Addition Of B4C Research Articles

Intermetallic/Ceramic Composites Synthesized from Al–Ni–Ti Combustion with B4C Addition

The fabrication of intermetallic/ceramic composites by combustion synthesis in the mode of self-propagating high-temperature synthesis (SHS) was investigated in the Al–Ni–Ti system with the addition of B4C. Two reaction systems were employed: one was used to produce the composites of xNiAl–2TiB2–TiC with x = 2–7, and the other was used to synthesize yNi3Al–2TiB2–TiC with y = 2–7. The reaction mechanism of the Al–Ni–Ti system was strongly influenced by the presence of B4C. The reaction of B4C with Ti was highly exothermic, so the reaction temperature and combustion velocity decreased due to increasing levels of Ni and Al in the reactant mixture. The activation energies of Ea = 110.6 and 172.1 kJ/mol were obtained for the fabrication of NiAl- and Ni3Al-based composites, respectively, by the SHS reaction. The XRD (X-ray diffraction) analysis showed an in situ formation of intermetallic (NiAl and Ni3Al) and ceramic phases (TiB2 and TiC) and confirmed no reactions taking place between Ti and Al or Ni. The microstructure of the product revealed large NiAl and Ni3Al grains and small TiB2 and TiC particles. With the addition of TiB2 and TiC, the hardness of NiAl and Ni3Al was considerably increased and the toughness was also improved.

TG/DTA studies on the oxidation and thermal behaviour of Ti-6Al-4V-B4C coatings obtained by magnetron sputtering

Thermogravimetric analysis (TG) is a rapid method for the determination of protecting the ability of thin film coatings in addition to oxidation kinetics. Boron carbide (B4C) reinforced Ti-6Al-4V thin films were deposited through the magnetron sputtering coating technique. The effect of 0, 2, 4, 6 and 8 Wt. % of B4C adding on microstructure, thermal behaviour and hardness of Ti-6Al-4V-B4C coatings were investigated. Thermal analysis of Ti-6Al-4V-B4C coatings with varying percentage of B4C resulted in the establishment of an exothermic peak, for the reason that reduction in the oxidation of coating. The thermal behaviour of coating was improved by B 4C addition; those coatings are recommended for practical application. It was proven that the addition of B 4C not only alters the thermal stability but also transforms the mechanism of oxidation. It was absolutely unconcealed that the Ti-6Al-4V-B4C film oxidization may be a multi-staged procedure subject on the heating rate. An occurrence of formal treatment for obtaining Kissinger’s assessment mechanics for various oxidization levels is additionally valid. The addition of B4C was supported to enhance the nanohardness of the coating. The morphology, composition and structure of the thin film coatings were examined by way of SEM, AFM and XRD.

A review on mechanical and tribological characterization of boron carbide reinforced epoxy composite

This article is a review of the properties of boron carbide (B4C)-reinforced polymer composites. B4C have recently become attractive to researchers, engineers, and scientists as an alternative reinforcement for polymer composites due to its attractive physical and mechanical characteristics. The tensile strength of the B4C-reinforced epoxy was lower than the neat epoxy due to the poor bonding of the materials. Various surface treatments of the reinforcement were suggested in the literature to improve the bonding between the reinforcement and the matrix. B4C addition improved the elastic modulus of the epoxy. No clear trend was observed for the flexural behavior of the same. It was mainly dependent on the type of epoxy used and size and concentration of reinforcement. A higher B4C particulate addition in epoxy improved the hardness values of the composites. There was a marginal improvement in the shear strength of the B4C-reinforced composites. The commonly observed plasticization tendency of epoxy after moisture absorption was less severe when epoxy was reinforced with B4C particulates. Poor anchoring of B4C particulates in the resin hampered the wear resistance of the composite. The situation further worsens after moisture absorption. However, cavitation erosion behavior of the composite improved and limited to localized areas.

Synthesis of B4C and BN reinforced Al7075 hybrid composites using stir casting method

In the present study an effort has been made to synthesize B4C and BN reinforced Al7075 hybrid composites using stir casting method by varying its weight percentage (3%, 6% and 9%) of B4C and keeping (3%) of BN constant for marine applications. Morphology of the synthesized aluminum hybrid composite and reinforced particle distribution was studied in detail using optical microscopy. It virtually shows the homogeneous distribution of the reinforcement particles in the base metal matrix and it forms Al3BC, AlB12 and AlN as interfacial reactions. Vickers micro-hardness test has been carried out to evaluate the hardness of hybrid composites. It has been found that with increase in percentage of reinforcement the hardness of the synthesized hybrid composites found to be increased compared with the Al7075 base matrix alloy. Mechanical testing has been carried out on the cast composites specimen of different compositions. It has been inferred that addition of reinforcement B4C and BN to base metal matrix added 22% strength to the hybrid composites. ASTM E9 standard has been used to evaluate the compressive properties of hybrid composites and it has been found that inclusion of harder reinforcement tends to resist the load applied and hence the compression properties of such hybrid composites has been improved. ASTM-B117 has been used to study the corrosion behavior of hybrid composites. The corrosion rate decreased by 18.5% between 3% and 6% boron carbide addition whereas it decreased by 22.4% between 6% and 9% boron carbide addition.

Wear resistant aluminum alloy - B4C composites fabricated by rheo-casting and rolling process

To reveal the formation and wear mechanisms of rheo-formed aluminum alloy - B4C composites, A356 alloy − 10 mass% B4C composite material was fabricated by semi-solid stirring rheo-casting and rolling process. The presence of Al3BC was confirmed by XRD analysis and hinted that chemical bonding formed at interfaces between aluminum matrix and B4C particles. Tensile test results demonstrated that addition of B4C facilitated improving the tensile strength by refining matrix and providing particle strengthening. Failure tests revealed that the failure type of the composite transferred from interfacial debonding to particle cracking with increasing wear load. The wear rate of the composite was approximately 48% lower than that of aluminum alloy under 60 N load. The friction coefficient of the composite under 60 N load also significantly decreased due to formation of B2O3 and H3BO3 as solid lubricants.

Neutron attenuation and mechanical properties of polymer composites filled with boron carbide particles

In this work, neutron attenuation and mechanical properties of thermoplastic natural rubber (TPNR) blend filled with boron carbide (B4C) have been studied as a function of filler loading. Thermoplastic natural rubber of high density polyethylene/natural rubber (HDPE/NR) blend with different amounts of boron carbide (5–20 wt%) have been prepared via melt blending method. All samples were subjected to neutron transmission and tensile tests. The results showed that neutron shielding performance of the composites were improved significantly with the addition of B4C into TPNR matrix. On the other hand, mechanical properties of the composites were found to decrease with increasing filler loading.

On the role of B4C on hardness and toughness of TiCN - SiC - TiN -Cr3C2 - Co cermet

This paper reports the development of TiCN - SiC- TiN - Cr3C2 - Co cermet modified with B4C for cutting tool applications. Cermets of three different composition with varying B4C in TiCN - SiC - TiN - Cr3C2 - Co were fabricated for a study of addition of B4C on hardness and toughness. The cermet pellets were sintered using Spark Plasma Sintering (SPS) at 50 MPa pressure, 1500 °C temperature at a heating rate of 100 °C/min with 10mins soaking with pulse rate of 12/2 ms. Microstructure examination revealed a typical core-rim structure. Vickers hardness test was done at a load of 30 kg and duration of 10s. Fracture toughness was computed using crack length data measured from the hardness test. The cermet with composition 65% TiCN - 15% SiC - 5% TiN - 5% Cr3C2–10% Co showed high hardness of 16.2 GPa and toughness of 10.7 MPa √m and 50% TiCN - 15% SiC - 5% TiN - 5% Cr3C2–10% Co - 15% B4C exhibited high fracture toughness of 16.5 MPa √m with hardness value of 12 GPa. The addition of B4C greatly enhanced the toughness value and reduced the hardness value slightly.

Single step heat treatment for the development of beta titanium composites with in-situ TiB and TiC reinforcement

Titanium matrix composites have been attracting great interest from aerospace industry due to favorable properties like thermal stability, high specific strength, corrosion, and wear resistance. Optimal relation between mechanical properties demands complex processing routes and, in this context, the effects of a single-step processing route on microstructure and mechanical properties of β titanium matrix composites was placed on focus in this study. The commercial TIMETAL Beta 21S alloy and its modification with the addition of B4C were developed, allowing in-situ formation of TiB and TiC particles in a β matrix. The composites presented highest values of mechanical strength and hardness, and the addition of 3% of B4C provided a significant reduction in grain size, and compressive yield strength and ultimate compressive strength values of 1205 MPa and 1636 MPa, respectively, with a maximum deformation of 20.5%. An orientation relationship investigation provided information about some unconventional relation between the present phases.

Effect of B4C addition on the oxidation behavior of borosilicate glass repairing coating for C/C brake materials

The thermal properties of the borosilicate glass repair coating with B4C as a ceramic additive were analyzed, and the changes of thermal expansion, density, and porosity of the glass materials were investigated to characterize the physical characteristics of the repair coating. The results showed that this repair coating displayed variable oxidation resistance and self-healing property at temperatures from 700 to 900 °C, depending on the B4C content. The B2O3 generated from B4C can be dissolved into the borosilicate glass, which could significantly change the coefficient of thermal expansion and the softening temperature of the glass. When B4C content was 25 wt%, the coating with the lowest porosity and oxygen permeability was formed. A model of structure transition of the oxidation-resistant mechanism of the B4C added borosilicate glass coating was discussed.

Enhanced mechanical properties of AA6061-B4C composites developed by a novel ultra-sonic assisted stir casting

The increase of B4C addition into an AA6061-B4C composite system will not be always an ideal choice for improved properties because of the issues related to incorporation, distribution, and interfacial wetting while stir-casting. In such a case, ultrasonication is considered to be an alternative to get the advantage of microstructural changes which in turn improve the properties. In the present study individual B4C distribution and the refinement of microstructure was achieved at 4wt.%B4C. The improved specific ultimate and compressive strengths at 4wt.%B4C were observed as 36.32% and 43.92% whereas specific Vicker’s and Brinell hardness as 53.41% and 50.89% respectively.2009 Elsevier Ltd. All rights reserved.

Effects of Fe2O3 and B4C Addition on the Mechanical Properties and Corrosion Resistance of Al–Mg–Si Alloy in 3.5% Brine Solution

In this present investigation aluminum Al6061 alloy and 5 wt% of Fe2O3 in addition to 2%, 4%, 6% weight of B4C reinforced matrix composites (AMCs) is fabricated by stir casting method. Upon increasing the amount of weight percentage to the composites, the mechanical properties also increased. The AC impedance spectra and polarization studies have been utilized to investigate the resistance towards corrosion of the Fe2O3 and B4C reinforced Al6061 metal matrix composites (AMCs). Corrosion current (Icorr), Linear Polarization Resistance (LPR), corrosion potential (Ecorr), capacitance (C), charge transfer resistance (Rct) parameters were considered by the materials submerged in 3.5% of Brine solution and the resistance towards corrosion of the material is determined. Scanning Electron Microscopy (SEM) is utilized to identify the before and after corrosion of the prepared composites. The resistance towards the corrosion is significantly increased with increasing the wt% of reinforced composites.

Characterization, corrosion and failure strength analysis of Al7075 influenced with B4C and Nano-Al2O3 composite using online acoustic emission

This paper aims to establish the mechanical, corrosion and failure analysis using online acoustic emission of Al7075 alloy, Al7075-B4C composite and Al7075- B4C-Al2O3 hybrid composite with different Boron Carbide (B4C) content of 5, 10, 15 & 20% and Nano Aluminium Oxide (Al2O3) content of 2% on a weight basis with the high energy stir casting method. The casted samples have been characterized by x-ray Diffraction (XRD), Thermo gravimetric analysis (TGA/DSC), Energy Dispersive Spectrum (EDS), and Scanning Electron Microscope (SEM). In case of hybrid composite, the hardness and the tensile strength decrease when the content of Al2O3 increases. However, in the present research, the addition of B4C with nano Al2O3 particles in certain proportions has increased the hardness and tensile strength. In addition, the tensile fractographs of the specimens were analysed using SEM. Acoustic Emission (AE) method was used for monitoring the acoustic energy that are released at the time of deformation process and early crack detection. The influence of the volume fraction of the B4C particulates on the microstructural and corrosion characteristics of Al7075- B4C with nano Al2O3 metal matrix composites (MMCs) was also studied. It has been observed from the literature that the direct strengthening of composites occurs due to the presence of hard ceramic phase, while the indirect strengthening arises from the thermal mismatch between the matrix alloy and reinforcing phase during solidification. Based on the database for material properties, the application area of HAMCs has been proposed in the present review. The effects of nanomaterial dispersion in the metal matrix and the formation of interfacial precipitates on these properties are also addressed. Particular attention is paid to the fundamentals and the structure–property relationships of such novel Nano composites.

Effect of B4C and graphite particulates on the mechanical and micro structural characteristics of AA 5052 hybrid composites

Reinforced aluminium metal matrix composites are being applied in various fields like automobile, aerospace and other industries. In this study the mechanical behavior of aluminium alloy (AA 5052) composites reinforced with boron carbide and graphite are studied. Aluminium matrix composite specimen was prepared by adding 2, 4, 6, and 8% of boron carbide and graphite by stir casting process. The composites were subjected to tensile, hardness and elongation studies. Scanning Electron Microscopy (SEM) was employed to analyze the uniform distribution of boron carbide and graphite of in the aluminium matrix metal. The microphotographs of the composites specimen exposed fairly uniform distribution of boron carbide and graphite particles in composites. Addition of B4C and graphite in aluminium matrix exhibited better mechanical properties and can be used as a possible material in marine, offshore and other industrial applications.

Surface structural features and wear analysis of a multilayer Ti6Al4V-B4C thin film coated AISI 1040 steel

The deprived wear resistance of AISI 1040 steel often results in higher wear rates. The best ways to upgrade their wear resistance are to introduce hard particle reinforcement to produce a metal matrix composite which can be used as a coating. In the present study Ti-6Al-4V-4B4C metal matrix composite coatings were coated on AISI 1040 steel using the magnetron sputtering process and their dry sliding wear behavior was studied at room temperature. The coating morphology was explored by SEM, XRD, FT-IR, and AFM. The constant coating thicknesses of 80 nm and 115 nm were achieved for 0.5 h and 1 h coating duration, respectively. The effects of introducing B4C on the hardness, thermal behavior, wear, and friction characteristics were studied. The nano hardness and elastic modulus were attained by AFM nanoindentation technique which showed a maximum of 21.7 GPa and 218.4 GPa, respectively. It was proven that the adding of B4C increases the thermal stability of Ti-6Al-4V-4B4C coatings as well as modifies the oxidation mechanism. It is expected that the addition of B4C will improve the thermal behavior of thin film coatings for their practical application. Wear tests were executed by ball-on-disc wear tester with E-52100 sphere as the counterface at a sliding velocity of 2 m s−1 with 3 N load. Wear rate and coefficient of friction (CoF) reduced with an increase in load and sliding distances also composite coatings exhibited higher wear resistance within entire loading conditions, hereafter suggesting that it could be a favorable substitute to other hard coatings.

Study of mechanical properties of Al2014-B4C-Gr hybrid nano composite

Aluminium hybrid metal matrix nano composite (AHMNC) material has all the advantages of conventional metal matrix nano composite with multifunctional properties because of the hybrid reinforcement. As a result, these materials offer a unique combination of properties that are not possible to achieve in conventional materials. The present study deals with the fabrication of aluminium hybrid nano composites by reinforcing Al2014 with nano sized B4C and graphite, processed through stir casting route followed by ultrasonic and squeeze casting. The addition of B4C improves the hardness, whereas Gr particles improve wear resistance in the composite. These combinations of the reinforcements are chosen for application under high abrasive conditions. Ultrasonic agitation has been done to uniformly distribute the reinforcement, whereas squeeze casting is done to reduce the porosity of the cast. The cast composite has been cut to prepare specimens for hardness, tensile strength, and microstructure as per the ASTM standards. The mechanical properties of the composite were evaluated and compared to the conventional. The microstructure of the composites was studied using optical microscopy to investigate the proper distribution of reinforcement and microstructure in the AHMNCs. The result indicates a significant improvement in the hardness. Further, the microstructure studies reveal that the reinforcement was fairly uniformly distributed over the matrix material.

Effect of weight percentage of B4C reinforcement on physical and mechanical properties of polyamide 6/polystyrene composites

ABSTRACT Blends of polyamide 6/polystyrene (PA6/PS) (50/50 wt./wt. %) were loaded with different concentrations of boron carbide (B4C), (0, 5, 10, 15, 20 and 30 wt./wt. %) separately for EMI shielding. The effects of different weight fractions of fillers on thermal, electrical, as well as, mechanical behavior of the prepared composites were investigated. Thermal stability and hardness (shore D) of composites are studied. Addition of B4C enhances thermal stability of the prepared composites which attributed to the increase in physical and chemical cross-linking points, also to the interactions between the filler and polymer blend. Confirmation of thermal stability was done by determining the activation energy (E a) for the thermal decomposition of all composites. Characterization of the prepared composites was done using SEM. With B4C-loaded PA6/PS blend composites, samples of 2 mm thick, SE values of 5–36 dB were achieved, satisfying the requirement for common commercial applications.

Processing and Mechanical Characterization of ADC12 alloy B4C RHA Hybrid Composites

The effects of dual particulates addition on the mechanical behaviour of ADC12 alloy composites were studied. Boron carbide (B4C) and rice husk ash (RHA) particulates were used as the reinforcements in the ADC12 alloy base matrix. Hybrid composites were prepared by using liquid melt method, keeping 5 wt. % of B4C reinforcement constant and varying rice husk ash particles in steps of 3 and 6 wt. % in the ADC12 alloy. Samples were tested for microstructural characterization by using SEM and EDS. Mechanical behaviour like hardness, ultimate tensile strength; yield strength, percentage elongation and compression strength were evaluated as per ASTM standards. SEM photographs revealed the uniform distribution of B4C and RHA particulates in the ADC12 alloy and these particles were confirmed by EDS analysis. Further, hardness, tensile and compression properties of base matrix ADC12 alloy was enhanced with the addition of B4C and RHA particulates. Ductility of ADC12 alloy decreased after the incorporation of B4C and RHA particles.

The microstructure, mechanical and wear properties of AZ91-x%B4C metal matrix composites in as-cast and extruded conditions

In the present work, the AZ91 Mg alloy reinforced with different weight percentages of B4C (1 wt%, 3 wt%, 5 wt%, 10 wt% and 15 wt%) was investigated with the aim of improving its mechanical and wear resistance in the as-cast and extruded conditions. A simple and cost-effective method, stir casting process, was employed to fabricate light-weight AZ91-x%B4C composites. Microstructural characterization of the as-cast specimens revealed the reasonably uniform distribution of B4C particles, well-bonded B4C particles to the matrix and the presence of minimal porosity. It was revealed that B4C addition has a slight influence on the microstructure in as-cast state, whereas extrusion process had intense grain refinement and fracturing and dispersion of the Mg17Al12 phase resulted in the significant enhancement of compressive strength, hardness and wear properties. After the incorporation of B4C, a significant reduction in weight loss was observed, although the friction coefficient was increased. Scanning electron microscopic observation of the worn surfaces was conducted and the dominant wear mechanism was recognized as oxidation assisted abrasive for AZ91-xB4C composites. These results designate that the AZ91-xB4C composite can be considered as an outstanding material where high compressive strength and wear-resistant components are of great importance, primarily in the aerospace and automotive engineering parts.

Effect of Boron Carbide Additive on SiC Ceramic Sintered by Solid-Phase Method under Ar Atmosphere

With boron carbide (B4C) as sintering additives, silicon carbide (SiC) ceramics were prepared in 2100°C by solid-phase sintering under argon atmosphere. The change of microstructure, phase composition and density for all sintered samples were studied. The results showed that with the increase of B4C addition, the density of SiC ceramic was significantly increasing between 0-4 wt% of B4C addition and slightly increasing between 4-8 wt%. XRD analysis showed that all the ceramics without B4C were SiC-6H crystal, while those with B4C contained SiC-4H crystal, B4C turned SiC-6H to SiC-4H, and the more B4C added, the more change it made. SiC ceramic particles changed from equiaxial shape without B4C to flake shape with B4C added, and the particle sizes increased significantly with the amount of B4C additive.

Microstructure evolution and mechanical properties of selective laser melted bulk-form titanium matrix nanocomposites with minor B4C additions

Crack-free and almost fully dense (≥99%) bulk-form titanium matrix nanocomposites in-situ synthesized from a ball-milled mixture of Ti-6Al-4V and B4C powders were achieved through an optimized selective laser melting (SLM) process. The effects of minor B4C addition on microstructure evolution, hardness, compressive properties and fracture mechanisms of the composites were systematically investigated. The in-situ synthesized nanoscale TiBw or TiCp ceramic reinforcements, exhibiting a quasi-continuous (TMC1) or full-continuous structure (TMC2), could play a prominent role in determining the microstructure refinement and mechanical properties of the composites. Results indicate that the SLM-processed nanocomposites exhibit a maximum increase of 45% of Vickers microhardness and 26% of ultimate compressive strength over the Ti-64 alloy. The enhancement of mechanical properties is mainly attributed to the second-phase strengthening, grain refinement strengthening as well as solid solution strengthening induced by the interstitial carbon in Ti matrix. This study provides a novel solution for microstructure tailoring with minor B4C addition and producing high-performance titanium matrix composites via SLM additive manufacturing.