B4C Particles Research Articles

Magnesium Based Hybrid Nanocomposites: An Insight into Nanoparticle Effects on the Microstructure and Mechanical Properties

Aims: The primary aim of this research is to understand the effects of type of nanoparticles on the microstructure and mechanical properties of Mg-based hybrid nanocomposites. For this reason, new Mg-based hybrid nanocomposites containing 2.2 vol.% Ti and 1.1 vol.% nano-Al2O3 or nano B4C particles were synthesized and their properties were studied in comparison with Mg-Ti and pure Mg. Background: Magnesium with excellent weight-saving potential is ideal for automotive and aerospace applications. But its use in pure Mg is restricted due to inherent limitations such as poor absolute strength, elastic modulus, deformability, and corrosion susceptibility. While most of these limitations can be circumvented by the judicious addition of micron-sized ceramic reinforcements, ductility is often compromised. One of the promising ways for ductility enhancement involves the use of nano-length scale reinforcements. Similar ductility improvements were also reported when hybrid reinforcements were introduced into the Mg matrix. While the role of hybrid reinforcement preparation, the particle size distribution, and volume fraction of hybrid reinforcements were studied extensively in the past, no detailed investigation on the effects of type of nanoparticles has been conducted so far. Objective: The objectives of this research include the successful synthesis and property characterization of Mg-based hybrid nanocomposites containing hybrid (Ti+Al2O3 or Ti+B4C) reinforcements. Result: While both hybrid nanocomposites displayed fine grains when compared to pure Mg and Mg-Ti, there was no noticeable difference between the grain size distribution profiles of Mg- (Ti+Al2O3) and Mg-(Ti+B4C) hybrid composites. The results of property measurements indicated an improvement in dimensional stability, indentation, tension, and compression properties of Mg due to the addition of either individual Ti or hybrid (Ti+Al2O3) or Mg-(Ti+B4C) particles. Among the hybrid composites, Mg-(Ti+B4C) containing hybrid (Ti+B4C) reinforcement exhibited a better combination of strengths and ductility. While the inherent strengthening contribution from B4C and Al2O3 reinforcements resulted in slightly different strength properties, the ductilization benefits of boron compounds enhanced the tensile fracture strain of Mg-(Ti+B4C). Conclusion: Since the particle size distribution and volume fraction of (Ti+Al2O3) and (Ti+B4C) are similar, the difference in strength values between Mg-(Ti+Al2O3) and Mg-(Ti+B4C) can be attributed to the matrix strengthening contribution from reinforcement type.

Optimization of dry sliding wear behavior of aluminium-based hybrid MMC's using experimental and DOE methods

Due to its exceptional mechanical characteristics combined with lightweight and fuel-efficient materials, metal matrix composites (MMCs) have largely been developed for the automotive and aerospace industries. In this paper, an attempt was made to investigate the dry sliding wear behavior of aluminium-based hybrid MMC's through the experimental approach. The experiments were performed for three types of filler materials: Boron carbide (B4C), Molybdenum Di-sulphide (MoS2), and graphite (Gr) particulates of 50 μm were reinforced into aluminium-2219 matrix using stir casting technique. On the other hand, data computing is a trend in mechanical engineering and is increasing drastically in recent years. It has proved one of the most cost-efficient methods to identify the optimum results with a limited number of experiments. Hence, this research was carried, with an emphasis on optimization, utilizing the design of experiments (DOE) technique with specified parameters. For DOE, additional experiments were conducted based on full factorial design and then different analyses were performed such as ANOVA, regressions equation, and confirmation tests to examine the effect of parameters on the wear behavior of composites. Besides, the influence of wear parameters such as applied load (L), sliding speed (S), and sliding distance (S-D) on the wear loss were investigated. The current investigation realized that B4C particles in the matrix increases the wear resistance of MMC when compared to other selected materials of this study.

Correlation between Laser-Ultrasound and Microstructural Properties of Laser Melting Deposited Ti6Al4V/B4C Composites

The presence of large microtextured clusters (MTC) composed of small α-phase crystallites with preferred crystallographic orientations in 3D printed near-α titanium alloys leads to poor mechanical and fatigue properties. It is therefore crucial to characterize the size of MTCs nondestructively. Ti6Al4V/B4C composite materials are manufactured using Laser Melting Deposition (LMD) technology by adding an amount of nano-sized B4C particles to the original Ti6Al4V powder. TiB and TiC reinforcements precipitating at grain boundaries stimulate the elongated α crystallites and coarse columnar MTCs to equiaxed transition, and microstructures composed of approximately equiaxed MTCs with different mean sizes of 11–50 μm are obtained. Theoretical models for scattering-induced attenuation and centroid frequency downshift of ultrasonic waves propagating in such a polycrystalline medium are presented. It is indicated that, the studied composite material has an extremely narrow crystallographic orientation distribution width, i.e., a strong degree of anisotropy in MTCs. Therefore, MTCs make a dominant contribution to the total scattering-induced attenuation and spectral centroid frequency downshift, while the contribution of fine α-phase crystallites is insignificant. Laser ultrasonic inspection is performed, and the correlation between laser-generated ultrasonic wave properties and microstructural properties of the Ti6Al4V/B4C composites is analyzed. Results have shown that the deviation between the experimentally measured ultrasonic velocity and the theoretical result determined by the Voigt-averaged velocity in each crystallite is no more than 2.23%, which is in good agreement with the degree of macroscopically anisotropy in the composite specimens. The ultrasonic velocity seems to be insensitive to the size of MTCs, while the spectral centroid frequency downshift is approximately linear to the mean size of MTCs with a goodness-of-fit (R2) up to 0.99. Actually, for a macroscopically untextured near-α titanium alloy with a relatively narrow crystallographic orientation distribution, the ultrasonic velocity is not correlated with the properties of MTCs, by contrast, the central frequency downshift is dominated by the size and morphology of MTCs, showing great potentials in grain size evaluation.

Mechanical characterization of eggshell ash and boron carbide reinforced ZA-27 hybrid metal matrix composites

This study aimed at discovering the influence of low-cost eggshell ash (ESA) and boron carbide (B4C) addition on microstructure and mechanical characteristics of ZA-27 hybrid composites. Six different composites were fabricated utilizing the stir casting technique with different weight percentages of ESA and B4C particles varied from 0-5 wt.%. Composites were tested for density, hardness, compressive strength, tensile strength, and impact strength. X-ray diffraction (XRD) and scanning electron microscope (SEM) were utilized for the characterization of composites. Microstructure examination using SEM exhibited homogeneously dispersed reinforcements in the matrix. ESA particles decreased the composite density by 3.12%, and after the addition of B4C particles, density was found to be increased but was still lower than the base ZA-27 alloy. The hardness, tensile and compressive strength of the composites increased with the addition of reinforcements. However, composite reinforced with maximum wt.% of B4C particles showed a decreasing trend. The impact strength of the composites decreased when compared with the base alloy, but the reduction was marginal. Improved hardness, tensile and compressive strength of the composites was attributed to homogeneously dispersed ESA and B4C particles in the matrix. Higher tensile strength resulted from strong interfacial bonding between reinforcements and metal matrix, and low impact strength was due to brittle failure and plastic deformation.

Comparison of wear behaviour of LM13 Al−Si alloy based composites reinforced with synthetic (B4C) and natural (ilmenite) ceramic particles

Dry sliding wear behaviour of stir-cast aluminium matrix composites (AMCs) containing LM13 alloy as matrix and ceramic particles as reinforcement was investigated. Two different ceramic particle reinforcements were used separately: synthetic ceramic particles (B4C), and natural ceramic particles (ilmenite). Optical micrographs showed uniform dispersion of reinforced particles in the matrix material. Reinforced particles refined the grain size of eutectic silicon and changed its morphology to globular type. B4C reinforced composites (BRCs) showed maximum improvement in hardness of AMCs. Ilmenite reinforced composites (IRCs) showed maximum reduction in coefficient of friction values due to strong matrix−reinforcement interfacial bonding caused by the formation of interfacial compounds. Dry sliding wear behaviour of composites was significantly improved as compared to base alloy. The low density and high hardness of B4C particles resulted in high dislocation density around filler particles in BRCs. On the other hand, the low thermal conductivity of ilmenite particles resulted in early oxidation and formation of a tribo-layer on surface of IRCs. So, both types of reinforcements led to the improvement in wear properties of AMCs, though the mechanisms involved were very different. Thus, the low-cost ilmenite particles can be used as alternative fillers to the high-cost B4C particles for processing of wear resistant composites.

Effect of Magnetic-Mechanical Coupled Stirring on the Distribution of B4C Particles in Al-B4C Composites

Effect of Magnetic-Mechanical Coupled Stirring on the Distribution of B4C Particles in Al-B4C Composites

WEAR CHARACTERIZATION OF LM29 ALLOY WITH40 MICRON SIZED B4C REINFORCED METAL COMPOSITES

This paper deals with the fabrication and evaluation of wear properties by introducing40 micron size B4C particulates into LM29 alloy matrix. LM29 alloy based metal matrix composites were prepared by stir casting method. 3, 6 and 9 wt. % of 40 micron sized B4C particulates were added to the base matrix. For each composite, the reinforcement particles were pre-heated to a temperature of 600 degree Celsius and then dispersed in steps of two into the vortex of molten LM29 alloy to improve wettability. The Micostructural study was done by using Scanning Electron Microscope (SEM), which revealed the uniform distribution of B4C particles in matrix alloy, EDS analysis confirmed the presence of B4C particles in the LM29 alloy matrix.A pin-on-disc wear testing machine was used to evaluate the wear loss of prepared specimens, in which a hardened EN32 steel disc was used as the counter face. The results revealed that the wear loss was increased with increase in normal load and sliding speed for all the specimens. The results also indicated that the wear loss of the LM29-B4C composites were lesser than that of the LM29 matrix. The worn surfaces and wear debris were characterized by SEM microanalysis.

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

This study aims to investigate the tribological behaviour of lamb bone ash (LBA) and boron carbide (B4C) reinforced ZA-27 hybrid metal matrix composites fabricated using a stir casting process. The weight percentage of LBA and B4C particles in the composites were varied from 0–5 wt%. The composites have been evaluated for density, porosity and microhardness before tribological testing. Dry sliding friction and wear behaviour of composites were studied on a pin-on-disc tribometer by varying load from 10–50 N at a fixed sliding speed of 1 m s−1. Also, to investigate the effect of sliding speed on friction and wear behaviour of composites, tests were carried out at 2 m s−1 and 3 m s−1 of sliding speed. A scanning electron microscope (SEM) was used for examining the microstructure and worn surface morphology of composite samples. SEM micrographs revealed the presence and homogeneous distribution of reinforcement particles, and energy-dispersive x-ray spectroscopy (EDS) analysis confirmed the presence of LBA and B4C particles in the composites. Composites density decreased, and porosity increased with the addition of reinforcement particles. The microhardness of the 5 wt% reinforced LBA composite improved by 18.38%, whereas hybrid composite containing (2.5 wt% LBA + 2.5 wt% B4C) showed an improvement of 42% compared to the base alloy. The coefficient of friction (COF) and wear loss increased with the increase in load, whereas COF decreased and wear loss increased with the increase in sliding speed. Composites showed superior wear resistance even at higher loads and sliding speeds. SEM micrographs of worn surface revealed adhesion and abrasion type of wear mechanisms. Therefore, with the improvement in wear resistance this developed composite can be used as a bearing material over monolithic ZA-27 alloy in the automotive sector.

Microstructure and tensile behaviour of B4C particles reinforced Al6061 matrix composites

In an ongoing work an exertion is made to get fabrication of aluminium 6061 matrix composites reinforced with 8 µm average size of 7 wt% B4C particulates of with two stage melt stirring fabrication technic and are examined under scanning electron microscopy, Energy Dispersive X-ray Spectroscopy, and X-ray diffractometer to characterize the surface morphology, chemical elements and its percentage of distribution in addition to phase elements of composites. Then evaluation of prepared composite for Hardness and Tensile properties using micro hardness testing machine and UTM machine at room temperature are carried as per ASTM standards and found that Al6061-7 wt% B4Cp composite material’s hardness, Yield stress and ultimate tensile strength are magnified by 24.15%, 15.17% and 23.577% respectively while percentage of elongation is sink by 39.07% as compare to Al60610 alloy. Finally, the tensile facture surface was examined for micro mechanisms of failure and its surface morphology stipulates ductile kind of fracture and frail interface leading to facture mechanism.

In situ formed TiB2/TiC complex structure in laser-alloyed coatings with improved wear property

Laser-alloyed composite coatings were fabricated on Ti–6Al–4V by using Ni60A + micro-sized B4C particles as the precursor material. The composite coatings were mainly comprised of a kind of TiB2/TiC complex structure, assembled by TiB2 lamellae and TiC pillars. In this study, the formation mechanism of the TiB2/TiC complex structure was discussed intensively. TiB2 lamellae were firstly precipitated from the melt pool. Subsequently, TiC particles nucleated heterogeneously and grew on the TiB2 plates. The nucleation and growth of TiB2 and TiC proceeded synchronously, further forming the TiB2/TiC complex structure. The composite coating fabricated under a moderate scan velocity (450 mm⋅min−1) exhibited a good combination of high micro-hardness and wear resistance.

Processing, and Characterization of AZ91D Magnesium Alloy Reinforced Nano TiC, B4C, and HBN Composites

This paper presents the development of AZ91D Magnesium Alloy metal matrix composites having optimum mechanical and tribological properties by adding a various in-organic Nano reinforcements such as Titanium Carbide (TiC), Boron Carbide (B4C) and Hexa Boron Nitride (HBN). The processing techniques and characteristics of AZ91D Magnesium Alloy metal matrix nanocomposites and their application developed a new era in the material science, engineering and other related technologies has been discussed and how AZ91D Magnesium Alloy metal matrix with TiC, B4C, and HBN Nano particles have proven plat form and contribute to make a in depth engineering research.

Fabrication and characterization of AZ31-B4C composites

In the present study, Magnesium Alloy (AZ31) and AZ31-B4C composites reinforced with the varying amount (0–2 wt%) of nano-sized B4C in particulate form are fabricated through an Ultrasonic stir casting process. The mechanical properties and microstructure characterization are mainly investigated. The microstructural characterization is done through an optical microscope (OM) and scanning electron microscope (SEM) to examine the dispersion and homogeneity of B4C particulates in the Magnesium matrix. Elemental analysis is carried using an energy dispersive X-ray Spectrometer (EDAX). EDAX results indicate the presence of different elements such as Mg, B, C, Al, Zn etc. in base alloy and composites. Mechanical properties such as microhardness and density of base alloy and composites are also determined. Hardness and Density are found to increase with the increasing weight percentage of reinforcement. Microstructure examination found equiaxed grains in fabricated Alloy and Nano Composites. The mechanical characterization shows good interfacial bonding between the Mg matrix and B4C reinforcement material.

Microstructure, tensile and compression behaviour of B4C particles reinforced Al7075 matrix composites

Aluminium 7075 alloy has zinc as its highest composition next to Aluminium with percentile of 5–6%. This makes the Aluminium 7000 series have good tensile strength, ductility, toughness and fatigue resistant. This is further enhanced by the addition of B4C. In this work 3 and 6 wt% of B4C is added, Tensile and compression test is performed accordingly with ASTM standards to know the yield strength, tensile strength, elongation percentage and compression strength. The mechanical behavior of the composite is enhanced. The scanning electron microscope images are seen on the surface of pure Al7075 alloy, 3 wt% of Al7075-B4C and 6 wt% of Al7075-B4C composite so that the well distribution of the B4C particulates can be observed clearly. The density of the Al7075 also reduced by the addition of B4C.

Friction stir processing of boron carbide reinforced aluminium surface (Al-B4C) composite: Mechanical characteristics analysis

In this article, the boron carbide reinforced Aluminium alloy surface composite material was fabricated through the friction-stir processing method. The Al6061 alloy and B4C particles were used as matrix and reinforced materials respectively. The influences of volume percentage of boron-carbide, traveling feed rate, and rotational speed on tensile strength and wear were investigated using the L9 Taguchi technique. The moderate rotating speed and traveling speed of the tool have been preferred to attain optimum responses. The highest tensile strength of 347 MPa and minimum wear of 55 µm were obtained from 15% of the volume of boron carbide particles, 1400 rpm of rotating speed, and 40 mm/min traveling speed of the tool. The optimum Al6061-B4C surface composites micro-structure has also been studied through scanning electron microscope images.

Micro-structural and mechanical characterization of stir cast AA5052/B4C metal matrix composite

In the present work moderate strength 5052 Al alloy is reinforced with extremely hard B4C particulates by using a sand mould and implementing the stir casting technique. The particle size of the B4C reinforcement particulates was 63 µm and the wt. % was 5%. The microstructure of the fabricated AMMC was characterized with the help of micrographs taken from optical microscopy, scanning electron microscope (SEM), and X-ray diffraction crystallographic structure of the AA5052/B4C MMC. For the physical and mechanical properties investigation of the prepared AA5052/B4C MMC; its density, compressive strength, and micro hardness were analysed and compared these results with the unreinforced AA5052 matrix. The results show that the distributions of B4C particulates are uniform in the AA5052 matrix. The developed MMC has improved compressive strength and hardness along with a decrease in density compared to non-reinforced AA5052.

Fabrication of C/C–SiC–ZrB2 Ultra-High Temperature Composites through Liquid–Solid Chemical Reaction

In this paper, we aimed to improve the oxidation and ablation resistance of carbon fiber-reinforced carbon (CFC) composites at temperatures above 2000 °C. C/C–SiC–ZrB2 ultra-high temperature ceramic composites were fabricated through a complicated liquid–solid reactive process combining slurry infiltration (SI) and reactive melt infiltration (RMI). A liquid Si–Zr10 eutectic alloy was introduced, at 1600 °C, into porous CFC composites containing two kinds of boride particles (B4C and ZrB2, respectively) to form a SiC–ZrB2 matrix. The effects and mechanism of the introduced B4C and ZrB2 particles on the formation reaction and microstructure of the final C/C–SiC–ZrB2 composites were investigated in detail. It was found that the composite obtained from a C/C–B4C preform displayed a porous and loose structure, and the formed SiC–ZrB2 matrix distributed heterogeneously in the composite due to the asynchronous generation of the SiC and ZrB2 ceramics. However, the C/C–SiC–ZrB2 composite, prepared from a C/C–ZrB2 preform, showed a very dense matrix between the fiber bundles, and elongated plate-like ZrB2 ceramics appeared in the matrix, which were derived from the dissolution–diffusion–precipitation mechanism of the ZrB2 clusters. The latter composite exhibited a relatively higher ZrB2 content (9.51%) and bulk density (2.82 g/cm3), along with lower open porosity (3.43%), which endowed this novel composite with good mechanical properties, including pseudo-plastic fracture behavior.

Parametric optimization of friction stir processing on micro-hardness of Al/B4C composite

Abstract Friction stir processing was used to prepare aluminium metal matrix composite reinforced with B4C particles. The micro-hardness of the composite was improved by selecting the process parameters. Friction stir processing parameters, namely tool rotational speed, tool tilt angle and different pin profiles, were explored by using Taguchi’s L9 orthogonal array and analysis of variance. Optical microscopy and scanning electron microscopy were employed for microstructural analysis. X-ray diffraction was used to evaluate the residual stress. Experimental results illustrated that increased rotational speed, reduced tilt angle and square pin profile of the tool gave more uniform dispersal of B4C content with maximum micro-hardness. Small amounts of compressive residual stress developed at the stirred and thermo-mechanically affected zones confirmed the adequate improvement in micro-hardness. Micro-hardness of fabricated Al 6063/B4C composite surfaces was enhanced by 30% as compared to Al 6063 alloy.

Ytterbium impulse laser for surface modification of tool steel with B4C-Al powders

The paper deals with a new application solution of Ytterbium Picosecond Pulsed Fiber Laser for surface modification of 3Kh2V8F hot-work tool steel (the analog of AISI H21 steel). Surface modification was conducted by B4C-Al powders from preplaced pastes followed by laser heating. The ratio of B4C-Al powders was taken as 5/1 by weight and the paste thickness was approximately 1 mm. Laser treatment was conducted according to the following parameters: 1070 nm of wavelength, 100 W of power, 1 mJ of pulse energy, 100 ns pulse duration, pulse frequency range from 50 kHz to 90 kHz. Several tracks with different widths were obtained as a result of treatment depending on velocity of the laser move. EDS analysis showed that B4C particles were not completely dissolved in the weld beads. However, an enhanced concentration of boron (8-12 wt.%) was revealed in the vicinity of B4C particles. The aluminum concentration was low (up to 0.79 wt.%) on the surface of the weld beads.

Influence of pulse frequency on corrosion resistance and mechanical properties of Ni-W/B4C composite coatings

In this research, the effects of different pulse frequencies on the properties of Ni-W/B4C composite coatings are investigated in detail. First, we evaluate Ni-W coatings prepared from different bath compositions and select suitable electrolyte as bath solution. Then, the purchased boron carbide nanoparticles are characterized and their dispersion and suspension properties in bath electrolyte are verified. After that, Ni-W/B4C composite coatings are manufactured through different pulse frequencies (1, 10, 100 and 1000 Hz) and the prepared alloy coatings are characterized in detail. The results show that when the pulse frequency is increased from 1 Hz to 1000 Hz, the grain size of coatings decreases by 40%, the content of nickel in the coating decreases 3%, the content of W increases by 1.5%, the content of B4C particles is increased, and the roughness of the coating decreases significantly. In addition, the micro-hardness test, tensile test, impact test, bending test and reciprocating wear test are used to explore the mechanical properties of composite coatings, the water contact angle test and porosity test are used to study the surface properties, and the electrochemical test are adopted to predict the corrosion resistance. The results show that the composite coating prepared at 1000 Hz has the best mechanical properties, while the composite coating prepared at 100 Hz has the best corrosion resistance.

IMPACT OF VARIATION IN SIZES OF BORON CARBIDE ON PROPERTIES OF NOVEL COMPOSITE OF ALUMINIUM ALLOY 6063-T6 AND BORON CARBIDE

Composites are continuously evolving as the most demanding materials among various industries because of their reinforced mechanical properties and lesser weight. The present work aimed to fabricate a novel aluminium matrix composite using Aluminium Alloy 6063 T6 as base metal and ceramic boron carbide particles with three different micro sizes viz.104μm, 74μm, and 53μm as reinforcement. For composite fabrication, stir casting technique has been utilized. Micro-structure and mechanical behavior of base alloy and prepared composites has been analyzed in this work. Observing through optical microscopy reveal a uniform and proper distribution of B4C particle in Al matrix, along with cluster formation at few sites. The results also exhibit that hardness of reinforced composite has been found to be more than that of base alloy by 81.35 %, in which composite with particle size 53μm has shown maximum hardness of 75.77HV. The trend in tensile strength indicates that the ultimate tensile strength of composite with boron carbide of mesh size 53μm is more than the base alloy by 20.79% and is also highest among the rest of composites with a value of 219.196MPa.