B4C Nanocomposites Research Articles

Investigations on Mechanical Properties of Nano Particulates (Al<sub>2</sub>O<sub>3</sub>/B<sub>4</sub>C) Reinforced in Aluminium 7075 Matrix Composite

Metal Matrix Nano Composites (MMNCs) with the addition of nano-particulate reinforcements can be of significance for automobile, aerospace, and numerous applications due to their low density and good mechanical properties, better corrosion and wear resistance, low coefficient of thermal expansion as compared to conventional materials. Designing the metal matrix composite material aims to combine the desirable attributes of metals and ceramics. The present work is focused on studying the mechanical properties of aluminium alloy (7075) with Al2O3 and B4C nanocomposite produced using the stir casting technique and ultrasonic cavitation method. Different % age of reinforcement is used. An ultrasonic cavitation technique is used to achieve a uniform dispersion of nano-particulate Al2O3 and B4C in molten aluminium alloy. Tensile, Hardness, and Impact tests were performed on the samples obtained by the fabrication processes. A structural study will be carried out through a Scanning Electron Microscope (SEM) to know the distribution of Al2O3/B4C Nano particulates in Al alloy.

Prediction of effect of fabrication parameters on the properties of B4C ceramic particle reinforced AA2024 matrix nanocomposites using neural networks

In the present study, a prediction model was created to predict the impact of B4C content, milling time and matrix size on the hardness and density of AA2024-B4C nanocomposites produced by means of flake powder metallurgy. The process involved synthesizing AA2024-B4C nanocomposite powders by mechanical milling followed by preparing nanocomposites by hot pressing. The matrix size of the AA2024 alloy powders, the milling time, and the B4C content were selected as the input parameters. On the other hand, the density and the hardness of the AA2024-B4C nanocomposites were designed as the output parameters. The results showed that the sintered density is significantly improved by decreasing matrix size. It was found that density of AA2024–3 wt%B4C nanocomposites is lower than AA2024–1 wt%B4C nanocomposites. However, the hardness of AA2024–3 wt%B4C nanocomposites is better than AA2024–1 wt%B4C nanocomposites. The AA2024-B4C nanocomposite prediction model could predict hardness and density with a mean absolute percentage error (MAPE) of 0.32% and 1.38%. The results show that the ANN model is a useful tool for the matrix size effect prediction, milling time and B4C content on the density and hardness of AA2024-B4C nanocomposites prepared by flake powder metallurgy.

Investigation of the mechanical, corrosion, and tribological characteristics of AZ61 Mg with boron carbide nano particles via the stir casting route

Abstract Magnesium composites are innovative, compact, and distinctive materials. Because of their low density, magnesium composites are suitable for applications in the automobile, aviation, semiconductor, and pharmaceutical sectors. To enhance the mechanical wear and corrosion behavior of theAZ61 Mg alloy, different weight percentages of nano-B4C reinforcements (2.5, 5, 7.5, and 10wt%) were strengthened with magnesium matrix. Fabrication of magnesium composites was achieved through the stir casting method. The as-cast specimens were subjected to microstructural analysis, which showed that the B4C nanoparticles were dispersed uniformly, well bonded to the matrix, and had a minimal level of porosity. This shows that the inclusion of B4C nanoparticles has aninsignificanteffect on the microstructure of the as-cast material. The material’s tensile strength, compressive strength, hardness, corrosion resistance, and wear resistance were all greatly increased by the Mg17Al12 phase’s fracture and dispersion. Scanning electron microscopy was utilized to inspect the surfaces of AZ61/B4C nanocomposites and witnessed the uniform dispersal of reinforcement within the matrix.The maximum value for mechanical properties was obtained for AZ61/7.5wt%B4C nanocomposite and the lowest value was found to be the corrosion test. These results show that the AZ61/7.5wt%B4C nanocomposite is a superior material for aerospace and automotive engineering components where high compressive strength, corrosion resistance, and wear resistance are required.

Enhancement of saltwater ageing behavior of nanocomposites and lap joints with boron nanoparticles

The presented research aims to enhance the ageing performance of nanocomposites and bonded joints in the saltwater medium with boron nanoparticle doping. Epoxy nanocomposites and bonded aluminum 2024-T3 joints doped with 2 wt% silane-functionalized boron carbide (B4C) and boron nitride (BN) nanoparticles and undoped were produced for that purpose. The produced samples were immersed in a saltwater (10% NaCl) solution at 40 °C for 480, 960 and 1440 h. By performing the weight change test, Fourier transform infrared (FT-IR) spectroscopy, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), tensile test and scanning electron microscope (SEM), the research aimed to comprehensively assess the changes in the properties of nanocomposites and lap joints after exposure to saltwater ageing, shedding light on the effectiveness of boron nanoparticle doping in improving their performance in saltwater environments. The result showed that thanks to the anti-plasticisation behaviour of nanoparticles, 18.4% and 19.6% higher Tg values were obtained in B4C and BN-doped nanocomposites after 1440 h of ageing, respectively. Similarly, the static tensile strength of the undoped composite decreased by 22%, while B4C and BN-doped nanocomposites decreased by 15% and 14%, respectively, at the end of ageing. After 1440 h, the storage modulus of undoped, B4C and BN-doped nanocomposites decreased by 24.2%, 15.3% and 11.9%, respectively. It was found that B4C and BN-doped bonded joints performed superior mechanical properties compared to their undoped counterparts. The joints doped with B4C and BN nanoparticles carried 50% and 52% higher loads than the undoped joint.

An effect of nano-SiC with different dielectric mediums on AZ61/7.5% B4C nanocomposites studied through electrical discharge machining and Taguchi based complex proportional assessment method

An effect of nano-SiC with different dielectric mediums on AZ61/7.5% B4C nanocomposites studied through electrical discharge machining and Taguchi based complex proportional assessment method

Ballistic performance of boron carbide nanoparticles reinforced ultra-high molecular weight polyethylene (UHMWPE)

Ultra-high molecular weight polyethylene (UHMWPE) is well known for its remarkable mechanical properties including excellent ballistic performance. These properties might be further improved by reinforcement fillers, especially nanoparticles (NPs). In the present work, UHMWPE is incorporated with 0.01, 0.05 and 0.1 wt% of boron carbide (B4C) NPs by twin-screw extrusion at 200 °C. These nanocomposites are characterized by high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) and then, for the first time, ballistic tested with 0.22 caliber ammunition. HRTEM images reveal B4C NPs with sizes in the range of 10–55 nm. SEM disclosed uniform incorporation of 0.01 and 0.05 wt% B4C NPs. The nanocomposites crystallinity index, obtained by XRD, remained practically constant (44–49%) but significantly lower than the neat UHMWPE (66%). A slight decrease in the nanocomposite's thermal stability was shown by TGA, while no significant changes were found by DSC as compared to the neat UHMWPE. The DMA properties of all nanocomposites were improved. In particular, the storage modulus of the 0.05 wt% B4C nanocomposite increased by 89% compared to neat UHMWPE. The ballistic result of the 0.05 wt% B4C nanocomposite showed the lowest bullet penetration depth and confirmed its advantage for personal armor application.

Development from Alloys to Nanocomposite for an Enhanced Mechanical and Ignition Response in Magnesium

The current study reports on the evolution of microstructure, variations in compressive properties and the ignition resistance of Mg through compositional variation, using alloying elements and nanoreinforcement. The alloys were designed with the use of a singular alloying element, Ca, and a binary alloying element, Ca+Sc, to develop Mg1Ca (wt.%) and Mg1Ca1Sc (wt.%) alloys. B4C nanoparticles were addedas the reinforcement phase in the Mg1Ca1Sc alloy to create the Mg1Ca1Sc/1.5B4C (wt.%) nanocomposite. The most effective compressive properties and level of ignition resistance was displayed by the developed composite. The grain sizes were significantly reduced in the Mg alloys (81%) and the composite (92%), compared with that of the Mg. Overall, the microstructural features (i.e., grain refinement, the formation of favorable intermetallic compounds, and hard reinforcement particles with an adequate distribution pattern) enhanced both the compressive strength and strain of the alloys and the composite. The ignition resistance was progressively increased from the alloys to the nanocomposite, and a peak ignition temperature of 752 °C was achieved in the composite. When compared with the ignition resistant of Elektron 21 (E21) alloy, which met the Federal Aviation Administration (FAA) requirements, the Mg1Ca1Sc/1.5B4C nanocomposite showed a higher specific yield strength and better ignition resistance, asserting it as a potential candidate material for lightweight engineering applications, including aerospace and defense sectors.

Effects of manufacturing parameters on the corrosion behavior of Al–B4C nanocomposites

The purpose of this paper is to investigate the microstructural and corrosion behaviors of Al–B4C nanocomposites fabricated by the stir casting technique. Two parameters included the stirring time and temperature have changed in the manufacturing process to affect the characteristics of nanocomposites. Both the optical microscopy (OM) and the field emission scanning electron microscopy (FESEM) were utilized for microstructural evaluations. Moreover, the X-ray diffraction (XRD) and the energy dispersive spectroscopy (EDS) methods were used to identify various phases and to study the elemental analysis of specimens, respectively. In addition, the polarization and electrochemical impedance spectroscopy (EIS) techniques were employed to peruse the corrosion properties of fabricated nanocomposites in various corrosive environments. The FESEM images showed that B4C nanoparticles were distributed uniformly in the aluminum matrix. Polarization test results demonstrated that the corrosion rate of Al–B4C nanocomposites decreased to lower than 99% compared to the aluminum alloy in 0.6 M NaCl solution; however, such a reduction was about 22–42% in 2 M NaOH solution. The EIS test results depicted that the total increase in the charge transfer resistance values for Al–B4C nanocomposites was about 23–59% with respect to the aluminum matrix in 0.1 M HCl solution. Regression analysis results displayed that for acidic solutions (such as HCl and H3BO3) the stirring temperature was more effective than the stirring time to reduce the corrosion rate.

Effect of different reinforcement on the microstructure and mechanical properties of AA2024-based metal matrix nanocomposites

Abstract In this study, AA2024-B4C and AA2024-SiC nanocomposites were successfully produced by hot pressing and consolidation methods. The effects of different SiC and B4C contents on the mechanical properties and microstructure of the nanocomposites were investigated. The bending and tensile strength of AA2024-2 wt.% B4C nanocomposites reached up to 1286.7 MPa and 392.9 MPa, respectively. The bending strength of 676.7 MPa and tensile strength of 377.7 MPa were obtained for AA2024-2 wt.% SiC nanocomposites. The addition of the reinforcement can increase the bending strength of the nanocomposites even if porosity increases. Comparing the experimental results showed that B4C reinforced nanocomposites exhibited better mechanical properties than those of SiC reinforced nanocomposites. The type of Al2Cu phase plays a major role in the improvement of mechanical properties of the composites.

Effect of different reinforcement on the microstructure and mechanical properties of AA2024-based metal matrix nanocomposites

Abstract In this study, AA2024-B4C and AA2024-SiC nanocomposites were successfully produced by hot pressing and consolidation methods. The effects of different SiC and B4C contents on the mechanical properties and microstructure of the nanocomposites were investigated. The bending and tensile strength of AA2024-2 wt.% B4C nanocomposites reached up to 1286.7 MPa and 392.9 MPa, respectively. The bending strength of 676.7 MPa and tensile strength of 377.7 MPa were obtained for AA2024-2 wt.% SiC nanocomposites. The addition of the reinforcement can increase the bending strength of the nanocomposites even if porosity increases. Comparing the experimental results showed that B4C reinforced nanocomposites exhibited better mechanical properties than those of SiC reinforced nanocomposites. The type of Al2Cu phase plays a major role in the improvement of mechanical properties of the composites.

Gravity Die Casting based analysis of aluminum alloy with AC4B Nano-composite

The main aim of manufacturers is to cast the aluminum alloys without any defects. Hence, in this work we present the casting of aluminum alloy LM25 to manufacture intricate automobile components and compared it with AC4B Nano-composite Alloy through the process of Gravity Die Casting. The mechanical properties of these alloys are characterized by implementing tensile test, hardness test and compressive test. The Scanning Electron Microscope is used further to test the microstructure investigations. The quantitative results of microstructural study shows the presence of grain refinement, uniform distribution and less number of pores in nano-composite specimen. Further, the addition of B4C Nano-composite in the aluminum alloys increases the mechanical properties like yield strength, hardness and ultimate strength. Such improvement in mechanical properties is due to the usage of particle size and fabrication process.

The effect of particle size on microstructure, relative density and indentation load of Mg-B4C composites fabricated at different loading rates

The effect of reinforcing particle size on microstructure, relative density and indentation of Mg reinforced by 0, 1.5, 3, 5 and 10% volume fractions of nano- and micro-sized B4C was investigated. The composites were fabricated through powder compaction technique at strain rates of 1.6 × 103 s−1, 8 × 102 s−1 and 8×103 s−1 using split Hopkinson bar, drop hammer and Instron, respectively. The results indicated that the size of B4C and loading rate had significant effect on relative density. For example, the relative density of Mg-10 vol.% B4C nanocomposite was around 2.5% higher than that of its corresponding microcomposites. The relative density of the samples produced at high rate of loading was in average 1.2% higher than that of the samples fabricated quasi-statically. The results of indentation tests on the produced nanocomposite and microcomposite samples also revealed that loading rate and B4C particle size had significant effect on strength of specimens. For example, for Mg-5 vol.% B4C, the maximum load in load–depth curve of the specimens produced by split Hopkinson bar increased from 530 N for micron-sized B4C to 780 N for nano-sized B4C, around 45% improvement. Moreover, nanocomposites had better indentation resistance compared to similar micro composites fabricated using the three methods.

Enhancing Properties of Aerospace Alloy Elektron 21 Using Boron Carbide Nanoparticles as Reinforcement

In this study, the effect of nano-B4C addition on the property profile of Elektron 21 (E21) alloys is investigated. E21 reinforced with different amounts of nano-size B4C particulates was synthesized using the disintegrated melt deposition technique followed by hot extrusion. Microstructural characterization of the developed E21-B4C composites revealed refined grains with the progressive addition of boron carbide nanoparticles. The evaluation of mechanical properties indicated a significant improvement in the yield strength of the nanocomposites under compressive loading. Further, the E21-2.5B4C nanocomposites exhibited the best damping characteristics, highest young’s modulus, and highest resistance to ignition, thus featuring all the characteristics of a material suitable for several aircraft applications besides the currently allowed seat frames. The superior mechanical properties of the E21-B4C nanocomposites are attributed to the refined grain sizes, uniform distribution of the nanoparticles, and the thermal insulating effects of nano-B4C particles.

The effect of compaction loading rate on hardness and wear resistance of Mg–B4C nanocomposite

Hardness and wear resistance of Mg–B4C nanocomposites produced using dynamic and quasi-static compaction method were investigated. Micron-sized Mg particles were mixed with 1.5%, 3%, 5% and 10% volume fractions of nano-sized B4C. High rate compactions were conducted at 723 °K and at strain rates of and using Split Hopkinson Bar (SHB) and Drop Hammer (DH), respectively and low rate were conducted at strain rate of The results revealed that the hardness was increased by 25% at high rate loading compactions with respect to the low rate compactions. The results also indicated that the hardness of Mg-10 vol%B4C nanocomposites fabricated by SHB was around 50% higher than that of the as-received Mg. The same trend was observed in wear resistance of the high and low rate compacted specimens so that the wear resistance of Mg-10 vol%B4C nanocomposites fabricated by SHB was around 70% higher than that of the as-received Mg. Finally, the friction coefficient of the samples was 43% lower than the dynamically produced samples.

Influence of B4C nanoparticles on mechanical behaviour of Silicon brass nanocomposite through mechanical alloying and hot pressing

Abstract This research article has concentrated to develop a novel silicon brass of [82Cu4Si14Zn]100-x – x wt.% B4C (x = 0, 3, 6, 9, and 12) nanocomposites which were synthesized by mechanical alloying followed by vacuum hot pressing for consolidation of powders into bulk samples. Single vial planetary ball mill was used to synthesize the nanocomposite powders in which the ball-to-powder ratio of 10:1 with the milling time of 20 h was used. The milled powders were compacted and sintered simultaneously using vacuum hot pressing equipment for 1 h at 900 °C. The structural, mechanical and tribological properties were characterized and investigated by x-ray line profile analysis (XRD), scanning electron microscopy (SEM), electron backscattered diffraction images (EBSD), energy dispersive x-ray spectroscopy (EDS), Vickers microhardness, compression test, and dry sliding wear behaviour analysis. It has been found that B4C nanoparticles had homogeneously distributed and embedded in the nanocrystallite matrix. As a result, the fabricated nanocomposites were exhibited superior properties than the conventional alloy. Here, 12 wt% B4C reinforced silicon brass of bulk nanocomposite was produced higher hardness and compressive strength than the unreinforcement matrix. Further, the worn morphologies were evidenced the mild wear occurred at higher reinforced nanocomposites owing to decohesion and lower wear rate with considerable wear resistance.

Microstructure Analysis and Mechanical Properties of LM25 alloy with AC4B Nano-Composite using Gravity Die Casting Method

Casting of Aluminium alloys with zero defects would be the ultimate aim of any manufacturer. In the present work, the Alloy LM25 which was being used for the manufacturing of intricate Automobile components is compared to Alloy AC4B Nano-composite using Gravity Die Casting method. In order to investigate the mechanical properties of the concerned materials, Tensile followed by Hardness, and Compressive tests was implemented. Microstructure investigation is examined using Scanning Electron Microscope. The outcome from micro structural study confesses the uniform distribution, grain refinement, and low porosity in Nano-composite specimen. Mechanical results affirm that addition of B4C Nano-composite leads to enhancement of yield strength, ultimate strength and hardness. The uplift in mechanical properties manifested that the type of fabrication process and particle size involved in it.

Effects of Mechanical Milling Time and Boron Carbide Reinforcement Content on Powder and Hot Extruded Al–2wt.%Cu–B4C Nanocomposites: Microstructural, Mechanical and Fracture Characterization

The main objective of this study is an investigation on influences of mechanical milling time and B4C reinforcement content on microstructure and mechanical properties of powder and hot extruded B4C reinforced Al–2wt.%Cu aluminum alloy matrix nanocomposites. These composites were fabricated through mechanical milling, cold isostatic pressing and hot extrusion processes. Results of powder characterization showed that steady-state time of mechanical milling was predicted to be around 20 h. Microstructural analyses of Al–Cu–4wt.%B4C composite powder revealed that strain-induced dissolution of fine B4C reinforcements and in situ formation of Al3BC phases within the nanocrystalline aluminum matrix were detected only when the composite powder was subjected to at least mechanical milling time of 20 h and subsequent heat treatment. Strength and hardness of the nanostructured samples were significantly improved by increasing mechanical milling time and B4C reinforcement weight percent due to higher level of severe plastic deformation applied to the powders during the fabrication process.

Preparation of super-high strength nanostructured B4C reinforced Al-2Cu aluminum alloy matrix composites by mechanical milling and hot press method: Microstructural, mechanical and tribological characterization

In this research, super-high strength nanostructured B4C reinforced Al-2Cu aluminum alloy matrix composites produced by mechanical milling and hot press method. Nanostructured Al-2Cu powder containing 4, 6 and 10 wt.% B4C reinforcement particles synthesized using a high-energy attritor under argon atmosphere. Results showed that with increasing the content of B4C particles the matrix grain size decreased. Since the compressibility of mechanically milled powders is very low, hot press processing used for consolidation of nanostructured Al-2Cu/B4C powders. The hot pressed Al-2Cu/10 wt.%B4C nanocomposite, when tested in compression, exhibited extremely high strength (1.1 GPa) which is 735 MPa higher than that of coarse grain Al-2Cu sample. Moreover, the hardening capacity (Hc) of hot pressed nanocomposites decreased with the increase in the content of B4C particles. According to Orowan strengthening mechanism, since B4C particles act as a barrier to the dislocations movement, the increase of B4C particles leads to the increase of barriers and as a result, ΔσOrowan increases. Therefore, the strength of composite increases but work hardening capacity (Hc) decreases. The results of wear test indicated that wear rate and friction coefficient declined gradually as the B4C particles fraction increased. Based on this result, hot-pressed sample containing 10 wt.% B4C showed the lowest wear rate and friction coefficient (1.9 × 10−5 mm3/m and 0.48 respectively).

Analysis of Particle Distribution in Milled Al-Based Composites Reinforced by B4C Nanoparticles

In the present work, high-energy ball milling was employed to synthesize Al-(5-10 wt.%)B4C nanocomposite. To do this, two sizes of particles of 50 nm as nanoparticles (NPs) and 50 μm as coarse particles (CPs) were used. The morphology and microstructure of the milled powders were characterized using particle size analyzer, SEM, TEM and EDX techniques. It was found that milling time, B4C particles size and their content strongly affect the characteristics of powders during milling process. The breaking and cold welding of powders was recognized as two main competitive actions during the milling process that influence the microstructural evolutions. It was found that the presence of CPs led to the formation of microcracks which promote the fracture process of Al powders. The dominated mechanisms during the fabrication of composites and nanocomposites were discussed. Also, the theoretical issues regarding the changes in morphology and distribution of B4C particles in CPs and NPs are clarified.

Reactions in Ternary System Al-B<sub>2</sub>O<sub>3</sub>-C during Mechanical Alloying

One possible route for producing the fine and homogenous distribution of hard particles in composite microstructure is the mechanochemical processing in which high-energy ball milling promotes the reaction in a mixture of reactive powders. This investigation aims to produce Al – B4C nanocomposite by reaction between aluminum, boron (III) oxide and graphite powder via a mechanochemical process. The effect of milling time and the ratio the balls to powder on this process were investigated. The face transformation ans structural evaluation were investigated means of X – Ray diffractometry (XRD) and scanning electron microscopy (SEM).