Alloy Matrix Material Research Articles

Microstructure and properties of aluminium matrix hybrid nanocomposite

ABSTRACT Aluminium metal matrix nanocomposites (MMNCs) reinforced with particulate have been in the limelight recently due to their improved tribological and mechanical properties such as stiffness, strength, impact resistance, wear resistance, etc. It is well known that carbon nanotube and silicon carbide nanomaterials are widely used as reinforcements in various types of metal or alloy matrix materials. However, hybrid metal matrix nanocomposites reinforced with more than one type nanomaterials are rarely reported in the literature. In this work, a novel aluminium matrix hybrid nanocomposite with carbon nanotube and nano SiC has been fabricated. Properties of hybrid nanocomposites are compared with nanocomposites reinforced with individual reinforcements. Vicker’s micro-hardness property of specimens was tested at 100 gmf load applied at 10 s dwell time. The hardness and compressive strength have increased 111% and 58%, respectively with the reinforcement of nanoparticles in the metal matrix. Dry wear property of specimens was carried out at 35, 40 and 45 N load with variable speeds viz. 500, 550 and 600 rpm. Wear resistance increases as the carbon reinforcement increases in the metal matrix. The wear mechanism of nanocomposite materials has been evaluated by using scanning electron microscopic analysis.

Erosion Performance of TiAlSiN Coatings Prepared by High-Power Pulsed Magnetron Sputtering

Erosion seriously threatens the safety of high-speed rotating mechanical components in very harsh service environments, particularly for lightweight titanium alloy matrix material. In order to improve the erosion resistance of titanium alloy, TiAlSiN coatings with different phase compositions are deposited on TC6 titanium alloy using a high-power pulse magnetron sputtering discharge (HPPMS) system under various discharge voltages. The componential and microstructural evolution as well as mechanical properties of the TiAlSiN coatings are evaluated by X-ray diffraction, scanning electron microscopy, and nanoindentation, respectively. The erosion performance relative to titanium alloy is investigated by a sand blasting tester. With the increase in discharge voltage from −500 to −600 V, the peak of discharge current increases from 105 to 225 A. The prepared TiAlSiN coatings show a shift of the preferred crystallographic orientation from (220) to (200), but all of them have a dense nanocomposite structure. Their hardness (H) and elastic modulus (E) gradually increase before decreasing, arriving at maximum values of 35.34 and 360.5 GPa at −570 V. The erosion resistance of the TiAlSiN coatings dependent on the discharge voltage is consistent with the H/E ratio change. The TiAlSiN coatings prepared at −560 V exhibit the optimal erosion resistance, which is 15 times that of the TC6 substrate. The erosion behavior of the coatings is positively correlated with their hardness and toughness. Adjusting the discharge voltage of the HPPMS pulse is finally proved to be an effective way of tailoring the coating phase compositions to improve the erosion resistance of titanium alloy.

The effect of reinforcement ratio on corrosion properties in Al2O3 reinforced composites with AA2024 aluminum matrix produced by hot pressing

In this study, corrosion properties of AA2024 aluminum alloy matrix composite materials reinforced with Al2O3 in three different ratios were investigated. After mixing the aluminum alloy matrix material powders and the reinforcement material powders at 10%, 20% and 30% Al2O3 ratios homogeneously, composite materials were produced by keeping them in an axial mold under 50 MPa pressure and 550 °C for 1 hour by hot pressing method. According to the corrosion test results, the corrosion resistance of the composite materials containing 20% and 30% Al2O3 reinforcement was very close to each other. The corrosion rates of these two samples were determined to be lower than the sample containing 10% Al2O3 reinforcement.

Large-Arc Discharge Mechanism and Avoidance in Micro-Arc Oxidation of Magnesium Alloy

The large-arc discharge problem occurs in the processing of magnesium alloy by micro-arc oxidation. It will cause local ablation of ceramic coating and even magnesium alloy matrix material. Thus, clarifying the mechanism and influencing factors is a necessary approach to avoid the large-arc discharge problem. In this study, a new “cooling time” parameter based on frequency and duty cycle is proposed to study the large-arc discharge trend and understand the relationship between large-arc discharge and process parameters. Then, the mechanism of the large-arc discharge phenomenon and the action of the cooling time were investigated by the theory of local-arc discharge mechanism and load characteristics of micro-arc oxidation. The results show that the mechanism of large-arc discharge is that the arc discharge is continuous in situ, and the aggregation or merger of arc discharge occurrence. Therefore, the large-arc problem can be resolved effectively through discretizing the arc discharge by adjusting the cooling time and regulating the pulse frequency and duty cycle. The cooling time made the location area of arc discharge and oxides fully cooled, and provided time for the sufficient discharge of the load capacitance, to effectively inhibit the problem of large-arc discharge.

Comparative study on tensile characteristics of friction stir welded aluminium hybrid composite plates

The recent promising fields of material development include biomaterials, nanomaterials, smart materials, composites, materials for energy generation and storage along with advanced manufacturing processes. The challenge of developing new material is becoming more interesting. A lot of research work is in progress to fulfill the necessity or requirement for special or advanced engineering materials. This research work prominently concentrated on various parameters of friction welding on low melting aluminium alloy matrix materials constitutes with reinforcement ingredients like E-Glass short fibers and Silicon carbide fine particles and subjected to ASTM standard tensile specimens for unidirectional tensile test, the results should be tabulated and compared.

Effect of addition of titanium carbide and graphite reinforcement on Al7075 hybrid metal matrix composites by gravity stir casting method

In recent years composite materials play vital role on automobile and aerospace industries and the maximum researcher developed the composite, they are used maximum addition of reinforcement particle to the base aluminium matrix is less than 10 % of weight fraction. An attempt is made to increase the addition of reinforcement to the aluminium base material more than 10 % weight fraction. In this research work is to evaluate the mechanical properties of Al7075-Titanium carbide (TiC)-Graphite (Gr) composites developed by gravity stir casting method with increasing the addition of weight percentage of ceramic reinforcement of titanium carbide from 10%,12% and 14% weight fraction with fixed 2% weight percentage of graphite to the composite. The developed Al7075-TiC-Graphite composites were exposed to tensile hardness, and impact studies. The tensile strength, Hardness and impact strength of the composite were decreased while increasing the addition of ceramic reinforcement. Scanning electron microscope confirms the presence of reinforcement of titanium carbide and graphite in the hybrid metal matrix composite. The average tensile strength of the composite increased from 80.87 MPa to 139.87 MPa for the addition of titanium carbide of 10% and 12% weight fraction addition of TiC, beyond that the average tensile strength were decreased when further increasing the addition of reinforcement to base alloy matrix material. The hardness of the Al7075-TiC-Graphite composites increased to 41.31% while increasing the addition of weight percentage of TiC to base matrix where as impact strength of composites decreased while increasing the addition of reinforcement due to higher brittle nature of reinforcement than the base aluminium matrix material. The scanning electron microscope (SEM) confirms the presence of Aluminum, TiC and Graphite particle in the cast composite.

Enhanced Antiwear Property of Cu-Sn-Bi Bimetal Composites with TiB2 under Different Working Conditions

The present study investigated the effect of TiB2 on the tribological properties of CuSn10Bi3 bimetallic bearing materials. CuSn10Bi3 samples with different contents of TiB2 were fabricated by powder sintering technology. Their metallographic structures and tribological characteristics under different working conditions were analyzed and compared. The results showed that TiB2 refine the copper alloy grains, passivate the grain boundary edges and reduce the surface porosity of the sample. When the content of TiB2 is 1%, the wear rate under different oil conditions (oil-rich, oilless, and dry friction) is reduced by 42%-95%. The sharp decrease in the wear rate is attributed to the enhancement of the micro-grain structure of the copper alloy matrix material by TiB2 hard particles with antiwear properties, and the high hardness and high wear resistance of TiB2. The wear tracks were analyzed through SEM and EDS, and it was concluded that the addition of TiB2 enhanced the wear resistance.

Recovery of Cr from chrome-containing leather waste and its utilization as reinforcement along with waste spent alumina catalyst and grinding sludge in AA 5052-based metal matrix composites

The present investigation deals with the development of AA 5052-based metal matrix composites (MMCs) by utilizing industrial wastes, spent alumina catalyst, chrome-containing leather waste, and grinding sludge as a reinforcement material. The chrome-containing leather waste has been utilized to extract the collagen powder, which is a form of chromium oxide. The presence of Al2O3, Fe2O3, and SiO2 phases in the spent alumina catalyst and grinding sludge ball-milled powder encourages its utilization as reinforcement material (in the form of Cr) for the development of MMCs. The stir-casting technique has been used to develop the aluminum-based MMC with waste spent alumina catalyst, chrome-containing leather waste, and grinding sludge. Further, results revealed that the matrix material mechanical properties compressive strength, tensile strength, and hardness were significantly increased by 12.93%, 5.34%, and 31.81% after adding spent alumina catalyst, Cr, and grinding sludge with the weight percentage (wt.%) of 4.5%, 1.5%, and 4.5%, respectively, but the toughness was reduced. The microstructural investigation indicated the uniform distribution of reinforcing elements spent alumina catalyst (4.5 wt.%), GS (4.5%), and Cr (1.5%) in the aluminum matrix material. Further, the influence of given reinforcement elements on the thermal expansion and corrosion weight loss properties of aluminum alloy matrix material has also been investigated.

Corrosion resistance of aluminum fluoride modified 6061 aluminum alloy

The oxide film formed naturally on the surface of aluminum alloy is easy to be damaged in marine and lake environment, resulting in corrosion and damage of aluminum alloy matrix materials. Compared with alumina, aluminum fluoride has excellent chemical stability. It is insoluble in acid, alkali and most organic solvents. In this study, polyvinylidene fluoride (PVDF) was used as the surface treatment material. A protective layer of aluminum fluoride was deposited on the surface of aluminum alloy by chemical vapor deposition. The coating enables the corrosion potential of aluminum alloy shift positively and decreases the corrosion current, indicating improved corrosion resistance of aluminum alloy.

A Review on Role of Aluminum Matrix Materials, Failure Causes and Optimization Techniques

Aluminum is a metal matrix material which is widely used in different industrial as well as engineering applications.it has a great advantage due to its remarkable properties like less density, formability, and light in weight, recyclability and other properties. but, failure of aluminum matrix materials are the main problems in aluminum industries now a days.in this review role of aluminum and its alloys as matrix materials, their failure modes, causes of failure and optimization techniques to minimize this failure modes and causes of failure are discussed. Sources are reviewed which are from 2005 to recent one. Consequently, most modes of failure, causes of failure and most optimization techniques of aluminum and its alloy matrix materials are found. most modes of failure are mechanical related like fatigue failure, surface cracking, ductile failure, porosity formation, and stress related like stress corrosion cracking, surface weakness due to repeated stresses and other factors are summarized.in causes of failure mostly like corrosion formation, wear formation and poor mechanical properties are discussed.

A Review on Role of Aluminum Matrix Materials, Failure Causes and Optimization Techniques

Aluminum is a metal matrix material which is widely used in different industrial as well as engineering applications. It has a great advantage due to its remarkable properties like less density, formability, and light in weight, recyclability and other properties. but, failure of aluminum matrix materials are the main problems in aluminum industries now a days.in this review role of aluminum and its alloys as matrix materials, their failure modes, causes of failure and optimization techniques to minimize this failure modes and causes of failure are discussed. Sources are reviewed which are from 2005 to recent one. Consequently, most modes of failure, causes of failure and most optimization techniques of aluminum and its alloy matrix materials are found. most modes of failure are mechanical related like fatigue failure, surface cracking, ductile failure, porosity formation, and stress related like stress corrosion cracking, surface weakness due to repeated stresses and other factors are summarized. In causes of failure mostly like corrosion formation, wear formation and poor mechanical properties are discussed.

Effect of the matrix material and electroplating process on the microstructure and properties of isolation switch contacts

In the KI system, Ag plating, hard-Ag plating and graphene-Ag plating were prepared on the surface of the copper and Cu–Cr alloy matrix materials by the electrodeposition method. The purpose of this paper is to define the copper-based material and related plating process suitable for the contacts of the isolating switch, obtaining excellent comprehensive properties and revealing the strengthening mechanism and wear mechanism of contact materials. Copper alloy was obtained by smelting in a high-frequency vacuum induction furnace, and then cold rolled. Effects of different plating processes and matrix materials on the microstructure, bonding degree between the plating and matrix, microhardness, contact resistance and wear resistance of copper-based contact materials were studied. The results showed that the matrix and the plating are well bonded. Both the Cu–Cr alloy matrix and the hard-Ag plating were rich in a large number of nano twins, dislocations and precipitates, which can strengthen the matrix and the plating. Moreover, they are beneficial to obtaining contact materials with high strength, high toughness and high conductivity. The contact resistance of the 3 kinds of plating changed little. The contact resistance of the Ag plating was the smallest, which was the largest of the hard-Ag plating, increased by 19.5%. The hard-Ag plating has the highest hardness and best wear resistance. Under the same test conditions, the combination of the hard-Ag plating and the Cu–Cr alloy matrix enables the copper-based contact material to obtain good cooperation of hardness, wear resistance and conductivity, and the comprehensive performance is the best.

Wear rate and hardness characteristics of Al7075/kyanite (Al2SiO5) composites

In the present work kyanite (Al2SiO5) used as reinforcement material by varying weight-percentage of 2 wt%, 4 wt%, 6 wt% and 8 wt% in Al7075 alloy matrix material. Al7075-kyanite composites prepared using vortex method by stir casting technique. Microstructural studies of cast composites is carried out using optical microscopy and X-ray diffraction studies. XRD studies shows the peaks subsequent to Al, Al2SiO5 and minor Al2O3, SiO2 phases. Optical microscopy results the uniform distribution of kyanite in Al7075 matrix. The dry pin-on-disc unlubricated wear tests conducted to observe the wear behaviour of the Al7075-alloy and its casted composites. The dry sliding wear tests carried out at various sliding speeds (0.6, 0.8 and 1 m/s), sliding distances (250, 500, 750 and 1000 m) and loads (20, 40 and 60 N). It is contingent that, wear rate of Al-Al2SiO5 composite is lesser than unreinforced Al 7075 in all combination of sliding speeds, sliding distances and loads. The wear rate is decreases 9.9 × 10−4 ± 6.1 × 10−4 mm3/m increase in wt% of kyanite in matrix material and sliding speed. Wear rate is decreases 7.19 × 10−4 ± 1.71 × 10−4 mm3/m increasing sliding distance. Wear rate is increases 1.52 × 10−3 ± 0.3 × 10−3 mm3/m increasing load. Brinell hardness tested increases hardness with increase in wt% of kyanite in matrix. Worn surface analysis is carried out to analyze the effect of reinforcement on worn surfaces. Hardness is superior for Al7075/8 wt% kyanite composites. Composites gives higher hardness and wear resistance compared to Al7075 matrix.

Influence of carbon nanotubes and dispersions of SiC on the physical and mechanical properties of pure copper and copper‐nickel alloy

AbstractThis paper investigates the physical and mechanical properties of copper‐nickel alloy (at 50 wt.%–50 wt.%) and pure copper, mixed with various types of reinforcement materials such as carbon nanotubes (0.5 wt.%–2 wt.%) as nanoparticles, silicon carbide (1 wt.%–4 wt.%) as microparticles. The acquired composite specimens characteristics were estimated such as microstructure, density, electrical and thermal conductivity, hardness, and compression stress properties to determine the suitable reinforcement percentage that has the best physical and mechanical properties with different main matrix material whether copper‐nickel mechanical alloying or pure copper powder. The micron‐sized silicon carbide and nanosized carbon nanotubes were added to improve the mechanical and physical properties of the composite. The electrical and thermal conductivity of pure copper alloy enhanced compared with the copper‐nickel alloy matrix material. The hardness and compression yield stress of both pure copper and copper‐nickel composites have enhancement values and for copper‐nickel base composites hardness and compression yield stress have enhanced with the most positive enhancement values to examined an optimum percentage of reinforcing material.

An investigation of abrasive and erosion behaviour of AA 2618 reinforced with Si3N4, AlN and ZrB2 in situ composites by using optimization techniques

AA 2618 alloy matrix material is mixed with silicon nitride (Si3N4), aluminium nitride (AlN), and zirconium boride (ZrB2) reinforcement particles. AA 2618 composites were prepared by stir casting method by the following various amounts of weight percentage (wt%): about 0, 2, 4, 6 and 8. AA 2618 composites were analyzed by various mechanical properties such as micro-hardness, tensile strength, and compressive strength. The mechanical properties were increased by increasing wt% of reinforcements. The microstructure and worn surfaces’ analysis have been done for the dispersion and bonding structure of the reinforced particles in composites; also, the AA 2618 composites were involved with different characterizations such as abrasive and erosion wear tests at various wt% to find the wear resistance of the composites. The mass loss was considered as the result of wear testing. Before and after worn surface has been analyzed by scanning electron microscope (SEM), the abrasive and erosion wear test results were analyzed by using traditional and nontraditional techniques like Taguchi method, analysis of variance (ANOVA) and genetic algorithm (GA) to obtain the better wear resistance of various wt% of AA 2618 composites and to study the most influencing input and output process parameters by using different optimization techniques.

Mechanical Behavior of Aluminium Matrix Composite Reinforced with Untreated and Treated Waste Fly Ash

Background/Objectives: To fabricate Aluminium Matrix Composites (AMCs) using liquid stir casting technique, in which waste fly ash obtained from thermal power plant is to be applied as reinforced material. Method/Statistical Analysis: In one type, 14.3% (by volume) of the reinforcement material was directly employed as received from the power plant and in the other type, 13.2% (by volume) fly ash was thermally treated and reinforced with the Al-Si alloy matrix material. Results/Findings: The Energy dispersive X-ray analysis (EDAX) analysis and X-ray studies have revealed nearly complete conversion of SiO2 to SiC by thermal reduction in a plasma reactor. Particle sizes obtained were in the range of 2µm-40µm with different shape and aspect ratios. Mechanical properties like hardness, compression strength and tensile properties such as UTS, YS are more for AMC prepared with thermally treated fly ash in comparison to AMC prepared with untreated fly ash and Al-Si alloy. Conclusion/Application: A novel in-situ ternary ceramic mixture composite of Al2 O3 -SiC-C is fabricated by carbothermal reduction of fly ash in a plasma reactor.Keywords: Aluminium Matrix Composite, Mechanical Property, Microstructure, Treated Fly Ash

The fabrication and characterization of Al/SiC-MMC castings produced by vacuum assisted solidmould investment casting process

In this paper, a promising manufacturing approach to cast metal matrix composites is proposed. In order to produce metal matrix composites by investment casting, SiC preforms were fabricated in 3D structure. Afterwards, A6063 aluminium alloy matrix material was infiltrated into preforms which were placed in the solid investment casting moulds with vacuum assistance. Preforms were characterized using Archimedes' test, scanning electron microscope anâ Xray diffraction analysis. Also, fabricated cast speci� mens, were characterized using hardness tests, image analysis and scanning electron microscope observa� tions. The results show that, in the vacuum assisted solidmould investment casting method; infiltration, of the preforms by molten metal was successfully achieved. Moreover, hardness of the composite higher than the matrix up to ratio of 100% by SiC reinforcement and T6 heat treatment.

An investigation into the wear behaviour of TiB2 particle reinforced aluminium composites produced by mechanical alloying

AbstractIn this study, wear behaviour of TiB2 particle reinforced aluminium (Al) composites produced by the mechanical alloying method was investigated. TiB2 ceramic particles of four different volume fractions were mechanically alloyed with Al and A356 alloy matrix materials. The mechanically alloyed particles were cold presses and then sintered at 550°C. After the sintering process, the composites were characterised through hardness measurements, scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Wear tests were also carried out on a pin-on-disc type wear apparatus under 10, 25 and 50 N loads. Wear loss of the composites were found to decrease with increasing hardness which increased with increasing TiB2 particle volume fraction. However, increasing the applied load and sliding distance increased the wear loss. Wear surface examinations showed that various wear mechanisms were effective in wear of the composites.

Compaction of fly ash–aluminum alloy composites and evaluation of their mechanical and acoustic properties

The density and elastic moduli of green compacts can be determined by ultrasonic method with the help of pre-prepared diagrams. In this way, pressing conditions can be taken under control easily. In this study, fly ash particles were used as fillers in an aluminum alloy matrix material. The weight fractions of fly ash in the composites were in the range of 5–30%. The resulting composites were compacted at pressures ranging from 63 MPa to 316 MPa. It was observed that the green density increased with increasing compacting pressure and decreased with increasing weight percent of fly ash particles resulting in lightweight composites. The green compact composites were also tested using an ultrasonic non-destructive evaluation method. Results showed that ultrasonic velocities are a strong function of the density and the fly ash fraction in this material and could be potentially used to predict the density and the fly ash fraction as well as the elastic moduli of the metal matrix composite.

Stratified Sampling Applied to Estimation of the Volumetric Fraction of Alumina in Cast Metal Matrix Composites

Abstract In this paper, we propose a statistic procedure for estimating the amount of alumina incorporated in a particulated metal matrix composite synthesized by the stir casting method. Composite specimens, consisting of A356 Al alloy matrix material containing 5 wt% of alumina particles, were prepared using the compocasting technique. An intermediate traversal section of each composite ingot was stratified into 24 parts and the volumetric fraction of alumina was measured by image analysis at 279 separate points to study the alumina distribution in the material. Alumina particle distribution was observed to have considerable heterogeneity. The stratification technique employed in this study permits an ideal trade-off between the accuracy of the estimated alumina and the required measurement labor.