Ultrasonic Assisted Stir Casting Research Articles

Abrasive wear behavior of AZ31 −B4C composites

Abrasive wear behavior of AZ31 −B4C composites having varying amount of B4C particles (0 −2 wt%) is investigated. AZ31 −B4C composites are synthesized through ultrasonic assisted stir casting method. Characterizations of as-cast composites are performed through optical microscopy and field emission scanning electron microscopy. Compositional analyses are performed using energy dispersive X-ray analysis (EDS). Microstructural analyses disclose uniform distribution of B4C ceramic particles in AZ31 matrix. Compositional analyses confirm incorporation of B4C particles in AZ31 matrix. Both microhardness testing and density measurements are performed. Microhardness value is enhanced by 54.9% compared to base alloy by incorporating 2 wt% of B4C particles. Pin-on-disk tribotester is employed to scrutinize abrasive wear and friction characteristics of developed materials at varying sliding distance (40, 50 and 60 mm track dia.) and different abrasive grits (400, 500 and 600 grit). Wear rate of AZ31 alloy is about 1.3 − 1.5 times more than AZ31 − 2.0B4C composite for all experimental conditions. Wear rate reduces with increase in abrasive grit size while the same increases with increase in sliding distance. Finally, worn surface morphology of developed materials is also analyzed through FESEM and EDAX spectra. Examination of worn surface morphology discloses that abrasion and oxidation are dominant for composite samples.

Mechanical and wear characteristics of (Al7075/SiC/Gr/Zr) hybrid metal matrix composites using ultrasonic assisted stir casting process

Mechanical and wear characteristics of (Al7075/SiC/Gr/Zr) hybrid metal matrix composites using ultrasonic assisted stir casting process

Influence of hybrid reinforcements on the mechanical properties and morphology of AZ91 magnesium alloy composites synthesized by ultrasonic-assisted stir casting

In the present study, AZ91 magnesium alloys reinforced with a fixed weight fraction of aluminium oxide (Al2O3: 1.5 wt%) and titanium di-boride (TiB2: 1, 3, and 5 wt%) particle hybrid metal matrix composites were developed using the stir casting method assisted with ultrasonic agitations. The microstructural analysis reveals that the structure of monolithic alloy is made up of α-Mg grains with evenly distributed β-Mg17Al12 intermetallic secondary phases near the grain boundaries. Incorporating hybrid reinforcements into the matrix alloy decreases the average grain size and also leads to the breakdown of the β-Mg17Al12 phase from a rounded shape to sharp needle-like profiles. The micro-hardness, ultimate tensile strength, and impact strength outcomes revealed a direct correlation with varying TiB2 particulate contents, the peak values of which have been achieved with the addition of 3 wt% of TiB2 particulates with AZ91 + 1.5 wt% Al2O3 hybrid composite.

Development of Al 7075 alloy with nano SiC Composites through ultrasonic assisted stir casting Techniques and Mechanical Testing of Properties

ABSTRACT Al-7075 alloy with nano-SiC composite has superior mechanical properties that can be used in automobile, aerospace and defence sector to manufacture various components and body structures. In the present study, Al-7075 alloy with nano-SiC composite with different wt% of nano-SiC particles has been fabricated by the ultrasonic-assisted stir casting method. Uniform mixing of the nanosized SiC particles in the Al-7075 alloy has been achieved from ultrasonification and as-cast and T6 heat-treated samples were prepared. The diverse mechanical properties such as tensile strength, impact strength and hardness have been examined for the as-cast samples with different wt% of nano-SiC and T6 heat-treated samples.

Optimization of process variables on Electrical Discharge Machining of novel Al7010/B4C/BN hybrid metal matrix nanocomposite

In this paper, determination of optimum EDM input variables like discharge current (DC), pulse on time (Pon), pulse off time (Poff), and gap voltage (GV) on responses like material removal rate (MRR) and surface roughness (SR) using Taguchi technique on the novel Al7010/2%B4C/2%BN hybrid metal matrix nanocomposite (HMMNC) manufactured through ultrasonic assisted stir casting (UASC) route. The various experiments were planned and carried out L16 orthogonal array and regression equations were established by using Analysis of variance (ANOVA) to examine the impact of pulse factors. The outcomes exposed that discharge current greatest effect factor on MRR and SR was found with % contribution of 82.07% and 86.86%. It is also identified that the optimum level conditions of pulse factors for MRR and SR is A4B4C1D1 and A1B1C4D4. The outcomes were further determined by utilizing confirmatory experiment. The machined surface morphology was observed through Scanning electron microscope (SEM).

Effect of TiO2 inoculants on the wear conduct of the aluminium AA 6061/red mud high performance hybrid composite

The current work focuses on the manufacturing of aluminium AA 6061 composites and its tribological characterization. This is achieved by reinforcing the matrix with red mud. However, the uniform dispersion of red mud requires ultrasonic assisted stir casting and the use of optimum wt.% of TiO2 inoculants. In this regard, the composition of red mud is fixed at 2 wt.%, since the addition of red mud beyond 2 wt.% results in the agglomeration, while the wt.% of TiO2 inoculants is varied from 2 wt.% to 6 wt.%. The wear tests are conducted as per the L9- Orthogonal Array (OA) for a load range of 10 N to 30 N, sliding distance of 500 m to 2500 m, disk rotation speed of 200 RPM to 600 RPM. The regression coefficients are more than 0.9 and close to unity and the error between the experimental outcomes and statistical values are within the tolerance band. The SWR and COF is minimized for 2 wt.% of red mud, 4 wt.% of TiO2, beyond which there is a slight increase in the wear of the composites attributed to the agglomeration of the reinforcments in certain localized regions and the presence of voids in other regions.

Empirical Modelling and Multi-Objective Optimisation of Laser Micro Machining on Magnesium Alloy AS21-SiC Metal Matrix Composite

Micromachining techniques are now being used more frequently as a result of miniaturization. This technique has been supported by the requirement for material processing at an affordable cost and microatomic resolution in numerous sectors. Laser micromachining is a precise, non-contact method of machining that is used to create tiny, up to 500 m, components. The small elemental areas are the focus of laser ablation, which helps absorb a high amount of energy. In this micro-machining, metal removal rate and surface finish are represented by the deepness of the groove and the height of the recast layer. While machining, a layer called a recast layer forms on the work piece surface as a result of the tremendous heat generated, and this layer is damaging to the component's surface quality. For accurate applications, the recast layer must be as tiny as possible. As a result, the objective functions are the height of the recast layer and the deepness of the groove. Experiments designed by the DOE are used to generate empirical models. For each experimental run present in the matrix, the specified input parameter combination is set and the work piece is machined accordingly. The response surface methodology based on mathematical modeling and analysis of the machining properties of a pulsed Nd: YAG laser during micro-grooving operation on a work piece of Magnesium Silicon Alloy metal matrix composite is the focus of this research study. Initially, magnesium alloy AS21-SiC metal matrix composites are manufactured with Ultrasonic pro assisted stir casting. For the machined samples, the deepness of the groove and the height of recast layer will be measured by an optical measuring microscope. Consequently, the measured data is used by the GP to develop the mathematical models. In this work, an efficient GA-based genetic algorithm (NSGA-II) is applied to obtain the optimal parameters. As the chosen objectives are conflicting in nature, the problem is formulated as a multi-objective optimization problem.

Experimental investigation on the two body abrasive wear of AA6061-SiC-Gr nano and hybrid nanocomposites

Aluminium based hybrid nanocomposites can be employed in many applications owing to their desirable traits. Depending on the constituents of the hybrid metal matrix composites, they must be tested for their wear performance since there is a high chance that these materials will experience rapid wear. Determining the tribological behaviour of AA6061/ 2 wt. % SiCp nanocomposite and AA6061/2wt. % SiCp/2 wt. % graphite hybrid nanocomposite is the prime objective of this study. With AA6061 as the metal matrix and nano sized silicon carbide, graphite particles as primary and secondary reinforcements respectively, all the composite samples have been fabricated using ultrasonic assisted stir casting. Evaluation of the wear behaviour of the aforementioned materials is done using the two body abrasive wear tests conducted on a pin-on-disc apparatus. Wear coefficients and friction coefficients have been computed and were also analyzed with respect to various parameters. Additionally, wear mechanisms involved were deciphered and subsequently, wear maps have been developed for all the samples. The sample consisting 2 wt. % SiC and 2 wt. % graphite was found to have excellent wear resistance among all. Additionally, coefficient of friction was the lowest for the aforementioned sample itself.

Machinability Study on AA6061/2 SiC / Graphite Hybrid Nanocomposites Fabricated through Ultrasonic Assisted Stir Casting

Aluminium-based hybrid metal matrix nanocomposites (AA-HMNCs) have numerous applications due to their higher strength-to-weight ratio and good mechanical and tribological properties. However, the machinability aspect of these materials must be carefully explored before employing them in various engineering applications. The present study involves the fabrication of AA6061/2 wt.% SiC/x wt.% graphite (x= 1, 2, 3) hybrid nanocomposites and subsequently subjecting them to machinability investigation. All the hybrid nanocomposite samples are fabricated through ultrasonic assisted stir casting technique. The effect of machining parameters and graphite content of the sample on cutting force and surface roughness is discussed based on experimental data. Experiments are performed based on the central composite design of response surface methodology, and the corresponding output responses are recorded. ANOVA analysis revealed that the graphite content has the highest authority over surface roughness and cutting force. High cutting speeds accompanied by low feed and depth of cut have resulted in reduced cutting forces and better surface finish. Chip morphology studies have also subsequently indicated better machinability with increased graphite content.

Influence of SiC/TiB2 Particles Addition on Corrosion Behavior of As-Cast Zn-Al-Cu Alloy Hybrid Composites

In this work, the silicon carbide (SiC) and titanium diboride (TiB2) reinforced as-cast Zn-Al-Cu alloy-based hybrid composites were produced with ultrasonic-assisted stir casting. The corrosion behavior of as-cast Zn-Al-Cu/TiB2/SiC hybrid composites with varying 0, 5, 10, and 15 weight percent of SiC + TiB2 particulates in Zn-Al-Cu matrix alloy was investigated in this study, The effect of additional reinforcements content on the corrosion behavior of hybrid composites with respect to Zn-Al-Cu alloy was investigated. The corrosion rate of hybrid composites was taken by using potentiodynamic polarization equipment (with 3.5 wt.% NaCl solution). The potentiodynamic polarization test findings showed that the hybrid composites’ uniform and localized corrosion resistances were enhanced by the addition of dual reinforcements. As the weight fraction of the SiC/TiB2 reinforcement increases, weak microgalvanic cells that form between the constituent phases of the fabricated as-cast Zn-Al-Cu hybrid composites weaken, improving their resistance to uniform and localized corrosion. The results revealed that the corrosion rate values were reduced to 28.88% at 15% of reinforcement when compared to the base alloy.

Experimental investigation on mechanical behavior of as cast Zn-Al-Cu/SiC/TiB2 hybrid metal matrix composite by ultrasonic assisted stir casting technique

Now a days, the Zn-Al-Cu alloy-based composites have great impact on modern trends for bearing applications because of its reliable mechanical performance. In this paper the mechanical characteristics of as cast Zn-Al-Cu alloy-based hybrid metal matrix composites have been investigated, as well as the influence of reinforcements Silicon Carbide (SiC) and Titanium Diboride (TiB2) on the composite. The ultrasonic assisted stir casting technique has been adopted for fabricating the composites with the addition of dual reinforcements like 5 wt% of SiC as constant and by varying the wt% of TiB2 as 0 wt%, 5 wt% and 10 wt%. The ceramic particles SiC and TiB2 are taken with 20 and 30 microns in size. The ASTM standards were used to conduct the different tests, and the findings demonstrate the significance of adding reinforcements to alloy and also noticeable increase in mechanical performance in terms of hardness, tensile strength, young’s modulus and impact strength. As cast Zn-Al-Cu/5 wt.% of SiC/10 wt.% of TiB2 hybrid composite gives the minimum density as 4.79 g cc−1 and maximum hardness as 156Hv.

Synthesis and characterization of MWCNTs/Al6082 nanocomposites through ultrasonic assisted stir casting technique

The objectives of this work are to investigate the microstructural characterization of multi-walled carbon nanotubes (MWCNTs) produced by chemical vapor deposition method and to prepare Al6082/MWCNT nanocomposites by stir casting method. MWCNTs were developed and then ball milled with aluminum powder to obtain its coating on MWCNTs to improve wettability. Similarly, ultrasonic mixing was used to de-agglomerate the bundled MWCNTs during the stir casting process. MWCNTs were added to molten Al6082 with varying weight percentages (0.3–1.2 wt. %) during the stirring process, and microstructural characterization was performed with field emission scanning electron microscope (FESEM) along with energy dispersive X-ray spectrometer (EDX) for evaluation of elements. EDX analysis of the developed and purified MWCNTs revealed the absence of nickel and other impurities after purification. The Results from the microstructure of nanocomposites indicate that MWCNTs were uniformly distributed for up to 0.9 wt. % of MWCNT and on further increment of MWCNTs, agglomeration was noticed.

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting

Preparation and characterization of AZ63A/Boron Nitride composites using hybrid mechanical and ultrasonic assisted stir casting

Magnesium (Mg) is become progressively used in the transportation business because of its low weight. The poorer mechanical properties of magnesium (Mg) compared to aluminium and steel limit its widespread use. Improved mechanical properties can be achieved through grain refinement in cast alloys. Particle substrates can be added to the liquid melt to serve as nucleation sites for the formation and development of grains, resulting in a finer grain size. Mechanical stirring (MS) with impeller is most common technique for dispersing inoculants into the molten metal. However, it is difficult to achieve uniform dispersion of inoculants using this method. Ultrasonic treatment (UST) has also been investigated as an alternative to MS treatment. Particle inoculants BN were studied to see how they would disperse inside the alloy AZ63A Mg in this study. To create the cast composites, either MS or UST were used. Thermal tensile tests and theoretical models were used to determine the mechanical properties of these materials. The UST-treated specimens outperformed the base alloy and the MS-produced samples in terms of mechanical properties. Inoculant dispersion in sonicated samples was shown to be improved due to the use of finer grains, a thermal development discrepancy between the refiner and matrix, and other factors. Using sonication and grain refinement, researchers were able to make a exclusive relationship between theoretic strengthening mechanism forecast models and the actual outcomes they attained. The mechanical properties of Mg alloy can be improved by utilising cutting-edge new technologies, such as UST, in the production of cast alloys.

Parametric Optimisation of Tribological Characteristics of Novel Al7010/B4C/BN Hybrid Metal Matrix Nanocomposites Using Taguchi Technique

ABSTRACT In this present experimental investigation, Al7010/B4C/BN hybrid metal matrix nanocomposites with equal weight percent of B4C and BN in steps of 0.5 from 0 to 2.5 are prepared using ultrasonic-assisted stir casting technique. Tribological characteristics of the prepared composites at room temperature are evaluated using pin-on-disc apparatus. Taguchi technique is used to study the influence of process variables on tribological behaviour of nanocomposites. The experiments were conducted based on the orthogonal array L18 through Taguchi technique and evaluated for the optimum process variables using Analysis of Variance (ANOVA). The experimental outcomes reported that the wear rate is mostly affected by composition (78.79) followed by applied load (19.68), sliding speed (0.55) and least is sliding distance (0.02). Coefficient of friction is influenced by composition (60.14) followed by sliding speed (29.34), sliding distance (6.47) and applied load (3.38). The confidence interval was predicted for a confidence level of 95%. Finally, the confirmation test is conducted to check the predictive values with the experimental results. The worn surface of the composite resulted from conformation test is studied using Scanning Electron Microscope (SEM).

Optimization of Fretting Wear Parameters and Effect of High Temperature on Fretting Wear Behavior of Al6061 Alloy and Al6061-SiC Composite

Al 6061 alloys are being used in vast industrial applications. The dry sliding wear behavior of SiC based Al6061 composites has been thoroughly explored in recent decade while its fretting wear behavior at high temperatures has not been studied well. In this work, the fretting wear parameters of Al6061 alloy and Al 6061 reinforced with 2 wt% SiC have been optimized and high temperature fretting wear behavior analyzed. Ultrasonic assisted stir casting method has been employed to prepare Al6061-2SiC composite. Integrated Taguchi and TOPSIS methods have been used to optimize the input parameters viz. temperature, material type, applied load, time and frequency of strokes. It is observed that out of temperature, applied load, time and frequency of strokes, temperature proves out to be the most critical parameter affecting the wear behavior of the matrix alloy and its composite the most. Through integrated Taguchi and TOPSIS optimization technique, it is found that the most optimal combination of parameters for minimal wear rate and friction coefficient is Al6061 + 2 wt% SiC composite at 200 N load, 100 °C temperature, 10 min time, and 40 Hz frequency of fretting strokes. The microscopic analysis of the samples revealed that fretting wear operates in partial slip regime in the composite tested at optimum combination of parameters. Wear regime changes from partial slip to mixed fretting with rise in temperature in the composite. In the alloy, the transition from mixed fretting to gross slip regime takes place with the rise in temperature. Al6061 alloy reinforced with 2 wt% SiC at optimum combination of parameters can prove to be a good replacement of conventional materials used in machinery prone to fretting wear.

Influence of the Fly Ash Material Inoculants on the Tensile and Impact Characteristics of the Aluminum AA 5083/7.5SiC Composites.

The choice of suitable inoculants in the grain refinement process and subsequent enhancement of the characteristics of the composites developed is an important materials research topic, having wide scope. In this regard, the present work is aimed at finding the appropriate composition and size of fly ash as inoculants for grain refinement of the aluminum AA 5083 composites. Fly ash particles, which are by products of the combustion process in thermal power plants, contributing to the large-scale pollution and landfills can be effectively utilized as inoculants and interatomic lubricants in the composite matrix–reinforcement subspaces synthesized in the inert atmosphere using ultrasonic assisted stir casting setup. Thus, the work involves the study of the influence of percentage and size of the fly ash dispersions on the tensile and impact strength characteristics of the aluminum AA 5083/7.5SiC composites. The C type of fly ash with the particle size in the series of 40–75 µm, 76–100 µm, and 101–125 µm and weight % in the series of 0.5, 1, 1.5, 2, and 2.5 are selected for the work. The influence of fly ash as distinct material inoculants for the grain refinement has worked out well with the increase in the ultimate tensile strength, yield strength, and impact strength of the composites, with the fly ash as material inoculants up to 2 wt. % beyond which the tensile and impact characteristics decrease due to the micro coring and segregation. This is evident from the microstructural observations for the composite specimens. Moreover, the role of fly ash as material inoculants is distinctly identified with the X-Ray Diffraction (XRD) for the phase and grain growth epitaxy and the Energy Dispersive Spectroscopy (EDS) for analyzing the characteristic X-Rays of the fly ash particles as inoculant agents in the energy spectrum.

Effect of Tribological Properties on Boron Carbide and CNT Reinforced Copper based Composites

The study focuses on the influence and contribution of multi-walled Carbon-Nano tube (MWCNT) and boron carbide (B4C) to the tribological properties of copper matrix composites. The Samples are prepared using ultrasonic assisted stir casting for different weight fractions. The tribological properties like wear and corrosion studies been carried out according to ASTM standards. Wear rate increased with the increase in speed and load for every combination of the composite. However, with CNT being the main reinforcement with addition of CNT wear rate has reduced marginally. Addition of Boron Carbide also to some extent decreased the wear rate but CNT plays a major role in reducing the wear rate. Corrosion studies of the composite materials is carried out by Weight loss corrosion techniques, it is clearly evident from the critical analysis of the results that with the addition of reinforcements to the composite material, the corrosion rate in weight loss corrosion technique decreases drastically with the duration of time, this is due to the formation of a passive oxide layer on the composite specimen.

Influence of nano fly ash on wear behavior of friction stir weld joints of Al6063/nano fly ash composites

The manufacturing industries attracted aluminium metal matrix composites (AMCs) to utilize in the modern spectrum of applications. Inexpensive particulate reinforced composites are exhibiting superior qualities at reduced costs. Fly ash is an industrial waste that can be adopted as reinforcement, particularly for aluminium matrix materials. Friction stir welding (FSW) is best suitable to weld aluminum-based materials. In this work, the Al6063/nano fly ash composites with 0, 1, 2, and 3% wt. of nano fly ash were fabricated through ultrasonic-assisted stir casting. Consequently, FSW joints were obtained for the fabricated composites by considering rotational tool speed and transverse tool speed as welding parameters. Wear analysis carried on weld beads of composites through the pin on disc equipment. The nano fly ash addition in the composites results in increased wear resistance in the FSW joints. Higher wear resistance was achieved with increased reinforcement inclusion. Increased tool feed rate also enhances the wear resistance of FSW joints. It can be concluded that the nano fly ash particles are the most influential in improving the mechanical properties of the AMC weld beads, and FSW is the better option to weld aluminum composites.

End mill studies on Al6061 hybrid composite prepared by ultrasonic-assisted stir casting

To produce the lightweight material for the high payload with excellent strength in particular for defense applications, reinforcements were introduced into the aluminum to form a hybrid composite. SiO2 was extracted through suitable techniques from rice husk ash particles. Through the ultrasonic probe sonication stir-casting process, the standard composition of 3% SiO2 was added along with varying weight percentages (3, 6, 9, and 12) of TiC particles as reinforcement in Al 6061 matrix. The machinability of the fabricated hybrid composite was evaluated through end face milling with varied machining parameters such as spindle speed, feed rate, and depth of cut. The output performance measurable characteristics were temperature and Ra. Thermal energy generated during the machining conditions was studied through the thermal image FLIR camera. From the machining conditions, machining level with SS of 1000, FR of 100, and DOC of 0.2 lead to having the highest temperature of 119 °C. The working temperature for the N2 sample was recorded to be 17% higher with an increase of 3% of TiC. The impact of wt% of reinforcements and governing parameters on tool wear was analyzed by SEM images. The addition of RHA and TiC reinforcements leads to raising cutting zone temperature, tool wear, and Ra. The thermal distortion effect on tool wear, chip morphology, and the surface profile of the samples were discussed and reported.