B4C Particles Research Articles

On the effect of compaction velocity, size, and content of reinforcing particles on corrosion resistance of Mg–B4C composites

In this study, the effect of the compaction velocity as well as the size and volume fraction of the reinforcing particles on the corrosion properties of Mg–B4C composites were investigated. Micron/nano particles of boron carbide at different volume fractions (0, 5, and 10%) were added to the matrix (magnesium powder). Powder mixtures were milled in a planetary ball mill and compacted at 450 °C and different strain rates, using Split-Hopkinson bar (SHB), drop hammer, and Instron devices. Microstructural analysis and corrosion tests were carried out on the produced samples. The results indicated that the samples produced at higher compaction velocities had the lower corrosion rate mainly due to the lower porosity and higher relative density of the samples. For example, the measured corrosion rates for the magnesium samples reinforced with 5 vol% of micron B4C particles and compacted by the SHB method were 54 and 76% lower than the similar samples produced by the drop hammer and Instron device, respectively. It was also shown that decreasing the size and content of the reinforcing particles resulted in a reduction in the corrosion rate values. The recorded corrosion rate values for the samples reinforced with 5 and 10 vol% of B4C nanoparticles and compacted by the drop hammer device were 18.3 and 29.18 mm/year, respectively. These valuses were approximately 16 and 13% lower compared to the similar composites reinforced with micron-sized particles. The lowest corrosion rate (1.84 mm/year) was observed in the pure magnesium sample compacted by the SHB which was 29.42% lower than that of the magnesium sample reinforced with 10 vol% of micron-sized B4C.

Influences of B4C content and particle size on the mechanical properties of hot pressed TiB2–B4C composites

ABSTRACT TiB2 ceramic has attracted many attentions due to its excellent performances both on mechanical and functional properties. However, it is still very difficult to obtain TiB2 bulks with full densification. Herein, TiB2–B4C composites were prepared via hot pressing at 1900°C under the pressure of 35 MPa with TiB2 and B4C as the raw materials. The influences of B4C content (0, 10 vol%, 20 vol% and 30 vol%) and particle size (0.50 µm, 3.12 µm and 7.09 µm) on the phase composition, relative density, microstructure and mechanical properties of TiB2–B4C composites were investigated. The using of 0.50 µm B4C brought more B2O3 which induced oriented growth of TiB2 grains and coarsened the obtained composites. When the raw B4C powders were 3.12 µm and 7.09 µm, the obtained composites with 20–30 vol% B4C could be fully densified. TiB2–30 vol% B4C composite prepared from 3.12 µm B4C powder resulted in the optimal mechanical properties. The bending strength, Vickers hardness, fracture toughness were 671 MPa, 27.93 GPa, and 3.91 MPa·m1/2, respectively. The excellent performance was attributed to its fine and homogenous microstructure.

Effect of TiB2 content on microstructure and mechanical properties of (TiB2p+B4Cp)/Al composites fabricated by microwave sintering

Abstract This study demonstrates a novel method to improve the density, interface bonding strength and mechanical properties of the B4Cp/Al composites by directly adding TiB2 to the material. Specifically, the (TiB2p+B4Cp)/Al composites with different TiB2 contents were successfully fabricated by ball milling (BM) and microwave sintering (MS). The results indicate that the developed (TiB2p+B4Cp)/Al possess a clean interface, with the absence of any reaction, thus, confirming microwave sintering as one of the preferred ways to prepare the (TiB2p+B4Cp)/Al composites. On adding TiB2, the densification in the microstructure is noted to initially increase, followed by a decrease. Overall, the TiB2 and B4C particles are noted to synergistically improve the densification as well as ameliorate the interfaces and microstructure. As a result, the optimized composites exhibit the compactness and Vickers hardness as high as 94.6% and 153.42HV0.3 respectively. The highest value of the compressive strength is determined to be 578.71 MPa at 50.0%. Further, no macroscopic fracture is noted to occur after 50% compression strain.

Dual sided composite formation in Al 6061/B4C using novel bobbin tool friction stir processing

Abstract A novel material processing approach using the bobbin tool technique called bobbin tool friction stir processing (BTFSP) was developed to simultaneously fabricate two-side composites. The feasibility of simultaneous fabrication of composites on the top and bottom sides of the workpiece using B4C reinforcement particles into Al 6061 alloy was successfully studied in the present paper. Excellent dispersion of the B4C particles obtained at the bottom side of the workpiece by this technique. The metallurgical investigation of Al 6061/B4C double side composites was carried out using optical and scanning electron microscopy. The mechanical properties include sliding wear behavior, and microhardness of the fabricated composites was studied in detail. The results indicated a more uniform distribution of B4C particles with 3 passes. The grain refinement and homogeneous distribution of the B4C significantly improved microhardness and wear properties of the fabricated composites compared to as-received Al.

Effect of B4C particles addition on microstructure and mechanical properties of Fe50Mn30Co10Cr10 high-entropy alloy

High entropy alloy used as the metallic matrix of composites gives birth to a new family of composites. In this work, the effect of B4C particles on microstructure and mechanical properties of Fe50Mn30Co10Cr10 high-entropy alloy matrix is systematically investigated. B4C particles can stabilize austenite (γ) phase to form single γ phase and effectively refine grain size. Two different sizes and compositions of B4C particles are formed in B4C/Fe50Mn30Co10Cr10 composite. The fine B4C particles with the lower Cr contents can induce significant coherent strain and then strengthen the matrix, while the coarse B4C particles with the higher Cr content can induce micro-crack at the B4C/matrix interface due to the low interfacial metallurgical bonding. As compared to Fe50Mn30Co10Cr10 matrix, B4C/Fe50Mn30Co10Cr10 composite shows the higher tensile strength with the relative lower fracture strain. In addition, the composite possesses a better ability of wear friction than the matrix, revealing the oxidative wear and abrasive wear mechanism.

Effect of boron carbide and Kaoline reinforcements on the microstructural and mechanical characteristics of aluminium hybrid metal matrix composite fabricated through powder metallurgy technique

ABSTRACT In the present work Al- 10% B4C- X% Kaoline (X = 0, 2, 4, 6, 8) hybrid metal matrix composite (HMMC) was fabricated through powder metallurgy technique. Physical and mechanical properties like density, Hardness, Porosity, Ultimate tensile strength (U.T.S) and Impact energy were studied for the fabricated composite samples. Results concluded that there was a 91.93% increment in hardness and 75% increment in U.T.S of the fabricated samples was observed for Al-10%B4C-4%Kaoline HMMC. However, incorporation of kaoline reinforcement beyond 4% leads to the formation of agglomerates in the composites reducing the U.T.S from 238 MPa to 186 MPa and hardness from 119 VHN to 101 VHN. The fabricated composite specimens were characterised using an X-ray Diffractometer (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The XRD patterns reveal the presence of Aluminium, B4C and kaoline particles. In addition to this, the presence of intermetallic phases was observed for Al-10%B4C-6% Kaoline and Al-10%B4C-8% kaoline HMMC. Uniform distribution of reinforcements and formation of agglomerations for 6% and 8% kaoline reinforcements was confirmed by SEM and their respective EDS mapping. Results showed that the Al-10 % B4C- 4% Kaoline has superior mechanical properties compared to monolithic aluminium

Microstructure and Mechanical Properties of Aluminum Cast Alloy A356 reinforced with Dual-Size B4C Particles

The paper details the studies carried out on a dual-size particulate composite prepared by stir casting using A 356 aluminum alloy and B4C powders. Three composite compositions, viz., A356 plus 2% B4C (44µm size and 105µm size in 1:1 ratio), 4% B4C (3:1 ratio), and 6% B4C (1:3 ratio) were cast in finger molds, from which test specimens were prepared for hardness and tensile tests as well as for metallography. Vickers hardness tests, tensile tests and microstructure analysis using an optical microscope were conducted. The results obtained indicated that the B4C particles were evenly distributed in the alloy matrix. EDS also revealed the presence of B4C in all the three composites. In general, the hardness and tensile strengths increased with increase in concentration B4C powders. While the increase in hardness was increases less than 15%, there was significant increase (more than 35 %) in tensile strength. However, the ductility represented by % elongation, which was already very low in A 356 cast alloy (24.2%,), further decreased in composites. Tensile fractography results shows inter crystalline fracture where the breakage in the B4C particle instead of deboning were observed.

Effect of Boron Carbide Addition on Wear Resistance of Aluminum Matrix Composites Fabricated by Stir Casting and Hot Rolling Processes

In this study, to evaluate the effect of boron carbide (B4C) addition on the wear performance of aluminum (Al), Al6061 and 5, 10, and 20 vol.% B4C/Al6061 composites were manufactured using the stir casting and hot rolling processes. B4C particles were randomly dispersed during the stir casting process; then, B4C particles were arranged in the rolling direction using a hot rolling process to further improve the B4C dispersion and wear resistance of the composites. Furthermore, a continuous interfacial layer between B4C and the Al6061 matrix was generated by diffusion of titanium (Ti) and chromium (Cr) atoms contained in the Al6061 alloy. Wear depth and width of the composites decreased with increasing B4C content. Furthermore, with B4C addition, coefficient of friction (COF) improved as compared with that of Al6061. The results indicate that interface-controlled, well-aligned B4C particles in the friction direction can effectively increase the wear properties of Al alloys and improve their hardness.

Investigations on Mechanical Behaviour of Micro B4C Particles Reinforced Al6061 Alloy Metal Composites

Objective: To develop and evaluate the mechanical behavior of 3, 6, 9 and 12 wt. % of B4C reinforced Al6061 alloy composites. Method: These composites were produced by utilizing stir cast process. The prepared metal composites were characterized by SEM, EDS and XRD analysis to know the distribution of particles as well as presence of particles in the Al6061 alloy. Various mechanical properties were evaluated as per ASTM standards to know the impact of boron carbide particles on the properties of metal composites. Findings: By adding B4C particles the hardness, ultimate tensile, yield strength and compression strength of the Al6061 alloy matrix was enhanced 23.9%, 15.4 14.9% and 34.7% respectively. Further, there was slight decrease in the percentage elongation of B4C reinforced composites. Novelty: In the present research Al6061 alloy with 3 to 12 wt. % of B4C composites were synthesized by novel stir casting method called as two stage reinforcement addition process. In this process 80 micron sized boron carbide particles added in two stages into the molten Al6061 alloy to improve the wettability between the matrix and reinforcement particles. Keywords Al6061 Alloy, B 4 C Particles, Hardness, Tensile Strength, Microstructure

Morphological evolution of boron carbide particles: Sol-gel synthesis of nano/micro B4C fibers

Herein we present a novel non-catalytic sol-gel route to synthesize nano/micro boron carbide fibers. By in-situ decoration of the precursor surface with boric acid crystals during the thermal decomposition stage, the growth kinetics of boron carbide particles was manipulated. Therefore, the formation of anisotropic crystals instead of polyhedral-equiaxed ones was successfully enabled. The results indicated that highly crystalline boron carbide (B4C) particles with a low amount (<1 ± 5 wt%) of free carbon were obtained. The SEM and HR-FESEM micrographs revealed that B4C particles with fully polyhedral-equiaxed morphology were obtained from the precursors, which were thermally decomposed with 2 h holding time at 675 °C. As a result of increased thermal decomposition duration of precursor, B4C particles with various morphologies, such as rhomboid-plate, nanobelt, and fiber were formed beside the polyhedral-equiaxed particles. The yield of boron carbide fiber formation was increased, and polyhedral-equiaxed particles were decreased in the final products by tailoring the structure of the preceramic precursor. The products containing at least 50% of boron carbide fiber were achieved using 12 h of thermally decomposed precursors. The formation and growth mechanisms of boron carbide particles were speculated and comprehensively discussed.

Experimental Investigation of Mechanical and Thermal Study of Mg/B4C/Cr Hybrid Composites

This study explores the investigation of enhanced mechanical and thermal properties of Mg/B4C/Cr hybrid composites having varying 3, 5, 7 wt. % of B4C and Cr reinforcements in Mg-matrix. The bottom pouring vacuum-based squeezed stir casting process is used to fabricate these composites. The Mg/B4C/Cr hybrid composites evaluate ultimate strength, elongation percentage, expansion coefficient, heat conductivity, hardness, and then compared with Mg/5B4C and Mg/5Cr composites. Each of Mg-based hybrid composites results indicates higher thermal conductivity and expansion coefficient than Mg/5B4C and Mg/5Cr composites. The tensile results reveal that the Mg/B4C/Cr hybrid composites show mixed morphologic behaviour of brittle-ductile while Mg/5B4C and Mg/5Cr composites are individually evident with brittle behaviour. The proper interfaces between Cr particles and Mg matrix illustrate reduced dislocations with efficient strength and thermal results. However, B4C particles present in the base matrix is liable for the effective hardness and ultimate strength in the Mg/B4C/Cr hybrid composites. In comparison with other composites (Mg/B4C and Mg/Cr), Mg/B4C/Cr hybrid composite shows efficient thermal conductivity with high thermal conductance which diverges towards the application of gas cylindrical liners.

Multi Ceramic Particles Inclusion in the Aluminium Matrix and Wear Characterization through Experimental and Response Surface-Artificial Neural Networks.

Lightweight composite materials have recently been recognized as appropriate materials have been adopted in many industrial applications because of their versatility. The present research recognizes the inclusion of ceramics such as Gr and B4C in manufacturing AMMCs through stir casting. Prepared composites were tested for hardness and wear behaviour. The tests’ findings revealed that the reinforced matrix was harder (60%) than the un-reinforced alloy because of the increased ceramic phase. The rising content of B4C and Gr particles led to continuous improvements in wear resistance. The microstructure and worn surface were observed through SEM (Scanning electron microscope) and revealed the formation of mechanically mixed layers of both B4C and Gr, which served as the effective insulation surface and protected the test sample surface from the steel disc. With the rise in the content of B4C and Gr, the weight loss declined, and significant wear resistance was achieved at 15 wt.% B4C and 10 wt.% Gr. A response surface analysis for the weight loss was carried out to obtain the optimal objective function. Artificial neural network methodology was adopted to identify the significance of the experimental results and the importance of the wear parameters. The error between the experimental and ANN results was found to be within 1%.

The effect of carbon nanotubes introduction on the mechanical properties of reaction bonded boron carbide ceramics

The influence of carbon nanotubes (CNTs) on the mechanical properties and structure formation during reactive sintering of B4C materials with Si addition was studied. Upon infiltrating the B4C structure with molten silicon, a non-porous composite was formed with a density of 2.45-2.55 g/cm3 and a hardness of 22-27 GPa. The formation of highly dispersed B-C-Si phases was observed in the interphase of adjacent B4C particles due to the incorporation of Si into B4C structures. These phases increase the bonding strength between B4C particles. In spite of the fact that the addition of 1-5 wt% Multi-Walled Carbon Nanotubes decreases the green density of the compacts, the flexural strength of the infiltrated material significantly increased. The improvement of the strength of ceramics modified with MWCNTs was interpreted in terms of the formation of thin flattened SiC crystals at the interfaces between B4C and B-C-Si particles, which strengthen the interfaces between ceramic particles.

WITHDRAWN: Effect of bonding time and boron carbide percentage on diffusion bonding characteristics for copper/copper matrix composites (Cu + Cu%B4C)

Abstract In this study, the Joining characteristics of pure copper (Cu) and copper matrix composites reinforced by 2.5, 5.0, 7.5 wt% of Boron Carbide (B4C), were investigated. The diffusion bonding (DB) process was prepared at a temperature of 800 °C, and different holding times of 30, 45, and 60 min. During DB, a uniaxial load of 2 MPa was applied. The dissimilar materials joining quality was studied to determine the influences of diffusion time and B4C particulates on bonding properties. Scanning electron microscopy SEM assays and energy dispersion spectrophotometry EDS element analyzes were performed to determine joint interface properties and to determine mechanical characterization with shear strength SS measurements.

Failure investigation on high velocity impact deformation of boron carbide (B4C) reinforced fiber metal laminates of titanium / glass fiber reinforced polymer

High velocity ballistic impact deformation behaviour of Titanium/GFRP Fiber Metal Laminates (FML) has been explored. Both single and multiple projectiles impact conditions were considered. Ti/GFRP FML targets were fabricated with addition of 5% and 10% weight percentage of boron carbide (B4C) particles. Mechanical properties of Ti/GFRP FML targets were determined as per ASTM standards. High velocity ballistic experiments were conducted using Armour Piercing Projectile (APP) of diameter 7.62 mm and velocity ranging between 350 and 450 m/s. Depth of penetration of the projectile into the target was measured. The deformation behaviour of Ti/GFRP targets with and without the presence of ceramic powder (B4C) was investigated. “Ductile hole growth” failure mode was observed for pure GFRP target when subjected to single projectile impact whereas “plugging” failure mode was noted for Ti/GFRP targets. The presence of B4C (5% by weight) particles has significantly improved the ballistic resistance of the Ti/GFRP FML target by offering frictional resistance to the projectile penetration. Further addition (10% by weight) of B4C has reduced the ballistic performance due to agglomeration. None of the targets showed ‘brittle cracking’ or ‘fragmentation’ failures. When compared to the published results of Aluminium (Al 1100/GFRP and Al 6061/GFRP) FMLs, Ti/GFRP FML showed lesser DoP which increases its potential application to aerospace industry.

Development of lightweight and highly efficient fast neutrons composites shields based on epoxy, UHMWPE fibres and boron carbide particles

In a vision to design wearable and lightweight protective thermal neutrons shields, a new hybrid composite was developed from Ultra High Molecular Weight Polyethylene (UHMWPE) fibres, epoxy and boron carbide (B4C) particles. The hybrid constituents were selected in a way to maximize both the shielding performances and the overall mechanical behaviour. Indeed, two first constituents of the hybrid attenuate the incident neutrons through scattering, while the B4C particles mainly interact with neutrons by absorption. More importantly, the UHMWPE fibres, as one of the strongest polymeric fibres, were also chosen to sustain the mechanical loads and provide the requested flexibility. The measurements were performed using an optimized experimental setup at NUR research reactor, Algiers. The effect of the amount of the B4C particles was also studied to maximize the shielding ability. The obtained results confirmed the high shielding efficiency of all the developed materials. Meanwhile, the best performance was recorded at B4C amount of 10 wt% with a macroscopic cross-section (Σ) of 0.188 cm−1 equivalent to a mean free path (λ) of 3.7 cm. In general, the developed materials performed better than the traditional neutrons shields and can be seen as promising materials for the intended use.

Laser powder bed fusion processability of Ti-6Al-4V powder decorated by B4C particles

Understanding the laser-powder interaction during laser powder bed fusion (LPBF) of composite systems is vital in producing robust parts. The currently existing mechanically mixed composite powders are unable to meet the requirements of an ideal powder for the LPBF process, even if the metallic particles remain highly spherical with a second constituent attached to them. It was found that the presence of a reinforcing agent (i.e., B4C) on the surface of metallic particles (i.e., Ti-6Al-4V), rather than its embedment, hinders the full melting of the metallic constituent and deteriorates the powder flowability by creating inter-particle tangling. Despite the significant improvement in the optical absorption caused by the incorporation of the reinforcing agent, the composite powder showed inferior processability compared to the monolithic system.

Mechanical characterization of 44 micron sized B4C particles reinforced Al2618 alloy composites

In the current exploration an impact of 44 µm estimated B 4 C support expansion on the mechanical conduct of Al2618 combination has been contemplated. The Al2618 compound metal composites with 2, 4, 6 and 8 changing weight rates of B 4 C were created by stircast strategy. The orchestrated 44 µm estimated B 4 C particles built up Al2618 combination composites were exposed to microstructural considers, mechanical properties testing. Microstructural portrayals of acquired examples were completed by SEM microscopy and EDS spectrums. The B 4 C particles were uniformly disseminated and existences of these particles were affirmed by the EDS patterns. The hardness and tensile qualities of metal composites have been upgraded with the expansion of B 4 C support. There was decline in the ductility of the Al2618 compound after the joining of the support. Different crack and failure systems were seen in the Al2618-B 4 C composites utilizing SEM.

Microstructural and mechanical characterization of lamb bone ash and boron carbide reinforced ZA-27 hybrid metal matrix composites

ZA-27 hybrid metal matrix composites reinforced with lamb bone ash (LBA) and boron carbide (B4C) were fabricated by employing stir casting route. Single-reinforced composite with 5 wt.% of LBA and hybrid composites reinforced with LBA/B4C in the ratio of (3.75:1.25, 2.5:2.5, 1.25:3.75) were developed. Composites were processed as per ASTM standards and subjected to physical characterization (density and porosity), microstructural characterization, and mechanical characterization (hardness, compressive strength, tensile strength, and impact strength). Microstructural studies of ZA-27 composites using a scanning electron microscope (SEM) revealed the uniform dispersion of reinforcements. X-ray diffraction (XRD) patterns and energy-dispersive X-ray spectroscopy (EDS) of the developed composites confirmed the existence of LBA and B4C particles in the matrix. The density of the composites declined, and porosity increased with the increment in B4C wt.% compared with base alloy. Mechanical properties like hardness, compressive strength, and tensile strength improved significantly in the case of hybrid composites than single-reinforced composite. Hardness, compressive strength and tensile strength of the hybrid composites increased to a maximum of 41.12%, 24.40%, 61.08% respectively compared to the base alloy, whereas single-reinforced composite showed maximum improvement of 19.26% (hardness), 11.16% (compressive strength), and 28.38% (tensile strength) compared to the base alloy. Ductility of the composites decreased with the addition of reinforcements. Impact strength of the composites showed a marginal reduction; however, the reduction was higher in the single-reinforced composite than hybrid reinforced composites. Fractured morphology showed dimples, cracks, tear ridges, and voids.

Experimental ballistic performance of friction stir processed aluminum (AA6061-B4C) surface composite

In this paper, the ballistic performance of AA6061-B4C surface composite targets fabricated by Friction Stir Processing (FSP) technique has been investigated. The paper is divided into two stages. Stage I identifies the suitable process parameters namely, the rotational speed and feed to produce defect free surface composite targets. Standard tests such as tensile test, microhardness and macroscopic examination are carried on FSPed AA6061-B4C surface composite to identify the best process parameters. In stage II, ballistic experiments are conducted on FSPed AA6061-B4C targets for both single and multiple hit conditions. The ballistic performances of the targets are measured in by Depth of Penetration (DoP) method. It is seen that, in both single and multiple impact conditions, radial cracks are observed near the crater region of BM AA6061 targets. Especially in multiple hit, severe cracking occurred around the craters present near the edges of BM AA6061 target. On the other hand, no cracks are observed in FSPed AA6061-B4C targets after both single and multiple hit conditions. A 13%–20% DoP is observed in FSPed AA6061 target compared to BM target. It is inferred that, improvement in microhardness and frictional characteristics offered by B4C particles have played a vital role in improving the ballistic performance of FSPed AA6061-B4C targets.