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Additive manufacturing technology is being developed for manufacturing SiC ceramic parts with designed shape and microstructure. In this study, direct ink writing (DIW) was adopted to print SiC ceramic parts. To avoid incorporating volatile organic solvents or water, a SiC ceramic precursor liquid polycarbosilane (LPCS) was used as the binder of SiC powder and the rheological adjustment additive. The content of LPCS with the content and diameter of SiC powder were optimized to improve the fluidity of slurry, increase its ceramic yield and reduce its shrinkage during pyrolysis. According to the results of rheological analysis and shrinkage during pyrolysis, 78 wt% SiC powders composed of 40 nm SiC powder and 5 μm SiC powder in a ratio of 1:6 was appropriate. For achieving rapid solidification rate of the slurry at low temperature, a free‐radical initiator which can trigger the crosslinking of allyl group on LPCS was incorporated. According to the results of rheology, DSC and FT-IR, the preferred platform temperature for fast curing of DIW slurry was 150 °C. As the slurry accumulated layer by layer on heating platform, the cured green bodies were successfully prepared. After pyrolysis to 1200 °C, SiC ceramic parts were obtained with only 4.43 % linear shrinkage associated with the precursor-to-ceramic conversion. Because the shrinkage was limited, no obvious deformation or crack was found. [ABSTRACT FROM AUTHOR]

The present research investigation utilizes nano-sized graphite (Gr) and silicon carbide (SiC) as secondary fillers incorporated into a primary aluminium alloy (Al6061) matrix using a two-step stir casting method. Investigate the impact of this advanced two-step stir technology on the microstructure of the hybrid composite using a scanning electron microscope equipped with a tungsten-heated cathode electrode. This study assesses the effects of Gr and SiC on the porosity, density, tensile properties (yield strength, ultimate strength, and elongation), microhardness, and impact toughness of the hybrid nanocomposite at room temperature with a relative humidity of 60 %. The homogenous structure of the Al6061/5 wt% Gr/9 wt% SiC hybrid nanocomposite exhibits superior mechanical properties compared to other compositions. Specifically, the two-step stir casting technique has demonstrated the ability to reduce the porosity level to less than 1 %, resulting in enhanced yield strength (124±4 MPa), tensile strength (153±3 MPa), and microhardness (92±2 HV). [ABSTRACT FROM AUTHOR]

The primary purpose of this study is to gain a deeper understanding of the structure and mechanics of an ex-situ A356/Cu-coated with different weight percentages (x: 1, 3) of SiC stir-cast metal matrix composite. This study aims to improve silicon carbide's wetting and adhesion characteristics by fabricating a Cu-coated composite utilizing an electrolytic deposition technique based on aluminum. This green manufacturing method significantly reduces environmental impact compared to traditional coating processes, a crucial aspect in today's world. Examination of the optical microstructure of the SiC composite revealed a clustering of reinforcements within the matrix, potentially resulting from additional barriers formed during the stirring process that impede the movement of SiC particles. Furthermore, incorporating copper-coated SiC reinforcement led to a more even distribution of reinforcements in the matrix. The ultimate tensile strength, yield strength, and hardness of the 3 wt% copper-coated metal matrix composite cast are 225.97 MPa, 130.27 MPa, and 76.5 BHN, respectively, demonstrating superior mechanical properties compared to the other cast composites. The study opens potential paths for further advancements in composite technology. [ABSTRACT FROM AUTHOR]

A novel α/β SiC-(Ti, Nb)B 2 toughened (Ti, Nb)C-based composites was fabricated by reactive hot pressing with TiC, NbB 2 and Si powders at 1500 °C and 1600 °C, respectively. The influence of NbB 2 , Si content, and sintering temperature on the microstructure and mechanical properties of the composite was investigated. The intermediate product NbC reacts with Si to form NbSi 2 and β-SiC phases. With addition of 10 mol% NbB 2 , a toughening phase α-SiC was formed. During the reaction process, insufficient diffusion of Nb atoms in TiC leads to the formation of a specific "core-shell" microstructure, which improves the flexural strength of the composite ceramics. The (Ti, Nb)C has a specific crystallographic orientation relationship with NbSi 2 and α-SiC. The high-density stacking faults and ordered structures in β-SiC crystals enhances its hardness. The rod-shaped α-SiC and plate-like (Ti, Nb)B 2 by in situ reactions effectively improve the fracture toughness of the composites. TiC-32 mol% Si-10 mol% NbB 2 (raw powder composition) sintered at 1600 °C has excellent comprehensive mechanical properties, with fracture toughness, flexural strength, and Vickers hardness of 5.45 MPa·m1/2, 665 MPa, and 22 GPa, respectively, which provide a new insight into the optimization strength and toughness of TiC-based composites. In addition, under high temperature oxidation of 1000∼1200 °C, the 30NB (54 mol% TiC-16 mol% Si-30 mol% NbB 2) sample has better high-temperature oxidation resistance than the 30ZB (54 mol% TiC-16 mol% Si-30 mol% ZrB 2) sample. [ABSTRACT FROM AUTHOR]

AbstractThe present investigation focuses on the synthesis of mono (AA5052/SiC and AA5052/graphene) and hybrid (AA5052/SiC/graphene) surface composites using friction stir processing (FSP). This work examines the synergistic effect of SiC and graphene on the fabricated surface composites. Macro/microstructure, microhardness, and wear test analysis were done on these samples, and the results were compared with the base material AA5052-H32. The microstructure analysis showed that the distribution of reinforcement particles in the aluminum matrix is made more uniform by adding hard SiC with graphene nanoparticles, which can reduce the occurrence of particle clustering and agglomeration. As a result, the smallest grain size of 11.2 µm and the highest microhardness obtained was 84.1 HV obtained in hybrid surface composites. Consequently, the hybrid surface composites obtained more improved wear properties than mono surface composites. Thus, the hybrid surface composites achieved the lowest average friction coefficient of 0.304. [ABSTRACT FROM AUTHOR]

Aluminum-based hybrid nanocomposites, namely the Al6061 alloy, have gained prominence in the scientific community due to their unique properties, such as high strength, low density, and good corrosion resistance. The production of these nanocomposites involves incorporating reinforcing nanoparticles into the matrix to improve its mechanical and thermal properties. The Al6061 hybrid nanocomposites were manufactured by conventional powder metallurgy (cold pressing and sintering). Ceramic silicon carbide (SiC) nanoparticles and carbon nanotubes (CNTs) were used as reinforcements. The nanocomposites were produced using different reinforcement amounts (0.50, 0.75, 1.00, and 1.50 wt.%) and sintered from 540 to 620 °C for 120 min. The characterization of the Al6061 hybrid nanocomposites involved the analysis of their mechanical properties, such as hardness and tensile strength, as well as their micro- and nanometric structures. Techniques such as optical microscopy (OM) and scanning electron microscopy (SEM) with electron backscatter diffraction (EBSD) were used to study the distribution of nanoparticles, the grain size of the microstructure, and the presence of defects in the matrix. The microstructural evaluation revealed significant grain refinement and greater homogeneity in the hybrid nanocomposites reinforced with 0.75 wt.% of SiC and CNTs, resulting in better mechanical performance. Tensile tests showed that the Al6061/CNT/SiC hybrid composite had the highest tensile strength of 104 MPa, compared to 63 MPa for the unreinforced Al6061 matrix. The results showed that adding 0.75% SiC nanoparticles and CNTs can significantly improve the properties of Al6061 (65% in the tensile strength). However, some nanoparticle agglomeration remains one of the challenges in manufacturing these nanocomposites; therefore, the expected increase in mechanical properties is not observed. [ABSTRACT FROM AUTHOR]

The microstructure of SiC ceramic particle-reinforced FeCoNiCrAl high-entropy alloy specimens prepared by laser cladding was observed, and the effects of SiC and Al content and laser process parameters on the microstructure of laser cladding high-entropy alloy were analyzed. The results show that increasing the scanning speed and laser power or reducing the powder feeding rate is conducive to obtaining smaller grains and forming a denser microstructure. However, when the laser power and scanning speed are too large, pores and unmelted powder will appear. Increasing the content of SiC ceramic particles significantly increases the number of heterogeneous nucleation points, resulting in a decrease in the grain size in the cladding layer and a more tortuous grain boundary, which is conducive to improving comprehensive performance. However, when the SiC content is too high, defects, such as cracks and inclusions, are prone to occur. With the increase of Al content, the grain size in the cladding layer increases first and then decreases. [ABSTRACT FROM AUTHOR]

The development of lightweight and high-strength materials is critical for many industries, including aerospace, automotive, and electronics. Metal matrix composites (MMCs) have shown great promise in meeting these requirements. The structural and physical properties of Al6061 alloy reinforced with hybrid MMCs, including TiB2, SiC, and fly ash (FA), were investigated in this research review. The MMCs investigated were made using the stir-casting process. Their microstructure, structural characteristics, and mechanical features were examined. The inclusion of TiB2 and SiC enhanced the composite’s hardness, tensile strength, and wear resistance, while the addition of FA lowered its density and improved its thermal and corrosion resistance. However, the volume percentage, particle dimension, and arrangement of the reinforcing components all had an effect on the physical characteristics of the composite. Therefore, the optimum combination of the reinforcing materials must be carefully selected to achieve the desired properties. The result of this review provides valuable insights into the development of high-performance MMCs for various industrial applications. [ABSTRACT FROM AUTHOR]

In this study, the researchers have attempted to reinforce ZK60 alloys with 5% SiC, 10% SiC, 5% B4C, 10% B4C and 5%SiC + 5%B4C microparticles and investigated the dry wear behavior of these composites. The reinforced composites were produced by the stirred casting method under the atmosphere of SF6. The high-temperature oxidation tendency of Mg and B elements can cause the oxidized-unsuccessful product in the stirred casting process. Therefore, the researchers used the semi-solid temperature stirring method in production as a new solution. The reinforced composites were homogenized at 420 °C for 24 hours and extruded at a rate of 2.25. Following the production process, all samples underwent microstructural characterization analyses, hardness tests, compression tests and dry wear tests. Comparative analysis was done between the results of unreinforced ZK60 alloy and composites from compression and wear tests. This study's results reveal a superior enhancement; the addition of 5% SiC increased the compressive strength of ZK60 alloy by 15%, while the addition of 5% B4C increased by 26%. Furthermore, adding the 5%SiC reinforcement reduced the wear rate by 4.3%, and the 5% B4C reinforcement reduced the wear rate by 11.1%. [ABSTRACT FROM AUTHOR]

In this study, mechanical grinding, chemical surface treatment and copper electroplating were adopted to treat the inner surface of the outer A356 layer of the A356/A356-10SiCp double-layer cylinder liner. The effects of different surface treatments on the microstructure and mechanical properties of the composite interface were investigated. The results show that the composite interface treated with mechanical grinding is bonded mechanically because of the secondary oxidation on the inner surface of the outer A356 aluminum alloy cylinder liner, and there are many gaps at the interface, resulting in a compromised interfacial bonding strength of merely 4.05 MPa. Both the chemical method and copper electroplating surface treatments effectively inhibited the secondary oxidation on the internal surface of the outer A356 aluminum alloy cylinder liner, enhancing interfacial wettability. The microstructure revealed no discernible gaps at the composite interface, achieving a good metallurgical bonding interface. Notably, the shear fracture surface of the copper electroplated treatment exhibited minimal oxide and inclusions, resulting in superior interface bonding strength of 13.27 MPa which is higher than that of the chemical surface treatment of 6.37 MPa. [ABSTRACT FROM AUTHOR]

Environment coatings are frequently considered, to improve the corrosion resistance of silicon carbide (SiC) in pressurized water reactor (PWR) and boiling water reactor (BWR) surroundings. Chromium (Cr) is one of the main candidate materials for coatings on zirconium-based alloys for accident-tolerant fuel (AFT) cladding. In this work, the magnetron sputtered Cr coatings on SiC substrates were irradiated by the 500 keV He+ ions at room temperature. Moreover, the microstructural characterization was conducted on the irradiated specimens by using scanning electron microscope (SEM), and transmission electron microscope (TEM). The scratch test showed that the coating-substrate adhesion decreased from 41 N to 28 N (∼31.7%) before and after the irradiation, maybe due to that the irradiation produced tensile strain in the coating and mesophase along the coating-substrate interface. It revealed that irradiation accelerated the migration and aggregation of C elements on the surface of the coating. After the 800 °C annealing for 20 min, massive Cr atoms diffused into the SiC matrix and reacted with Cr to form a chromium silicide interlayer. Some cracks were observed at the interface, being attributed to the Kirkendall effect. Therefore, it is very necessary to avoid the formation of chromium silicide interlayer and decrease swelling mismatch between the metal coatings and the SiC substrate for the actual application in nuclear systems.

In this study, SiC-reinforced aluminum matrix composites were powder metallurgically (PM) prepared and sintered using high-frequency induction system (HFIS). The samples with different ratios of SiC (wt.%10, 20 and 40) added to the aluminum matrix were sintered at 660, 800, and 1000 °C. In addition, Al/SiC composites were compared by sintering with the conventional sintering (CS) method under similar sintering conditions. The heating rate for the sintering process using HFIS was 500 °C/min, while the CS method used a heating rate of 10 °C/min. The effect of the temperature and SiC ratio on the density, hardness, phase structure, and microstructure of composites was investigated. The optimum sintering temperature was determined according to the SiC additive amount. When 10%, 20%, and 40% SiC by weight were added to the aluminum matrix in the sintering process with HFIS, the required sintering temperatures were determined as 660, 800, and 1000 °C, respectively. While new phases were not formed as a result of short-term HFIS sintering, a high-temperature Al4C3 phase was detected in CS sintering. HFIS sintered Al/SiC composite samples were obtained in Al and SiC phases with high density and hardness ranging from 43-118 HV. In the high-temperature sintering process with HFIS, the formation of Al4C3 was prevented and its physical and mechanical properties were improved. [ABSTRACT FROM AUTHOR]

Ni‐based alloys provide good brazing filler characteristics for the many applications of SiC ceramics. Nevertheless, the presence of graphite is unavoidable in the reaction between Ni and SiC, leading to a significant degradation of the mechanical properties of the joint. This study investigates the effect of Mo in Ni–30Si alloy on the brazing of SiC at 1300°C, to regulate interfacial reactions and reduce residual stresses by decreasing overall coefficient of thermal expansion (CTE) values throughout the brazing process. The addition of Mo up to 8 at.% efficiently suppresses graphite accumulation by converting it into Mo2C + Ni3Mo3C phases and lowering the CTE to 5.4 × 10−6/°C. When the Mo loading exceeds 12 at.%, the interactions between the filler and SiC are reduced as a result of the non‐homogeneous dispersion of Mo. The experimental findings indicate that the joint without graphite has a lap shear strength of 107 MPa, which is nearly three times greater than the joint with graphite. Thermodynamic analyses are performed to provide a comprehensive understanding of the underlying mechanisms responsible for the formation of distinct phases in brazed joints. [ABSTRACT FROM AUTHOR]

The preparation of SiC-based ceramics with high densification, high strength and exceptional toughness is still a severe challenge. In the present work, an advanced sintering technique namely oscillatory pressure sintering (OPS) was applied to prepare SiC ceramics with one-dimensional silicon carbide whiskers (SiCw) and two-dimensional graphene nanoplatelets (GNPs) as reinforcing phases, and the microstructure and mechanical properties were comprehensively investigated. When the contents of GNPs and SiCw were 1 wt% and 5 wt% respectively, the relative density of SiC-based ceramics reached 99.86%, while the Vickers hardness, flexure strength and fracture toughness were 31.55 GPa, 742 MPa and 7.32 MPa m1/2, respectively. The interface was strengthened, meanwhile the grain size was decreased, both of which enhanced the flexural strength of the composites. Results also proved that crack deflection and bridging as well as the bridging of GNPs and SiCw toughened SiC-based ceramics. Furthermore, the coherent interfaces of SiC/GNPS and SiC/SiCw with good match were observed, leading to an enhancement of mechanical properties of such ceramics. [ABSTRACT FROM AUTHOR]

Solid state sintering of cast aluminum powders by resistance heating sintering (RHS), also known as spark plasma sintering or field-assisted sintering technique, creates a very fine microstructure in the bulk material. This leads to high performance material properties with an improved strength and ductility compared to conventional production routes of the same alloys. In this study, the mechanical behavior of an RHS-sintered age-hardenable A357 (AlSi7Mg0.6) cast alloy and a SiCp/A357 aluminum matrix composite (AMC) was investigated. Aiming for high strength and good wear behavior in tribological applications, the AMC was reinforced with a high particle content (35 vol.%) of a coarse particle fraction (d50 = 21 µm). Afterwards, separated and combined effects of particle reinforcement and heat treatment were studied under compressive load both at room temperature and at 350 °C. At room temperature compression, the strengthening effect of precipitation hardening was about twice as high as that for the particle reinforcement, despite the high particle content. At elevated temperatures, the compressive deformation behavior was characterized by simultaneously occurring temperature-activated recovery, recrystallisation and precipitation processes. The occurrence and interaction of these processes was significantly affected by the initial material condition. Moreover, a rearrangement of the SiC reinforcement particles was detected after hot deformation. This rearrangement lead to a homogenized dispersion of the reinforcement phase without considerable particle fragmentation, which offers the potential for secondary thermo-mechanical processing of highly reinforced AMCs. [ABSTRACT FROM AUTHOR]

Friction stir spot welding (FSSW) is a prominent solid-state adhesion process. In the recent past, several investigations are performed for the property enhancement of FSSW welded joints especially on the mechanical and metallurgical characterization. In this work, an attempt has been made to analyze the effect of environmental conditions on the output quality characteristics of SiC reinforced Al6061-T6 welded joints, fabricated at optimal parametric setting. For this, welded joints are preserved at sub-zero temperature of −18 ± 2 °C for 90, 180, 270 and 360 days. Output quality characteristics in terms of tensile-shear and micro-hardness test in combination with microstructure analyses using SEM, EDS Mapping, and XRD analysis are emphasized. It is revealed that during sub-zero cooling, weld strength and micro-hardness of weldments increased over time. Additionally, a decrease in crystal size and increase in dislocation density are observed with increase in cooling period of weld joint, which eventually made suitable for extreme applications.

Aluminum-based hybrid nanocomposites, namely the Al6061 alloy, have gained prominence in the scientific community due to their unique properties, such as high strength, low density, and good corrosion resistance. The production of these nanocomposites involves incorporating reinforcing nanoparticles into the matrix to improve its mechanical and thermal properties. The Al6061 hybrid nanocomposites were manufactured by conventional powder metallurgy (cold pressing and sintering). Ceramic silicon carbide (SiC) nanoparticles and carbon nanotubes (CNTs) were used as reinforcements. The nanocomposites were produced using different reinforcement amounts (0.50, 0.75, 1.00, and 1.50 wt.%) and sintered from 540 to 620 °C for 120 min. The characterization of the Al6061 hybrid nanocomposites involved the analysis of their mechanical properties, such as hardness and tensile strength, as well as their micro- and nanometric structures. Techniques such as optical microscopy (OM) and scanning electron microscopy (SEM) with electron backscatter diffraction (EBSD) were used to study the distribution of nanoparticles, the grain size of the microstructure, and the presence of defects in the matrix. The microstructural evaluation revealed significant grain refinement and greater homogeneity in the hybrid nanocomposites reinforced with 0.75 wt.% of SiC and CNTs, resulting in better mechanical performance. Tensile tests showed that the Al6061/CNT/SiC hybrid composite had the highest tensile strength of 104 MPa, compared to 63 MPa for the unreinforced Al6061 matrix. The results showed that adding 0.75% SiC nanoparticles and CNTs can significantly improve the properties of Al6061 (65% in the tensile strength). However, some nanoparticle agglomeration remains one of the challenges in manufacturing these nanocomposites; therefore, the expected increase in mechanical properties is not observed.

In this study, TaB 2 -20 vol% SiC composites with and without rare-earth oxides (RE 2 O 3 , RE = Y and La) were fabricated via hot pressing at or above 1800 °C. 3 vol% RE 2 O 3 additions improved the sinterability of TaB 2 -SiC composite and resulted in a finer microstructure in addition to the crystalline RE 2 Si 2 O 7 grain-boundary phase. The shear and Young's moduli as well as hardness of the composites decreased with RE 2 O 3 additives. Conversely, the fracture toughness of the composites increased with RE 2 O 3 additives and the toughening effect was better for La 2 O 3 than for Y 2 O 3. On the other hand, the additions of RE 2 O 3 substantially enhanced the flexural strength and the strengthening effect was significantly stronger for Y 2 O 3 than for La 2 O 3 , the strengthening was ineffective at or above 1400 °C, however. Additionally, the temperature dependence of strengths varied with and without RE 2 O 3 additions, as a result of the difference in the chemistry of the intergranular phases. [ABSTRACT FROM AUTHOR]

The present study aims to refine the solidification structure of 2319 Al-alloy Wire Arc Additive Manufacturing (WAAM) deposits by adding SiC powder to the interlayer during deposition. The fabricated deposits are subjected to aging treatment. The influence of SiC particle addition and aging treatment on evolution of microstructure and the corresponding hardness and tensile properties was investigated. To enable systematic understanding of the process, thermal simulation using ANSYS has been done for a single layer deposition and compared with the experimental data. The peak temperature for the deposits made with and without SiC particle addition is around 927.53 °C and 915.43 °C respectively. Three distinct structural zones were clearly seen in as-deposited specimens made without SiC particle addition. However, the deposits with SiC favored the formation of equiaxed grain throughout the specimen. The presence of α-Al and θ-Al2Cu phases in the as deposited specimen (without SiC) is confirmed through X-Ray Diffraction (XRD) and Electron Probe Micron Analyzer (EPMA), while the specimen deposited with addition of SiC particles demonstrates the presence of α-Al, θ-Al2Cu, and SiC phases. Post-Deposition Heat Treatment (PDHT) aids in uniform formation of θ-Al2Cu precipitates in both specimens. Deposits fabricated with SiC (308 ± 5 MPa) recorded higher Ultimate Tensile Strength (UTS) in comparison to without SiC deposits (260 ± 5 MPa). On the other hand, after heat treatment, the as-deposited specimen (without SiC) achieved an UTS of 468 ± 5 MPa, while the deposit fabricated with SiC recorded an UTS of 484 ± 5 MPa. [ABSTRACT FROM AUTHOR]

The borosilicate glass was used to join reaction bonded silicon carbide through two steps, namely: laser cladding and low-temperature heat treatment. The wettability and microstructure of the laser cladding glass layer were examined, while joint microstructure and strength were analyzed at various temperatures and times. The results show that the laser cladding layer improved the wetting of glass on the substrate, formed a good interfacial bond, and reduced the joining temperature. The joints primarily consist of the glass phase, the boron-rich phase, and a few crystals. The high-strength joints obtained after heating the joint interface at 950 °C for 30 min had a flexural strength of 250 ± 20 MPa, a 68% improvement compared with direct connection under the same conditions. The joints also exhibit good thermal shock resistance and high-temperature strength. At 400 °C (thermal shock temperature) and 600 °C (test temperature), the residual flexural strengths were 122 ± 25 and 152 ± 12 MPa, respectively.

A specialized CaO–Al 2 O 3 –SiO 2 (CAS) glass-ceramic was innovated to join SiC ceramics. The crystallization kinetics of the CAS glass was studied, revealing distinct anorthite precipitates in the CAS glass-ceramic. The impact of process parameter variations on microstructure and mechanical properties was studied. It revealed that post-joining crystallization heat-treatment could change the size and the content of crystals and significantly improve the shear strength of the joint. It was duly observed that a remarkable shear strength of 86 MPa was achieved when the joint was formed at the temperature of 1450 °C and treated at 1050 °C for crystallization. Notably, this exceptional mechanical endurance remained impressively high, maintaining a value of 85 MPa at 800 °C. Based on density functional theory calculations, it was confirmed that glass/C–SiC (0001) has a stronger interface bond than glass/Si–SiC (0001), resulting in a reliable joining at the glass/C–SiC (0001) interface for CAS glass and SiC. [ABSTRACT FROM AUTHOR]

In the present work, the microstructures and mechanical properties of Cu-foam-(graphene, LiAlSiO 4 and graphene/LiAlSiO 4) and a CoCrNiFeCuSn high-entropy alloy as a composite interlayer for brazing Zr and silicon carbide (SiC) ceramics are explored. Further, the effects of graphene, LiAlSiO 4 , and graphene/LiAlSiO 4 on the mechanical properties and microstructure of the SiC/Zr joint are investigated. The results of the data analysis reveal a good connection between SiC and Zr at 1040 °C for 20 min using the different composite interlayers, Cu-foam-graphene, Cu-foam-LiAlSiO 4 , or Cu-foam-graphene-LiAlSiO 4 , with shear strengths of 122, 147, and 235 MPa, respectively. Particularly, the Cu-foam-graphene-LiAlSiO 4 brazed joint demonstrates the highest shear strength. Furthermore, the dispersion of LiAlSiO 4 in the joint reduces the coefficients of thermal expansion of difference between the brazing materials and ceramics, as well as the residual stress in the joint. Moreover, the synergistic effect of the solid-solution phase, Zr(s, s), with excellent plastic deformation, and enhanced Zr(Cr, Fe) 2 phase further improves the strength and plasticity of the joint. [ABSTRACT FROM AUTHOR]

To decrease impacts on the environment and maintain competitiveness in the market, various industries (for example, fabrication and construction) are concentrating on minimizing material and energy usage. Aluminium (Al) and its alloys are contending possibilities for various complex applications to meet these industrial needs since they have improved qualities like good weight-to-strength ratios. Fusion welding causes the joints to deteriorate while joining Al. Friction stir welding (FSW) or friction Stir Processing (FSP) creates joints below melting point temperatures, eliminating the drawbacks of excessive heat input but necessitating an increase in the joint's final characteristics. Nanoparticle reinforcement is an emerging field that provides great methods to create composite joints with improved joint characteristics. The surface attributes of composite joints can be improved, including hardness, strength, corrosion resistance, and wear resistance. This paper critically reviews the work carried out in the field of FSW/FSP welding AA5083 and AA6082 with carbide and oxide as reinforced nanoparticles. Further trends in nanoparticle reinforcement, oxide and carbide effect on welding parameters, microstructural formation, and mechanical properties are being analyzed. Analysis shows that the diffusion of the reinforcing nanoparticles, which affects the joint characteristics, is significantly influenced by FSW/FSP parameters. Additionally, the dispersed nanoparticles enhance joint characteristics and help refine grains. The kind, quantity, & size of reinforced nanoparticles and the welding conditions greatly influence the joint characteristics and microstructures in similar and different Al welds. Finally, prospects for a reinforced FSW are examined, followed by a look ahead and concluding notes. [ABSTRACT FROM AUTHOR]

The α-SiC/SiO 2 and α-SiC/β-SiC composites were prepared by pressureless sintering. The physical properties and microstructure were characterized. Compared to SiO 2 , the in situ formation of β-SiC was more beneficial to density of α-SiC composites. The stability in magnesium metallurgy environment of different SiC composites was investigated. The SiC composites are corroded by two ways: SiC activated oxidation and grain boundary corrosion by slag. In low oxygen environment, the activated oxidation of SiC forms SiO, resulting in the destruction of SiC surface structure. The CaO and other oxides in the slag are easy to react with SiO 2 , which continuously corrodes the grain boundaries and eventually leads to the continuous shedding of SiC grains. In particular, the conversion of β-2CaO · SiO 2 to γ-2CaO · SiO 2 results in volume expansion of about 12%, resulting in grain boundary expansion and structural failure. The α-SiC/β-SiC composites had higher density and better corrosion resistance to magnesium slag. [ABSTRACT FROM AUTHOR]

The purpose of this study was to explore the effect that stir casting has on a TiO2 and SiC nanoparticles reinforced aluminium matrix composite. In order to study the development of ceramic particle reinforced aluminium matrix composite, density, tensile strength, hardness, and fracture analyses were carried out. The scanning electron microscope (SEM) investigation showed that the reinforcement particles were distributed consistently throughout the aluminium matrix. Electron backscatter diffraction (EBSD) study revealed the grain refinement of composites on inclusion of nanoparticles. The results of the experiments revealed that addition of 3 weight percent TiO2 and SiC particles to AA7178 alloy led to an increase in both the maximum strength and the hardness properties but, the elongation percentage of the manufactured composites progressively deteriorated. From the fractured surface of tensile samples, a microstructural study showed that AA7178, AA7178/TiO2, and AA7178/SiC nanocomposites were showing both ductile and brittle behaviour because of micro-cutting and micro-voids. [ABSTRACT FROM AUTHOR]

In the present study, SiC-Al ball milled powder reinforcement composite for AA6061 parent metal was synthesized by the gravity die casting process. Investigation for the impact of reinforcement addition was conducted according to the metallurgical and microstructural properties. In the process, refined SiC + Al powder mixture was added in AA-6061 slurry by stirring action and mixed liquid slurry was poured inside the cavity of the gravity die casting mold. Solidification of the melt was allowed under room temperature and conventional cooling took place inside the mold cavity. Solidified cast composites were investigated according to the impact, hardness and density with microstructural characteristics for 2% and 4% by wt. of SiC with respect to a combination of Al powder and AA6061 alloy. Investigation reveals that properties of cast composite are improved according to the reinforcement addition for SiC. Cast microstructure, EDX and XRD of the composite shows the formation of interfaces of Al + SiC near the cavities and spaces available at various location which is a key candidate for improvement in properties. [ABSTRACT FROM AUTHOR]

The bottleneck problems of SiC particles reinforced AlSi10Mg composites (SiC/AlSi10Mg) prepared by traditional casting method, such as composition segregation, interface reaction and coarse microstructure, can be effectively improved by powder metallurgy with lower processing temperature. In this study, the influence of SiC particle size and content on the properties of SiC/AlSi10Mg was systematically analyzed. SiC/AlSi10Mg composites were prepared by planetary ball milling, spark plasma sintering (SPS) and hot extrusion composite preparation process. The obtained composites presents dense microstructure without the formation of interfacial reaction phase. The distribution of micron SiC particles (μm-SiC) in the matrix is relatively uniform, and nano SiC particles (nm-SiC) slightly agglomerates with the increase of the content. The strength of SiC/AlSi10Mg increases with the increase of nm-SiC content, which is mainly attributed to dispersion strengthening, dislocation strengthening and grain refinement strengthening. The strength of SiC/AlSi10Mg hardly changes with the increase of μm-SiC content, but the elongation decreases gradually. The deformation between μm-SiC and AlSi10Mg matrix is not coordinated and μm-SiC cleave the AlSi10Mg matrix. The irregular boundaries of μm-SiC are easy to produce stress concentration during loading, leading to interface cracking or μm-SiC fracture. Therefore, μm-SiC are difficult to play a significant strengthening effect to composites. With the increase of SiC content, the fracture mechanism of composites gradually changes from ductile fracture to brittle fracture in SiC agglomeration region. This study lays a theoretical and experimental foundation for the controllable preparation and performance optimization of high strength and toughness AMCs reinforced by SiC particles.

Magnesium matrix composite is another competitive light metal matrix composite following aluminum matrix composite, with excellent application prospects in the aerospace and automotive fields. In this paper, the Mg - 3Y – xSiCp (x = 0, 1, 3, 5 wt%) composites are fabricated by stir casting with ultrasonic vibration followed by extrusion. The microstructure of the alloys is investigated by means of scanning electron microscopy (SEM) imaging and electron backscatter diffraction (EBSD) techniques. The results reveal that the composites have a finer grain size due to the particle promoted nucleation (PSN) mechanism. When the SiCp content is 3 wt%, the grain size is the smallest (0.76 μm), and the refinement rate is about 16.7%. Moreover, the addition of SiCp can inhibit the transformation from low-angle grain boundaries (LABGs) to high-angle grain boundaries (HABGs), thus hindering the dynamic recrystallization (DRX) of the alloy, which decreases from 55.7% to 15.4%. The reduction in the proportion of recrystallized grains in the composite leads to increasing the maximum intensity of the texture. In addition, the tensile properties and the strengthening mechanism of the alloys are investigated. The results show that the composites have higher ultimate tensile strength (UTS) and yield strength (YS) due to the combination of grain refinement and dislocation strengthening. When the SiCp content is 5 wt%, the UTS (291 MPa) and YS (283 MPa) increase by ∼12.7% and ∼17.1%, respectively, over the matrix alloy. However, the addition of SiCp causes more oxides and holes in the alloys, which leads to a fracture strain (δ) decrease in the composites.

The object of the research is electrically conductive ceramics. It aims to analyze the microstructure of electrically conductive ceramic composites based on silicon carbide and investigate the influence of silicon carbide content on their properties. This study is pivotal for enhancing materials used in high-tech applications, particularly in fields where distinct electrical insulation and mechanical characteristics are crucial. The microstructure analysis conducted through scanning electron microscopy confirmed the presence of silicon carbide in all examined ceramic samples, except in those where silicon carbide was not added. Special attention should be given to the sample with 30 % silicon carbide, distinguished by the lowest open porosity. These findings are corroborated by previous research where this sample exhibited superior properties: open porosity – 12.51 %, water absorption – 5.88 %, apparent density – 2.13 g/cm², specific resistance – 0.43·106 Ω·m. These characteristics indicate low porosity and high structural-physical property values. The results not only affirm the successful incorporation of silicon carbide into the ceramic matrix but also highlight the prospects for applying the researched ceramic materials in areas where electrical insulation and mechanical properties are crucial. Specifically, the sample with 30 % silicon carbide appears particularly promising due to its high characteristics and lower porosity, making it potentially interesting for applications in high-tech industries such as electronics and telecommunications. The conclusions suggest the potential use of these ceramic materials in various high-tech industries where both electrical and mechanical properties are essential. The sample with 30 % silicon carbide, with its exceptional characteristics, holds potential for applications in advanced technologies. Further research in this direction could lead to the development of new materials for effective radiofrequency absorption, finding broad applications in different technological fields. [ABSTRACT FROM AUTHOR]

Organic-carbon-precursor-added B 4 C and B 4 C–SiC ceramics were subjected to pressureless sintering at various temperatures. The carbon precursor increased the densification of the B 4 C and B 4 C–SiC ceramics sintered at 2200 °C to 95.6 % and 99.1 % theoretical density (T.D.), respectively. The pyrolytic carbon content of the B 4 C–SiC composite decreased with increasing SiC content. The graphitization degree of pyrolytic carbon decreased slightly with the amount of carbon precursor and content of SiC. The 95 wt. % B 4 C–5 wt. % SiC composite added with 7.5 wt. % carbon precursor and sintered at 2200 °C outperformed the other B 4 C–SiC composites, and its sintered density, flexural strength, Young's modulus, and microhardness were 98.6 % T.D., 879 MPa, 415 GPa, and 28.5 GPa, respectively. These values were higher than those of composites prepared via pressureless sintering and comparable to those of composites fabricated via hot pressing and/or using metal or oxide additives. [ABSTRACT FROM AUTHOR]

This study is showing the performance of two different silicon-based nano material acting as possible nanofiller in aluminium alloy metal matrix composites. The major objective of this research was to examine the effectiveness of both the fillers in tribo-mechanical behaviour and their influence in microstructure when they are reinforced into the aluminium matrix. The Si3N4 fine particles are produced from rice husk ash by carbothermal reduction and nitridation (CTRN) whereas the SiC particles utilised here were as-received. The composites of aluminium with variable proportion of nanofillers were produced by stir casting method. The samples were characterised using ASTM standards. According to the results, the addition of SiC particles enhanced the density and wear resistance whereas the addition of Si3N4 improved the fatigue and mechanical characteristics with smaller density gain. The microstructure of aluminium indicated fine incorporation of Si3N4 than SiC in Al matrix. The fine precipitates were shown for the increase of strength in composite. These plant waste generated silicon-based fillers may be a great alternative for existing fillers like SiC, SiO2, CBN, B4C, and WC and therefore enhanced the circular economy and waste-derived economy. [ABSTRACT FROM AUTHOR]

The stir casting technique was used to produce A356 alloy composite foams reinforced with different volume fractions of mullite (5, 7.5, 10, and 12.5%) and SiC (5, 7.5, 10, and 12.5%) particles. The microstructure of the fabricated foams reveals a uniform distribution of these particles within the cell walls, as well as good interfacial interaction with the alloy matrix. Compressive stress–strain curves of the composite foam increase smoothly with strain, and there is very marginal stress oscillation occurred in the plateau region of foam throughout the test. It is worth noting that, regardless of foam composition, plateau stress and energy absorption of foams follow power-law relationships with relative density, while densification strain follows a linear trend with relative density. Furthermore, as compared to the SiC particles reinforced composite foams, the mullite reinforcement exhibits higher plateau stress and energy absorption. [ABSTRACT FROM AUTHOR]

The demanding material quality criteria in the automotive and aerospace industries have recently had an impact on the development of lightweight aluminium alloys. The choice and application of metal-matrix composites as structural materials in this context are known to offer a variety of benefits. These benefits include the ability to combine high elastic modulus, toughness, and impact resistance; minimum sensitivity to change in temperature or thermal shock; durability of the surface is good; moisture absorption leads to a potential issue while minimum exposure which leads to environmental degradation; and improved fabricability with conventional metalworking equipment. Aluminium metal matrix composites (AMMCs) are a potential material for advanced structural, aviation, aerospace, marine, and defense applications, as well as for the automotive sector and other related fields, due to their outstanding combination of qualities. The stir casting procedure is used to create an aluminium metal matrix composite (AMMC), which is the most efficient way to do so. In this study, the aluminium alloy 7075 is strengthened using neem leaf powder and SiC. The Vickers hardness examination method is used to govern the hardness of hybrid composites. Eventually, the mechanical and tribological properties of the composites were assessed, and their relationship to the composites' matching microstructure and wear was addressed. [ABSTRACT FROM AUTHOR]

Aluminum composites exhibit high resistance to wear and corrosion, possess high strength, offer durability and more such properties. In this study, Al7075, reinforced with nano size SiC - Gr was produced by a stir casting technique and its microstructure and mechanical behavior were evaluated. Reinforcements were added in the range of 0 - 3 wt. %. The microstructure study, tensile and compression strength of the developed hybrid Metal Matrix Composites have been analyzed and examined. From the investigational study, it was found that the reinforcements are evenly dispersed in the base material. The porosity and density of the developed composites were found to be enhanced. The mechanical properties such as ultimate tensile and compressive strength of the developed MMCs could be improved by addition of SiC particulates compared to base material. Further, the strength of developed hybrid composites was found to be decreased by adding of solid lubricant such as graphite (Gr) particulates along with hard ceramic particulates. Finally, fractured surface of the tensile test specimens were analysed using a SEM analysis

Owing to the poor self-diffusion coefficient of TiC, the mechanical and tribological properties of the TiC matrix composites were difficult to improve simultaneously by adding reinforcements. In this paper, the degradation of Ti 3 SiC 2 was exploited as an advantage in obtaining the high-performance TiC matrix composites. The TiC matrix composites reinforced by SiC and Ti 3 SiC 2 were in-situ fabricated by spark plasma sintering at 1400–1600 °C for 10 min. SiC and Ti 3 SiC 2 were homogeneously distributed in the TiC matrix with well interfacial bonding with TiC matrix. The twin boundaries and stacking faults appeared in TiC particles. With the sintering temperature of 1500 °C, the TiC matrix composites exhibited excellent mechanical and tribological properties, which the bulk density, relative density, hardness, fracture toughness, and flexural strength reached the values of 4.76 g/cm3, 99.36%, 15.38 GPa, 5.38 MPa m1/2, and 562.3 MPa. The friction coefficient and wear rate of the TiC matrix composites sintered at 1500 °C reached the values of 0.48 and 3.04 × 10-9 mm3N-1m-1 at room temperature, and 0.55 and 6.63 × 10-9 mm3N-1m-1 at 500 °C, respectively. The wear mechanism of the TiC matrix composites was mainly ascribed to adhesive wear both at room temperature and 500 °C. A Fe–Si-oxide-Ti 3 SiC 2 lubricating film was formed on the friction surface of the TiC matrix composites after a friction test at room temperature, while a Ti–Si–Fe-oxide lubricating film was formed after a friction test at 500 °C. [ABSTRACT FROM AUTHOR]

Graphene nanoplates reinforced AgCuTi composite fillers are applied to braze SiC ceramic with Al 0.3 CoCrFeNi high entropy alloys. Graphene nanoplates, together with active element Ti which could restrain the activity of multiple elements from Al 0.3 CoCrFeNi, impede the intense diffusion towards SiC and thus avoid the formation of bulk brittle compounds unfavorable to the joint performance. The in situ synthesized reaction between Ti and graphene nanoplates leads to dispersive TiC reinforcements which not only promote the refinement of the joint microstructure but also relieve the residual stress that existed in SiC/Al 0.3 CoCrFeNi joint. Vigorous dissolution and diffusion across Al 0.3 CoCrFeNi/liquidus filler interface lead to laminated Ti-rich layers formed adjacent to Al 0.3 CoCrFeNi substrate. The uniform and continuous reaction layer of TiC/Ti 2 Ni-type compounds/Ag(Cu) inclusions is formed adjacent to SiC ceramic. Tiny TiC particles and Ti 2 Ni-type compounds distribute evenly in the brazing seam, strengthening the joint performance. Eventually, the maximum shear strength of 36.7 MPa is achieved when adding 0.3 wt% graphene nanoplates. [ABSTRACT FROM AUTHOR]

6 MeV Si ions with fluences of 2 × 1016 ions/cm2 and 400 keV H ions with fluences of 5 × 1016 ions/cm2 implantation experiments were performed for single-crystal 6H-SiC samples. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the evolutions of the surface damage and internal microstructure of these irradiated 6H-SiC samples before and after annealing. Bumps were observed on the surface of the Si+ ions irradiated samples after annealing. The internal damage caused by irradiation recovered well after annealing, and the peak damage zone disappeared after the 1200 °C annealing process. Circular bubbles occurred on the surface of the H+ ions irradiated samples, which peeled off after annealing. The morphology and distribution of bubbles and spalling on the Si+-H+ dual ion beam irradiated sample surface were more irregular as the more severe damage induced by the pre-implanted Si ions hindered the aggregation and migration of hydrogen atoms. [ABSTRACT FROM AUTHOR]

This research is directed to examine the influence of silicon nitride additive (2.5–5%) Si3N4 on the microstructure, sinterability, densification, and mechanical features of (TiB2–10SiC) and (TiB2–20%SiC) and, more uniquely, the impact of the aforementioned properties on the wear behaviour of the resulting composites. Higher densification with optimal hardness and fracture toughness of 99.4%, 24.9 GPa and 4.63 MPa·m1/2 was achieved respectively when 2.5% Si3N4 was introduced into TiB2–20SiC composite. Microstructural observation depicts that in-situ phases such as TiC contributed to the enhancement of the relative as well as the mechanical properties. However, increasing the sintering additive of Si3N4 to 5% in the composite lowers the relative density, consequently lowering the hardness of the composites. More also, the wear behaviour of the fabricated composites revealed that the composite having enhanced densification and hardness contributed to its improved wear resistance of the resulting composites.

In this paper, microstructure, mechanical, immersion and potentiodynamic corrosion behaviours of extruded ZK60 matrix composites reinforced with forty-five µm 15% silicon carbide (SiC) particles and aluminium nitride nanoparticle (AIN) (0.2–0.5% 760 nm) were investigated. The SiC and AlN mixtures, which are the reinforcing elements of the composites, were first mixed with magnesium powder as the main alloy, then pressed under a pressure of 450 MPa and sintered at 420 °C. Second, the sintered compacts are placed in the ZK60 alloy matrix at the semi-solid melting temperature, and the melt is mixed mechanically. After the melts are mixed for 30 min and a homogeneous mixture is obtained, the mixtures are poured into metal moulds and composite samples are produced. After homogenization for 24 h at 400 °C, the composite samples were extruded at 300 °C with an extrusion ratio of 16:1 and a piston speed of 0.3 mm/s. Then, microstructure characterization of all composite samples was performed and potentiodynamic and immersion corrosion behaviours were analyzed in 3.5% NaCl solution. It was seen that the corrosion resistance increased depending on the percentages of SiC and AlN reinforcement elements in the matrix. As a result, it was seen that the potentiodynamic corrosion resistance of reinforced ZK60 + 15% SiC (ZK60SiC15), ZK60 + 15% SiC + 02AIN (ZK60SiC15AlN0.2) and ZK60 + 15% SiC + 0.5% AIN (ZK60SiC15AlN0.5) compounds increased by 1.6, 1.8 and 3.5 times compared to the unreinforced ZK60 alloy. The immersion corrosion rates were calculated as 2090.73, 1748.19, 1479.84 and 1397.79 (mg/year) for the unreinforced ZK60, ZK60SiC15, ZK60SiC15AlN0.2 and ZK60SiC15AlN0.5 reinforcements, respectively. As a result of the SEM and elemental spectrum response analysis of the corrosion surfaces, the presence of a layer rich in Si-O elements on the surface of the AlN + SiC reinforced composites enhanced corrosion resistance. Additionally, the formation of the Mg2Si intermetallics in the structure of the SiC reinforced composites improved corrosion resistance, according to the XRD results.

Monolithic TiB2 are known to have a good combination of densification and hardness, which are sometimes helpful but limited in application. However, their usage in service at elevated temperatures such as in thermal power plants, cutting tools, tribological purposes (mechanical seals, blast nozzles, wheel dressing tools), etc. leads to catastrophic failure. Hence, the introduction of sintering additives in the TiB2 matrix greatly influences the sinterability and properties (fracture toughness, wear resistance, etc.) of the resulting composite needed to meet the requirement for various industrial applications. In this study, the influence of SiC as sintering additives on the microstructure, densification, hardness and wear performance of TiB2 ceramic was observed. Hence, TiB2, TiB2–10wt%SiC and TiB2–20wt%SiC were sintered at 1850 °C for 10 min under 50 MPa. The impacts of SiC on the TiB2 were observed to improve the microstructure and correspondingly improve the densification and mechanical properties, most especially with the composite with 20wt% SiC. Combined excellent densification, hardness and fracture toughness of 99.5%, 25.5 GPa, 4.5 MPa.m1/2 were achieved, respectively, for TiB2–20wt%SiC. Diverse in-situ phase and microstructural alterations were detected in the sintered composites. It was discovered that the in-situ phase of TiC serves as the contributing factor to the enhanced features of the composites. Moreover, the coefficient of friction and wear performance outcomes of the synthesized composites described a decreased coefficient with an enhanced wear resistance via the increasing SiC particulate. However, applying the load from 10 to 20 N increased the wear rates. [ABSTRACT FROM AUTHOR]

A series of SiC/Al composites with different contents of 3-dimensional graphene networks (3DGN) were prepared by using mechanical alloying (MA) and spark plasma sintering (SPS). The effects of 3DGN on the microstructure, mechanical properties and corrosion behaviors of SiC-3DGN/Al composites were investigated. The results show that the 3DGN can substantially enhance the synergistic strength-toughness of SiC/Al composites. Compared with SiC/Al composites, the SiC-3DGN/Al composites demonstrate stronger interface cohesion, and an increase in hardness (56.5%), density, ductility and corrosion resistance in NaCl solution. The reason is that 3DGN results in enhanced interface cohesion by reducing defective interface between the reinforcement and the matrix. [ABSTRACT FROM AUTHOR]

The article describes the Ti3SiC2 powder synthesis process. The influence of the molar ratio and two forms of carbon on the phase composition of the obtained powders was investigated. The synthesis was carried out using a spark plasma sintering (SPS) furnace. In addition, using the obtained powders, composites reinforced with SiC particles were produced. The obtained results showed no effect of the carbon form and a significant impact of annealing on the purity of the powders after synthesis. The composites were also consolidated using an SPS furnace at two temperatures of 1300 and 1400 °C. The tests showed low density and hardness for sinters from 1300 °C (maximum 3.97 g/cm3 and 447 HV5, respectively, for composite reinforced with 10% SiC). These parameters significantly increase for composites sintered at 1400 °C (maximum density 4.43 g/cm3 and hardness 1153 HV5, for Ti3AlC2—10% SiC). In addition, the crack propagation analysis showed mechanisms typical for granular materials and laminates. [ABSTRACT FROM AUTHOR]

Pioneering studies on the additive manufacturing of a cermet heterogeneous material using SiC ceramic fiber were carried out. Unique studies of the damage staging (cratering) and the transition to the destruction of the formed material during high-speed impact created with the help of an electrodynamic mass accelerator have been carried out. It has been shown that the use of ceramic fiber in a metal matrix reduces the impact crater depth by 22% compared to material with ceramic particles. For the first time, the phase composition of the resulting composite was studied using synchrotron radiation. It was shown that, as a result of laser exposure, silicon carbide SiC is dissolved in the titanium matrix with the formation of secondary compounds of the TiC and Ti5Si3C types. It has been established that the use of SiC ceramic fibers leads to their better dissolution, in contrast to the use of SiC ceramic particles, with the formation of secondary phase compounds, and to an increase in mechanical characteristics. [ABSTRACT FROM AUTHOR]

Particle reinforced MMC succeeds in developing the metallic matrix with ceramic particle reinforcements to result in improved strength, mainly at elevated temperatures but adversely affects the ductility of the matrix. The present study aims to disperse different weight % (3,6,9) of SiC and 3wt.% Al2O3 particles in aluminum melt and fabricated composite. The evolution of microstructure and morphology of composite are studied using FESEM, Optical Microscopy, EDAX and deformation characteristics of Al-SiC+Al2O3 composite at cold conditions was studied. Cast nd forged composite material was subjected to hardness test and tensile test. The results show that hardness and strength of fabricated Al-SiC composite improves and ductility declines as compared to Al alloy in both as-cast and hot forged conditions. [ABSTRACT FROM AUTHOR]

The microstructure and oxidation behaviour of the pure AlON ceramics and 8 wt.% SiC-AlON composite were investigated at 700-1500°C. With increasing oxidation temperature, the surface morphology of two ceramics showed a change from acicular to flaky-like and then to granular features. With the addition of nanosized SiC particles, the oxidation resistance of the ceramics was remarkably enhanced above 1100°C. This is attributed to the formation of a dense oxide layer composed of Al2O3, SiO2 and mullite, which could cover the whole matrix and suppress further penetration of oxygen. Due to the dense oxide layer, the oxidation kinetics of the 8 wt.% SiC-AlON composites conformed to a parabolic law, while that of the pure AlON conformed to a linear law. After oxidation at 1500 °C for 40 h, the weight gain of the 8 wt.% SiC-AlON composites was 3.07mg/cm2, which was only 22.5% of that of the pure AlON.