B4C Particles Research Articles

Relationship between the B4C reinforcement content and the properties of MAO films on the B4C/Al matrix composites

Thermal control coating is necessary for the B4C/Al matrix composites (AMCs) used in nuclear power field. Micro-arc Oxidation (MAO) technology is a suitable method to prepare thermal control coating on B4C/AMCs, but the B4C reinforcements has a great influence on the MAO process. In this paper, the effects of the B4C content on the spark discharge, microstructure and properties of the MAO films were studied by a Dual-channel Oscilloscope, Scanning Electron Microscopy (SEM) and Electrochemical Impedance Spectroscopy (EIS). The results indicate that the spark discharge in the early stage of oxidation is inhibited with the increase of the B4C particles in AMCs, but the effect declines in the later stage. Also, the compactness and blackness of the MAO films reduce due to the negative effect of the B4C particles on the oxidation process, but the lowest emissivity of the MAO film is still higher than 0.85, which can still meet the general requirement for thermal control coatings in actual applications.

Microstructure and properties of a HIP manufactured B4Cp reinforced highly alloyed Al-Zn-Mg-Cu-Zr aluminum matrix composite

In this study, an aluminum matrix composite with good mechanical property and excellent corrosion resistance, B4C particles (B4Cp) reinforced highly alloyed Al-Zn-Mg-Cu-Zr matrix composite, was successfully fabricated through ball-milling, cold isostatic pressing, vacuum degassing, hot isostatic pressing (HIP), homogenization, hot extrusion, solution treatment, and aging treatment. It was found that the B4C/MgAl2O4/Al was the dominant interface structure, which was coherent and enhanced the bonding between the particles and the matrix considerably, while the B4C/Al2O3/Al was the minor interface structure. The grain boundary was very clean in both T4 and T6 aging states, without aging precipitates and O element segregation. In T4 aging state, the composite exhibited superior properties, with the mass density of 2.84 g cm−3, the elastic modulus of 119.18 GPa, the yield strength of 576.08 MPa, the ultimate tensile strength of 655.27 MPa, the tensile elongation of 1.48 %, and the very low electrochemical corrosion current density of 4.4581 × 10−8 A cm−2 in 3.5 wt% NaCl water solution. The MgAl2O4 and BO3-rich interface phases, the strengthening mechanisms and the anti-corrosion mechanisms of the composite were discussed in detail.

Tensile strength and strain energy absorption in twist extruded Al 6061-B4Cp metal matrix composites

ABSTRACT Due to its accessibility and ease of use in various sectors, the twist extrusion method is gaining significant acceptance for improving the strength and hardness of structural components. However, only a few experiments on twist-extruded MMCs of aluminium 6061 alloy reinforced with ceramic boron carbide (B4C) particles have been reported. The development of an Al-6061 alloy reinforced with 1.5–8 weight percent B4C particles and its twist extrusion, a severe plastic deformation method, are the main subject of this work. The study aimed to investigate the influence of particles and the extrusion process on the tensile strength and specific strain energy absorption of both the matrix and the composites. It was observed that the addition of B4C particles and the extrusion process increased the hardness and tensile strength of the alloy by 29.1% and 68.3%, respectively and for the composites with 8 wt.% particles, the increases were 31.8% and 62%, respectively. However, the theoretical density, ductility and absorbed strain energy decreased by 3.97%, 35.7%, and 27.9%, respectively, for the composite with 8% B4C, compared to the extruded matrix. A microscopic study determined the ASTM grain size number, which supported the observed physical and mechanical properties of both the as-cast and twist-extruded Al 6061-B4Cp composites.

Fabrication of kenaf fiber reinforced boron carbide fillers embedded epoxy matrix composite – An antimicrobial and structural analysis

This study investigates the incorporation of boron carbide (B4C) filler particulates into a kenaf fiber-reinforced epoxy matrix to explore its potential in lightweight applications, focusing on antimicrobial effectiveness, mechanical integrity, thermal properties, and microstructural characteristics. The composite material was formulated by blending varying seven different concentrations of boron carbide (0–50 g) and kenaf fibers (KFs) with an epoxy resin, aiming to achieve a balance between mechanical strength and minimal weight. Antimicrobial test revealed that the composite material, consisting of kenaf fiber reinforced with B4C particulates, exhibited significant antibacterial activity against common pathogens. Mechanical testing indicated that the addition of boron carbide and kenaf fibers significantly improved the tensile strength and flexural rigidity of the composites. Specifically, enhancements in tensile strength and flexural modulus were quantitatively analyzed, showing notable increases compared to the base epoxy resin. Scanning Electron Microscopy (SEM) was employed to examine the fracture surfaces following mechanical testing, revealing improved interfacial bonding between the kenaf fibers and the epoxy matrix due to the presence of boron carbide. This microscopic analysis also highlighted areas where stress distribution was optimized, contributing to the composite's enhanced mechanical properties.

Study on the microstructure, mechanical and corrosion behaviors of 2A12 Al matrix composites containing B4C and 50% K2TiF6 flux

This study presents an innovative exploration into the development and characterization of boron carbide (B4C) reinforced aluminum (Al) metal matrix composites (AMMCs), specifically focusing on the 2A12 Al alloy. Utilizing a cutting-edge vacuum induction melting process, the research investigates the effects of varying B4C particle concentrations in conjunction with 50% K2TiF6 flux additions. This novel approach aims to enhance the microstructural integrity, mechanical properties, and corrosion resistance of the AMMCs. The research unveils a significant improvement in microhardness and tensile strength with the increase of B4C content. This enhancement is attributed to the efficient load transfer mechanism from the aluminum matrix to the B4C phase and the thermal expansion coefficient mismatch-induced dislocations. A critical finding of this study is the uniform distribution of B4C particles and the formation of a Ti-rich layer around these particles, facilitated by the K2TiF6 flux. This layer acts as a barrier, minimizing interfacial reactions. Electrochemical testing reveals that there is a slight decrease in corrosion resistance with increased B4C content. The outcomes of this research contribute to the field of metal matrix composites, offering a path forward for the application of B4C-reinforced AMMCs in demanding industrial environments where high strength, stiffness, and durability are critical. The study's findings open new avenues for advanced materials development in aerospace, automotive, and energy sectors.

Influence of thinner flaked Al powder with larger diameter on the distribution of B4C particles and tensile properties of B4C/Al composite

Abstract The thinner flaked Al powders are used to improve the strength of the B4C/Al composite. The effect of the flaked Al powder on distribution of B4C particles is investigated. The tensile properties of the B4C/Al composites with the flaked Al powders are also studied. The results show that during ball milling process, spherical Al powders are flaked with the thinner thicknesses and larger diameters. The thinner flaked Al powders are not easy to be deformed and are bonded together as the laminated structure after thermal compression. B4C particles are evenly dispersed and embedded in Al laminated structure. With increasing the volume fraction of B4C particles, the deformation of the thinner flaked Al powders become difficult and the thinner flaked Al powders coat on the surface of B4C particles, resulting in the disappearance of the laminated structure of the thinner flaked Al powder.

Composition design and mechanical properties of B4C/Al-Zn-Mg-Cu functionally graded materials prepared by laser additive manufacturing

In this study, three types of three-layer functionally graded materials (FGMs) were designed by mainting the average content of the reinforcement constant and changing the span of the composition. The B4C particle-reinforced Al-matrix FGMs and a homogeneous composite (HC) with the same average composition were prepared using the laser additive manufacturing technique. The FGMs had a higher average secondary-phase content and grain size than the HC. Large (black) and reticulated (white) secondary phases corresponding to B4C phase, T phase, and MgZn2 were observed in the as-deposited FGM samples. The content of the secondary phase in the middle layer was generally low. The bottom layer, which was in direct contact with the substrate, exhibited the smallest grain size. The hardness and wear resistance significantly improved owing to the high B4C content in the top layer. The flexural behaviors of each layer of the FGM in different directions were systematically studied. The plasticity of the single-layer material decreased with increase in the B4C content. When the bottom layer had a high B4C content, the flexural ability significantly reduced. Among all the samples, G2 with 8% B4C particle content in the top layer exhibited the best comprehensive mechanical properties. The hardness value, wear rate of the top layer, maximum bending stress, and maximum bending strain of the FGM were 177.5 HV, 0.367 × 10−3mm3/(N·m), 585.6 MPa, and 7.36%, respectively. This study can provide a reference value for the future design and development of wear-resistant gradient materials for aerospace applications.

Analysis of the Wear and Mechanical Behavior of Stir-Casted Al-6061 Composites Reinforced by B4C Particles

Analysis of the Wear and Mechanical Behavior of Stir-Casted Al-6061 Composites Reinforced by B4C Particles

Optimization of Dry Sliding Wear in Hot-Pressed Al/B4C Metal Matrix Composites Using Taguchi Method and ANN.

The presented study investigates the effects of weight percentages of boron carbide reinforcement on the wear properties of aluminum alloy composites. Composites were fabricated via ball milling and the hot extrusion process. During the fabrication of composites, B4C content was varied (0, 5, and 10 wt.%), as well as milling time (0, 10, and 20 h). Microstructural observations with SEM microscopy showed that with an increase in milling time, the distribution of B4C particles is more homogeneous without agglomerates, and that an increase in wt.% of B4C results in a more uniform distribution with distinct grain boundaries. Taguchi and ANOVA analyses are applied in order to investigate how parameters like particle content of B4C, normal load, and milling time affect the wear properties of AA2024-based composites. The ANOVA results showed that the most influential parameters on wear loss and coefficient of friction were the content of B4C with 51.35% and the normal load with 45.54%, respectively. An artificial neural network was applied for the prediction of wear loss and the coefficient of friction. Two separate networks were developed, both having an architecture of 3-10-1 and a tansig activation function. By comparing the predicted values with the experimental data, it was demonstrated that the well-trained feed-forward-back propagation ANN model is a powerful tool for predicting the wear behavior of Al2024-B4C composites. The developed models can be used for predicting the properties of Al2024-B4C composite powders produced with different reinforcement ratios and milling times.

Microstructure and properties of multiple hybrid reinforced CNTs-TiB2-TiC/Cu laminated composites

Cu matrix laminated composites reinforced with CNTs exhibit excellent mechanical properties; however, the Cu matrix between the laminated structures suffers from insufficient strength. To improve the strength of the matrix and the laminated structure in CNTs/Cu laminated composites, TiH2 and B4C particles were introduced into the Cu matrix via mixing powder, adsorption, hot-pressed sintering and cold rolling, furnishing CNTs-TiB2-TiC/Cu laminated composites. The tensile strength of the CNTs-TiB2-TiC/Cu laminated composites (513 MPa) increased by 26.04 % and 81.27 % compared with those of CNTs/Cu-Ti laminated composites (407 MPa) and CNTs/Cu laminated composites (283 MPa), and the elongation was 18.47 %. The in situ generated TiB2 and TiC reinforcement particles dispersed in the matrix materials induce particle strengthening, enhancing the dislocation density and load-bearing effect. Meanwhile, the CNTs with a laminated structure transfer and share the load. This multiply hybrid reinforcement structure of dispersed TiB2 and TiC particles along with CNTs lamination improves the mechanical properties of the resulting CNTs-TiB2-TiC/Cu laminated composites.

Analysis and optimization of laser cladding Ti-B4C composite coatings based on the interaction and GABP-NSGAII algorithm

Laser cladding process parameters are important to the quality of cladding layer, but the interaction between parameters is not clear. In this work, the effects of parameters, especially interaction, on laser cladding of Ti-B4C coating were studied by orthogonal experiments. And the optimal process parameters were obtained by GABP-NSGAII multi-objective optimization algorithm. The results show that the interaction (B4C content and laser power) had the greatest effect on the coating aspect ratio, cladding angle, and dilution rate. The microhardness of the coatings prepared with the optimum parameters of 15 wt%, 2200 W, and 800 mm/min is 434 HV0.5, which consists of columnar, dendritic, and equiaxial structures from the interface to the surface, respectively. The interaction affects the molten pool flow and the distribution of unfused B4C particles, and influences the concentration and distribution of reinforcing phases in the coating, as well as the heat input and phase transitions in the heat affected zone. This paper provides a reference for the preparation of high-performance and high-quality titanium matrix composite coatings by laser cladding.

Microstructure and Wear Behaviour Assessment of Different Micron-Sized B<sub>4</sub>C Reinforced Al2021 Alloy Composites

This study examines the impact of the size and wt.% of reinforcement particles on the wear characteristics of Al2021 alloy composites. Composites of Al2021 reinforced with B4C particles of varied sizes (45 and 90 microns) were synthesised utilising a unique two-stage stir cast technique. The composites were primed with B4Cc content of 5 and 10 wt.%. The microstructural characterisation of Al2021 alloy with B4C composites of 45 and 90-micron sizes was conducted using Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS). In addition, wear and worn morphology tests were conducted to examine the impact of particle size on the behaviour of Al2021 alloy. Furthermore, another set of wear studies was conducted with the load maintained at 40N and the sliding speeds changed from 100 to 400 rpm. The microstructural analysis disclosed that the particles in the Al2021 alloy were evenly distributed, and the presence of elements was verified using EDS spectra. Using B4C particles of different sizes enhanced wear characteristics with resistance to wear. The load and the speed affected the wear behaviour of every prepared sample. The morphological analysis of the worn samples recognised multiple wear mechanisms.

High strength and fatigue performance achieved for L-PBF processed hybrid particle reinforced Al-Cu-Mg composite

This study highlights the successful manufacturing of a crack-free, dense, hybrid ex-situ/in-situ particle reinforced (Ti + B4C)/Al-Cu-Mg composite, fabricated by laser powder bed fusion and exhibiting exceptional mechanical performance. In its as-built (AB) state, the composite displays a unique microstructure characterized by equiaxed grains with an average grain size of 1.0 ± 0.3 μm, notable interdendritic microsegregation of Cu, Mg, Mn, and Fe, randomly distributed ex-situ added Ti and B4C particles featuring a surface interaction layer with the metal matrix, and in-situ formed reinforcing particles, such as TiB2 and TiC. After subjecting the material to hot isostatic pressing (HIP) and subsequent aging treatment, dissolution of interdendritically segregated elements occurs, and precipitation of Al2Cu, Al12Mg17, and Al-Fe-Cu-Mn phases is observed. Significantly enhanced fatigue performance is recorded, reaching to 107 cycles at 250 MPa in AB and 330 MPa in HIP state, marking a 32 % improvement. The current study highlights the intricate relationship between the different microstructural features in AB and HIPed state, leading to fracture during tensile and fatigue loading conditions.

Effect of sliding speed and sliding distance on wear behavior of AZ31-B4C composite

Emphasis of current research is to investigate the dry sliding behavior of AZ31 magnesium alloy and AZ31–1.5B4C magnesium metal matrix composites (MMCs) at varying sliding speeds and sliding distances. Magnesium alloy and composite are fabricated through ultrasonic assisted stir casting method. Optical microscope (OM), scanning electron microscopy (SEM), and energy dispersive x-ray analysis (EDAX) are used to characterize developed materials. Microhardness of all materials is measured using a Vickers microhardness tester. Wear-friction behavior is investigated in dry sliding mode using pin-on-disc tribometer at room temperature. Magnesium alloy and composite are tested over a range of sliding speeds (0.25–1.25 m s−1) and distances at a moderate normal load (20N). Wear morphology is finally investigated for composites and alloy under SEM and EDAX. SEM micrographs of as-cast AZ31-1.5B4C composite reveals uniform distribution of B4C particles with noticeable refinement in grain structure. EDAX spectra of AZ31-1.5B4C composite depict the presence of boron and carbon along with existing elements of AZ31 alloy. Microhardness has enhanced around 30% for Mg-MMC by incorporating 1.5 wt% B4C in AZ31 alloy. Furthermore, the use of B4C as reinforcement increases the density of the composite. Wear rate is reduced by around 20% and COF is reduced by around 25% for AZ31-1.5B4C composite compared to AZ31 alloy for all experimental conditions. Abrasion, oxidation, adhesion and delamination wear mechanisms are observed as dominant mechanism for varying sliding speeds and distances.

Multi-material structures of Ti6Al4V and Ti6Al4V-B4C through directed energy deposition-based additive manufacturing

The demand for advanced materials has driven innovation in titanium alloy design, particularly in the aerospace, automotive, and biomedical sectors. Additive manufacturing (AM) enables the construction of multi-material structures, offering potential improvements in mechanical properties such as wear resistance and high-temperature capabilities, thus extending the service life of components such as Ti6Al4V. Directed energy deposition (DED)-based metal AM was used to manufacture radial multi-material structures with a Ti6Al4V (Ti64) core and a Ti6Al4V-5 wt.% B4C composite outer layer. X-ray diffraction analysis and microstructural observation suggest that distinct B4C particles are strongly attached to the Ti6Al4V matrix. The addition of B4C increased the average hardness from 313 HV for Ti6Al4V to 538 HV for the composites. The addition of 5 wt.% B4C in Ti6Al4V increased the average compressive yield strength (YS) to 1440 MPa from 972 MPa for the control Ti6Al4V, i.e., >48% increase without any significant change in the elastic modulus. The radial multi-material structures did not exhibit any changes in the compressive modulus compared to Ti6Al4V but displayed an increase in the average compressive YS to 1422 MPa, i.e., >45% higher compared to Ti6Al4V. Microstructural characterization revealed a smooth transition from the pure Ti6Al4V at the core to the Ti64-B4C composite outer layer. No interfacial failure was observed during compressive deformation, indicating a strong metallurgical bonding during multi-material radial composite processing. Our results demonstrated that a significant improvement in mechanical properties can be achieved in one AM build operation through designing innovative multi-material structures using DED-based AM.

Additive friction stir deposition of Al 6061-B4C composites: Process parameters, microstructure and property correlation

Al 6061-B4C metal matrix composites were fabricated using a novel solid state additive manufacturing technique of additive friction stir deposition (AFSD). Incorporation of B4C particles into the deposit was achieved by employing hollow Al 6061 feed stock filled with B4C powder and three different AFSD tool rotational speeds (200, 300 and 400 rpm). Fabricated deposits exhibited remarkable metallurgical bonding across the substrate/deposit interface and interlayer interfaces for all tool rotational speeds, indicating a wider fabrication window. A physics based pseudo-thermo mechanical model was employed to evaluate the thermo-kinetic conditions experienced by the depositing material to correlate with the microstructural observations. Deposited layers exhibited refinement of grains to ∼10 μm from the corresponding coarse grain structure of feedstock (136 μm). The regions near the B4C particles were observed to have finer grains (<2 μm) signifying particle stimulated nucleation. Although considerable loss in the tensile properties (60 % drop in yield strength) was observed in the AFSD deposits due to the associated dissolution of β’’ precipitates, subsequent heat treatment restored the tensile properties to the level of as received material (∼290 MPa). The thermo-kinetic conditions (temperature in excess of 500 °C and strain rates in excess of 250 s−1) experienced by the builds under higher AFSD tool rotational speeds (300 and 400 rpm) appeared to result in refinement of Al–Fe–Si based secondary intermetallic precipitates/dispersoids leading to the observed higher stability of their microstructure during the subsequent post AFSD heat treatment. Samples AFSD fabricated with a lower tool rotational speed of 200 rpm, however, exhibited significant grain growth on account of relatively larger secondary precipitates/dispersoids.

Characterizing neutron irradiation-induced effects in the nanocrystalline B4C particles using EPR spectroscopy

The paramagnetic centers and their nature in nanocrystalline B4C particles have been comparatively studied before and after neutron irradiation. Electron Paramagnetic Resonance (EPR) spectroscopic analyses were conducted in the magnetic field range of 0.05–0.55 T (500–5500 Gauss). Furthermore, the region of 0.3270–0.3370 T, where more paramagnetic centers were observed, was specifically examined. The nature of newly formed paramagnetic centers due to the influence of neutron irradiation in B4C nanocrystalline particles has been elucidated through EPR spectra. The mechanism of VB and VC vacancy formation has been thoroughly investigated through neutron transmutation.

Simultaneously increasing the mechanical properties and corrosion resistance of B4C/Al composites via forming “TiO2–Al” interfacial layer

In this work, we use a simple and efficient method to introduce “TiO2–Al” interfacial layers between the B4C particles and aluminium (Al) matrix in TiO2@B4C/Al composites by combining the ball milling dispersion process with the pressure infiltration technology. It is anticipated that it would improve the mechanical properties and corrosion resistance. The work demonstrates that the coefficient of thermal expansion (CTE) of the “TiO2–Al” interfacial layer is between those of the matrix and the reinforcement. Thus, it relieves the residual stresses in the composites. Furthermore, the low residual stress of the composites achieved by introducing the “TiO2–Al” interfacial layer results in delayed failure and the low corrosion tendency. The composites containing “TiO2–Al” interfacial layers show remarkable bending properties (a strength of 668.6 MPa) and good corrosion resistance (a low corrosion current density of 6.81 μA cm−2). Thus, the TiO2@B4C/Al composites exhibit remarkable mechanical properties and corrosion resistance compared with the composites reported in the literature.

Determination of nano-graphene content for improved mechanical and tribological performance of Zn-based alloy matrix hybrid nanocomposites

The primary objective of this study is to explore the fabrication of a hybrid nanocomposite (HNC) composed of ZnAl40Cu2 alloy, graphene, and B4C particles, while also determining the optimal graphene reinforcement ratio for enhanced properties. Our methodology entails the production of HNC powders (HNPs) through mechanical milling, where we combine graphene nanoplatelets with B4C microparticles into ZnAl40Cu2 alloy powders. Throughout this process, we maintain a constant B4C content of 1.5 wt%, while varying the graphene content at 1.5 wt%, 3 wt%, and 4.5 wt%. Following the characterization of all produced powders, which includes an assessment of powder morphology, powder size distribution, and powder microhardness, we proceed to hot-press the HNPs to create bulk HNC samples. After consolidating the specimens, a comprehensive series of tests are carried out to determine microstructural, mechanical (hardness and tensile strength) and tribological properties. Our results reveal that the HNC specimen with graphene content of 3 wt% (referred to as A2) displays the most notable enhancements in properties. Specifically, A2 exhibits an impressive hardness of 163 HB, surpassing the hardness of the ZnAl40Cu2 matrix alloy, which measures at 133 HB. Furthermore, its ultimate tensile strength significantly outperforms the ZnAl40Cu2 matrix alloy, with a remarkable value of 223 MPa compared to 157 MPa. However, it is worth noting that the improvement in wear resistance for HNCs is most pronounced up to a certain threshold of graphene content, which is 3 wt%.

Synthesis and Tensile Characterisation of B4C Particles Reinforced Al7475 (Al-Zn) Alloy Composites

This experimental research analyses tensile and microstructural behaviour followed by Al7475 (Al-Zn) metal alloy with 3 and 6 wt% of composites of B4C. The liquid metallurgical technique was used in this analysis for creating the Al7475 alloy with 3 and 6 wt% percentages of B4C particle composites. Additional techniques such as EDS/SEM were also employed in this analysis to determine the microstructural behaviour. ASTM Standards are followed to study the mechanical behaviour of Al7475 alloy with B4C-reinforced composites. The incorporation of B4C particles into Al7475 resulted in extreme characteristics in the field of the composite material thereby enhancing its maximum application. By combining different materials, the hardness and tensile strength of the composites improved. Tensile fractured surfaces indicated the brittle and ductile mode of fracture behaviour in the Al7075-B4C composites.