Reinforcement Content Research Articles

In situ one‐step fabrication of layered double hydroxide deposited on cellulose: Effect of modified cellulose on physical properties of polyurethane composites

AbstractThe article reports the fabrication of cellulose‐layered double hydroxide (LDH) obtained by urea hydrolysis method. A wide characterization was carried out to assess the morphological, spectroscopic and barrier properties of LDH modified cellulose. The cellulose‐LDH was then used as hybrid reinforcement in polyurethane (PU) composites. A slight improvement in thermal stability of PU was achieved and a better hydrophilicity was obtained, due to the intrinsic polarity of LDH. Elastic modulus of PU composites increased up to 48 MPa for a filler loading of 10% wt. Finally, UV barrier properties were studied in the range 280–700 nm. The produced composite showed a noticeable decrease in light transmission as the reinforcement content increase, displaying high light‐blocking properties with a quasi‐total resistance to transmission in UV range.

Synthesis and characterization of stir casted Cu-ZrO2-Graphite hybrid metal matrix composites for thermal management structures

The present study aims at investigating the properties of copper matrix-based hybrid metal matrix composites (MMCs) reinforced with ZrO2 and Graphite. The MMCs were prepared using stir casting technique. The composite material was developed for its application in thermal management structures. The properties of the prepared MMCs were found to be dependent on the reinforcements content present in the MMCs. ZrO2 and Graphite reinforcements were added (0.5–0.5, 1.0–1.0, 1.5–1.5 and 2.0–2.0 wt %) in the four composite samples prepared via stir casting. Amongst several available techniques, stir casting was chosen to prepare the samples due to its simplicity and economic viability. The phase identification was done by using X-ray diffraction (XRD) and the microstructure was observed using Scanning Electron Microscopy (SEM). No intermediate phase was observed from the XRD results. The reinforcement phase was found to be dispersed in a uniform manner as observed through the SEM micrographs. The density of the samples was found to decrease with an increase in the reinforcements content. The density of the composite sample containing 2 wt. % of each reinforcement was found to be 8.01 g/cm3 which was 10% lesser than pure copper. Hardness of pure copper sample was found to be 35.71 BHN; however, the hardness of composite sample containing 4 wt. % of each of the reinforcements was found to be 70.14 BHN which indicates an increase of around 100%. Wear rate of pure copper and composite sample containing 5 wt. % of each of the reinforcements was found to be 0.3788 mm3/Km and 0.3603 mm3/Km, respectively, at 20 N load. However, the composite samples consisting of 4 wt. % of each of the reinforcements exhibited wear rate of 0.3001 mm3/Km which was 20% lesser than that of pure copper at the same load. The compressive strength of composite sample containing 2.0 wt. % ZrO2 and graphite was found to be 674.57 MPa which was around 1.25% higher than the composite sample containing 0.5 wt. % reinforcements. The specific heat of the samples was found to increase marginally with an increase in reinforcement content. It is expected that the hybrid composites developed will be suitable for use in structural applications pertaining to thermal management.

Overcoming the strength-ductility trade-off dilemma in TiBw/TC18 composites via network architecture with trace reinforcement

In order to improve the ductility of TC18 (Ti–5Al–5Mo–5V–1Cr–1Fe) titanium alloy without sacrificing its strength, TiBw/TC18 composites with low reinforcement content (≤2.0 vol%) were designed and successfully fabricated. The large spherical TC18 powers and fine TiB2 particles were selected for low energy ball milling (LEM) followed by reaction hot pressing (RHP) process. In situ synthesized TiB whiskers by Ti and TiB2 reaction are distributed only on the surface of spherical TC18 powders, generating a three-dimensional network microstructure. The results showed that both the tensile strength and elongation of the as-sintered 0.5 vol% TiBw/TC18 composite (1171 MPa, 15.6%) were remarkably enhanced compared with those of TC18 alloy (1151 MPa, 0.6%). This phenomenon can be mainly attributed to the network microstructure, β grain refinement, and elevation of the proportion of α-colony brought about by the introduction of TiBw. However, with the further increase of TiBw volume fraction (above 1.0 vol%), the strength and the ductility of the composites were decreased. Consequently, the network microstructure strategy with minor reinforcement addition offers a pathway to design engineering composites overcoming the strength-ductility trade-off dilemma.

Alumina catalyst waste utilization for aluminum-based composites using the friction stir process

Abstract A significant amount of environmental pollution is caused by oil refinery industries in the form of spent alumina catalyst (SAC) waste generated during the process. This waste causes various detrimental effects on human health. In this study, an effort has been made to consume the SAC in the fabrication of aluminum-based composite materials via the friction stir process (FSP). An X-ray diffraction image of the SAC powder used in this work confirms the occurrence of Al2O3, Fe2O3, SiO2, and CaO phases. These hard-phase materials form the basis for SAC to be used as reinforcement content with the aluminum alloy. The FSP is used to create the composite material. It is evident from the scanning electron microscopy image of the Al/SAC composite developed by the FSP technique that fair distribution of constituent ingredients is attained during the process. The incorporation of SAC contents in the aluminum alloy results in remarkable enlargement in tensile strength and hardness of the composite material. The Al2O3, Fe2O3, SiO2, and CaO phases of SAC showed a considerable effect on thermal expansion and corrosion weight loss of the composite.

PRODUCIBILITY OF FUNCTIONALLY GRADED AlB2/Al COMPOSITE MATERIAL

This study is intended to investigate producibility of functionally graded AlB2/Al composites which are used in the manufacture of ship machinery parts. AlB2 particles have been spontaneously formed in liquid matrix as reinforcement. A semi-solid composite (Al(l) - AlB2(s)) prepared at 850°C was solidified under a centrifugal force to grade functionally. The properties of composite materials such as hardness and microstructure have been examined. This research provided the following findings, AlB2 particles can be successfully synthesized with in situ reaction technique in molten aluminum. It was determined that the hardness value of the composites increases with increasing AlB2 reinforcement content within matrix. Functionally graded AlB2/Al composite materials can be successfully produced with centrifugal casting technique. It is also determined that AlB2 reinforcement ratio of the composite materials ranged from 0 to 7 vol. %. In addition, it was observed that the hardness values of the composites increased with the addition of reinforcement ratio.

Synergistic effect of bacterial cellulose and halloysite nanotubes on the properties of the sodium caseinate-based nanobiocomposites

In this study, nanobiocomposites based on sodium caseinate (SC) protein have been developed and characterized. Different levels of bacterial cellulose (BC; 1 and 2 wt%) and halloysite nanotubes (Hal; 1 and 3 wt%) as reinforcements were incorporated into SC films. Based on FE-SEM results, the pores on the surface of SC film were filled by reinforcements and nanocomposites containing both BC and Hal exhibited a uniform and homogenous surface. FTIR spectra verified the successful incorporation of BC/or Hal into the polymer matrix. XRD patterns of nanocomposites showed a wide reflection at 2θ angle of 20° belonging to sodium caseinate along with two main reflections at 21° and 29° which approved the intercalation of BC/or Hal into matrix. Both bacterial cellulose and halloysite promoted the crystallinity of the control film, but Hal was more efficient. As indicated in TG and DTG thermograms, the interaction of SC matrix with Hal improved the thermal stability of the nanocomposites in comparison with pure SC film. Simultaneous application of BC (2%) and Hal (3%) displayed a synergistic effect on the mechanical strength (11.62 MPa) of the nanobiocomposites. The moisture absorption capability of BC/or Hal-reinforced composites decreased by increasing the amount of fillers. As compared to pure SC film, water vapor permeation (WVP) of the nanocellulose/or Hal-reinforced nanocomposites decreased by increasing their reinforcement content. MTT assay result indicated the biocompatibility of the prepared nanocomposites. The improved mechanical, thermal and barrier properties of the sodium caseinate-based nanocomposite can be promised for food packaging.

Mechanical response and damage evolution of bio-inspired B4C-reinforced 2024Al composites subjected to quasi-static and dynamic loadings

Inspired by nacreous architecture, the 2024Al/20–50 vol% B4C composites with a lamellar-interpenetrated structure were successfully manufactured via freeze casting and pressure infiltration, and the quasi-static and dynamic characteristics were conducted at strain rates ranging from 0.001 to 3000 s−1. The strength of the composites enhanced as the strain rate increased up to 2000 s−1 since the strain rate hardening effect facilitated the accumulation of dislocations. At the strain rate of 3000 s−1, the adiabatic shear banding and its induced cracking were formed as the strengthening mechanisms were overcome by the thermal softening, which converted the dislocation structure from dislocation clusters to recrystallized grains, accompanied by a decrease in dislocation density, thereby degrading the compressive strength. A rigid network structure was formed in the composites with high particle content, and each particle had more inter-particle contact points, which made the strength of the composites increase with the increase of particle reinforcement content. This was also the reason why the strain rate sensitivity of the composites was considerably raised by introducing more particle reinforcement. However, increasing particle content heightened the composite susceptibility to strain localization and adiabatic shear damage, resulting in more brittleness of the 2024Al/50 vol% B4C composite at high strain rates. These findings could deepen the comprehension of the mechanical response and damage evolution of nacre-like composites exposed to extreme conditions and promote their applications.

Effects of the reinforcement content and reinforcement scale on the shear strength characteristics of mechanically biologically treated waste.

Mechanical and biological treatment (MBT), which can be used for waste reduction and for the burning of methane from biological treatments to generate electricity and heating, has become a popular research topic in environmental geotechnical engineering. This study investigated the mechanical behaviour of MBT waste and the effects of different reinforcement contents and reinforcement scales on its shear strength characteristics, and 68 groups of MBT waste samples from the Hangzhou Tianziling landfill were tested in the laboratory with a direct shear test apparatus. The samples exhibited displacement hardening behaviour in their mechanical response. The results show that the content and scale of the reinforced materials in MBT waste play an important role in the strength characteristics of MBT waste, and graphs showing the variation of the MBT waste shear strength and shear strength parameters with different reinforcement contents and reinforcement scales are shown. The range of cohesion c is 6.0-12.0kPa, and the internal friction angle φ is 15.6-26.6°, respectively. The results of this study provide a reference for the assessment of slope stability at MBT landfills.

Influence of SiC reinforcement content and heat treatment on the corrosion behavior of pulsed electrodeposited Ni-W alloy metal matrix composite

The influence of SiC content and heat treatment on the corrosion behavior of pulsed electrodeposited Ni-W/SiC composite coatings was studied by electrochemical polarization and impedance spectroscopy in 0.6 M NaCl. Structural and compositional analysis was carried out using X-ray diffraction, differential scanning calorimetry, transmission electron microscopy and depth profiling XPS analysis. It was observed that as deposited composites coatings demonstrated better corrosion resistance than heat-treated coatings. A higher corrosion and passive current density in the heat treated composite coatings was attributed to the defective nature of the passive film as indicated by Mott-Schottky analysis. A suitable corrosion mechanism is proposed and the results are rationalized based on mixed potential theory and a point defect model. This study indicate that heat treatment of coatings does not always result in better corrosion resistance.

Effects of machining parameters and reinforcement content on thrust force during drilling of hybrid composites

Abstract In this study, aluminum metal matrix composites were fabricated using the powder metallurgy technique with different ratios of alumina (Al2O3) and graphite as reinforcing elements. The obtained workpieces were then drilled using different machining parameters and the thrust force was measured using a force dynamometer. The thrust force data were modeled using a gene programming soft-computing technique and a function was obtained using the input parameters.

Effect of T6, RRA and nano chromium carbide content on microstructure and mechanical properties of AA7075-Cr3C2 nanocomposite

In the present study, AA7075 nanocomposites reinforced with varying weight percentage of Cr3C2 nano particles were successfully synthesized by stir casting technique. The pre-milled powder of Cr3C2 nano particles and aluminum powder was incorporated into molten AA7075 during stir casting for uniform dispersion of nano particles. Thereafter, the nanocomposite samples were aged at T6 and RRA (Retrogression and Reaging). The microstructural characterization examined by SEM and optical microscopy revealed uniform distribution of nano particles up to 1.5 wt.% content, above which the agglomeration occurred. The grain refinement was observed with increase in reinforcement content. The T6 and RRA aging treatment led to reduction in the amount of eutectic phases and grains were further more refined. The combined effect of reinforcement addition and aging, significantly improved the strength and hardness, but deteriorated the ductility. The hardness increased from 110.1 BHN for as cast alloy to 159.3 BHN for T6 treated 1.5 wt.% Cr3C2 nano particles reinforced nanocomposite. Similarly, the maximum value of ultimate tensile strength (308.77 MPa) and impact strength (9.3 J) were obtained for T6 treated 1.5 wt.% Cr3C2 nano particles reinforced nanocomposite. Also, T6 treated nanocomposite showed better strength and hardness whereas RRA treated nanocomposites possessed better ductility.

Effect of mixing method and particle size on hardness and compressive strength of aluminium based metal matrix composite prepared through powder metallurgy route

Properties of metal matrix composites (MMCs) are affected by various process variables such as particle size of powders, the proportion of reinforcement material, mixing methods, sintering temperature, and duration. The significant drawback of stir casting is reinforcement segregation, which is too difficult to avoid. Hence, the powder metallurgy route is utilized to prepare Al-MMC. In the current work, aluminium-based MMC is fabricated with varying proportions of silicon carbide (SiC) as a reinforcement material. Mixing of powders is done using V-Blender and barrel mixer with three different mixing techniques and the mixing quality of prepared powders is assessed. A significant reduction of mixing time, i.e., more than 50%, is achieved through a novel barrel mixer as compared to a conventional V-blender. Two important properties, hardness and compressive strength of fabricated Al-MMC, are experimentally investigated. At the same time effect of the mixing technique is also studied, and it is evident that hardness and compressive strength improved when powders are mixed using a barrel mixer. Thus, a novel approach to powder mixing has been achieved. An increase in SiC proportion by 5% resulted in an increase in hardness by 14%. The average compressive strength of Al-MMC is highest when reinforcement content is 25%. Due to the uniform dispersion of particles achieved through barrel mixer, compressive strength of MMC is 8–20% higher than the strength of those MMC for which powders are mixed through conventional V-blender. A similar effect is observed in the hardness also, where the average hardness of MMC is 10–20% higher, for which powders are mixed through barrel mixer. Hence, the newly designed barrel mixer provides an effective solution for the quality mixing of powders through the powder metallurgy process for fabricating Al-MMC.

Achieving synergistic strengthening and enhanced comprehensive properties of Cu matrix composites at high strength level by incorporating nanocarbons and Al2O3 dual reinforcements

Cu metal matrix composites (MMCs) incorporated with dual reinforcements of nanocarbons and Al2O3 particles with different contents were prepared by accumulative roll-compositing (ARC). Microstructure and properties of the dual-reinforced Cu MMCs were systematically investigated and compared with those of the individual-reinforced counterparts. Results showed that both the individual and dual reinforcements can be homogenously incorporated into and well-bonded with Cu matrix by ARC. The dual-reinforced Cu MMCs exhibited high strength (up to ∼747 MPa) and better comprehensive properties of strength/elongation and strength/electrical conductivity than those of the individual counterparts. Moreover, a synergistic strengthening effect of 1 + 1>2 of the dual reinforcements was revealed. The influences of content, distribution and interfacial interaction of the dual reinforcements on the properties of the Cu MMCs were discussed. This study indicated the method and mechanisms for further improving the comprehensive properties of Cu MMCs at high strength level by introducing dual reinforcements.

Wear and corrosion properties of low-cost eggshell-reinforced green AZ91 matrix composites

ABSTRACT The present work deals with the production of economical, recyclable and low-weight magnesium matrix composites with waste eggshell (ES). AZ91 magnesium matrix eggshell reinforced composites were fabricated by the powder metallurgy method, and their tribological and corrosion performances were investigated under different test conditions. Results showed that ES enhanced the microhardness value of unreinforced alloy up to 20.4%. Uniform distribution of eggshell particles in the matrix was achieved according to the microstructural investigations. Eggshell reinforcement exhibited a good lubricant effect and developed wear behaviour in almost all test conditions. When 5 wt-% eggshell was added to the alloy, 36.4 wt-% improvement of wear performance was achieved under the load of 20 N at 100 mm s−1 sliding speed. When the reinforcement content was increased, the corrosion rate began to accelerate. The corrosion rate increased almost four times as the reinforcement ratio increased at low pH values. The design of test conditions and the analysis of output responses were studied by the statistical analysis of Taguchi and analysis of variance (ANOVA). ANOVA indicated that the wear rate and corrosion rate were mainly affected by load (52.7%) and pH (21.7%), respectively.

Wear and Tensile Behaviour of Aluminium Matrix Hybrid Composites

Aluminium-based hybrid composites are well known for their great strength and wear resistance. In the aluminum matrix, the inclusion of reinforcements improves the strength and hardness. So, it is essential to study the tensile strength and wear behaviour of the developed samples. In this paper, aluminium-based hybrid composites are fabricated by incorporating graphite and Al2O3 in the aluminum base. The samples were prepared with varying reinforcement content and process constraints in a stir casting machine. The sliding behaviour was studied by measuring the wear rate by employing Taguchi analysis.

Optimization of parameters that affect wear of A356/Al2O3 nanocomposites using RSM, ANN, GA and PSO methods

PurposeThis study aims to present a novel methodology for the evaluation of tribological properties of new nanocomposites with the A356 alloy matrix reinforced with aluminium oxide (Al2O3) nanoparticles.Design/methodology/approachMetal matrix nanocomposites (MMnCs) with varying amounts and sizes of Al2O3 particles were produced using a compocasting process. The influence of four factors, with different levels, on the wear rate, was analysed with the help of the design of experiments (DoE). A regression model was developed by using the response surface methodology (RSM) to establish a relationship between the observed factors and the wear rate. An artificial neural network was also applied to predict the value of wear rate. Adequacy of models was compared with experimental values. The extreme values of wear rate were determined with a genetic algorithm and particle swarm optimization using the RSM model.FindingsThe combination of optimization methods determined the values of the factors which provide the highest wear resistance, namely, reinforcement content of 0.44 wt.% Al2O3, sliding speed of 1 m/s, normal load of 100 N and particle size of 100 nm. Used methods proved as effective tools for modelling and predicting of the behaviour of aluminium matrix nanocomposites.Originality/valueThe specific combinations of the optimization methods has not been applied up to now in the investigation of MMnCs. In addition, using of small content of ceramic nanoparticles as reinforcement has been poorly investigated. It can be stated that the presented approach for testing and prediction of the wear rate of nanocomposites is a very good base for their future research.

Mechanical, thermal, and flammability properties of polyamide-6 reinforced with a combination of carbon nanotubes and titanium dioxide for under-the-hood applications

The current study aims to explore the tensile fracture mechanism and thermo-mechanical efficiency of polyamide-6 (PA6) reinforced with titanium dioxide (TiO2) and multiwalled carbon nanotubes (MWCNTs). The uniform dispersion of the MWCNTs and appreciable interfacing between PA6, TiO2, and MWCNTs were revealed in the fractography figures. The crystallization temperature and degree of crystallinity have been enhanced by the addition of nanoparticles to the PA6 matrix. Young’s modulus, tensile strength, and Charpy impact strength improved proportionally concerning reinforcement content. The essential work of fracture (EWF) method was applied to evaluate the toughening and fracture behavior of PA6 hybrid systems. Considerable improvement (+60.6%) in the EWF of PA6–TiO2–MWCNT nanocomposites was observed at 4 wt.% CNT and 2 wt.% TiO2. Limiting oxygen index (LOI) findings demonstrate that a polymer with a combination containing titanium dioxide and multiwalled carbon nanotubes has a highly substantial retardant influence. As a result, the TiO2–CNT combination acts as a synergist filler, offering versatile PA6 composite products.

Synthesis and characterisation of chromium, eggshell and grinding sludge-reinforced aluminium metal matrix composite: an experimental approach

This investigation deals with the utilisation of industrial waste to develop an aluminium (Al)-based composite. Waste eggshell (ES) generated from the food industry has been used as the primary reinforcement material. Waste grinding sludge (GS) produced from the iron-forging sector was utilised as the secondary reinforcement content. Chromium (Cr) was also added to the composite material to prevent the composite material’s grain growth. The composite material was developed by the stir casting process. Experimental results concluded that the tensile strength, compressive strength and hardness of the base material (AA 5052 alloy) had been improved by about 18.02, 23.40 and 49.53%, respectively, by adding 4.5% of ES, 4.5% of GS and 1.5% of chromium. The microstructural analysis of the AA 5052/4.5% ES/4.5% GS/1.5% chromium composite shows the fair distribution of reinforcement content. The X-ray diffraction of the aluminium/4.5% ES/4.5% GS/1.5% chromium composite shows the occurrence of aluminium, ferric oxide (Fe2O3), calcium carbonate (CaCO3), calcium oxide (CaO) and chromium phases. The weight loss due to corrosion and thermal expansion behaviour of the developed composite have also been explored to observe the effect of ES, GS and chromium addition on the aluminium alloy.

Experimental study of microstructural and mechanical characterization of silicon-bronze copper alloy (C87600) hybrid composites reinforced with SiC-Gr particles by stir casting

In this study, the fabrication of copper-based hybrid metal matrix composites using the stir casting process was conducted. Ceramic particles i.e. SiC and graphite are considered as reinforcements for the fabrication of hybrid composites. The microstructure of composites was analyzed using Field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) spectroscopy. Uniform dispersion of the reinforcements throughout the matrix has been validated from the FESEM micrographs. The Vickers microhardness test was performed to examine the microhardness and its variation with respect to the reinforcement content. It was found that the microhardness value was found to be increased with an increase in reinforcement content. The tensile test of the fabricated composites was conducted using a Universal testing machine, and its variation with respect to the reinforcements is analyzed. It was observed that the tensile strength of the copper hybrid composites was enhanced with the increase in the reinforcement content. The composites with 8% SiC and 1% Gr had exhibited a maximum increase of 34% in the ultimate tensile strength as compared to the base matrix alloy. It is highly anticipated that the fabricated composites with their enhanced strength are suitable for potential applications in various structural applications.

Influence of process parameters in additive manufacturing of highly reinforced 316L / SiCp composites

Highly reinforced 316 L / SiCp metal matrix composites (MMC) walls have been additively manufactured by Direct Laser Deposition (DLD) using mixtures with different percentages of 316 L stainless steel powder and SiC particles (SiCp). The effect of the percentages of SiCp of up to 80 wt.% and DLD conditions on the geometry, microstructure, and hardness of the fabricated structures have been analyzed. SiC particles react with the molten 316 L steel and chromium and iron carbides are formed, and also graphite flakes and nodules are formed in the matrix. This reaction is also responsible for the dilution of the SiCp, which lose their initial shape and size. The incorporation of higher percentages of SiCp reduces the degradation of the particles as the matrix saturates in Si and C, and also enhances the size of the graphite precipitated phases. The different phases formed help to increase the hardness of the composites, and a maximum value of 1085 HV 0.1 was obtained for 40 vol.% of SiCp. Increasing further the amount of SiCp reduced the hardness to values of ∼890 HV 0.1 as the matrix is saturated in carbides and bigger and more brittle graphite precipitates are formed. The characteristics of the manufactured samples for the different reinforcement percentages used and for the different manufacturing conditions have been analyzed. From this study, the DLD processing maps for the 316 L/SiC MMC metal matrix composites with different content of reinforcement have been developed, and the optimal values of laser power, scanning speed, and layer height have been determined, and it has been observed that the optimum fabrication conditions displace to lower scanning speed for higher SiCp contents in the 316 L matrix. Showing that it is possible to manufacture cermets based on steel with lower density and greater hardness than the steel used.