Metal-ceramic Composites Research Articles

Structural features of tantalum carbide-copper composites obtained by liquid phase-assisted spark plasma sintering

Nearly fully dense metal-ceramic composites were synthesized by high-energy ball milling of (2Ta–C)+Cu powder mixtures followed by liquid phase-assisted spark plasma sintering (SPS). The concentration of copper in the starting mixtures was 30 wt% and 50 wt%, while the molar ratio of Ta/C was 2/1. The products of milling consisted of dense composite agglomerates. The agglomerates formed from (2Ta–C)+30 wt% Cu contained ∼10 wt% of iron introduced as contamination during milling. In the sintered composite obtained from (2Ta–C)+30 wt% Cu, Fe5Ta3 was present along with TaC and Ta2C. The reinforcing phase in the composite obtained from (2Ta–C)+50 wt% Cu was Ta2C. During SPS, the formation of melt locally at the inter-particle contacts enabled consolidation of the agglomerates into compacts with a low residual porosity (2–5%). Composites obtained in this work possessed interesting structural features: a Cu-rich network penetrated the structure such that each composite particle was surrounded by a Cu-rich layer. The Vickers hardness of the sintered composites obtained from mixtures containing 50 wt% Cu and 30 wt% Cu was 490 ± 50 HV1 and 715 ± 55 HV1, respectively.

Characterization of the elastic modulus of ceramic–metal composites with physical and mechanical properties by ultrasonic technique

Abstract The scope of this study, that is, the effect of the elastic modulus obtained by ultrasonic method on the physical and mechanical properties of tungsten carbide (WC)-based ceramic–metal composites, which have Ni and Co metallic binder composition produced by powder metallurgy and represented by high strength and hardness criteria, was investigated. In order to obtain composite samples in the study, it was sintered in a microwave furnace at different temperatures to combine the powder particles prepared at the rate of 60% Ni, 20% Co, and 20% WC by weight. Then, the velocities and longitudinal attenuation values of longitudinal and shear ultrasonic waves along the composite sample were measured using the ultrasonic pulse-echo method. The elastic modulus of the composites was determined using ultrasonic velocities and sample density. Hardness testing, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analyses were also performed. The results show that the elastic modulus increases with the increase in sintering temperature and ultrasonic wave speeds, but decreases with the longitudinal attenuation value, considering the SEM images and XRD analysis. There is also a linear relationship between elastic modulus and stiffness.

Multiscale Modeling of Metal-Ceramic Spatially Tailored Materials via Gaussian Process Regression and Peridynamics

In this paper, a micro-to-macro multiscale approach with peridynamics is proposed to study metal-ceramic composites. Since the volume fraction varies in the spatial domain, these composites are called spatially tailored materials (STMs). Microstructure uncertainties, including porosity, are considered at the microscale when conducting peridynamic modeling and simulation. The collected dataset is used to train probabilistic machine learning models via Gaussian process regression, which can stochastically predict material properties. The machine learning models play a role in passing the information from the microscale to the macroscale. Then, at the macroscale, peridynamics is employed to study the mechanics of STM structures with various volume fraction distributions.

Fabrication, microstructural characterization and finite element analysis of functionally graded Al-Al2O3 disk using powder metallurgy technique

In the present work, powder metallurgy technique was employed to fabricate a three-layer functionally graded (FG) disk. The volume fraction of metal-ceramic composition changes radially as layer-1 (100 % Al), layer-2 (95 %Al +5 % Al2O3), and layer-3 (90 %Al +10 % Al2O3). The microstructural investigation was carried out under an optical microscope and SEM (scanning electron microscopy) integrated with EDS, confirming a uniform distribution of reinforcement particles (alumina) in the matrix (aluminum). Interface microstructure indicates a successful fabrication of FGM (functionally graded material) as the transition is uniform in the graded layer without the development of any crack or void at the interface. In comparison to layer-1, the average increase in hardness values was found to be 18 % and 29 % for layer-2 and layer-3 respectively. An increment in hardness was observed in layers where alumina composition is higher. The Archimedes principle was employed to calculate the experimental density of the sample, and the theoretical models were presented to effectively estimate the density of porous FG materials. Furthermore, theoretical models for estimating material properties such as Young's modulus and yield strength of individual layers were proposed on the basis of material composition and particle shapes obtained from the microstructure of FG disk. These material properties were then used in finite element formulation for the application of rotating disk, the validation of which is also proposed. Subsequently, finite element analysis was employed to perform stress analysis on layered FG disk when subjected to centrifugal loading.

Full and Hollow Metal–Ceramic Beads Based on Tantalum and Alumina Produced by Alginate Gelation

Metal–ceramic composite beads containing different amounts of tantalum and alumina, particularly 100 vol% tantalum and 60–40 vol% tantalum/alumina, are produced by the alginate gelation process. Sodium alginate is used as gelling agent in the metal–ceramic suspension, while a calcium chloride solution is prepared to trigger the consolidation process. As in the previous study, different nozzles are used in order to obtain beads of three different sizes. The largest beads result to be hollow, and hence require a freeze‐drying step in order to prevent their collapse. After debinding in air, the composite beads are sintered at 1600 °C under inert atmosphere. Samples in green and sintered state are analyzed by digital light microscopy and scanning electron microscopy. Investigations by mercury intrusion porosimetry reveal that composite beads feature smaller pores compared to pure tantalum beads, as well as lower open porosity. The fracture strength is evaluated on single beads. Despite the high metallic content, both composite and pure tantalum beads show a brittle behavior. X‐ray powder diffraction (XRD) analyses reveal the presence of , , and alongside pure Ta in the samples prepared from pure tantalum. The impurities are due to reactions with Na, C, and Ca from the used additives.

Hybrid metal-ceramic biomaterials fabricated through powder bed fusion and powder metallurgy for improved impact resistance of craniofacial implants

The mechanical compliance of craniofacial implants is of paramount importance in the medical field, as the primary concern is to protect the cerebrum after trauma or neurosurgical operation. To develop novel cranial implants, three types of bioactive ceramic powders were embedded in the metallic scaffolds. The scaffolds were fabricated by combining powder bed fusion technology and powder metallurgy. Ti6Al4V lattice structures fabricated by selective laser melting were filled with three different wollastonite-based bioceramics applied for critical-sized craniofacial defects: 1. CaSiO3 (wollastonite, W), 2. Si-CaSiO3 (50 wt.% silicon-wollastonite, W-Si) and 3. CaSiO3Ca3(PO4)2−MgCa(SiO3)2 (62 wt.% wollastonite ceramic glass, W62) by spark plasma sintering. The mechanical behavior of the Ti6Al4V-CaSiO3 hybrid metal-ceramic biomaterial composite was evaluated by the dynamic impact test designed by the authors. Furthermore, the proposed fabrication process implies that the metallic scaffolds can bear the mechanical loads, hold the composite structure together, and deliberately induced cracks/pores in the ceramic region can be exploited for drug delivery. Except Ti6Al4V which is known for implants, the potential of using TiNi and Ti22Al25Nb is investigated here for dynamic impact-resistance applications. Due to ductility of TiNi and rigidity of Ti22Al25Nb, an average stress distributed in structures under loading is approximately 600, 550 and 400 MPa for Ti6Al4V, TiNi, and Ti22Al25Nb, respectively. Results show declination in the level of porosity from ceramic (W) to metalloid-ceramic (W-Si) and ceramic-glass (W62) in the composite, respectively, and limited cracking in the impact region of the ceramic and the metallic struts interface when subjected to multiple dynamic impacts.

Characterization of titanium ceramic composite for bone implants applications

Bone implants are widely used to restore bone loss due to several factors including but not limited to osteoporosis, osteoarthritis and road injuries. Current bone implant materials restore mechanical stability but suffer from a lack of osteointegration and will need to be replaced after long term use. To circumvent this, tissue engineering which capitalizes on the use of cells, biochemical factors and biodegradable materials aim to develop a biological substitute that restores, maintain or improve tissue functions. Central to the improvement of the tissue function and its stability through the implant relies on its interaction with the host tissue. Hence, a bioactive implant that promotes osteointegration is more desirable than an inert implant. In this study, metal-ceramic composites are explored for their suitability to be used as bone implants in the future. Fabrication of the composite was optimized using hot press compression and vacuum sintering method. Data presented include physicochemical characteristics of titanium-hydroxyapatite and titanium-wollastonite analyzed via SEM, FTIR, XRD, 3D laser microscopy and mechanical test. Evidence of material biocompatibility with primary human osteoprogenitor cells is also provided. Both titanium hydroxyapatite and titanium wollastonite possess the potential as the future of metal-ceramic composites as they possess the bioactivity of ceramic while still maintaining its core titanium body as a source of strength.

Mechanical properties of Al2O3 and Al2O3/Al with Gyroid structure obtained by stereolithographic additive manufacturing and melt infiltration

To obtain both plasticity and toughness of the material at the same time, various manufacturing techniques of ceramic-metal composites and structures have been studied. In this work, a bio-inspired Al2O3 ceramic scaffold with Gyroid structure was designed and prepared by stereolithographic (SL) additive manufacturing, then the Al2O3/Al ceramic-metal hybrid structure was prepared by infiltrating molten Al into the Al2O3 ceramic structure. The performances of the Al2O3 ceramic scaffold and the Al2O3/Al ceramic-metal hybrid structure were compared and analyzed by a quasi-static compression experiment. The quasi-static compressive strength of the pristine Al2O3 scaffold was 14.36 MPa, while that of the Al2O3/Al ceramic-metal hybrid structure was up to 89.06 MPa. Moreover, the plasticity of the Al2O3/Al ceramic-metal hybrid structure was much higher than that of the Al2O3 scaffold. During compression, the Al2O3/Al ceramic-metal hybrid structure had excellent energy absorption, reaching up to 2569.16 KJ/m³, 15 times that of the Al2O3 scaffold. Therefore, this method can obtain materials with excellent ductility and toughness.

Investigation of Ultrasonic Attenuation and Hardness Relationship in Ceramic-Metal Composites

In material characterization, they contain a large amount of information at the frequency obtained about the mechanical and physical properties of the material under investigation, thanks to shear waves during the longitudinal passage of ultrasonic waves from materials.In this study, an experimental study was carried out on metal matrix composite samples to examine the variation of some ultrasonic parameters such as wave attenuation coefficients. Ultrasonic longitudinal and shear attenuation values obtained in copper-silicon carbide composites were measured at 4 MHz using the pulse-echo technique. All of the produced samples were sintered at 1050 ºC using microwave sintering technique. The variation of the shear attenuation values with the longitudinal wave in the material with the % SiC volumetric percentages of the hardness in the samples were measured. The experimental results obtained are discussed and analyzed to develop a technique in ultrasonic nondestructive testing for microstructure determination. It contains a large amount of information in the frequency obtained about the mechanical and physical properties of the material examined by the passage of ultrasonic waves through the materials. In this study, an experimental study was carried out to examine the variation of some ultrasonic parameters such as wave attenuation coefficients on metal matrix SiC doped composite samples. Ultrasonic longitudinal and shear attenuation values of produced copper-silicon carbide composite samples were measured at 4 MHz frequency by pulse-echo technique. Variations of longitudinal and shear attenuation values and hardness with % SiC volume percentages were determined. The experimental results obtained are discussed and analyzed to improve the ultrasonic nondestructive testing method for microstructure determination.

3D modeling and experimental investigation on the damage behavior of an interpenetrating metal ceramic composite (IMCC) under compression

In this study, an interpenetrating metal–ceramic composite, manufactured via gas pressure infiltration of AlSi10Mg into an open porous alumina foam is investigated three dimensionally on its damage behavior under compression. Experimentally, compression tests as well as in-situ computed X-ray tomography experiments with digital volume correlation evaluation were carried out. Numerically, the reconstructed microstructure of the interpenetrating metal–ceramic composite was modeled and compression tests were simulated via FEM simulation, to investigate the microstructural damage onset and failure behavior. Three stages of failure could be observed, which are described in detail on microstructural as well as macroscopic level. Additionally, a comparison between simulation and experiment is made, correlations are elaborated and observed differences discussed.

Selective laser melting of Ti6Al4V-B4C-BN in situ reactive composites

Desire for higher application temperatures and complex geometries for metallic materials has spurred significant development in additive manufacturing (AM) of metal-ceramic composites; however, limited process-microstructure-properties relationships exist for these materials and processing strategies. Herein we investigate the processing window and high-temperature oxidation performance of an in situ reactive, oxidation-resistant titanium metal-matrix composite reinforced with boron nitride (BN) and boron carbide (B4C) via selective laser melting (SLM) to understand the effects of processing parameters on the in situ reactive characteristics and their effects on build reliability and high-temperature oxidation performance. SLM processing required a 50% decrease in overall energy density relative to titanium's optimal parameters to avoid processing failure due to the high in situ reactivity and exothermic reaction between feedstock materials. A precise balance was necessary to combine decreasing the input energy to avoid cracking (due to in situ reactivity) while simultaneously providing enough input energy to keep the bulk density as high as possible to limit porosity that contributed to processing inconsistency at low input energy. Process optimization resulted in composites with as high as 98.3% relative density, comparable to some of the highest metal-ceramic composite densities reported in the AM literature. High-temperature oxidation testing revealed a 39% decrease in oxidation mass gain compared to AM-Ti6Al4V at 850°C, owing directly to ceramic reinforcement. Our results indicate that control of SLM processing parameters can yield advanced composites with enhanced properties and characteristics compared to the base material, revealing an array of design possibilities for researchers and engineers in many fields.

Realization of Phase and Microstructure Control in Fe/Fe2SiO4-FeAl2O4 Metal–Ceramic by Alternative Microwave Susceptors

This study provides a novel method to prepare metal–ceramic composites from magnetically selected iron ore using microwave heating. By introducing three different microwave susceptors (activated carbon, SiC, and a mixture of activated carbon and SiC) during the microwave process, effective control of the ratio of metallic and ceramic phases was achieved easily. The effects of the three susceptors on the microstructure of the metal–ceramics and the related reaction mechanisms were also investigated in detail. The results show that the metal phase (Fe) and ceramic phase (Fe2SiO4, FeAl2O4) can be maintained, but the metal phase to ceramic phase changed significantly. In particular, the microstructures appeared as well-distributed nanosheet structures with diameters of ~400 nm and thicknesses of ~20 nm when SiC was used as the microwave susceptor.

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

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.

High virucidal potential of novel ceramic-metal composites fabricated via hybrid selective laser melting and spark plasma sintering routes.

In this work, we combine selective laser melting (SLM) and spark plasma sintering (SPS) to fabricate new materials with high virucidal potential. Various bioactive disc-shaped ceramics, metal alloys, and composites were fabricated and tested against bacteriophage Phi6—a model system for RNA-enveloped viruses. We prepared silver-doped titanium dioxide (TiO2 + 2.5‒10% Ag), copper-doped titanium dioxide (TiO2 + 2.5‒10% Cu), Cu2NiSiCr, and Cu15Ni8Sn composite materials (metal lattices filled with ceramics). The virucidal tests of the ceramic and metal powders were performed in buffered suspensions, while the surfaces of the discs were tested by swabbing. The results show that the virus titer on the TiO2 + 10% Ag ceramic and CuNi2SiCr metal discs decreased by 4 logs after 15 min of exposure to the surfaces compared to the control ceramic and steel discs. We show that SLM 3D printed pre-alloyed CuNi2SiCr filled with bioactive TiO2 + 10% Ag nanopowders and sintered by the SPS process combines the simplicity of printing with the strength and virucidal properties of Ag and Cu materials. The proposed new virucidal materials were also used for the fabrication of prototype elevator buttons.

The mechanism of heavy injection of electric charges to realize linear strain behavior of textured PMN–24%PT ceramics combined with Pt grains

Strain hysteresis is one of the important issues on piezo-ceramic actuators conducting fast and high-precision actuation. In this work, a new regulation mechanism was employed to resolve this issue using 0–3 type metal–ceramic composite. Pb(Mg1/3Nb2/3)76%Ti24%O3 <001> textured ceramics modified by fine Pt grains (Pt@<001>PMN–24%PT) were designed and achieved. Linear strain behavior with zero hysteresis was achieved by 1 vol%Pt@<001>PMN–24%PT composite ceramics. Element maps and TEM images indicated that there was no diffusion between Pt and PMN–24%PT. We explored the correlation between composite structure and strain hysteresis performance. Experimental results and simulation analysis indicated that widely-distributed conjunctions between platinum and PMN–24%PT grains helped to inject a great quantity of charges into PMN–24%PT oxide. The inner high bias field caused by heavy injection of electric charges could pre-tighten the ferroelectric domains of textured PMN–24%PT ceramics. Only when the domain structure has been pre-tightened, linear piezoelectric strain is available.

Effect of WC addition on TiC reinforced Fe matrix composites produced by laser deposition

The TiC/Fe ceramic metal composite (MMC) with WC particles addition was successfully produced by laser deposition process. The effect of the WC addition to the Fe-based MMC on microstructure and mechanical properties was investigated. The results indicated that the MMC deposit consisted of primary TiC, (Ti, W)C, M6C(Fe3W3C and Fe4W2C), austenite, and a little martensite besides initial TiC and WC particles. The MMC matrix was refined by the various M6C including blocks, faceted dendrites, coarse eutectics, eutectic groups, and nanoparticles. With the M6C strengthing, the hardness of the mixed matrix was 13% higher than that of the TiC/Fe composite. Moreover, a core-rim structure appeared on the primary TiC bonding with (Ti, W)C solid solution, as well as the initial TiC. The rim of the (Ti, W)C solid solution can not only improve the MMC toughness but also reduce the lattice misfit of the TiC/Fe interface, which was supposed to improve the interface strength.

Mo–SiBCN metal-ceramic composites with enhanced and tunable thermophysical properties and thermal shock resistance

In this study, Mo–SiBCN metal-ceramic composites with or without sintering additives of MgO, Al2O3, and SiO2 were fabricated by hot-press sintering at 1800 °C/60 MPa/30 min to investigate their phase composition, microstructural evolution, mechanical properties, thermophysical properties and thermal shock resistance. With the increase in amorphous SiBCN, a competition of reaction products between Mo and SiBCN as Mo3Si → Mo3Si + Mo5Si3 + MoSi2 → Mo4.8Si3C0.6 + Mo5Si3 + MoSi2 → Mo4.8Si3C0.6 were detected. Meanwhile, the bulk density, elastic modulus and bending strength of the Mo–SiBCN composites gradually decrease with increasing SiBCN content, but their hardness first increases and subsequently decreases, reaching the highest value of 14.46 ± 0.43 GPa with 30 vol% SiBCN incorporation. Due to the oxide additives that promoted the sintering of composites, the bending strength and hardness of Mo–SiBCN composites with the additives increased 3–6 times. The residual bending strength of the Mo–SiBCN composites after thermal shock at 900 °C and 1600 °C decreased with increasing SiBCN content, while for the composites with 10–20 vol% SiBCN, the residual bending strength increased by 140–147%.

Vat Polymerization of Ceramic-Metal Composites: Influence of Additives on Rheological Properties, Cure Depth and Microstructure of Composites

Vat Polymerization of Ceramic-Metal Composites: Influence of Additives on Rheological Properties, Cure Depth and Microstructure of Composites

Фотокаталитическая деградация фармацевтических поллютантов при облучении УФ- и видимым светом с применением железосодержащих металлокерамических композитов

The adsorption and photocatalytic activity of iron-containing metal-ceramic composites produced by the self-propagating combustion of aluminum ferrosilicon in nitrogen with the addition of metallic tantalum (0, 5, 10, 15 wt%) during oxidative degradation of pharmaceutical pollutants (chloramphenicol, metamizole, cinnarizine) under UV and visible light was evaluated. The phase composition of the composite materials was determined by X-ray diffraction and infrared spectroscopy. The morphological features and optical properties of the composites were investigated, and the band gaps of the semiconductors included in the ceramic matrix were determined. The acid properties of the surface of the composites were studied using pH-metry and the Hammett indicator. The correlation of the number of surface-active sites and adsorption of pollutants with the corresponding value of pKa was shown, and the mechanisms of adsorption were proposed. Optimal conditions for the oxidative degradation of chloramphenicol (~100%) under visible light were found: a composite (5% Ta) with the addition of H2O2 to combine heterogeneous catalysis with the homogeneous photo-Fenton system.

Determining the influence of the microstructure and phase composition of glass-metal-ceramic coatings on their basic physical-technical properties

Given the development of new heat-resistant nickel alloys that operate at temperatures up to 1,250 °C, as well as the introduction of additive technologies for the production of various parts, it is a relevant task to devise new compositions of highly heat-resistant coatings. Determining the influence of the phase composition of glass-metal-ceramic coatings on its basic properties could improve the effectiveness of protecting those parts that operate under extreme conditions. Therefore, it is promising to conduct a study aimed at establishing the relationship between the microstructure and phase composition of glass-metal-ceramic coatings and the main physical-technical characteristics. This study's results have established that the most high-quality coatings were obtained on the basis of non-crystallizing glass. Such glass is characterized by a temperature coefficient of linear expansion of 92·10-7 degrees-1, a glass transition temperature of 625 °C, and surface tension of 260·10-3 N/m at 850 °C. These properties contribute to the formation of a defect-free coating, providing uniform spreading and high-quality adhesion to the substrate. The resulting optimal coating is characterized by the adhesion strength of 98 %, the thermal resistance (mode 950↔20 °C) of 50 cycles, and the high heat resistance (a weight gain after 100 h in the temperature range of 1,000‒1,050 °C) of 0.03 g/m2·h. Coatings with a minimum amount of glass bonding are distinguished by uniformity and high quality. The optimal ratio of phases "glass:metal-ceramic composition" is 10:90. The structure of the recommended coating is uniform, characterized by the homogeneous distribution of components, the absence of cracks, visible defects, and high quality. The phase composition of the coating after firing is represented by crystals of metallic nickel and silicon, as well as a small amount of residual glass phase.