Dispersion Of SiC Particles Research Articles

Effect of hot rolling on microstructures and mechanical properties of SiCp/A356 aluminum matrix composites

This study focuses on the fabrication of SiCp/A356 aluminum matrix composites (AMCs) through stir casting and hot rolling, with the objective of investigating the effects of reduction on microstructural evolution and mechanical properties of SiCp/A356 AMCs. The composites were subjected to hot rolling at 500 °C for varying reduction levels of 30%, 50%, 70%, and 90%. As the reduction increased to 70%, the size of α-Al grains and SiC particle clusters increased. However, further reduction to 90% resulted in the flattening and elongation of α-Al grains, the dispersion of SiC particles into the grains, and a more uniform distribution of SiC particles. The relationship between reduction and SiC particle distribution was established. The ultimate tensile strength (UTS) and yield strength (YS) of SiCp/A356 AMCs showed a gradual increase with increasing reduction. The rolled composite with a 90% reduction exhibited the optimal combination of UTS, YS, and elongation (EL) values. Besides, the strengthening mechanisms were discussed and the dislocation strengthening has a significant contribution to the improvement of YS.

Enhanced microstructures, mechanical properties, and machinability of high performance ADC12/SiC composites fabricated through the integration of a master pellet feeding approach and ultrasonication-assisted stir casting

Integrating ceramic particles into aluminum matrices poses significant challenges due to their limited wettability and high specific volume ratio. This research focused on developing ADC12/SiC aluminum composites with varying SiC concentrations (1.5, 2.5, and 3.5 wt%) through an innovative fabrication process. Initially, ADC12/SiC master pellets containing a high concentration of homogenously dispersed 1-μm SiC particles were produced. Subsequently, these master pellets were introduced into the molten ADC12 alloy, followed by the dispersion of SiC particles via stir casting assisted by ultrasonication. The study assessed the impact of SiC weight fractions on the microstructures, mechanical properties, and machinability of the fabricated composites. The results revealed significant microstructural improvements and a more even distribution of SiC reinforcement inside the ADC12 matrix after the application of this innovative processing method. Increased SiC concentration led to notable refinement of α-aluminum grains and eutectic Si, as well as a more uniform dispersion of intermetallic phases. Additionally, a substantial increase in tensile properties and hardness was observed with the increment of SiC content. Particularly, the ADC12/3.5 wt%SiC composite exhibited a 46.73% increase in hardness and notable enhancements in yield strength, ultimate tensile strength, and elongation, denoted as 201.7 MPa, 241.1 MPa, and 3.40%, respectively, as compared with those of the unreinforced ADC12 alloy. Moreover, the ADC12/SiC composites demonstrated reduced surface roughness compared to the unmodified ADC12 alloy, indicative of a superior surface finish. With the addition of a high SiC content, the chip morphology was observed to change from continuous to discontinuous following a turning operation.

Phase formation, microstructure and mechanical properties of TaB2–SiC composites synthesized by reaction hot pressing: Effects of SiC contents and oxygen impurity

TaB2–SiC composites with 0–20 wt% SiC contents were prepared by reaction hot pressing using Ta, B and SiC powders as starting materials. Densification, constituent phases, microstructure and mechanical properties, namely Vickers hardness, fracture toughness and flexure strength, were evaluated by means of inspection of sintering shrinkage, density measurement, XRD, SEM, TEM, HRTEM, EDS, SAED, indentation and three-point bending tests. Phase formation, including dominant (TaB2, SiC) and minor (TaC, glassy SiO2) phases, was checked by thermodynamic assessment relevant with Ta2O5 and B2O3 impurities introduced into the reaction system by the starting powders. The results showed that mixtures of Ta, B and SiC powders would initiate self-propagating combustion synthesis (SPCS) at about 900 °C; a transient hold at 800 °C for 1 h could suppress this reaction. Volatilization of B2O3 impurity in association with local high temperature due to SPCS helped reduce the TaC and glassy SiO2 minor phase formation. TaB2–SiC composites could reach 99 % relative densities with 3 wt% SiC addition and above. Compositions with <7.5 wt% SiC additions showed uniform dispersion of SiC particles at multi-TaB2 grain junctions while compositions with higher SiC content revealed SiC segregation. Bending strength of 503 MPa and fracture toughness of 6.69 MPa⋅m1/2 could be reached with 7.5–20 wt% SiC addition.

Global and Local Deformation Analysis of Mg-SiC Nanocomposites: Digital Image Correlation (DIC) and Representative Volume Element (RVE) Techniques

Improving the ductile deformation behavior of Mg-SiC nanocomposites without compromising strength is critical to enhancing their mechanical properties. Mg-SiC nanocomposites are produced through mechanical milling, cold isostatic pressing, sintering, and hot extrusion processes. This study investigates the uniaxial stress–strain response and deformation behavior of the Mg-SiC nanocomposite compared to pure Mg samples with and without the milling process. The deformation behavior was investigated by two-dimensional (2D) digital image correlation (DIC) at two macroscopic and microscopic scales, employing light micrographs and in situ loading samples, respectively, in the scanning electron microscope. Compared to the pure Mg samples, the mechanical test results demonstrated a significant improvement in strength (80 MPa) and fracture strain (23.5%) of the Mg-SiC nanocomposite. The three-dimensional (3D) representative volume element (RVE) model revealed the particle dispersion effect on the mechanical properties of the nanocomposite. The RVE results demonstrate ductile deformation behavior in the sample with homogenous dispersion of SiC particles compared with the heterogeneous dispersion of SiC particles in Mg-SiC nanocomposite. The results demonstrated a good agreement between DIC and RVE predictions for Mg-SiC nanocomposites across macro- and microscales.

Effect of multiple passes on the properties of Al-5052/SiC surface composites fabricated via friction stir processing

Friction stir processing (FSP) has emerged as a promising technique for producing surface composites with enhanced mechanical, microstructural and tribological properties. This work investigates the influence of multi-pass FSP on various properties of aluminium 5052 alloy reinforced with silicon carbide (Al-5052/SiC). The results indicated that multi-pass FSP effectively dispersed SiC particles within the aluminium matrix, resulting in a refined microstructure and improved mechanical properties. As the number of FSP passes increased, hardness, tensile strength, and wear resistance improved, reaching levels significantly higher than the base Al-5052 alloy. Tensile strength, yield strength, and average microhardness in the five-pass FSPed specimen were improved by about 25 %, 26 %, and 28 % respectively. Wear and corrosion resistance improved with the increase of FSP passes. The quantitative results of the study strongly corroborate with microstructural evolution.

Optimal Performance of Mg-SiC Nanocomposite: Unraveling the Influence of Reinforcement Particle Size on Compaction and Densification in Materials Processed via Mechanical Milling and Cold Iso-Static Pressing

Achieving uniformly distributed reinforcement particles in a dense matrix is crucial for enhancing the mechanical properties of nanocomposites. This study focuses on fabricating Mg-SiC nanocomposites with a high-volume fraction of SiC particles (10 vol.%) using cold isostatic pressing (CIP). The objective is to obtain a fully dense material with a uniform dispersion of nanoparticles. The SiC particle size impact on the compressibility and density distribution of milled Mg-SiC nanocomposites is studied through the elastoplastic Modified Drucker-Prager Cap (MDPC) model and finite element method (FEM) simulations. The findings demonstrate significant variations in the size and dispersion of SiC particles within the Mg matrix. Specifically, the Mg-SiC nanocomposite with 10% submicron-scale SiC content (M10Sµ) exhibits superior compressibility, higher relative density, increased element volume (EVOL), and more consistent density distribution compared to the composite containing 10% nanoscale SiC (M10Sn) following CIP simulation. Under 700 MPa, M10Sµ shows improvements in both computational and experimental results for volume reduction percentage, 2.31% and 2.81%, respectively, and relative density, 4.14% and 3.73%, respectively, compared to M10Sn. The relative density and volume reduction outcomes are in qualitative alignment with experimental findings, emphasizing the significance of particle size in optimizing nanocomposite characteristics.

Investigating microstructural and mechanical behavior of stir-squeeze cast TiO2–SiC/Al6082 bimodal hybrid composites

Greater advantages of employing hybrid reinforced advanced aluminum matrix composites over single particle reinforced composites have been the highlights of recent times. Herein, Al6082 bimodal hybrid composites embedded with different proportions of SiC and TiO2 particles were fabricated via modified stir-squeeze cast technique. A transmission electron microscopy was used for morphological evaluation of TiO2 particles while microstructure of fabricated composites and fractured surfaces were analyzed by using field emission scanning electron microscopy. Energy dispersive X-ray spectroscopy was used for evaluation of elements and phase analysis was done by using X-ray diffraction technique. Microstructural analysis confirms the homogeneous dispersion of SiC particles up to 3 wt.% and beyond that, clusters of SiC were observed which deteriorates the properties of composites. Maximum enhancement in mechanical properties of Al6082 alloy was noticed for incorporation of 3 wt.% of SiC and 0.5 wt.% of TiO2. 0.5 wt.%TiO2-3 wt.% SiC reinforced Al6082 composites enhanced yield strength, Ultimate tensile strength, and compressive strength by 215.84 ± 1.43 MPa, 268.84 ± 1.75 Mpa and 321.42 MPa, respectively, over as-cast Al6082 alloy.

Optimization of squeeze casting process parameters on mechanical properties of SiCp reinforced LM25 composites through Taguchi technique

Abstract The aim of the present work is to examine the influence of processing parameters on fabricated composites of LM25 alloy with SiC particle reinforcement through a squeeze casting technique. The following process parameters, like stirring speed from 550 to 750 rpm, SiCP (4 wt% to 8 wt %), and melting temperatures (from 600 to 700 °C) were employed. Then, the processed composites were subjected to microscopy analysis and mechanical tests to ascertain their metallurgical and mechanical properties. SEM micrographs of an LM 25 composite sample show better bonding of SiC particles with matrix, which is due to homogeneous dispersion of SiC particles in the stir casting process. The maximum tensile strength (211 MPa) and hardness (91 Hv) were achieved on the composite samples with processing parameters of 750 rpm stirring speed, 8% SiC proportions, and 650 °C melting temperature, respectively. From the design of the experiment by the Taguchi method, it is observed that the stirring speed plays a significant role in achieving a better distribution of SiC particles in the composite samples than other parameters like SiC weight ratios and the melting temperature of the alloy.

A modified artificial neural network to predict the tribological properties of Al-SiC nanocomposites fabricated by accumulative roll bonding process

This work highlights the major influence of SiC concentration and plastic deformation on boosting wear rates of aluminum composites supplemented with SiC particles comprising varied volume fractions (0–4%). It also shows how a basic neural network model augmented with a particle swarm optimizer can forecast wear rates and coefficients of friction for complicated composites. According to the experimental findings, increasing the quantity of accumulative roll bonding (ARB) enhances SiC particle dispersion homogeneity. Increasing the number of cycles and introducing additional SiC particles helped to reduce the wear rate and increase the friction coefficient. After nine ARB cycles, the Al-4 wt.% SiC nanocomposite had the best improvement in both wear rate and friction coefficient. The same sample was also used in efforts to enhance the characteristics of hardness, and it was selected as having the highest level of hardness, which has grown by 139%. All of the generated composites evaluated at four different wear loads were able to be predicted by the proposed model with great accuracy, with determination coefficient R2 values of 0.9768 and 0.9869 for the frictional coefficient and wear rates, respectively.

Effect of Spark Plasma Sintering Temperature on Phase Evaluation and Mechanical Behaviour of cu- 4 Wt% SiC Composite

Spark plasma sintering (SPS) is a novel approach to fabricate Cu- SiC composites which have a relatively broad range of potential uses in space applications. The Cu- 4 wt% SiC composite with homogeneously dispersed SiC particles has been successfully synthesized at various SPS temperatures. In this study, the effect of SPS temperatures on the phase evaluation and mechanical characteristics of the Cu- 4 wt% SiC composite was investigated. From the results, it was confirmed that the optimum sintering temperature for Cu- 4 wt% SiC composite is 950°C. Raising the spark plasma sintering temperature from 850°C to 950°C led to a higher concentration of copper-liquid phase which accelerates the SiC particle rearrangement and fills the interstitial voids present in the interfaces of matrix and reinforcements which improves the mechanical properties of the Cu- 4 wt% SiC composite. However, increasing the SPS temperature by more than 950°C prone to the generation of the copper net and inhomogeneous SiC particle dispersion in the copper phases and declines the performance characteristics of the synthesized composite. The Cu- 4 wt% SiC composite sintered at 950°C exhibits superior mechanical characteristics than the composite sintered at 850°C, 900°C and 1000°C.

背应力平衡策略实现非均质Al-SiC复合材料的强塑 性协同

Strength-ductility trade-off dilemma remains a significant obstacle to high-strength composites due to the undesirable dislocation storability. Herein, an ingenious nano-micro SiC-reinforced Al matrix composite (AMC) with heterogeneous grain structures of coarse and fine grains was designed via a novel deformation-driven metallurgy method. The accumulated geometrically necessary dislocations and the intragranularly dispersed SiC particles were tailored based on the principle of back stress amelioration, which was a key point to maintain the dynamic balance with the applied stress toward strength-ductility synergy. The ultimate tensile strength and uniform elongation of the designed SiC5np-5µp/Al composite reached 324 MPa and 12.9%, respectively, and the strength was 181% as high as that of the SiC10µp/Al with only 3% ductility loss. As such, a new strategy was provided herein to promote strength-ductility synergy via the further modified back stress.

Structure, composition, and preparation of thermal conductive composite materials based on polyurethane and modified silicon carbide particles

This paper presents the first data on the dependence of thermal conductivity of DFPCM on generalized parameters and type of structure, according to the classification (dilute – low filled – medium filled – high filled systems), using the system of polyurethane + modified silicon carbide particles as an example. New plasma-modified silicon carbide particles with a unique structure and high specific surface area have been obtained, and their main characteristics necessary for calculating the compositions, generalized parameters, and determining the type of disperse structure of DFPCM have been determined. The main regularities are established that describe the relationship between the thermal conductivity coefficient (λ pcm) and the generalized parameter Θ, the type of structure of the DFPCM, and the surface morphology of SiC particles. For the first time, the contribution of the specific surface area of dispersed SiC particles (S BET − from 3 to 45 m2/g) to the thermal conductivity of disperse systems is shown.

Effect of tool rotational speed on microstructure and mechanical properties of AA6061/SiC surface composites using friction stir processing

An investigation was conducted into how the tool rotation speed affected the microstructure and mechanical properties of friction stir processed samples based on AA6061-T6/SiC surface composites. The tool rotated between 700 and 1500 rpm with steps 400 rpm, while the other process variables were kept constant. Visual inspection reveals a sound and defect-free weld surface. The microstructure and particle dispersion of composite surface based on synthesis of aluminium alloys were revealed using an optical microscope. The findings demonstrate that rotational speed has a substantial impact on the uniform dispersion of SiC particles, which were observed at 1100 rpm found that refined and uniform distribution of particles as compared other rotational speeds. At tool rotational speed (TRS) of 1100 rpm, the friction stir processed specimen's microhardness and tensile strength, which seem to be 128 HV and 305 MPa, respectively.

Synergistic effect of SiC nano-reinforcement and vibrator assistance in micro-friction stir welding of dissimilar AA5052-H32/AA6061-T6

Several studies have reported methods for improving the weldability in micro-friction stir welding (μ-FSW). Among them, the use of nano-reinforcement in FSW enhances the mechanical properties of the material. The particles are dispersed via micro-friction stir processing (μ-FSP) several times via reinforcement particle aggregation. In this study, a long processing time and non-uniform particle dispersion are the disadvantages of μ-FSP. Experiments were conducted to compare the microstructure and mechanical properties of SiC nano-reinforcement addition and vibration-assisted μ-FSW. To reduce the welding time, the vibration-assisted μ-FSP was performed using four magnetically attached coin-type vibrators on the material for reinforcement particle dispersion. Particle aggregation occurred only under SiC nano-reinforcement addition. However, the SiC particle dispersion was uniform under vibration assistance. Additionally, SiC nano-reinforcement dispersion led to more dislocations in the plasticized material due to the assisted vibration. The ultimate tensile strength and elongation were the highest, and a uniform hardness graph was obtained. Therefore, SiC-nano-reinforced and vibration-assisted μ-FSW not only makes the particle size of the weld relatively small and uniform, but also increases the dispersion range of the SiC particles, improving the mechanical properties and shortening the processing time two fold.

Effect of Graded Dispersion of SiC Particles on Dielectric Behavior of SiC/Epoxy Composite

Effect of Graded Dispersion of SiC Particles on Dielectric Behavior of SiC/Epoxy Composite

Properties and Simulating Research of Epoxy Resin/Micron-SiC/Nano-SiO2 Composite

The dielectric behavior of insulations is a key factor affecting the development of anti-corona materials for generators. Epoxy resin (EP), as the matrix, is blended with inorganic fillers of micron SiC and nano SiO2 to investigate the effect of micro and nano doping on the conductivity and breakdown mechanism of the composites. Using experimental and simulation analysis, it is found that the effect of nano-SiO2 doping concentration on the conductivity is related to the dispersion of SiC particles. The lower concentration of SiO2 could decrease the conductivity of the composites. The conductivity increases with raising the nano-SiO2 doping concentration to a critical value. Meanwhile, the breakdown field strength of the composites decreases with the rising content of SiC in constant SiO2 and increases with more SiO2 when mixed with invariable SiC. When an equivalent electric field is applied to the samples, the electric field at the interface of micron particles is much stronger than the average field of the dielectric, close to the critical electric field of the tunneling effect. The density of the homopolar space charge bound to the surface of the stator bar elevates as the concentration of filled nanoparticles increases, by which a more effective Coulomb potential shield can be built to inhibit the further injection of carriers from the electrode to the interior of the anti-corona layer, thus reducing the space charge accumulation in the anti-corona layer as well as increasing the breakdown field strength of the dielectric.

Influence of SiC content to control morphology of in-situ synthesized ZrB2–SiC composite through single-step reduction process

The present work focuses on the influence of SiC content on the morphology and microstructure of in-situ synthesized ZrB2–SiC composite using ZrO2, B4C and Si via a single-step reduction process under argon atmosphere. The ZrB2–SiC composite was synthesized with variation in mole content of starting reactant and calcination temperature. The molar ratio of ZrO2:B4C:Si was increased from 2:1.5:0.5 to 2:1.67:1.34 at 1300–1500 °C, resulting SiC content increased and average grain size reduced. Major phase of ZrB2 and SiC were detected in the composite using XRD and XPS techniques. Morphology and microstructure of synthesized ZrB2 and SiC were determined by SEM and TEM analysis. The results revealed that a homogenous layer of uniformly dispersed SiC particles was exhibited over the surface of rod and spherical granulation of ZrB2, which restricted the grain growth of ZrB2 particles during synthesis. With increasing the SiC content, the pinning effect on the grain boundary enhanced the dense structure of ZrB2–SiC composite. The feasibility of reaction for the synthesis of ZrB2–SiC composite was confirmed by thermodynamic calculation and experimental results. It can be concluded from experimental results that the composite was synthesized below the thermodynamically calculated synthesis temperature due to maintaining moderate vacuum backfilled by argon.

Effect of sodium dodecyl sulfate and different SiC quantities on electrodeposited Ni-Co alloy coatings

Ni-Co nanocomposites Prepared by electrodeposition in a modified Watts bath containing various quantities of silicon carbide SiC and the organic additive sodium dodecyl sulfate SDS as a surfactant. The influence of nanoparticle incorporation on the electrodeposit microstructure, mechanical characteristics, and deformation process was studied. Vickers micro-hardness and weight loss tests were used to study the mechanical properties and morphology. The microstructure has also been analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Co-deposition of uniformly dispersed SiC particles, on the other hand, was found to improve the extreme tensile strength of the deposits significantly; SDS lowered the surface tension, allowing the SiC particles to fill in all remaining gaps to achieve a homogeneous surface. A process involving atoms that can dramatically improve flexibility. The incorporation of SiC particles and raising the strain rate encouraged a ductile fracture mode in a nano-crystalline Ni-Co matrix, which demonstrated a mixed mod behavior of flexible and brittle fracture; it was evident that the addition of SDS increases the concentration of SiC particles in general on Ni-Co samples. Moreover, compare Ni-Co with various amounts of SiC and Ni-Co/SiC with adding SDS. Furthermore, to achieve the highest possible electroplating efficiency.

Investigation of the effect of tool probe profile on reinforced particles distribution using experimental and CEL approaches

In this study, to explore the dispersion of particle reinforcement in the base metal, aluminum-6061/SiC composites were made utilizing friction stir processing (FSP) tools with various probe profiles such as cylindrical, triflate, square, triangular, and hexagonal. A light microscope was used to examine the dispersion of SiC particles in the composite substrate. Then the mechanical properties of the composite were investigated using hardness and tensile tests. In addition, the coupled Eulerian-Lagrangian (CEL) approach is used to model the process and investigate particle dispersion further. The workpiece is modeled employing Eulerian formulation, whereas the tool is described using Lagrangian formulation. The model forecasts temperature and strain variations in composites made with various probe profiles. The result showed that the cylindrical pin could not spread particles in the base alloy, indicating that it was not viable for composite manufacture. Flat-surfaced tools, such as square and triangle probe profiles, have dispersed particles better in aluminum. The findings revealed that the inclusion of eccentricity and pulse creation in these tools enhanced particle dispersion. Hexagonal and triflate probes offer the highest performance in terms of particle dispersion in the base metal. As the number of smooth tool probe surfaces rises from triangular to hexagonal, the hardness distribution becomes more uniform, and the amount of hardness in the composite increases.

A Study on Characterization and Prevention of Shadows in Cast Mono‐Crystalline Silicon Ingots

AbstractDark shadow areas often appear in infrared images of cast monocrystalline silicon (CMC‐Si) ingots. In this work, the formation of shadow and how to avoid it by optimizing the growth process are analyzed. The analysis of scanning electron microscopy &amp; energy dispersive spectroscopy show that the shadows in CMC‐Si are caused by dispersed SiC particles. These particles will further induce a great number of dislocations, subgrain boundaries, and strip‐shaped grains, which decrease the quality and the minority carrier lifetime of CMC‐Si. In addition, an optimized process has proposed and successfully produced a silicon ingot without any shadows. By comparing the traditional and optimized processes, the shadow formation mechanism is studied and found preventing shadow formation by keeping the liquid phase temperature gradient smooth, the maximum crystal growth rate is not more than 1.1 cm h−1 and reducing the value of GL/V below 0.235.