of 30–55 vol.%. The results clearly indicate that obtaining the gradient structure of ceramic-ceramic composite pipes is closely related to the rheological properties of the suspensions from which the samples are cast. The phase gradient is obtainable from suspensions 30–40 vol.%, in which the possibility of moving ZrO₂ particles relative to the Al₂O₃ is quite high—these suspensions are characterized by low viscosity and the dominance of viscous over elastic properties (G′ > G″). Full article

(This article belongs to the Special Issue Advances in Metal and Ceramic Matrix Composites)

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18 pages, 8499 KiB

Open AccessArticle

Application of Nanosilicon to the Sintering of Mg-Mg₂Si Interpenetrating Phases Composite

by Anita Olszówka-Myalska, Hanna Myalska, Patryk Wrześniowski, Jacek Chrapoński and Grzegorz Cios

Materials 2021, 14(23), 7114; https://doi.org/10.3390/ma14237114 - 23 Nov 2021

Cited by 5 | Viewed by 2104

Abstract

The new in situ fabrication process for Mg-Mg₂Si composites composed of interpenetrating metal/intermetallic phases via powder metallurgy was characterized. To obtain the designed composite microstructure, variable nanosilicon ((n)Si) (i.e., 2, 4, and 6 vol.% (n)Si) concentrations were mixed with magnesium powders. [...] Read more.

The new in situ fabrication process for Mg-Mg₂Si composites composed of interpenetrating metal/intermetallic phases via powder metallurgy was characterized. To obtain the designed composite microstructure, variable nanosilicon ((n)Si) (i.e., 2, 4, and 6 vol.% (n)Si) concentrations were mixed with magnesium powders. The mixture was ordered using a sonic method. The powder mixture morphologies were characterized using scanning electron microscopy (SEM), and heating and cooling-induced thermal effects were characterized using differential scanning calorimetry (DSC). Composite sinters were fabricated by hot-pressing the powders under a vacuum of 2.8 Pa. Shifts in the sintering temperature resulted in two observable microstructures: (1) the presence of Mg₂Si and MgO intermetallic phases in α-Mg (580 °C); and (2) Mg₂Si intermetallic phases in the α-Mg matrix enriched with bands of refined MgO (640 °C). Materials were characterized by light microscopy (LM) with quantitative metallography, X-ray diffraction (XRD), open porosity measurements, hardness testing, microhardness testing, and nanoindentation. The results revealed that (n)Si in applied sintering conditions ensured the formation of globular and very fine Mg₂Si particles. The particles bonded with each other to form an intermetallic network. The volume fraction of this network increased with (n)Si concentration but was dependent on sintering temperature. Increasing sintering temperature intensified magnesium vaporization, affecting the composite formation mechanism and increasing the volume fraction of silicide. Full article

(This article belongs to the Special Issue Advances in Metal and Ceramic Matrix Composites)

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9 pages, 2752 KiB

Open AccessArticle

Influence of Alloying Elements on the Mechanical Properties of Anodized Aluminum and on the Adhesion of Copper Metallization

by Oleg S. Medvedev, Ekaterina E. Alyasova, Rona E. Besprozvannaya, Asadula A. Gadzhiev, Veronika V. Krivova, Andrey S. Kondratev, Artem E. Kim, Pavel A. Novikov and Anatoliy A. Popovich

Materials 2021, 14(22), 7028; https://doi.org/10.3390/ma14227028 - 19 Nov 2021

Cited by 2 | Viewed by 1875

Abstract

The active development of the power electronics market and a constant increase in the prices of components require new materials and approaches, including a power module packaging technology. The use of aluminum instead of copper in the power module baseplate is an interesting [...] Read more.

The active development of the power electronics market and a constant increase in the prices of components require new materials and approaches, including a power module packaging technology. The use of aluminum instead of copper in the power module baseplate is an interesting and promising solution. The insulated metal baseplate is one of the most extensively developed technologies nowadays. The object of this study is an insulated metal substrate based on anodized aluminum. The main goal of the article is the comparison of copper topology adhesion to an anodized aluminum oxide layer formed on different aluminum alloys with aluminum content of at least 99.3 wt %. Peel test and pull-off adhesions showed a twofold difference for both aluminum alloys. The high ordered defect-free anodized alumina formed on alloys with copper content of 0.06 wt % had a mean pull-off adhesion of 27 N/mm² and hardness of 489 HV. In the case of the alloy with copper content of around 0.15 wt %, it had hardness of 295 HV and a mean pull-off adhesion of 12 N/mm². The results of our microstructure investigation showed that anodized alumina based on alloys with copper content of around 0.15 wt % is fragile due to spherical holes. Summing up the results, it can be concluded that not all initial impurities are critical for anodized alumina, but some, specifically copper, dramatically decreased the mechanical properties of anodized alumina. Full article

(This article belongs to the Special Issue Advances in Metal and Ceramic Matrix Composites)

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25 pages, 5419 KiB

Open AccessArticle

Rheological and Technological Aspects in Designing the Properties of Shear Thickening Fluids

by Radosław Żurowski, Paweł Falkowski, Justyna Zygmuntowicz and Mikołaj Szafran

Materials 2021, 14(21), 6585; https://doi.org/10.3390/ma14216585 - 2 Nov 2021

Cited by 4 | Viewed by 2637

Abstract

This work focuses on shear thickening fluids (STFs) as ceramic–polymer composites with outstanding protective properties. The investigation aims to determine the influence of raw material parameters on the functional properties of STFs. The following analyses were used to characterize both the raw materials [...] Read more.

This work focuses on shear thickening fluids (STFs) as ceramic–polymer composites with outstanding protective properties. The investigation aims to determine the influence of raw material parameters on the functional properties of STFs. The following analyses were used to characterize both the raw materials and the STFs: scanning electron microscopy, dynamic light scattering, matrix-assisted laser desorption/ionization time-of-flight, chemical sorption analysis, rheological analysis, and kinetic energy dissipation tests. It was confirmed that the morphology of the solid particles plays a key role in designing the rheological and protective properties of STFs. In the case of irregular silica, shear thickening properties can be obtained from a solid content of 12.5 vol.%. For spherical silica, the limit for achieving shear thickening behavior is 40 vol.%. The viscosity curve analysis allowed for the introduction of a new parameter defining the functional properties of STFs: the technological critical shear rate. The ability of STFs to dissipate kinetic energy was determined using a unique device that allows pure fluids to be tested without prior encapsulation. Because of this, it was possible to observe even slight differences in the protective properties between different STFs, which has not been possible so far. During tests with an energy of 50 J, the dissipation factor was over 96%. Full article

(This article belongs to the Special Issue Advances in Metal and Ceramic Matrix Composites)

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22 pages, 9812 KiB

Open AccessArticle

Characterization of Sn–Sb–Ti Solder Alloy and the Study of Its Use for the Ultrasonic Soldering Process of SiC Ceramics with a Cu–SiC Metal–Ceramic Composite

by Roman Kolenak, Igor Kostolny, Jaromir Drapala, Paulina Babincova and Matej Pasak

Materials 2021, 14(21), 6369; https://doi.org/10.3390/ma14216369 - 25 Oct 2021

Cited by 16 | Viewed by 2708

Abstract

The aim of this research was to characterize soldering alloys of the type Sn–Sb–Ti and to study the ultrasonic soldering of SiC ceramics with a metal–ceramic composite of the type Cu–SiC. The Sn5Sb3Ti solder exerts a thermal transformation of a peritectic character with [...] Read more.

The aim of this research was to characterize soldering alloys of the type Sn–Sb–Ti and to study the ultrasonic soldering of SiC ceramics with a metal–ceramic composite of the type Cu–SiC. The Sn5Sb3Ti solder exerts a thermal transformation of a peritectic character with an approximate melting point of 234 °C and a narrow melting interval. The solder microstructure consists of a tin matrix, where the acicular constituents of the Ti₆(Sb,Sn)₅ phase and the sharp-edged constituents of the TiSbSn phase are precipitated. The tensile strength of the soldering alloy depends on the Ti content and reaches values from 34 to 51 MPa. The average strength of the solder increases with increasing Ti content. The bond with SiC ceramics is formed owing to the interaction of titanium, activated by ultrasound, with SiC ceramics, forming the (Ti,Si)₆(Sb,Sn)₅ reaction product. The bond with the metal–ceramic composite Cu–SiC is formed owing to the solubility of Cu in a tin solder forming two phases: the wettable η-Cu₆Sn₅ phase, formed in contact with the solder, and the non-wettable ε-Cu₃Sn phase, formed in contact with the copper composite. The average shear strength of the combined joint of SiC/Cu–SiC fabricated using the Sn5Sb3Ti solder was 42.5 MPa. The Sn–Sb–Ti solder is a direct competitor of the S-Bond active solder. The production of solders is cheaper, and the presence of antimony increases their strength. In addition, the application temperature range is wider. Full article

(This article belongs to the Special Issue Advances in Metal and Ceramic Matrix Composites)

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17 pages, 5762 KiB

Open AccessArticle

Manufacturing of Al₂O₃/Ni/Ti Composites Enhanced by Intermetallic Phases

by Marcin Wachowski, Justyna Zygmuntowicz, Robert Kosturek, Katarzyna Konopka and Waldemar Kaszuwara

Materials 2021, 14(13), 3510; https://doi.org/10.3390/ma14133510 - 24 Jun 2021

Cited by 9 | Viewed by 2010

Abstract

In this study, ceramic–metal composites in the Al₂O₃/Ti/Ni system were fabricated using the slip casting method. Two series of composites with 15 vol.% metal content and different solid phase contents were obtained and examined. A proper fabrication process allows [...] Read more.

In this study, ceramic–metal composites in the Al₂O₃/Ti/Ni system were fabricated using the slip casting method. Two series of composites with 15 vol.% metal content and different solid phase contents were obtained and examined. A proper fabrication process allows obtaining composites enhanced by intermetallic phases. The microstructure of the base powders, slurries, and sintered composites was analyzed by scanning electron microscope. Analysis of the sedimentation tendency of slurries was carried out. The phase composition of the sintered samples was examined by X-ray diffraction analysis. A monotonic compression test was used to investigate the mechanical properties of the composites. A fractography investigation was also carried out. The research conducted revealed that the slip casting method allows the obtaining of composites enhanced by intermetallic phases (TiNi, Ni₃Ti). The results show the correlation between solid-phase content, microstructure, and mechanical properties of the composites. Full article

(This article belongs to the Special Issue Advances in Metal and Ceramic Matrix Composites)

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18 pages, 8529 KiB

Open AccessArticle

Characterization of Al₂O₃ Samples and NiAl–Al₂O₃ Composite Consolidated by Pulse Plasma Sintering

by Katarzyna Konopka, Marek Krasnowski, Justyna Zygmuntowicz, Konrad Cymerman, Marcin Wachowski and Paulina Piotrkiewicz

Materials 2021, 14(12), 3398; https://doi.org/10.3390/ma14123398 - 19 Jun 2021

Cited by 7 | Viewed by 2230

Abstract

The paper describes an investigation of Al₂O₃ samples and NiAl–Al₂O₃ composites consolidated by pulse plasma sintering (PPS). In the experiment, several methods were used to determine the properties and microstructure of the raw Al₂O₃ [...] Read more.

The paper describes an investigation of Al₂O₃ samples and NiAl–Al₂O₃ composites consolidated by pulse plasma sintering (PPS). In the experiment, several methods were used to determine the properties and microstructure of the raw Al₂O₃ powder, NiAl–Al₂O₃ powder after mechanical alloying, and samples obtained via the PPS. The microstructural investigation of the alumina and composite properties involves scanning electron microscopy (SEM) analysis and X-ray diffraction (XRD). The relative densities were investigated with helium pycnometer and Archimedes method measurements. Microhardness analysis with fracture toughness (K_IC) measures was applied to estimate the mechanical properties of the investigated materials. Using the PPS technique allows the production of bulk Al₂O₃ samples and intermetallic ceramic composites from the NiAl–Al₂O₃ system. To produce by PPS method the NiAl–Al₂O₃ bulk materials initially, the composite powder NiAl–Al₂O₃ was obtained by mechanical alloying. As initial powders, Ni, Al, and Al₂O₃ were used. After the PPS process, the final composite materials consist of two phases: Al₂O₃ located within the NiAl matrix. The intermetallic ceramic composites have relative densities: for composites with 10 wt.% Al₂O₃ 97.9% and samples containing 20 wt.% Al₂O₃ close to 100%. The hardness of both composites is equal to 5.8 GPa. Moreover, after PPS consolidation, NiAl–Al₂O₃ composites were characterized by high plasticity. The presented results are promising for the subsequent study of consolidation composite NiAl–Al₂O₃ powder with various initial contributions of ceramics (Al₂O₃) and a mixture of intermetallic–ceramic composite powders with the addition of ceramics to fabricate composites with complex microstructures and properties. In composites with complex microstructures that belong to the new class of composites, in particular, the synergistic effect of various mechanisms of improving the fracture toughness will be operated. Full article

(This article belongs to the Special Issue Advances in Metal and Ceramic Matrix Composites)

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18 pages, 4270 KiB

Open AccessArticle

Sintering Behavior, Thermal Expansion, and Environmental Impacts Accompanying Materials of the Al₂O₃/ZrO₂ System Fabricated via Slip Casting

by Justyna Zygmuntowicz, Magdalena Gizowska, Justyna Tomaszewska, Paulina Piotrkiewicz, Radosław Żurowski, Marcin Wachowski and Katarzyna Konopka

Materials 2021, 14(12), 3365; https://doi.org/10.3390/ma14123365 - 17 Jun 2021

Cited by 10 | Viewed by 2191

Abstract

This work focuses on research on obtaining and characterizing Al₂O₃/ZrO₂ materials formed via slip casting method. The main emphasis in the research was placed on environmental aspects and those related to the practical use of ceramic materials. The [...] Read more.

This work focuses on research on obtaining and characterizing Al₂O₃/ZrO₂ materials formed via slip casting method. The main emphasis in the research was placed on environmental aspects and those related to the practical use of ceramic materials. The goal was to analyze the environmental loads associated with the manufacturing of Al₂O₃/ZrO₂ composites, as well as to determine the coefficient of thermal expansion of the obtained materials, classified as technical ceramics. This parameter is crucial in terms of their practical applications in high-temperature working conditions, e.g., as parts of industrial machines. The study reports on the four series of Al₂O₃/ZrO₂ materials differing in the volume content of ZrO₂. The sintering process was preceded by thermogravimetric measurements. The fabricated and sintered materials were characterized by dilatometric study, scanning electron microscopy, X-ray diffraction, and stereological analysis. Further, life cycle assessment was supplied. Based on dilatometric tests, it was observed that Al₂O₃/ZrO₂ composites show a higher coefficient of thermal expansion than that resulting from the content of individual phases. The results of the life cycle analysis showed that the environmental loads (carbon footprint) resulting from the acquisition and processing of raw materials necessary for the production of sinters from Al₂O₃ and ZrO₂ are comparable to those associated with the production of plastic products such as polypropylene or polyvinyl chloride. Full article

(This article belongs to the Special Issue Advances in Metal and Ceramic Matrix Composites)

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15 pages, 2961 KiB

Open AccessArticle

Numerical Analysis of Particulate Migration Behavior within Molten Pool during TIG-Assisted Droplet Deposition Manufacturing of SiC Particle-Reinforced Aluminum Matrix Composites

by Yubin Zhang, Jun Du, Huafeng Wang, Hua Li and Xiaoyun Zhao

Materials 2021, 14(9), 2430; https://doi.org/10.3390/ma14092430 - 7 May 2021

Cited by 3 | Viewed by 2278

Abstract

A transient three-dimensional (3D) numerical model was established to illustrate the heat transfer, fluid flow and particle migration behaviors in the molten pool during TIG-assisted droplet deposition manufacturing (DDM) of SiC particle-reinforced aluminum matrix composites (AMCs). The effect of temperature-dependent physical properties and [...] Read more.

A transient three-dimensional (3D) numerical model was established to illustrate the heat transfer, fluid flow and particle migration behaviors in the molten pool during TIG-assisted droplet deposition manufacturing (DDM) of SiC particle-reinforced aluminum matrix composites (AMCs). The effect of temperature-dependent physical properties and the interaction between the SiC reinforcement and the liquid metal matrix were considered. A double-ellipsoidal volumetric heat source model was adopted to simulate the energy interactions between the pulse square-wave variable polarity TIG welding arc and the moving substrate. Free surface fluctuations of molten pool due to arc force and sequential droplet impact are calculated with volume of fluid (VOF) method in a fixed Eulerian structured mesh. The numerical model, capable of capturing the impact, simultaneous spread, and phase change of the droplets as well as the motion trajectory and terminate distribution state of the reinforcement particles, is key tool to understand the formation mechanism of the TIG-assisted DDM of SiC particle-reinforced AMCs. The numerical model was validated by the metallographic observations, and the calculated particle distribution and solidification morphology of deposited layer agree well with the experimental measurements. Full article

(This article belongs to the Special Issue Advances in Metal and Ceramic Matrix Composites)

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20 pages, 6375 KiB

Open AccessArticle

Al₂O₃/ZrO₂ Materials as an Environmentally Friendly Solution for Linear Infrastructure Applications

by Justyna Zygmuntowicz, Radosław Żurowski, Justyna Tomaszewska, Marcin Wachowski, Janusz Torzewski, Paulina Piotrkiewicz, Michał Gloc and Katarzyna Konopka

Materials 2021, 14(9), 2375; https://doi.org/10.3390/ma14092375 - 3 May 2021

Cited by 10 | Viewed by 2412

Abstract

The present work deals with the evaluation of the effect of ZrO₂ on the structure and selected properties of shapes obtained using the centrifugal slip casting method. The samples were made of alumina and zirconia. The applied technology made it possible to [...] Read more.

The present work deals with the evaluation of the effect of ZrO₂ on the structure and selected properties of shapes obtained using the centrifugal slip casting method. The samples were made of alumina and zirconia. The applied technology made it possible to produce tubes with a high density reaching 99–100% after sintering. Very good bonding was obtained at the Al₂O₃/ZrO₂ interphase boundaries with no discernible delamination or cracks, which was confirmed by STEM observations. In the case of Al₂O₃/ZrO₂ composites containing 5 vol.% and 10 vol.% ZrO₂, the presence of equiaxial ZrO₂ grains with an average size of 0.25 µm was observed, which are distributed along the grain boundaries of Al₂O₃. At the same time, the composites exhibited a very high hardness of 22–23 GPa. Moreover, the environmental influences accompanying the sintering process were quantified. The impacts were determined using the life cycle analysis method, in the phase related to the extraction and processing of raw materials and the process of producing Al₂O₃/ZrO₂ composites. The results obtained show that the production of 1 kg of sintered composite results in greenhouse gas emissions of 2.24–2.9 kg CO₂ eq. which is comparable to the amount of emissions accompanying the production of 1 kg of Polyvinyl Chloride (PVC), Polypropylene (PP), or hot-rolled steel products. Full article

(This article belongs to the Special Issue Advances in Metal and Ceramic Matrix Composites)

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17 pages, 13540 KiB

Open AccessArticle

Predictive Computational Model for Damage Behavior of Metal-Matrix Composites Emphasizing the Effect of Particle Size and Volume Fraction

by Shaimaa I. Gad, Mohamed A. Attia, Mohamed A. Hassan and Ahmed G. El-Shafei

Materials 2021, 14(9), 2143; https://doi.org/10.3390/ma14092143 - 23 Apr 2021

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Abstract

In this paper, an integrated numerical model is proposed to investigate the effects of particulate size and volume fraction on the deformation, damage, and failure behaviors of particulate-reinforced metal matrix composites (PRMMCs). In the framework of a random microstructure-based finite element modelling, the [...] Read more.

In this paper, an integrated numerical model is proposed to investigate the effects of particulate size and volume fraction on the deformation, damage, and failure behaviors of particulate-reinforced metal matrix composites (PRMMCs). In the framework of a random microstructure-based finite element modelling, the plastic deformation and ductile cracking of the matrix are, respectively, modelled using Johnson–Cook constitutive relation and Johnson–Cook ductile fracture model. The matrix-particle interface decohesion is simulated by employing the surface-based-cohesive zone method, while the particulate fracture is manipulated by the elastic–brittle cracking model, in which the damage evolution criterion depends on the fracture energy cracking criterion. A 2D nonlinear finite element model was developed using ABAQUS/Explicit commercial program for modelling and analyzing damage mechanisms of silicon carbide reinforced aluminum matrix composites. The predicted results have shown a good agreement with the experimental data in the forms of true stress–strain curves and failure shape. Unlike the existing models, the influence of the volume fraction and size of SiC particles on the deformation, damage mechanism, failure consequences, and stress–strain curve of A359/SiC particulate composites is investigated accounting for the different possible modes of failure simultaneously. Full article

(This article belongs to the Special Issue Advances in Metal and Ceramic Matrix Composites)

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