Boron Carbide Particles Research Articles

Tribological behaviour of eggshell ash and boron carbide reinforced ZA-27 hybrid metal matrix composites under dry sliding conditions

The present investigation intends to study the tribological behaviour of ZA-27 alloy reinforced with low-cost eggshell ash (ESA) and boron carbide (B4C) particles by utilizing a stir casting process to fabricate hybrid metal matrix composites. The percentage of ESA and B4C particles are added in the range of 0–5 wt.%. Composites being tested for density, porosity and microhardness. A pin-on-disc DUCOM tribometer used to investigate the friction and wear behaviour of composites with a varying load of 10 to 50 N at a constant sliding speed of 1 m s−1 and a fixed sliding distance of 1500 meter. To study the influence of speed on friction and wear behaviour, tribological testing was also performed at a sliding speed of 2 m s−1 and 3 m s−1. The composites microstructure revealed the presence of ESA and B4C particles examined by scanning electron microscope (SEM) and energy-dispersive x-ray spectroscopy (EDS) analysis confirmed the elemental composition of reinforcement particles present in the matrix. Composites density decreased when reinforced with ESA and B4C particles and the maximum decrease in density was about 3.12%. Porosity of the composites increased with the increase in wt.% of B4C particles. Addition of ESA and B4C particles significantly improved composites microhardness. The coefficient of friction (COF) and wear loss showed an increasing trend with the increase in load, whereas COF decreased and wear loss increased on higher sliding speeds. Composites showed superior wear resistance over base alloy under all test conditions. Worn surface morphology indicated the delamination, plastic deformation and ploughing at low speed, whereas abrasion was the dominant wear mechanism at higher sliding speeds. Therefore, this hybrid composite may have the potential to be used as a bearing material for tribological applications over monolithic ZA-27 alloy.

Development properties of aluminum matrix composites reinforced by particles of boron carbide

Composite materials are an important class of economical structural materials with unique properties that expand the scope of mechanical engineering in various industries. One of the most interesting metal composite materials is metal structures with low cost of reinforcement and availability for mass production. Due to the development of the structural requirements of some aircraft components, the development of the accelerated aging process becomes necessary to observe and understand the aging of aluminum alloys and predict the effect of this process on the mechanical behaviors of these alloys under temperature. In this research boron carbide (B4C) is reinforced in the aluminum matrix composites to increase the more conductivity and characterized for their mechanical properties such as hardness and tensile strength. Al-5%Cu aluminum alloy metal matrix composites will be reinforced with Boron Carbide (B4C) particles up to 2, 5 and 7 % was produced by stir casting. Particulates may subsequently add using the squeeze casting process. The squeeze casting technique decreased the porosity of the final composites. The modes of aging of MMC reinforced with B4C particles are determined. It is shown that when aging at 225 °C with an increase in the content of B4C particles to 7%, the maximum hardness is reached after 7 hours, while in the matrix alloy after 9 hours. Aging at 250 °C reduces the time to reach maximum hardness by 1 hour.

Microstructure, Tensile and Flexural Strength of Boron Carbide Particles Reinforced Al2030 Alloy Composites

Objective: To synthesize and assess the mechanical behaviour of 12 wt. % of 80 to 90 micron sized B4C reinforced Al2030 alloy metal composites. Method: Al2030 alloy with 12 wt. % of B4C reinforced composites were developed by liquid melt stir cast method. These prepared composites were subjected to microstructural characterization by SEM, EDS and XRD. Mechanical properties like hardness, tensile and flexural strength were evaluated according to ASTM standards. Findings: Scanning electron micrograph of Al2030 alloy with 12 wt. % of B4C composites revealed the thorough distribution of boron carbide particles in the Al2030 matrix. EDS and X-ray diffractometer patterns confirmed the presence of boron carbide particles in the Al2030 alloy matrix. The addition of 12 wt. % of B4C particles enhanced the hardness by 74.8%, ultimate strength by 59.2%, yield strength by 64.8% and flexural strength by 44.2% with slight decrease in ductility. Novelty: Al2030 alloy is an aerospace grade aluminium alloy widely used for industrial applications. Advanced metal composites developed with the incorporation of 80 to 90 micron sized B4C particles in Al2030 alloy helps in weight reduction of aerospace components. Keywords: Al2030 Alloy; B 4 C Particles; Microstructure; Tensile Strength; Flexural Strength; Fractography

Outstanding thermal neutrons shields based on epoxy, UHMWPE fibers and boron carbide particles

Aiming the development of advanced and lightweight thermal neutrons shields, a new hybrid composite was developed from UHMWPE fibers, epoxy and boron carbide (B4C) particles. The UHMWPE fibres were chosen because of their high hydrogen contents and exceptional mechanical properties. The neutrons shielding tests were performed using an optimized experimental setup at NUR research reactor, Algiers. Overall, the developed materials displayed remarkable neutrons screening performances. Meanwhile, the best performance was recorded at B4C amount of 20 wt% with a macroscopic cross-section (Σ) of with a 0.313 cm−1 equivalent to a mean free path (λ) of 2.2 cm.

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.

Machine learning based predictive modeling and control of surface roughness generation while machining micro boron carbide and carbon nanotube particle reinforced Al-Mg matrix composites

Machine learning has revolutionized the way complex problems are solved in engineering. In the current work, machine learning methodology has been applied for predictive modeling of surface roughness generation during machining of Al-Mg based metal matrix composites (MMCs) reinforced with micro boron carbide and multiwalled carbon nanotube particles. Machine learning was used for parameter estimation of modeling structures such as auto regressive with exogenous variables (ARX), auto regressive moving average with exogenous variables (ARMAX), Box Jenkins (BJ) and Output Error (OE). The identified models were validated on the basis of FIT, final prediction error (FPE) and mean squared error (MSE). The PID, fractional order PID (FOPID), complex order PID (COPID) and model predictive controllers (MPC) were employed to effectively control machined surface roughness based on the best performing predictive models. Primary results indicate that: (1) CNT MMCs generate surface roughness comparable to that due to the micro MMCs with tenfold higher reinforcement fractions (2) ARX441 and ARMAX3331 are the best performing predictive models for the nano and micro MMCs respectively (3) PID and MPC are the best controllers for micro and nano MMC systems respectively considering the peak overshoots as the foremost performance metric (safety), followed by settling time (productivity).

Preparation of the Composite Powder Al – B4C by Ball Milling for Cold Spray

In the work, when ball milling of mixture of aluminum powder (ASD – 1) and boron carbide (F 500) powder in a high-energy planetary mill, composite particles sized from 10 to 100 microns were produced, in the volume of which ultrafine boron carbide particles were distributed in the size range from 0.1 to 20 microns. It is assumed that the use of such particles in the production of coatings by cold gas-dynamic spraying will increase the deposition efficiency and the weight fraction of boron carbide in the coating. An increase in the concentration of carbide particles in the processed powder mixture, under all other conditions being equal, leads to a decrease in the average volume size of the particles. It is noted that in this case, the boron carbide particles behave as a surfactant. The X-ray phase analysis has shown diffraction peaks corresponding only to aluminum and boron carbide, therefore, under the selected milling conditions, the phase composition remain the same as in the original powders.

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.

FRICTION BEHAVIOR OF ALUMINUM BRONZE REINFORCED BY BORON CARBIDE PARTICLES

A promising composite material for tribotechnical applications based on aluminum bronze with reinforcing boron carbide particles fabricated by a special electron beam additive deposition technique was studied experimentally and numerically. Tribological experiments showed that reinforcing by carbide particles allowed reducing the coefficient of friction from 0.26 to 0.19 and improving the wear resistance by 2.2 times. Computer modeling reveals two main factors playing a significant role in the friction behavior of the studied metal matrix composite: the mechanical effect of reinforcing ceramic inclusions and effective hardening of the metal matrix due to the peculiarities of the 3D electron beam printing. The mechanical effect of hardening inclusions determines a more rounded shape of wear particles, preventing wedging, and thereby increasing the stability of friction. Strengthening the metal matrix leads to reducing the number of wear particles.

Mechanical characterization of LM25 alloy matrix composite reinforced with boron carbide

Alumnium alloy LM 25 based composites reinforced with boron carbide at different weight fractions of 4%, 8%, and 12% were fabricated by stir casting technique. The microstructures and morphology of the fabricated composites were studied by scanning electron microscopy and energy dispersive spectroscopy. Elemental mapping of all fabricated composites were done to demonstrate the elements present in the matrix and fabricated composites. The results of microstructural analyses reveal homogenous dispersion of reinforcement particles in the matrix with some little amount of clustering found in composites reinforced with 12% wt. of boron carbide. The mechanical characterization is done for both alloy LM 25 and all fabricated composites based on hardness and tensile strength. The hardness increased from 13.6% to 21.31% and tensile strength 6.4% to 22.8% as reinforcement percentage of boron carbide particles increased from 0% to 12% wt. A fractured surface mapping was also done for all composites.

Dry sliding wear behavior of nano boron carbide particulates reinforced Al2214 alloy composites

In the current research wear behaviour of nano B 4 C particles with Al2214 alloy composites were studied. Al2214 alloy with 2 to 6 varying weight percentages of nano B 4 C particles composites were developed using stir cast route. Further, these developed composites were evaluated for the microstructural studies using SEM and EDS. The wear behaviour of Al2214 alloy and Al2214 with 2, 4 and 6 wt% of nano B 4 C composites were analysed using pin-on-disc wear apparatus. The dry wear tests were conducted at various loads and sliding speeds with 2500 m sliding distance as a constant parameter. The microstructural explanations revealed the thorough circulation of nano particles in the Al2214 alloy matrix, further the boron carbide particles were confirmed in the composites in the form of boron and carbon components. The Al2214 alloy with nano B 4 C composites displayed the greater wear resistance properties. The applied load and speed were impacted the wear of as cast alloy and its composites. Various wear mechanisms were identified by using SEM images of wear surfaces.

Numerical study of the compression property for Aluminium-based (Al-4% Cu) reinforced with different carbide particulates

The compression characteristic of an (AL-4% CU) alloy reinforced with different particles (boron carbide, silicon carbide, and titanium carbide) was numerically studied. For this purpose, a model was performed using COMSOL Multiphysics 4.1. Hence, three samples were selected and reinforced with carbide particles equal to 20 microns’ in diameter and then compared with that one not reinforced. An axial load of 20 Newton was applied for all samples from both sides. The results showed that the alloy (AL-4% CU) reinforced with boron carbide particles has the highest compressive resistance compared to the other reinforced particles. The elongation of boron carbide, silicon carbide and titanium carbide particles were 1x10−7mm, (1.3*10−7 mm) and (1.5*10−7 mm) respectively, while it was (5.5*10−8 mm) for not unreinforced particles.

Effect of Heat treatment on Fatigue Behavior of B4C and Copper Coated short Basalt fiber Reinforced Al 2014 Based Hybrid Composite

Boron carbide (B4C) particulate and Copper coated Basalt fiber reinforced Al2014 composites were fabricated by stir casting technique. Boron carbide particles and short copper coated basalt fiber were varied from 2 wt. % to 8 wt. % in steps of 2 %. To improve the interfacial bonding between basalt fiber and matrix Al2014 alloy, the fibers are coated with copper by electroless deposition method. The Scanning Electron Microscope (SEM) clearly shows the uniform coating of copper on the surface of fiber and also observed that, increased wt % of reinforcement in ascast composites results in momentous progress in fatigue strength. The addition of boron carbide shows better fatigue strength compared to the addition of copper coated basalt fiber in Al2014. The Heat treated hybrid composites for all weight % of reinforcement’s shows 1.2 to 2%better fatigue life as compared to ascast composites. This may be due to the refinement of grains and development of strong intermolecular bonding between the particles of composites. The fracture analysis done by SEM, clearly revealed that the crack initiated from the region of voids or porosity in the matrix and not in the region of boron carbide and copper coated basalt fiber interface.

Optimization of ductility and yield strength on Al2024/B4C composite material using Taguchi Technique

In the present investigation, Al2024 alloy reinforced with boron carbide particulates with three different mesh size (100, 200 and 300) have been chosen for the preparation of MMCs. Stir casting route was adopted by varying weight percentage of boron carbide particulates by 1 wt.%, 3 wt.% and 5 wt.%. The cast component was machined through conventional lathe machine tool as per ASTM E8-16a size for tensile test specimen. The tensile test specimens have been subjected to solutionzing treatment at 520 for24 hours followed by water quenching. The quenched test specimens are then subjected to artificial ageing at 175 for holding duration of 1 hr., 3 hrs. and 5 hrs. The tensile specimens after artificial ageing were tested using UTM to evaluate the ductility and yield strength of the formed composite material. It is noticed that ductility found to be decreased with increase in wt.% of boron carbide in the Al2024 alloy, whereas yield strength was found to be improved. Taguchi Technique was adopted to evaluate the S/N ratio, optimization, influence of process parameter and regression equation were derived for the confirmation of experimental results through Minitab software. SEM images reveal the uniform distribution of boron carbide in Al2024 alloy. Ductile tearing was observed in pure Al2024 alloy and the formed composite material.

The effect of boron carbide additive on the low‐velocity impact properties of low‐density foam core composite sandwich structures

AbstractSandwich structures with carbon fiber‐epoxy face sheets and polyvinyl chloride foam core material are known for their high strength and flexural stiffness despite their low weight. However, the structural response, in terms of crush strength, of the particles added sandwich structures are not very well known under impact loading conditions. In this study, the impact resistance and damage characteristics of particle added low weight composite sandwich structures were investigated with a low‐velocity drop weight impact test device. Boron carbide (B4C) particles, which had excellent hardness, thermoelectric, and radiation absorbing characteristics, were used as an additive for the epoxy matrix. For this purpose, 2%, 5%, and 10% by weight additives were mixed into the epoxy matrix and sandwich structures were produced with hand lay‐up followed by vacuum bagging method. All configurations were subjected to low‐velocity drop weight impact test at three different energy levels (10, 17.50, and 25 J). The results obtained from the experiments and the images of the post‐impact damage of the sandwich structures were presented comparatively. According to the test results, configurations containing 10% boron carbide (B4C) additive has shown the best performance in terms of resistance to impact load.

Nanoindentation determination for mechanical properties of submillimeter boron carbide particles simulating fuel debris fragments

It is essential to characterize fuel debris fragments that are to be retrieved from reactors at the Fukushima Daiichi power station prior to their large-scale retrieval. Using nanoindentation (NI) test, we have determined the mechanical properties of boron carbide (B4C) particles currently used to simulate hard covalent materials as included in the debris. We also examined the measurable minimum size among the particles sized to three types and found suitable sample preparation methods. While the minimum size was limited to 1000 μm among the particles fixed with grease in molding process, it was brought down to 500 μm by alternative polyvinyl alcohol (PVA) films. Indentation moduli of these successfully measured B4C particles are consistent with a referential value of 431 GPa with a difference of 3.5%. Furthermore, the hardness values of the particles are slightly lower than a referential value of 21.8 GPa within uncertainty of 9%. The particle surfaces were polished enough with only the roughest #240 abrasive papers, and surface flatness was a key issue for the successful indentation but not surface roughness. As a result of the detachment caused during polishing, both 500 μm particles and 100 μm particles fixed with the grease were insufficiently flattened, and then the indenter was slipped on the inclined surfaces during the NI tests. The values of modulus and hardness are at the minimum for the 100 μm particles at decreasing rates of 46% and 42% to the referential values. The thin uniform PVA films reduced the projection amount of the 500 μm particles from the surrounding resin and prevented the particle detachment during polishing. Residual resin was distinguished from an underlaying B4C particle using the NI tests.

Low Cycle Fatigue of an Ultrafine Grained AA5083 Aluminum Alloy Composite Produced by Cryomilling

Low cycle fatigue (LCF) properties were investigated for a novel cryomilled AA5083 aluminum composite with duplex coarse and ultrafine grain sizes and reinforced with boron carbide particulates, referred to as trimodal material. Fully reversed cyclic tests were conducted under plastic strain control at plastic strain amplitudes from 0.15 to 0.6 pct using a constant plastic strain rate in a servo-hydraulic testing system. A nonlinear elastic modulus was used to calculate the elastic contribution to the measured total strain. The LCF performance of this trimodal material is compared to previous results for unreinforced AA5083 aluminum alloy with bimodal grain size (85/15 pct CM/UM) and its coarse-grained wrought counterpart, AA5083-H131. Stress response curves for the trimodal material revealed slow hardening until failure associated with the presence of particulate reinforcements. The very small asymmetry between tension and compression stresses reflects a lack of strain localization beyond the initial cycles. The trimodal and 85/15 pct CM/UM alloys have similar and superior low cycle fatigue strength compared to AA5083-H131. From the Coffin-Manson plot, the trimodal material has a shorter fatigue life than 85/15 pct CM/UM alloy and AA5083-H131 for high plastic strain amplitudes, but nearly identical life at low amplitudes. Microcracks were observed near the dominant crack on trimodal specimen surfaces at failure. Back-scattered images revealed that particulates altered the crack propagation direction; cracks nearly always propagated around particulates.

Influence of process parameters on tensile strength and hardness of AW2024/B4C composite using Taguchi’s technique

Abstract The need for engineering materials in the aerospace industry is increasing day by day. AW2024 alloy with boron carbide particulates will suit specific applications like aircraft structure, window panel, seats, aircraft fittings, and wheels. Hence in this research paper, AW2024 alloy was selected as the matrix and boron carbide particulates as reinforcement. Boron carbide particles with three different mesh sizes have been chosen and varied in wt% into the AW2024 matrix routed through stir casting process. Taguchi's Technique was used to evaluate optimization, S/N ratio, influence of process parameters, and regression equation to validate the experimental values. It was noticed that tensile strength and hardness were found to be improved with an increase in wt% of boron carbide particulates in the AW2024 alloy. SEM images show that boron carbide particles are uniformly distributed in the AW2024 alloy and dimple structures were formed at the tensile fracture surface.