Stir Casting Research Articles

Effect of Reinforcement on Micro Structural and Compressive Deformation Behavior on Closed Cell AA7075 Aluminium Foam

Effect of Reinforcement on Micro Structural and Compressive Deformation Behavior on Closed Cell AA7075 Aluminium Foam

Strengthened Granite Particles on Al6082 Alloy for Lightweight Structural Applications

Objectives: An experimental effort is undertaken to enhance the mechanical properties of composite reinforced granite particles with Al6082 composition in contrast to previous research for lightweight structural applications. Methods : The stir casting process is used to develop the composite for the test samples. S1 sample contains 99.5 wt.% of Al6082 raw material and 0.5 wt.% of granite particles; S2 sample contains 99.0 wt.% of Al6082 raw material and 1.0 wt.% of granite particles; S3 sample contains 100 wt.% of Al6082 raw material and 0.0 wt.% of granite particles. The elemental content and particle size of granite particles were ascertained by means of SEM and EDS analysis. Findings: Tensile test was carried out for S1 & S2 samples. S1 test sample shown better results as compared to S2 sample. The microhardness of test specimen was measured at various locations for S1, S2 and S3 samples. S3 sample performed better as compared to S1 and S2 samples. Further, this microhardness value increased from S1 sample to S2 sample at two locations and the third location showed an equal value. The microstructure examination was also carried out by Using SEM analysis. The average tensile strength (UTS) of the S1 sample is 91 MPa, while the S2 sample's UTS is 50 MPa. The S1 sample can withstand a high load because of its elemental composition percentage, according to the UTS test. The average results of the microhardness test were 118 HV for the S1 sample, 133 HV for the S2 sample, and 143 HV for the S3 sample. It is suggested that this granite particle-reinforced material can be used as a lightweight structural engineering application based on previous research and this experimental investigation. Novelty: By using the granite particles as reinforced material the mechanical properties of the composite improved as compared to the existing available results with different reinforced materials. Keywords: Granite particles (GP), Al6082 alloy, Stir casting, Ultimate tensile strength, Microhardness, SEM & EDS Analysis

Wear behaviour of aluminium-based hybrid composites processed by equal channel angular pressing

In the present investigation, a systematic experimental wear study at room temperature on Al2618 and reinforced Al2618 in the solutionized state, and after each pass of equal channel angular pressing (ECAP) was taken up to obtain a fundamental understanding of the wear behaviour and generate reference data on wear properties. The authors prepared a hybrid composite using Al2618 with boron carbide (5 wt.%) and graphite (5 wt.%) by the stir casting process. Solution treated cylindrical specimens of Al2618 and reinforced Al2618 were subjected to four passes of ECAP through a 120° die at room temperature using the processing route (BC). From the results point of view, microhardness measurements were carried out at room temperature on the specimens from the solutionized work piece before and after each pass of ECAP. Scanning electron microscope and X-ray diffraction techniques were used to conduct the microstructural studies. After three passes through both routes, the microstructure showed elongated grains with many dislocations; and after four passes, the microstructure depicted nearly equiaxed grains. Sub micrometre sized grains were produced after three passes of ECAP. Moreover, there was a monotonic increase in the hardness values with an increase in the number of passes. Finally, we reported that there was an improvement in the wear resistance of Al2618 and reinforced Al2618 subjected to ECAP process. This scrutiny may accelerate the applications of aluminium alloys in the industrial sector.

Effects of hot extrusion on compressive strength and densification of aluminium-based metal matrix composites

ABSTRACT Metal matrix composites (MMC) made from powder metallurgy (PM) require post-processing to improve the mechanical properties or achieve the final shape. In this experimental study, Aluminium metal matrix composite (Al-MMC) was first fabricated through PM, followed by a hot extrusion process to study the effects of extrusion on compressive strength and density. Hot extrusion of Al-MMC results in microstructure refinement, enhanced dispersion of reinforcement particles and improved mechanical properties. The experimental findings revealed that hot extrusion of Al-MMC resulted in densification, reflected as an average improvement of 5% in the density. An average improvement of up to 22% was observed in the compressive strength of the Al-MMC. Therefore, hot extrusion can be considered an effective post-processing method for enhancing the Al-MMC fabricated through PM. It was also found experimentally that the extrusion ratio also affects the mechanical properties and performance of Al-MMC. It was revealed that the compressive strength is enhanced with an increase in extrusion ratio. It is also important to note that the PM process is one of the processes which offers reasonable control over the utilisation of starting material. Hence, reinforcement retention is higher than other methods like stir casting.

Tribological and Mechanical Properties of Graphene Nano Platelets (GNP)-Reinforced Aluminium 7075 Nano Composites

Background:: The present need for manufacturing industries is the creation of a new class of engineered materials with high specific properties. In this regard, nanocomposite materials have shown promising results compared to monolithic materials. Recent patents also show high mechanical and tribological properties. Objective:: The tribological and mechanical properties of graphene nanoplatelets (GNP)-reinforced aluminium 7075 nanocomposites are reported in this article with the objective of finding optimum properties. Methods:: The nanocomposites were successfully produced with the stir casting technique, a liquid metallurgy route with varying weight percentages of reinforcement composition of 0.5%, 1%, and 2%. Results:: The result showed an improvement in ultimate tensile strength of 69.5% and microhardness of 76.67% in contrast to the base alloy when it was cast. The wear rate was dropped significantly by 43% and 40% in 10N and 20N loading conditions with respect to as-cast conditions. Further, a decrease in the average coefficient of friction was observed from 0.680 to 0.565. Conclusion:: Graphene nanoplatelets came out as excellent reinforcement in the aluminium 7075 alloy, as they showed an impact on improved properties. The decreasing wear rate and coefficient of friction showed their self-lubricating nature. Additionally, X-ray diffraction (XRD) results and optical microstructure were also discussed.

Tribological analysis of titanium alloy (Ti-6Al-4V) hybrid metal matrix composite through the use of Taguchi’s method and machine learning classifiers

The preparation and tribological behavior of the titanium metal matrix (Ti-6Al-4V) composite reinforced with tungsten carbide (WCp) and graphite (Grp) particles were investigated in this study. The stir casting procedure was used to fabricate the titanium metal matrix composites (TMMCs), which had 8 weight percent of WCp and Grp. The tribological studies were designed using Taguchi’s L27 orthogonal array technique and were carried out as wear tests using a pin-on-disc device. According to Taguchi’s analysis and ANOVA, the most significant factors that affect wear rate are load and distance, followed by velocity. The wear process was ascertained by scanning electron microscopy investigation of the worn surfaces of the composite specimens. Pearson’s heatmap and Feature importance (F-test) were plotted for data analysis to study the significance of input parameters on wear. Machine learning classification algorithms such as k-nearest neighbors, support vector machine, and XGBoost algorithms accurately classified the wear rate data, giving an accuracy value of 71.25%, 65%, and 56.25%, respectively.

Investigation of ballistic and mechanical properties of AlNPB metal matrix composites reinforced with TiCN decorated graphene nano flakes for light armored vehicles

In response to evolving military strategies and technology advancements, this study investigates the ballistic and mechanical properties of novel defense grade Aluminium Nickel Phosphorized Bronze (AlNPB) Metal Matrix Composites (MMCs) reinforced with 2, 4, and 6 wt% of Titanium Carbonitride (TiCN) decorated graphene nanoflakes (TG NPs). The TG NPs were synthesized via modified Hummer's method, mechanically milled with TiCN, and integrated into the AlNPB matrix through the stir casting technique. The fabricated MMCs were characterized using XRD, FTIR, and SEM analyses to evaluate the formation of the nanocomposite and MMC. A series of mechanical tests, including tensile, impact, and compression analyses, identified 4 wt% as the optimum filler loading to enhance mechanical strength. The corrosion resistance of the MMCs was studied alongside their morphological analysis. Explicit ballistic tests yielded satisfactory results, bolstering the potential of the fabricated MMCs for use in Light Armored Vehicles (LAVs). This research contributes a valuable MMC candidate for enhancing the performance and durability of LAVs in challenging environments.

EBSD characterization of graphene nano sheet reinforced Sn–Ag solder alloy composites

This research explores the effects of incorporating Graphene Nano Sheets (GNS) on the microstructural characteristics and mechanical behavior of Sn–Ag solder alloys. The research was driven by the need for environmentally friendly, lead-free solder alloys with enhanced mechanical and thermal properties. The methodology involved incorporating graphene into the Sn–Ag alloy through stir casting, followed by a series of surface preparation techniques. The composite samples were then examined using EBSD to analyze crystallographic orientations and SEM/EDS for surface morphology and elemental composition. XRD provided insights into phase transformations and structural changes. Key findings reveal that the addition of GNS significantly refines the grain structure of the Sn–Ag alloy, leading to a bimodal grain size distribution. This refinement is attributed to the role of GNS as a nucleation site during solidification. Moreover, the study demonstrates a pronounced alteration in the texture of the material, with an increase in low-angle grain boundaries post-GNS addition. This texture change is indicative of enhanced mechanical properties. The results also show a shift in the orientation distribution function (ODF), suggesting a stronger crystallographic orientation due to GNS. These findings suggest that GNS incorporation could lead to improved mechanical and thermal properties in Sn–Ag solder, making them suitable for high-performance electronic applications. The study concludes that GNS not only serves as an effective reinforcement in Sn–Ag solder alloys but also significantly alters their microstructural and textural characteristics, contributing to the alloy's potential application in environmentally conscious electronic manufacturing.

Electrical discharge machining process investigation and optimization of parameters for machining of aluminum silicon dioxide (Al7075–SiO2) composite

AbstractThis research paper explores the impact of electrical discharge machining process parameters, including current, pulse‐on time (Ton), and pulse‐off time (Toff), on the material removal rate (MRR) and surface roughness (SR) during the fabrication of aluminum silicon dioxide (Al7075–SiO2) composites. The Al7075–SiO2 composites were produced through stir casting, incorporating 10% by weight of SiO2 reinforcements with an average particle size of 54 µm. To systematically investigate the process parameters' effects, Taguchi's L9 orthogonal array was implemented in the design of experiments. Subsequently, the experimental data underwent analysis of variance (ANOVA) for thorough analysis. The response table for MRR and SR demonstrated that the current significantly influenced both responses (MRR and SR). The ANOVA results provided valuable insights into the percentage contribution of each parameter to the responses. Through the analysis, the optimal control variable settings for achieving the highest MRR were identified as a current of 3 A, a pulse‐on time of 1500 µs, and a pulse‐off time of 1 µs. Conversely, to attain the lowest SR, the ideal control variable settings were determined to be a current of 1 A, a pulse‐on time of 500 µs, and a pulse‐off time of 1 µs. Results also suggest that the error was within admissible range of 5% and the percentage contribution of the current (70.19%) had the largest effect on MRR.

EFFECT OF SUGARCANE BAGASSE ASH ON AA7075 ALLOY-BASED COMPOSITES PREPARED THROUGH STIR CASTING ROUTE

Al7075 is employed as the matrix material and sugarcane bagasse ash (SBA) is a reinforcing material in this work, which is targeted at creating lightweight metal matrix composites (MMCs) at a reasonable cost. Hybridized improved composite castings have been produced and industrial as per ASTM standards with changing wt.% of 0%, 4%, 8%, 12%, and 16% wt.%, correspondingly, after mechanical testing for the evaluation of their strength. It is tested for hardness, tensile, impact, and flexural strength. Composites with hybrid enhanced metal matrix have greater tensile, hardness, and flexural strengths than single-reinforced MMCs. The composite’s tensile and flexural strengths were boosted by a 12[Formula: see text]wt.% increase in bagasse ash, which resulted in maximum values of 96.42% tensile and 23.58% flexural strength, respectively. As the bagasse weight percentage grew over 12%, these values fell, although Bagasse ash AA7075’s impact and ductility improved slightly.

Multi objective optimization of process variables using grey relational analysis for drilling of hybrid composites (LM6/B4C/fly ash)

Aluminium alloys continue to be an effective material for the aviation and automotive sectors in spite of the development of composites and other lightweight materials because of their sophisticated manufacturing techniques, strong durability against fatigue fracture propagation, and excellent impact endurance. As numerous holes are needed for creating rivets, drilling is the most difficult of all the machining operations. The primary problems with drilling these aluminium alloys are represented by a low hole quality, which increases the risk of airframe construction defects and lowers reliability. As a result, parts get discarded throughout the process of assembling, which affects the overall cost of production. To satisfy the needs of machined parts, the selection of Feed rate (F), Spindle Speed (S), Drill Material (D) and percentage of reinforcements (R) as well as drilling equipment, is necessary. The objective of this research work is to study the impact of cutting parameters on surface roughness (SR) and thrust force (TF) during drilling Hybrid MMCs, which were prepared by stir casting. The reinforcements used for fabrication were fly ash and boron carbide. A computer numerical control VMC with a cutting tool dynamometer for measuring TF was used for the experiments. The investigations used the L18 orthogonal array as their base of operation. The multi response optimization considering TF and SR was carried out using grey relational analysis (GRA) and the optimal level of cutting parameters like ‘F’, ‘S’, ‘D’ and ‘R’ were identified to obtain low TF and SR. The optimal machining parameters which give low TF and low SR are at 6 % reinforcement, coated carbide drill, S 3000 rpm and F 50 mm/min. Feed Rate (67.20 %) has the most significance on GRG trailed by S (15.88 %), Drill Material (6.39 %) and reinforcement percentage (3.65 %). Confirmation experiments demonstrated that grey relational analysis precisely optimized the process variables in drilling of hybrid MMCs.

Synthesis and wear characterization of Al7075/molybdenum disulfide/zirconium diboride hybrid composites

AbstractThe manuscript presents the synthesis and dry sliding wear performance of Al7075 alloy‐based composites. Five compositions namely Al7075 alloy, Al7075+3 vol % molybdenum disulfide, Al7075+3 vol % molybdenum disulfide+3 vol % zirconium diboride, Al7075+3 vol % molybdenum disulfide+6 vol % zirconium diboride and Al7075+3 vol % molybdenum disulfide+9 vol % zirconium diboride were stir cast and characterized for hardness, x‐ray diffraction, microstructure, and tribological properties. In‐situ formed zirconium diboride particles increase the hardness of Al7075 alloy whereas molybdenum disulfide shows the opposite trend due to its self‐lubricating nature. X‐ray diffraction analysis identifies subsequent phase particles in the matrix while microstructural images exhibit the dispersion and morphology of reinforcement particles. The wear tests and friction coefficient were analyzed with variations of sliding velocity, normal load, sliding distance, and compositions. Further, the obtained wear results were also correlated with microstructure and wear surface topography. Al7075+3 vol % molybdenum disulfide composite shows the lowest coefficient of friction because of its self‐lubricating nature. Al7075+3 vol % molybdenum disulfide+9 vol % zirconium diboride hybrid composite exhibits the lowest wear rate at high velocity as well as at high load and can be potentially used in manufacturing and tribological applications. Moreover, the use of this material may lead to the minimum requirement of external toxic lubricants that make it cost‐effective and environmentally sustainable.

Evaluating the Effect of Different Percentage Addition of SiC on Mechanical and Wear Properties of Al6061 Composite

AbstractAluminum 6061 alloy using silicon carbide (SiC) particles as a reinforcement is a promising metal matrix composite (MMC) that has gained significant attention in the automotive and aerospace industries. Till now the effect of the addition of SiC particles in Al6061 composite is not studied in depth and also very few studies are reported the on‐wear properties of Al6061‐SiC composite. So, to further enhance the properties of Al6061 alloy and to study in depth this work is carried out. In this study, MMCs are prepared using the stir casting route with varying weight fractions (5–10 wt%) of SiC particles. The properties of composites including tensile strength, compression strength, and wear are evaluated experimentally. The results demonstrated that the incorporation of SiC particles into the Al alloy matrix leads to a notable improvement in mechanical and wear parameters. The tensile and compression strength of the Al composites increases with an increase in the weight percentage addition of SiC particles (from 5% to 7.5%). At 7.5 wt% addition of SiC, it is found that the particles are uniformly distributed throughout the Al6061 alloy matrix. And also shows higher mechanical and wear properties as compared to 5% and 10% addition.

Analysis of wire-cut electric discharge machining behaviour of AA6061 / C / ZrO2 hybrid nano composites using Taguchi’s method

This study focuses on the optimization of wire-cut electric discharge machining (WEDM) process for hybrid metal matrix nanocomposites. AA6061 alloy reinforced with graphene (C) and zirconia (ZrO2) was fabricated through the stir casting method with ultrasonic assistance for three different weight proportions: 92% AA6061 / 3% C / 5% ZrO2, 87% AA6061 / 3% C / 10% ZrO2, and 82% AA6061 / 3% C / 15% ZrO2. Microstructural examination confirmed the uniform distribution of reinforcements in the matrix alloy. The fabricated composite was machined by WEDM using an L27 orthogonal array designed by Taguchi’s method. Four electrical control factors of pulse on-time, pulse off-time, wire feedrate and peak current were considered, along with one reinforcement factor and three output responses: kerf width, surface finish and material removal rate to analyse the machining behaviour. Analysis of Variance was performed to determine the significant parameters. The results revealed that the most significant factor is pulse on-time among the five different factors. Optimized parameters were identified and examined through confirmation experiments resulting in improved machining characteristics.

Synergistic effects of cold rolling and age hardening on the hardness and tensile characteristics of AA6061 hybrid composites

The present study involves the fabrication of aluminium alloy 6061 matrix hybrid composites with varying weight fractions of silica sand and copper particles by employing the conventional stir casting method. The combined influence of age hardening (AH) and low temperature thermomechanical treatment (LTMT) on the hardness and tensile properties of AA6061 hybrid composites was investigated. The uniform dispersion of the particles in the matrix was confirmed by microstructure analysis and the improvement of Brinell hardness values. The composites exhibited higher tensile strength and hardness than the base alloy. Both AH and LTMT enhanced the properties of the hybrid composites and a comparison between them revealed the best results for LTMT hybrid composites. The LTMT hybrid composite with 3 wt% silica sand and 3 wt% copper (3S3C) subjected to 12% rolling deformation and aged at 100 °C had the highest hardness and tensile strength of 144.26 HV and 290 MPa respectively. The hardness and tensile strength of AA6061-3S3C hybrid composite subjected to LTMT in peak aged condition showed an improvement of 125 and 97% respectively when compared with those of AA6061 alloy. Fracture surface analysis of the thermomechanical treated composites in peak aged condition showed a mixed mode of failure dominant with the ductile fracture.

Optimization of cutting force and surface roughness in end milling of AA-TiCp composite

Nowadays Aluminium alloy (AA) based composites are used in many fields such as automotive, aerospace, electronics, and marine industries. But for the utilization of these composites for different applications with different shapes, machining especially end milling is the essential process. Hence, this work describes the optimization of surface roughness and cutting forces during end milling of A356 aluminium alloy reinforced with titanium carbide particle (TiCp) metal matrix composites (MMCs). A356 alloy with 0, 3 and 6 vol% of TiCp (average size of 50 µm) composites were prepared using a stir casting process. The effects of milling process factors, namely cutting speed, feed, depth of cut, and volume % of TiCp, on average surface roughness (Ra) and cutting forces have been studied using a Box-Behnken design of the experiment technique. The end milling experiments were performed in a CNC vertical machining center without any cutting fluid using uncoated cemented carbide inserts. Using Design Ease software, the predictive model analysis and change in performance measurements for process variables were provided. The results showed that the depth of cut, followed by cutting speed, is the most important criterion and finally optimal levels of process variables were also identified to improve the machinability of the composites.

Microstructure and mechanical properties of friction stir welded AZ31 magnesium alloy reinforced with ZrB2

Abstract Metal matrix composites (MMC) have advantages over polymer matrix composites such as high stiffness and strength, high-temperature resistance, better abrasion resistance, creep resistance, resistance to degradation by fluids, dimensional stability, and non-flammability. Metal matrix composites are used for various applications in the automotive, aerospace and sporting goods industries. The primary objectives of the current research work encompass the fabrication of Metal Matrix Composites (MMCs) AZ31 with 0.5%, 1.0% and 1.5% zirconium boride (ZrB2) nano-powder by the stir casting process, followed by welding through Friction Stir Welding (FSW). The metallographic analysis was carried out on the weldments of all cases. The macroscopic and microscopic analysis confirmed the defect-free weld joint. Tensile and hardness tests were conducted to study the mechanical properties of the materials. The tensile strength and the percentage of elongation increased with the percentage of ZrB2. But, after 1.0% addition of nano particles the strength decreased. The same pattern had been observed in both base and welded samples. The defect-free welding joints were fabricated with an efficiency of 79.1%, 79.7% and 77.7% for the materials with 0.5%, 1.0% and 1.5% nano powder, respectively. EIS and PDP tests were conducted in 3.5% NaCl to study the corrosion behaviour of base and welded materials. The corrosion tests on the base MMC samples showed that the corrosion resistance increased after the addition of ZrB2 nanoparticles. In addition, the corrosion resistance of all the welded samples improved compared with their respective base materials.

The mechanical and tribological properties of composites of nanographene and an aluminium-metal matrix were studied, as was their corrosion behaviour, in order to develop materials suitable for use as shielding materials

In this investigation, pitting corrosion methods were used to investigate the corrosion behaviour of nanographene oxide-reinforced aluminium-copper metal matrix composites. S1 (AL 100% + 0% Cu + 0% Nano Graphene), S2 (AL 91% + 7% Cu + 2% Nano Graphene), S3 (AL 82% + 14% Cu + 4% Nano Graphene), and S4 (AL 73% + 21% Cu + 6% Nano Graphene) were the sample compositions. Ultrasonic stir casting was utilised to produce the aluminium-copper-nanographene composites. Nanographene was analysed with BET to determine its surface area, porosity volume, etc. The effects of nanographene oxide weight fraction on the corrosion behaviour of aluminium-copper composites were investigated. The surface texture of the corroded material was evaluated with an atomic force microscope, and the hardness was measured with a Vicker's microhardness tester. The results of the experiment revealed that the corrosion rate decreased as the percentage of nanoparticles in the matrix increased up to S3 composition. The microhardness values increased as the weight fractions of reinforcements in the matrix increased. And additional mechanical tests, such as tensile, wear, and flexural, to ascertain the composites' mechanical behaviour.

Characterization on properties of Al7050/TiC/BN hybrid metal matrix composite

Aluminum alloy and its allied composites are gaining popularity and find their exclusive application in all industries for more than two decades. Due to their increased usage, Al metal matrix composites were experimented by reinforcing them with variety of particles. The current study attempted the use of titanium carbide (TiC) and boron nitride (BN) as reinforcing materials for the Al7050 alloy through the stir casting technique. The percentage of reinforcement of TiC was kept constant as 8% by wt., and the BN was varied as 2% and 3% by wt. Mechanical properties, such as compressive strength, tensile strength, flexural strength, impact energy, microhardness (Vickers), the microstructure were studied using an optical microscope and by corrosion tests using polarization techniques. The results conclude that the Al hybrid composite with 8% TiC and 3% BN provides superior performance.

Effect of Short Heat Treatments on the Microstructural Evolution and Hardness of Thixoformed Graphene Reinforced Aluminium Composites

Aluminium metal matrix composites are increasingly being used in numerous industries due to their lightweight nature and high strength. The incorporation of graphene into aluminium metal matrix composites has garnered significant interest owing to graphene's capacity to enhance numerous properties concurrently. Hence, this study aimed to fabricate a 0.3 wt.% graphene nanoplatelets reinforced A356 alloy (GNP-A356) composite through stir casting followed by thixoforming and short T6 heat treatment processes. It also evaluated the microstructure and mechanical properties of GNP-A356 after the thixoforming process and short T6 heat treatment. The microstructure of alloy and composite was confirmed by optical microstructure, field emission scanning electron microscopy images, and X-ray diffraction. Microstructure investigations demonstrate the impact of the stirring process on the structural transformation of the 𝛼-Al phase from the dendritic into a rosette-like and globular-like structure. The result also indicated that there was a transformation of eutectic silicon from the shape of a needle-like to spheroid structure after a short heat treatment, showing the efficiency of T6 heat treatment with a shorter time of solution treatment and ageing. Moreover, the increase in relative density and addition of reinforcement led to a significant increment in hardness. The result shows the hardness improved by 35.77% and 77.8% for as-cast and heat-treated composites, respectively, compared to A356 alloy.