Boron Carbide Particles Research Articles

Experimental Investigation and Optimization of Material Removal Rate and Tool Wear in the Machining of Aluminum-Boron Carbide (Al-B4C) Nanocomposite Using EDM Process

Electrical discharge machining (EDM) is a cost-effective unconventional machining method used for machining any composites materials. EDM is based on the thermoelectric energy between the electrode and workpiece. In this work, boron carbide particles of 50 nm (6 wt.%) are reinforced with aluminum 7075 (94 wt.%) prepared using stir casting method. The stir casting process is carried out at speed of 700–800 rev/min. The fabricated aluminum-boron carbide nanometal matrix composites are used as workpiece (anode); copper electrode is used as tool (cathode). This work investigates the influence of EDM process parameters such as current (I), pulse on-time (ton), and tool diameter (d) during machining of Al-B4C composite on metal removal rate (MRR) and tool wear rate (TWR). The design of experimental plan is executed by Taguchi approach, and the responses of each parameter are influenced by analysis of variances (ANOVA). Response table for average value of MRR and TWR shows that the current is the significant parameter affecting MRR and TWR. From this work, it was observed that material removal rate increased with increasing the current, and the tool wear rate decreases.

Recycling Aluminium AA6061 Chips with Reinforced Boron Carbide (B4C) and Zirconia (ZrO2) Particles via Hot Extrusion

Compared to the recycling process by remelting, hot extrusion significantly reduces the energy consumption and CO2 emission and ensures good mechanical and microstructural properties. This study investigates the effects of reinforcing aluminium AA6061 chips with mixed boron carbide (B4C) and zirconia (ZrO2) particles by employing a design of experiment (DOE) under 550 °C processing temperature and three hours preheating time. The findings showed that compressive strength (CS) and hardness increased with up to 5% added particles, and beyond 5%, the yielded values decreased because of materials agglomeration. However, the decreasing density was dependent on the addition of ZrO2 particles. The distribution of particles with different volume fractions of mixed particles was investigated by employing SEM, AFM, and EDS tests. Thus, the process can produce a net shape structure that utilises material-bonding consolidation to provide sufficient support to reuse the recovered materials in engineering applications, such as in the automotive industry.

Microstructural Characterization, Mechanical And Wear Behaviour Of Al2024-B4C Composites For Aerospace Applications

<p>Metal matrix composite plays an important role in automobile and aerospace applications. Among all the metals, aluminium is considered as the lighter metal. In present investigation aluminium-2024 is considered as the base alloy and reinforced with boron carbide to increase its hardness. Aluminium metal matrix composite is obtained by combining different percentage of boron carbide particulates in the volume fraction 2.5 wt.% and 5 wt.%. Synthesis is done by stir casting technique and the characterization is carried out using scanning electron microscope. The properties of Al2024 reinforced with boron carbide is evaluated by using tensometer, pin on disc wear testing machine and vickers hardness tester. With the increase in the reinforcement high hardness, tensile strength and higher wear resistance is achieved. These types of MMCs are widely used in automobile and aerospace applications due to their great mechanical behaviours, low density, low factor of thermal expansion; corrosion resistance is better and increased wear resistance as compared to conventional metals and alloys. Improved mechanical property of these composites makes them very useful for various applications in many areas from technological point of view.</p>

Assessment of mechanical properties of LM13 aluminum alloy hybrid metal matrix composites

Aluminium LM13 alloy based hybrid particulate composites have been processed by adding boron carbide (B4C) and titanium diboride (TiB2) particles. The wt% of titanium diboride (TiB2) is varied as 0, 3, 6, 9, 12, 15 and a constant 3 wt% of boron carbide is used to prepare the composites. Stir cast route is used to fabricate the composites. The microstructures of castings are examined using computer aided image analyzer. Vicker hardness, yield strength, ultimate tensile strength and energy absorbed by the composites are examined and reported. The results show that uniform dispersion of TiB2 and B4C reinforcement phases in Al LM13 alloy. Micro hardness of composites enhanced upto 36.6% when compared to Al alloy reinforced with 3 wt% of B4C particles. Ultimate tensile strength of Al alloy is improved from 151 MPa to 192 MPa by reinforcing 15 wt% of titanium diboride particles. LM13 aluminium alloy hybrid particulate composites offers superior vicker hardness, yield strength, utlimate tensile strength and impact strength over LM13 aluminium alloy based single particle reinforced composites.

Experimental Study on Reinforced Aluminium Metal Matrix Composites with B<sub>4</sub>C through Different Techniques

Recently, aluminum alloys are extensively used in automobile and aeronautical industries due to its low density and excellent mechanical properties. The aim of this research work is to focus on develop an aluminum matrix composite reinforced with boron carbide particulates under different weight percentages by squeeze casting route. To obtain better results, it is essential to control the process variables involved in the process. The primary work focused to optimize the process variables involved in the fabrication of the composites using full factorial design. The experiments were carried out with various input parameters like squeeze pressure of 50, 100 and 150Mpa, melting temperature of 700, 750 and 800°C and weight fraction of reinforcement of 6, 8 and 10% using L27 orthogonal array. The significant parameters were identified by analysis of variance table and regression analysis was used to model the mathematical relationship for obtaining better mechanical properties. Final results reveal that, mechanical properties of 218VHN hardness and 412MPa tensile strength had been obtained based on the optimum combination levels. Also AA7075-B4C composites produced through this route with enhanced properties could be used as an alternative material for high strength structural applications like connecting rod, control arms, steering knuckle and other parts.

Influence of boron carbide content on dry sliding wear performances of AZ91D magnesium alloy

In this study, AZ91 magnesium alloy based metal matrix composites are made-up of bottom pouring stir casting with 0 wt.%, 1.5 wt.% and 3 wt.% boron carbide (B4C) particles reinforcements. The influence of hard reinforcements on mechanical properties such as hardness and tensile strength has been investigated for the casted composites samples. It was found that by adding 1.5 wt. % and 3 wt.% B4C particles, the Rockwell hardness value of 3.2% and 4.6%, Ultimate Tensile Strength (UTS) values of 15.5% and 26.3% of the composites increased respectively. The influence of B4C contents on AZ91D mg alloy wear study was carried out using pin on disc apparatus. Also, the effect of applied load (5N, 10N, and 20N) on wear properties was investigated. The results of the dry sliding wear tests show that AZ91D- B4C magnesium composite has less wear loss than the unreinforced AZ91D magnesium alloy. X-ray diffraction (XRD) analysis were performed for finding the various compounds such as MgO, B4C and Mg17Al12 present in the developed composites. Further, scanning electron microscopy (SEM) analysis were performed on the worn-out pin surfaces to investigate the wear pattern. These findings indicate that the addition of B4C content improved mechanical characteristics and wear resistance, which may also be used in the automotive and aerospace industries.

INFLUENCES OF BORON CARBIDE PARTICLES ON THE WEAR RATE AND TENSILE STRENGTH OF AA2014 SURFACE COMPOSITE FABRICATED BY FRICTION-STIR PROCESSING

In this article, a boron carbide particle (B4C) reinforced AA2014 surface composite was first fabricated by friction-stir processing (FSP) to investigate the impact of the volume percentage of B4C, tool rotational speed and table speed on the tensile strength (TS) and wear rate (WR). The AA2014 composite is one of the important candidates for making defense and aerospace components due to its high strength and minimum weight. Taguchi orthogonal array was employed to design and predict the maximum tensile strength and minimum wear rate. The volume percentage of B4C is the most momentous parameter for both the tensile strength and wear rate. The optimum parameter settings for attaining the maximum tensile strength of 605 MPa and a minimum wear rate of 1.2 mm3/Nm are a B4C volume of 15 %, tool rotational speed of 900 min–1 and table speed of 60 mm/min. The optimum process-parameter settings were used to make a specimen for validating the estimated results. The microstructure and chemical composition of the surface composite of the optimum specimen were illustrated using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), respectively. The surface profile and microscopic view of the worn-out surface composite were also examined using SEM images.

Production of Spherical Boron-Carbide Particles Encapsulated in a Graphite Shell

Laser ablation makes it possible to obtain boron-carbide nanoparticles suitable for subsequent use in boron neutron capture therapy. However, particles of boron and boric acid are formed in parallel. Boric acid is harmful to the human body, and boron can naturally form boric acid. A method is proposed for reducing the toxicity of the synthesis of boron-carbide nanoparticles by laser ablation by adding free carbon to the reaction and replacing the traditionally used buffer medium, ethyl acetate. Purified water is used as a dispersing medium. It is shown that the described technology has prospects for reducing the level of toxicity due to the choice of a suitable buffer medium. The formation of boron carbide is recorded by transmission electron microscopy and XRD analysis. The formed particles are predominantly spherical in shape and have a carbon shell. A mechanism is proposed for the formation of such a shell due to the diffusion of carbon from the bulk of the particle through the domain boundaries.

Mechanical and Wear Characterisation of Boron Carbide Particles Reinforced Al2030 Alloy Composites Developed by Two Stage Stir cast Method

ABSTRACT In this study, two-step stir process was used to synthesis aircraft Al2030 alloy reinforced composites with 3 and 6 weight percentages of B4C particles. This innovative two-step stir casting process improves the wettability of Al2030 and B4C particles. SEM and EDS were used to characterize the microstructures of the Al2030 alloy with B4C composites. Different mechanical features of Al2030 alloy composites were investigated to determine the impact of B4C particle addition on hardness, ultimate strength, yield strength, and ductility. In addition, the wear behavior of the produced Al2030 alloy with B4C composites was investigated utilizing a pin-on-disc apparatus with variable normal load and sliding velocity over a constant 2000 m sliding distance. SEM micrographs demonstrated homogeneous particle distribution, while EDS patterns validated the elements in the B4C reinforced Al composites. The addition of B4C particles increased mechanical characteristics; further improvement was obtained by increasing the weight fraction of B4C particles in the Al2030 matrix alloy. On the other hand, reduced ductility of the composites was observed due to the incorporation of B4C particles in the soft Al matrix. To determine the effect of B4C particles on tensile failure, wear surface of the composites, fractography and worn surface analyses were performed.

Mechanical Properties of Al7075 Hybrid Metal Matrix Composites as a functionality of SiO2 % in the RHA

Hybrid metal matrix composites are wide in applications due to their improved mechanical properties. Where the optimum selection of reinforcements becomes necessary for determining the feasibility of producing high-performance metal matrix composites with low cost. Consequently, in Al7075, a hybrid metal matrix composite (MMC) with boron carbide and rice husk ash was reinforced. This current research determines the effect of heating temperature on the production of rice husk ash, and it was discovered that the temperature effect improved the SiO2 content of the rice husk ash (RHA). In addition, the deposition method of RHA into the AI7075 substrate was used as a variable, and the effects on the microhardness and tensile properties of the resultant were investigated. The introduced hybrid MMC was reinforced with 2% boron carbide particles and 5%, 10%, and 15% RHA respectively using the stir casting technique. Hence, mechanical performances like tensile strength, compressive strength, impact tests, and hardness tests were performed efficiently.

Effect of High Operating Temperatures on the Wear Characteristics of Boron Carbide and Ilmenite Reinforced LM13 Alloy-Based Composites

Abstract Wear properties of LM13 alloy-based composites were studied by using boron carbide (B4C) and ilmenite particles (FeTiO3) separately as reinforcement. The different weight percentage of reinforcement (5 wt%, 10 wt%, and 15 wt%) was added to the base alloy through stir-casting. A comparison of B4C reinforced composites (LB composites) and FeTiO3 reinforced composites (LI composites) was done on the basis of interfacial bonding, refinement/morphology of eutectic silicon, friction, and wear behavior (both at room temperature and elevated temperature conditions). Microstructural analysis revealed uniform distribution of ceramic particles in the matrix. Significant reduction in grain size and change in morphology was obtained for LB composites whereas strong interfacial bonding was obtained for LI composites. Higher hardness, lower wear-rate, and higher coefficient of friction (COF) values were shown by LB composites. A decrease in COF for LI composites (at room as well as high temperatures) corresponded to the lubricity effect of ilmenite particles. At room temperature, wear track and debris showed a change in wear mechanism from abrasive to delamination wear with an increase in load from 10 N to 50 N. Under elevated temperature conditions, these mechanisms were combined with oxidation wear.

Surface modification of aluminum alloy 6061 by embedding B4C particles via friction stir processing

Aluminum alloy-based surface composites have been in numerous applications since the introduction of the Friction Stir Processing (FSP) method to develop multifunctional properties owing to its ease of use and control in process parameters to obtain desired properties. AA6061-T651 is used as a substitute for AA6082 in structural applications due to its higher strength in comparison. To further improve the surface properties of AA6061, the friction stir processing technique was employed to reinforce Boron Carbide (B4C) particles by the Blind-Hole method. To achieve uniformity in distribution, FSP with a different direction strategy has been adopted. The surfaces thus developed were characterized using Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) techniques. The grain size measurement was made on the processed samples using Heyn lineal intercept method. Tension and microhardness tests were also conducted to study the change in mechanical properties. The dark carbide zones with clear boundaries were identified in single pass processed specimens. Uniformity in the B4C distribution was observed on the dual-pass surface. In addition, Energy-Dispersive Spectroscopy (EDS) results have shown the presence of B4C embedded regions in the nugget zones along with the AA6061 matrix. Higher ultimate tensile strength was observed with the single-pass processed surface by 11% than the dual-pass processed surface.

Effect of percentage of reinforcement particulates on the corrosion behaviour of aluminium boron carbide composites

Aluminum based composites are generally used to build marine structures and liquid cargo containers because of its high strength and low weight. In the present investigation, the corrosion behaviour of B<sub>4</sub>C particle reinforced Al-6061 alloy has been studied. The aluminumboron carbide composite were prepared using stir casting method by varying percentage of reinforcement from 6 to 12% in steps of 2%. Salt spray method was adopted to investigate the corrosion behaviour of the composite. The test was conducted for a period of 240 hours and for every 48 hours the weight loss of the specimens was measured. The extent of corrosion was measured by using weight loss method. The results showed that the corrosion resistance of the composite decreases with the increase in the percentage of boron carbide particulates. The optical microscope was used to analyze the corroded surfaces and corrosion mechanism. The pit initiation side tends to the possibility of the accuracy corrosion on the interface between the hard reinforced particles and matrix alloy.

Study on the Design, Preparation, and Performance Evaluation of Heat-Resistant Interlayer-Polyimide-Resin-Based Neutron-Shielding Materials.

Polymers have an excellent effect in terms of moderating fast neutrons with rich hydrogen and carbon, which plays an indispensable role in shielding devices. As the shielding of neutrons is typically accompanied by the generation of γ-rays, shielding materials are developed from monomers to multi-component composites, multi-layer structures, and even complex structures. In this paper, based on the typical multilayer structure, the integrated design of the shield component structure and the preparation and performance evaluation of the materials is carried out based on the design sample of the heat-resistant lightweight polymer-based interlayer. Through calculation, the component structure of the polymer-based materials and the three-layer thickness of the shield are obtained. The mass fraction of boron carbide accounts for 11% of the polymer-based material. Since the polymer-based material is the weak link of heat resistance of the multilayer shield, in terms of material selection and modification, the B4C/TiO2/polyimide molded plate was prepared by the hot-pressing method, and characterization analysis was conducted for its structure and properties. The results show that the ball milling method can mix the materials well and realize the uniform dispersion of B4C and TiO2 in the polyimide matrices. Boron carbide particles are evenly distributed in the material. Except for Ti, the other elemental content of the selected areas for mapping is in good agreement with the theoretical values of the elemental content of the system. The prepared B4C/TiO2/polyimide molded plate presents excellent thermal properties, and its glass transition temperature and initial thermal decomposition temperature are as high as 363.6 °C and 572.8 °C, respectively. In addition, the molded plate has good toughness performs well in compression resistance, shock resistance, and thermal aging resistance, which allows it to be used for a long time under 300 °C. Finally, the prepared materials are tested experimentally on an americium beryllium neutron source. The experimental results match the simulation results well.

Mechanical Loading and Tribological Studies on Boron Carbide (B4C) and Lead (Pb) Particles Dispersed Epoxy-Based Multilayered Composites

The study aims in the development of functionally graded epoxy-based layered composites dispersed with B4C and lead particles. The development route adopted for the composites is a novel route called layered molding and curing. Various compositions of single and trilayered composites were prepared through the abovementioned route. The samples prepared were subjected to mechanical and tribological studies, and the results were reported in this article. It is found that the mechanical properties of the single-layered composites consisting of 20% lead and 20% B4C show superior characteristics than those of the samples with increased addition of lead. However, the trilayered samples with lead core showcased excellent mechanical properties. On the other hand, the wear rate and mass loss of the trilayered samples with B4C cladding show minimum wear rate than the samples with lead cladding. Furthermore, the coefficient of friction of the samples also showcases the better performance of single-layered samples with 20% lead. The worn surface analysis done through scanning electron microscopy and stereo zoom microscopy reveals the reason for the low specific wear rate of 20% lead sample as the self-hindrance of wear debris evolved during the wear study.

Investigation of Mechanical and Corrosion behaviour of AZ61 Mg nanocomposites with boron carbide particles

Investigation of Mechanical and Corrosion behaviour of AZ61 Mg nanocomposites with boron carbide particles

Towards the Enhanced Mechanical and Tribological Properties and Microstructural Characteristics of Boron Carbide Particles Reinforced Aluminium Composites: A Short Overview

This paper overviews the fabrication, microstructural characteristics, mechanical properties and tribological behaviour of B4C reinforced aluminium metal matrix composites (AMMCs). The stir casting procedure and parameters used to fabricate the Al-B4C composites are discussed. The influence of physical parameters such as applied load, sliding speed and sliding distance on tribological behaviour is analysed. The role of the mechanically mixed layer (MML) and wear mechanisms on the wear behaviour and friction coefficient are emphasised. The overview of tribological behaviour revealed that the Al-B4C composites possess excellent abrasion resistance and the ability to operate over a wide range of physical parameters. The Al-B4C composites exhibited better tribological behaviour when compared with the composites reinforced with conventional reinforcement particles (SiC).

Numerical Study of the Influence of Residual Thermal Stresses on the Fracture of Metal Matrix Composites

A numerical study of the mechanical behavior of the «aluminum-boron carbide» composite material under different thermomechanical loading is performed. The complex structure of the composites is explicitly taken into account in the calculations. Isotropic elastoplastic and elastic-brittle constitutive models are used to describe the mechanical response of the aluminum matrix and ceramic particles, respectively. Huber type fracture criterion taking into account the local stress state: bulk tension, or compression, is chosen to study the origination and propagation of cracks in ceramic particles. The composite material microvolume with a single boron carbide particle embedded into the aluminum matrix is considered. The influence of the residual thermal stresses arising during cooling of the composite material from temperature close to the temperature of recrystallization of aluminum to the room temperature on the ceramic particle fracture is investigated. Dynamic boundary value problems are solved numerically by the finite element method in the ABAQUS / Explicit software package.

Mechanism of boron carbide particles improving the wear resistance of UHMWPE: Structure-property relationship

Inorganic particles are often used to enhance the wear resistance of UHMWPE, but the mechanism of the “enhancement effect” of inorganic particles improving the wear resistance of UHMWPE is ambiguous. In this paper, boron carbide particles(B4C) were used to improve the wear resistance of UHMWPE, it was found that the wear resistance of UHMWPE was increased by up to 46% with appropriate filler loading of B4C. Subsequently, the mechanism of B4C improving the wear resistance of UHMWPE was studied and illustrated from the perspective of structure-property relationship. The B4C particles act as exotic entanglement points, forming an entanglement network of particle-coupling agent-matrix, improving the degree of entanglement of molecular chains in the amorphous region of UHMWPE, thus improving the shear resistance of the matrix and reducing the structure damage caused by strong shearing during friction. Meanwhile, the highly entangled molecular chains prevented the transition of the interphase to the crystalline region, thus increasing the content of the interphase of UHMWPE and consequently alleviating the structural damage during the friction. Furthermore, B4C particles played the role of load bearing, which enhanced the compression resistance of UHMWPE then reduced the structure damage caused by compression in the normal upward during friction. This paper could be helpful to better understand the role of fillers on the wear resistance of UHMWPE and provide theoretical guidance to improve the wear resistance of UHMWPE and other materials.

The influence of polyelectrolyte on the synthesis of B4C/BN nanocomposite powders via sol-gel method

In the present study, B4C-BN nanocomposite powders were synthesized by using the sol-gel method. To investigate the effects of polyelectrolyte on phase content, particle size, and final morphology of synthesized powders different amounts of ammonium polycarboxylate were used as a gel dispersing agent and a nitrogen source. Highly crystalline, sub-micron/micron-sized boron carbide particles with varying morphologies including polyhedral-equiaxed, belt-like, needle-like, and complex-shaped hierarchical structures were produced from the polymeric gel containing glycerine, tartaric acid, and citric acid as carbon sources, and boric acid as boron source. With the addition of ammonium polycarboxylate as a polymeric gel network modifier, nanocomposite powders containing micron-sized polyhedral-equiaxed boron carbide particles and boron nitride nanoflakes were obtained. The results indicated that the particles dimensions, crystallinity, and B4C to BN phase ratio of the synthesized powders are directly related to the preliminary formation of borate-ammonium and/or amine complexes in the polymeric gel. The SEM inspections revealed that the size of boron carbide particles tends to increase from 2 μm up to 40 μm as a function of ammonium polycarboxylate content. It was also observed that the average size and thickness of boron nitride nanoflakes within the range of 80 nm to 3 μm and 10–150 nm, respectively. B4C/BN nanocomposite powders were synthesized with up to 32% BN content using a 43 wt% ammonium polycarboxylate additive.