Hardness Of Composites Research Articles

Wear behaviour of T4 and T6 heat treated LM28 composite reinforced with ZrO2 particles by stir casting method

Abstract The current study was performed to investigate the metal alloy LM28’s wear characteristics, strengthened by fine and coarse ZrO2 were investigated after undergoing thermal treatment with T4 and T6 process. Aluminium degasification tablets were used during the stir casting liquid metallurgy process to produce the composites with less porosity. ZrO2 was employed as fine (10–30 μm) and coarse (80–120 μm) particles in a step size of 3% from 0 to 12 wt%. The traditional T4 and T6 HT process was applied to the composite materials (LM28 nZrO2). T4 heat treatment involved in elevating the composites to 450 °C for 120–180 min before quenching them into the oil and age them naturally for 8–42 days at ambient room temperature. T6 HT was performed in a routine fashion, but also underwent artificial aging at 190–240 °C for 3–7 h before normal cooling. When compared to T4 HT process and non-HT composites, the hardness of T6 HT composites gives better results against wear property. The ideal level of hardness and resistance to wear of the composite was found in T6 HT composites when tested with a pin on a disk throughout a range of sliding distances and loads. Scanning electron microscopy demonstrated that T4 HT and non-HT composites suffered more surface damage than T6 HT composites when subjected to the same load and sliding distance. Initially, material was removed by an abrasive wear process, but this shifted to an adhesive one as sliding distance increased. T6 thermal treated composites are ideal for usage in tough conditions as a result of their excellent hardness and resilience to wear.

Effect of different heat treatment on thermal and electrical conductivity, and microhardness of Erbium-reinforced in-situ processed (ZrB2/Al2O3) 7085 AA nanocomposites for high temperature applications

High structurally stable 7085 aluminium alloy (7085 AA) is increasingly gaining more attention in industries such as automotive, electrical and high-temperature applications due to its demand for prolonged usage. The performance potential of conventional 7085 AA properties can be enhanced by reinforcing it with appropriate ceramic nanoparticles (AZ), namely, Aluminium oxide (Al2O3), Zirconium diboride (ZrB2), and rare earth metals, i.e. Erbium (Er), which makes it to be utilized for high-temperature industrial applications. Thus, the primary objective of the present study is to develop 7085 AA/AZ-Er composites having enhanced thermal, electrical and mechanical properties. The composites was synthesized through an In-situ process, followed by homogenization, solution treatment and artificial ageing (T6 and T74 heat treatment). The results obtained through T6 and T74 heat treatment were compared. The concentration of AZ was maintained at 1.0 wt.%, whereas Er was varied by 0.1. 0.3 and 0.5 wt.% in the 7085 AA/AZ composites. The superior properties of 7085 AA/AZ- Er composites achieved in this study are as follows: Thermal conductivity- 153.5 ± 0.7 W/m·K, Electrical conductivity- 21.99 ± 0.08 MS/m, and Hardness- 217.12 ± 3.2 Hv. The hardness and thermal conductivity of T6 heat-treated Er-based composites are found to be superior, while T74 heat-treated composites exhibited significant improvements in electrical conductivity. It is concluded that the appropriate addition of Er concentration plays a vital role in enhancing mechanical, electrical and thermal properties irrespective of the heat treatment process.

Machine Learning Modeling of the Mechanical Properties of Al2024-B4C Composites

Aluminum-based composites are in high demand in industrial fields due to their light weight, high electrical conductivity, and corrosion resistance. Due to its unique advantages for composite fabrication, powder metallurgy is a crucial player in meeting this demand. However, the size and weight fraction of the reinforcement significantly influence the components' quality and performance. Understanding the correlation of these variables is crucial for building high-quality components. This study, therefore, investigated the correlations among various parameters—namely, milling time, reinforcement ratio, and size—that affect the composite’s physical and mechanical properties. An artificial neural network model was developed and showed the ability to correlate the processing parameters with the density, hardness, and tensile strength of Al2024-B4C composites. The predicted index of relative importance suggests that the milling time has the most substantial effect on fabricated components. This practical insight can be directly applied in the fabrication of high-quality Al2024-B4C composites.

Reinforcement of Epoxidized Natural Rubber with High Antimicrobial Resistance Using Water Hyacinth Fibers and Chlorhexidine Gluconate.

In this study, epoxidized natural rubber (ENR) was mixed using a two-roller mixer. Water hyacinth fiber (WHF) acted as a reinforcing agent in the preparation of the rubber composite at 10 phr (ENRC/WHF). Chlorhexidine gluconate (CHG) was added at different concentrations (1, 5, 10, and 20 phr) as an antimicrobial and coupling agent. The tensile strength increased with a CHG content of 1 phr (4.59 MPa). The ENRC/WHF/CHG20 blend offered high hardness (38) and good morphology owing to the reduction in cavities and fiber pull-out from the rubber matrix. The swelling of the sample blends in oil and toluene decreased as the CHG content increased. Reactions of -NH2/epoxy groups and -NH2/-OH groups occurred during the preparation of the ENRC/WHF/CHG blend. The FTIR spectroscopy peak at 1730 cm-1 confirmed the reaction between the -NH2 groups of CHG and epoxy groups of ENR. The ENRC/WHF/CHG blend at 10 phr and 20 phr exhibited zones of inhibition against three bacterial species (Staphylococcus aureus, Escherichia coli, and Bacillus cereus). CHG simultaneously acted as a crosslinking agent between ENR and WHF and as an antimicrobial additive for the blends. CHG also improved the tensile strength, hardness, swelling, and antimicrobial properties of ENR composites.

Effect of contemporary polishing systems on hardness and roughness of one-shaded dental composites

Effect of contemporary polishing systems on hardness and roughness of one-shaded dental composites

Effect of Al Addition to Mg Melt on Microstructure of Mg-Ti Composites in Liquid Metal Dealloying Process

This study investigates the effect of adding Al to Mg molten metal on the microstructural characteristics and hardness of Mg-Ti composites fabricated via a liquid metal dealloying (LMD) process. The addition of Al to the Mg melt significantly reduces the dealloying rate of Cu in a Ti30Cu70 precursor during LMD. The rapid reaction of Al atoms with Ti results in the formation of a Ti3Al phase, which in turn inhibits the spinodal decomposition of Ti and Cu. This inhibition decreases the formation rate of α-Mg channels, thereby slowing down the dealloying process of Cu. As a result, as the Al content in the Mg melt increases from 0 to 3 to 6 wt%, the residual Cu content in the composite substantially increases from 0 to 42 wt%. The main phases comprising the composite change from Mg and Ti for the composite using a pure Mg melt to TixCuy, TixAly, and MgxCuy for the composites using Mg-Al melts. The hardnesses of the composites fabricated using the Mg-3Al and Mg-6Al melts are 344 and 354 Hv, respectively, which are more than twice that of the composite fabricated using the pure Mg melt (116 Hv). These results demonstrate that adding small amounts of Al to Mg melt considerably influences the dealloying behavior during LMD as well as the resultant microstructure and mechanical properties of the Mg-Ti composite.

The microstructure, mechanical properties and tribological behaviors of YB2C2 reinforced Cu matrix composites prepared by spark plasma sintering

The first ternary layered ceramic reinforced copper matrix composites, Cu-xYB2C2 (x = 0, 5, 10, 20 vol%) composites without interfacial reaction were successfully fabricated by spark plasma sintering at 950 °C. Microstructures, phase compositions, mechanical properties and tribological behaviors of Cu-YB2C2 composites were investigated. The results indicated that Cu-YB2C2 composites had good chemical compatibility. Compared with pure copper, the hardness, tensile strength and wear resistance of Cu-YB2C2 composites were all significantly improved. Cu-10 vol% YB2C2 composites exhibited the highest tensile strength and the best tribological performance, with an ultimate tensile strength of 203 ± 2 MPa and a wear rate of (3.1 ± 0.4) × 10−8 mm3/mm. The wear mechanism changed from adhesive wear to a combination of adhesive wear and abrasive wear with the addition of YB2C2, while surface oxidation and fatigue were also present in all tribosystems. Cu-YB2C2 composites have application prospects in electrical contacts and aerospace fields.

Time-Dependent Evolution of Al-Al4C3 Composite Microstructure and Hardness during the Sintering Process.

In this study, Al-Al4C3 compounds were manufactured by mechanical milling followed by heat treatment. To analyze the microstructural evolution, the composites were sintered at 550 °C at different sintering times of 2, 4 and 6 h. The mechanical results suggest that dislocation density and crystallite size primarily contribute to hardening before the sintering process, with a minimal contribution from particle dispersion in this condition. The compound exhibited a significant 75% increase in hardness after 2 h of sintering, primarily attributed to the nucleation and growth of Al4C3 nanorods. The HRTEM analysis, combined with geometric phase analysis (GPA) at and near the Al-Al4C3 interface of the nanorods, revealed strain field distributions primarily associated with partial screw dislocations and the presence of closely spaced dislocation dipoles. These findings are consistent with the microstructural parameters determined from X-ray diffraction pattern analysis using the convolutional multiple whole profile (CMWP) method. This analysis showed that the predominant dislocation character is primarily of the screw type, with the dislocation dipoles being closely correlated. Based on these results, it is suggested that samples with a lower weight percentage of reinforcement and longer sintering times may experience reduced brittleness in Al/Al4C3 composites. Strengthening contributions were calculated using the Langford-Cohen and Taylor equations.

Exploring Water Absorption Behaviors on Mechanical Properties of Wheat Straw-Glass Fiber Hybrid Composites for Sustainable Engineering Solutions

The study explores the enhancement of epoxy composite performance by adding glass fiber and wheat straw, revealing improved tensile strength and hardness compared to unreinforced epoxy. Using a hand-layup procedure, glass fibers and wheat straw are incorporated unidirectionally into an epoxy resin matrix. This study aims to explore how different fiber volume fractions and moisture absorption over two months affect the tensile strength and hardness of hybrid composites. The tensile strength and hardness of weathered specimens are found to be lower values than those of raw samples because of the degradation of the structural integrity of the fibers during water absorption. After being exposed to water, the tensile strength was 20 wt. % fiber composite sample was reduced by roughly 32.43 %. A marginal decline in hardness of 5.63% occurred for 20 wt. % hybrid composite. The morphology of the composites after the tensile test and the interactions between the fibers and the epoxy matrix in the as-cast and weathered samples were investigated using SEM. Perfect fiber-matrix bonding was apparent in as-cast composites. However, fiber swellings and de-bonding in the fiber matrix due to voids and moisture absorption were observed in weathered specimens, which reduced the tensile strength and hardness.

Mechanical characterizations of waste face masks reinforced polyester composites: Recycling wastes into resources

Face masks are made of non-decomposable thin polypropylene sheets. People are discarding them in parks, beaches, drains, landfills, and roadsides because of a deficiency in recycling efforts. It poses health and environmental risks through soil, water, and air pollution, as well as implanting microplastics into aquatic and different active organisms via food chains. Therefore, the environment and ecosystem become unsustainable. This study explored the potential of recycling waste face masks (WFM) into composite materials. In this sense, WFM-reinforced three distinct polyester composites are developed with a 20 % fiber loading in the compression molding machine and employing shredded, parallel, and crisscross patterns of WFM. The tensile, flexural, and impact strengths of composites are assessed as per ASTM guidelines and contrasted with NFRP (natural fiber-reinforced polymer) composites. Besides, void contents and morphological features are investigated using the Field Emission Scanning Electronic Microscope (FE-SEM) to confirm the interaction between WFM and polyester. The maximum tensile and flexural strengths of 32.06 and 41.13 MPa, respectively, are found in the crisscross pattern WFM composite. The maximum impact strength of 0.053 J/mm is found in parallel, and the least void content of 0.63 % is found in crisscross WFM composites. Compared to NFRP composites, the mechanical strengths, void contents, and morphological properties of WFM composites are found promising. It proclaimed that WFM is an appropriate candidate for recycling into composites. It will deter environmental pollution and microplastic insinuation into living things, elevate sustainable development goals, and develop a circular economy by generating resources from WFM.

Effect of AlCrCuFeNi high entropy alloy reinforcements with and without B4C on powder characteristic, mechanical and wear properties of AA5083 metal-metal composites

This study presents a novel approach to enhancing the properties of the AA5083 alloy by incorporating a high entropy alloy (HEA), specifically AlCrCuFeNi, through mechanical alloying. The Al/HEA composites were thoroughly characterized in terms of powder morphology, microstructure, fracture and wear surface morphology, phase composition, and oxidation behavior using XRD, SEM-EDS, and TGA. The impact of HEA, both with and without B4C reinforcement, on the hardness, density, tensile strength, and wear properties of the AA5083 matrix composites was comprehensively evaluated. The findings revealed that the AA5083 alloy exhibited a baseline hardness of 74.7 HB and a tensile strength of 174.1 MPa. However, with the addition of HEA + B4C, these properties were markedly enhanced, with the hardness increasing to 150.1 HB (a 100 % increase) and tensile strength to 247.1 MPa (a 50 % increase). Furthermore, the wear resistance of the composite experienced a substantial improvement, with a nearly six-fold increase due to the HEA + B4C reinforcement.

Experimental analysis on the mechanical properties of Al6061 based hybrid composite reinforced with silicon carbide, bagasse fly ash and aloe vera ash

The demand for low-density automobile components for lightweight automobiles that have less energy consumption has initiated the production of chassis, wheels, bumpers, brakes, and steering using composite materials. This research aimed to fabricate an Al6061-based hybrid composite for automobile components reinforced with 10 wt% silicon carbide and varying aloe vera and bagasse ashes using the stir-casting method. The effects of the composition of reinforcements on the microstructure, hardness and compressive strength of the hybrid composites were assessed. It was found that an increase in bagasse ash and aloe vera ash contents improved the compressive strength. The hybrid composite with 10 wt% bagasse ash and 11 wt% aloe vera ash demonstrated maximum compressive strength of 376.3 MPa. The highest hardness of 91.6 HV was achieved with the hybrid composite having 10 wt% bagasse ash and 11 wt% aloe vera ash. The hardness value of the hybrid composite was increased by 16.27% when compared to a single reinforced Al6061/SiC composite. It was concluded that adding bagasse and aloe vera ashes greatly increased the hardness and compressive strength of Al6061/SiC composite materials. The findings of this research would be useful for automobile component manufacturers.

Mussel-inspired polydopamine functionalized PBO fibers as an efficient additive for UHMWPE composites with improved tribological performance

It is important to prepare self-lubricating polymers with low friction coefficient and wear rate. Herein, poly(p-phenylene-2,6-benzobisoxazole) fibers coated with polydopamine (PBO@PDA) were synthesized and introduced to enhance the tribological performances of the UHMWPE composites. The PBO@PDA, with a rough surface and a PDA layer of 13 nm thickness, exhibited a robust interfacial interaction with the UHMWPE matrix. The thermal stability of the UHMWPE composites steadily improved with the increasing content of PBO@PDA due to the enhanced thermal stability and char-forming ability of PBO@PDA. In addition, the presence of PBO@PDA also enhanced the rigidity and crystallinity of the UHMWPE composites. The UHMWPE composite containing 2 wt% PBO@PDA exhibited the best tribological performance with a friction coefficient of 0.042 and a wear rate of 2.38 × 10-5 mm3/N·m, which were maximally reduced by 76 % and 32 %, respectively, as compared with those of pure UHMWPE. The addition of PBO@PDA increases the hardness of the UHMWPE composites, thereby improving their wear resistance. Furthermore, the incorporation of PBO@PDA contributes to the formation of lubricating films. However, the high content of PBO@PDA can lead to aggregation, which deteriorates friction performance. This work offers a feasible approach to reducing the friction and wear on UHMWPE lubricated materials.

SIFAT MEKANIS KOMPOSIT MATRIKS ALUMINIUM BERPENGUAT ABU JERAMI DENGAN METODE METALURGI SERBUK

The powder metallurgy method is one method for making metal matrix composite products. This method provides researchers with material engineering.This study aims to determine how the effect of variations in mixing time and sintering holding time affects the hardness and compressive strength of composites made of aluminum powder and straw ash. The composition of this composite is 90%wt Aluminum and 10%wt straw ash. Preparation of specimens using powder metallurgy method. Mixing time variations were applied for 120, 150 and 180 minutes with the dry mixing method. Variation of sintering holding time was applied for 60, 120 and 180 minutes at 550°C.The mechanical test carried out are hardness test and compression test. The results showed that the optimum hardness value was found in the specimens with a mixing time of 150 minutes and sintering holding time of 180 minutes with an average hardness of 96 HRF. The optimum compressive strength is found in specimens with a mixing time of 150 minutes and sintering holding time of 120 minutes with an average compressive strength of 101.28 MPa. It can be concluded that mixing time and sintering holding time affect the hardness and compressive strength of the metal matrix composite.

Learning based model for predicting mechanical properties and sustainable filler band for NBR composites using lignin and carbon black

Experimental determination of mechanical properties of rubber composites, such as tensile strength and hardness, involves complex multistage preparation procedures that are laborious and expensive. In this study, a hybrid filler of carbon black (CB) along with a sustainable filler of lignin is added for reinforcement in the nitrile butadiene rubber (NBR) matrix, with the total filler content varying from 10 parts per hundred rubber (phr) to 80 phr. This work aims to develop a data-driven predictive model for the mechanical properties of rubber composites. An artificial neural network (ANN) model using multilayer feed-forward back-propagation has been created to forecast the tensile strength (Ts) and hardness (Hd) of rubber composites. The model predicts the uniaxial tensile response and hardness using input parameters that include total filler and lignin loading levels. The effectiveness of the suggested prediction method was demonstrated by statistical analysis using confidence intervals, showing a prediction error between 5.47% and 3.23% for the Ts and between 3.03% and 1.85% for Hd at 95% confidence intervals. A sustainable green band could be defined in the developed model, which is handy for designers to replace CB with lignin in various NBR based products, such as hoses, seals, etc., without compromising on tensile strength and hardness.

Effect of addition of Ce and accumulative roll bonding on structure-property of the Mg-Ce-Al hybrid composite and its prediction and comparison using artificial neural network (ANN) approach

Abstract Light alloys play a crucial role in realizing the national strategy for energy conservation and emission reduction, as well as promoting the upgrading of manufacturing industries. Mg/Al composite laminates combine the corrosion resistance and ductility of aluminium alloy with the lightweight characteristics of magnesium alloy. The addition of Ce (rare earth elements) can improve the mechanical properties of magnesium via grain refinement and improve the ductility of the hybrid composites. In the present work, an investigation on addition of Ce into the Mg/Al matrix through Accumulative Roll Bonding (ARB) has been presented. The Mg/Ce/Al hybrid composite consists of Mg-4%Zn alloy and Al 1100 alloy with 0.2% Ce particles added between the dissimilar layers. The changes occurred in the evaluation of microstructure, corrosion and mechanical properties of the Mg/Ce/Al hybrid composite as a result of deformation process and also the addition of Ce have been explicated. The ARB parameters: temperature, rolling speed, percentage reduction, and aging time, have been studied. An increase of about 2.36 times in strength and hardness of the hybrid composite, has been reported. Further, the structure–property relations in the Mg/Ce/Al hybrid composites were aslo predict and compare using machine learning models: Decision Tree and Multi-Layer Perceptron (MLP) models.

Microstructure, Mechanical and Tribological Properties of Cu40Zn-Ti3AlC2 Composites by Powder Metallurgy

The exploration of unleaded free-cutting Cu40Zn brass with excellent mechanical and tribological properties has always drawn the attention of researchers. Due to its attractive properties combining metals and ceramics, Ti3AlC2 was added to Cu40Zn brass using high-energy milling and hot-pressing sintering. The effects of Ti3AlC2 on the microstructure, mechanical and tribological properties of Cu40Zn-Ti3AlC2 composites were studied. The results showed that Ti3AlC2 could suppress the formation of ZnO by adsorbing oxygen impurity and promote the formation of the β phase by releasing the β-forming element Al to the substrate. The hardness and wear resistance of Cu40Zn-Ti3AlC2 composites increased with increasing Ti3AlC2 content from 0 to 5 wt.%. The proper Ti3AlC2 additive was beneficial to both the strength and plasticity of the composites. The underlying mechanisms were discussed.

Improvement of wear-resistant and thermal conductivity of aluminum matrix composite reinforced AL2O3/SiCw/Mg powder

Technological progress demands the development of materials that have special characteristics such as high strength, stiffness, light weight, and good thermal conductivity at a low price. The development of hybrid metal matrix composites is the most important field in advanced materials science engineering. This research determines about aluminum matrix composites (AMC) reinforced with alumina (Al2O3), Silicon carbide whisker (SiCw), and magnesium (Mg) addition. The matrix is made of 90 % pure aluminum powder, and commercially available reinforcing materials include Al2O3, SiCw, and Mg. Objectives include variation of reinforcement fraction and matrix, sintering holding temperature and time. The selection of the sample making process using powder technology followed by the sintering process at different temperatures namely 350, 450 and 550 °C with variations in holding time of 1, 2 and 3 hours. The purpose of this study was to determine the effect of variations in the fraction of reinforcement and sintering treatment on the properties of wear resistance, hardness and thermal conductivity of aluminum matrix composites. The results showed that the composition ratio of reinforcement to aluminum in sintering treatment significantly affected the mechanical properties. The wear resistance of the material shows excellent performance, namely wear resistance of 0.000065 gr/s, hardness of 45.234 VHN and thermal conductivity of 184.855 Watt/m °C, at a reinforcement composition combination of 10 %AL2O3, 10 %SiCw and 20 %Mg and a sintering temperature of 550 °C. This indicates that the Aluminum matrix composite reinforced with Al2O3/(SiCw/Mg) is able to support the friction load due to its low wear rate, good hardness, and good thermal conductivity. This material is very suitable to be used as tribology material, brake element, especially brake drum

Preparation of boron nitride grafted carbon nanotubes for enhancing the tribological performance of poly (ether ether ketone) composite

The impendency demands for the excellent wear resistance materials are blossoming as the increasing possibilities of complex application environments. Poly (ether ether ketone) (PEEK) is regarded as a promising candidate for its outstanding mechanical properties and remarkable thermal stability. Herein, a feasible strategy is proposed to obtain hydroxylated boron nitride (BNO) grafted carbon nanotubes (CNTs). Then, introduce the as- prepared reinforcements into the matrix to fabricate the BNO-CNT/PEEK composites. The incorporation of BNO-CNT significantly increases the nano- hardness and elastic modulus of composites. The interfacial interactions between components promote the synergistic enhancement effects, ultimately increasing the thermal conductivity and tribological performance of composites. The coefficient of friction and wear rate remarkably decline with the introduction of 3 wt% BNO-CNT. Thus, this facile approach demonstrates its potential for improving tribological properties in PEEK composites.

Influence of SiO2 Nanoparticles Extracted from Biomass on the Properties of Electrodeposited Ni Matrix Composite Films on Si(100) Substrate.

Lab-made biosilica (SiO2) nanoparticles were obtained from waste biomass (rice husks) and used as eco-friendly fillers in the production of nickel matrix composite films via the co-electrodeposition technique. The produced biosilica nanoparticles were characterized using XRD, FTIR, and FE-SEM/EDS. Amorphous nano-sized biosilica particles with a high SiO2 content were obtained. Various current regimes of electrodeposition, such as direct current (DC), pulsating current (PC), and reversing current (RC) regimes, were applied for the fabrication of Ni and Ni/SiO2 films from a sulfamate electrolyte. Ni films electrodeposited with or without 1.0 wt.% biosilica nanoparticles in the electrolyte were characterized using FE-SEM/EDS (morphology/elemental analyses, roundness), AFM (roughness), Vickers microindentation (microhardness), and sheet resistance. Due to the incorporation of SiO2 nanoparticles, the Ni/SiO2 films were coarser than those obtained from the pure sulfamate electrolyte. The addition of SiO2 to the sulfamate electrolyte also caused an increase in the roughness and electrical conductivity of the Ni films. The surface roughness values of the Ni/SiO2 films were approximately 44.0%, 48.8%, and 68.3% larger than those obtained for the pure Ni films produced using the DC, PC, and RC regimes, respectively. The microhardness of the Ni and Ni/SiO2 films was assessed using the Chen-Gao (C-G) composite hardness model, and it was shown that the obtained Ni/SiO2 films had a higher hardness than the pure Ni films. Depending on the applied electrodeposition regime, the hardness of the Ni films increased from 29.1% for the Ni/SiO2 films obtained using the PC regime to 95.5% for those obtained using the RC regime, reaching the maximal value of 6.880 GPa for the Ni/SiO2 films produced using the RC regime.