Step Stir Casting Research Articles

Effect of nanoparticles reinforcement of silicon dioxide derived from prosopis juliflora on Silver-Grey magnesium nanocomposite: utilization of silicon dioxide mechanical and tribological properties

Abstract The automotive and aviation industries require lightweight materials to enhance working efficiency. Composites combine materials such as aluminium, magnesium, titanium, steel, and copper with various forms of reinforcements to offer lightweight alternatives for a range of applications. The present investigation aims to fabricate a Silver-Grey Magnesium (Mg-25%Si) alloy-based nanocomposite with silicon dioxide (SiO2) nano reinforcement at weight % of 0, 3.25, 6.5 and 9.75 utilizing the two step stir casting method. Prosopis juliflora is utilized in the production of different weight percentages of SiO2 nano reinforcements. The microhardness, tensile, wear, and impact tests are performed on the Silver-Grey Magnesium nanocomposites (Mg-25%Si/SiO2) utilizing a computerized tensometer testing machine, a Vicker’s hardness tester, a pin-on-disc tribometer, and an Izod impact, respectively. The x-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), and Energy-dispersive x-ray spectroscopy (EDAX) with elemental mapping microstructure were employed to scrutinize the tensile specimen fracture, EDAX, elemental mapping microstructure, wear, CoF, and worn surface characterization and impact strength analysis. When compared to the Silver-Grey Magnesium (Mg-25%Si) base alloy, the results of the Mg-25%Si/SiO2 nanocomposites demonstrated an increase in SiO2 nano reinforcements that significantly increased microhardness, tensile strength, wear resistance, and impact strength. The corresponding values are 113.36 VHN, yield and ultimate tensile strength of 603.25 MPa and 665.84 MPa, 0.00478 mm3 m−1, CoF of 0.38421 and 400 J m−1.

Fabrication of aluminium metal matrix composites with Al 6063 reinforced with Al<SUB align="right">2O<SUB align="right">3 by two step stir casting method for investigation of mechanical properties

Fabrication of aluminium metal matrix composites with Al 6063 reinforced with Al<SUB align="right">2O<SUB align="right">3 by two step stir casting method for investigation of mechanical properties

Fabrication of aluminium metal matrix composites with Al 6063 reinforced with Al<SUB align="right">2O<SUB align="right">3 by two step stir casting method for investigation of mechanical properties

Fabrication of aluminium metal matrix composites with Al 6063 reinforced with Al<SUB align="right">2O<SUB align="right">3 by two step stir casting method for investigation of mechanical properties

EVALUATION OF MECHANICAL BEHAVIOUR AND EFFECT OF PARTICLE SIZE ON LM26/Gr METAL MATRIX COMPOSITE

In automotive industries, Aluminium cast alloy (LM26) is well-renowned material in the fabrication of pistons for both diesel and petrol engines for its superior casting and mechanical properties. However, diminishing strength at higher temperatures drives metal matrix composites in cast alloys. The present study focused on the impact of naturally available ceramic particles Garnet on the microstructure and mechanical properties of Aluminium cast alloy (LM26). Samples were fabricated with varied Garnet (Wt. % of 3, 6, 9, and 12) by dual step stir casting technique. Two different particle sizes (400µm and 250µm) were incorporated to determine the effect of particle size on composite mechanical behaviour. Scanning electron microscope images unveiled the dissemination of ceramic particles inside the cast alloy matrix. It was found that ultimate tensile strength, yield strength, and impact strength were increased up to a certain Garnet percentage and started diminishing with the rise in particulate fraction for both particle sizes. However, the increase in hardness value indicates the brittleness of Metal matrix composite with the increase in ceramic reinforcement. Validation of Experimental results with theoretical values was also discussed.

Experimental investigations of AA6061/Al2O3/WC/SiC hybrid metal matrix composite fabricated by two step stir casting

ABSTRACT Hybrid metal matrix composites have emerged as an epicentre of material research due to their vast applications and a wide array of reinforcement combinations. In this experiment, two-step stir casting method had been used to fabricate hybrid aluminium 6061 metal matrix composites. The micro-structural and mechanical evaluation (density measurement, impact, tensile, hardness, and flexural) of the fabricated aluminium (AA6061) hybrid metal matrix composite had been performed. The reinforcements used were Al2O3 (3 wt.%), RHA (2 wt.%), WC (2 wt.%), and SiC (5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%). The mechanical properties had been found to improve with increasing wt.% of SiC. The maximum experimental density (2999.2 Kg/m3), impact energy (6 J), tensile strength (130.15 N/mm2), hardness (35 HRA), and flexural load (6720 N) had been obtained with 20 wt.% SiC reinforcement. The presence of reinforcements (Al2O3, RHA, WC, SiC) and their uniform distribution in the Al6061 matrix was confirmed by micro-structural analysis. Other surface morphological information like agglomeration of less soluble alumina and presence of dendrite structures at higher SiC concentration were also revealed. Further, the observations from this investigation have been compared with already existing literature. In conclusion, prospects for future research have also been explored.

Study on microstructure, mechanical and wear behavior of AA7075/hBN composites fabricated via liquid metallurgy

These research works investigate microstructure, mechanical strength and wear characteristics of AA7075/ hBN composites. AA7075/hBN composites are manufactured through two- step stir casting techniques with varying (0–7.5 wt%) hBN particles and subjected to T6 heat treatment. The optical microscopy of the composites shows that the reinforcement particles were distributed finely and with few cluster formations. The results stated that improved hardness on AA7075/5.0 wt% hBN composite as compared to as-cast alloy. The wear behaviour of alloy and composites are analysed on a pin-on-disc tribometer with varying applied loads of (20–60 N), a sliding velocity of 2.0 m/s, and a sliding distance of 3000 m, with EN31 steel as a counterpart. The wear rate and coefficient of friction of the composite reduced as the hBN particle concentration increased. A scanning electron microscope (SEM) is used to analyses the wear process on the worn surface, its reveals abrasion, oxide layer, and delamination as wear mechanisms under varying applied load conditions.

Influence of Microstructure on Tribological Behaviors of Al6061 Metal Matrix Composite Reinforced with Silicon Nitride (Si3N4) and Silicon Carbide (SiC) Micro Particles

Dual step stir casting method was utilized to develop Al6061 composite reinforced with SiC (micron) and Si3N4 (submicron) particles in varying proportion and weight percentage. A homogeneous and uniform distribution of hybrid reinforcement without significant porosity was observed in the microstructure of the composites. X-ray diffraction (XRD) results manifest that Si3N4 and SiC particles are thermodynamically stable during the processing and no unwanted phases were detected. Elemental mapping was also performed for phase identification. With reference to the base alloy significant improvement was noticed in physical and tribological properties of hybrid composites. Maximum rise in hardness was 54.64%. Abrasive wear test results from pin on disc reveals that wear resistance get enhanced for all composition and load is found to be most dominating factor affecting wear behavior.

Evaluation of Wear Behaviour Based on Mechanical Properties and Particle Size in LM26 MMC

Abstract Based on its superior casting and mechanical properties, LM26 is a well-known material in the automobile sector for the manufacturing of pistons for both diesel and gasoline engines. However, cast alloys diminishing the strength at higher temperatures leads to metal matrix composites. The present work deals with fabrication and characterisation of aluminium cast alloy LM26 reinforced with ceramic particles of Almandine Garnet with varying percentages fabricated by dual step stir casting technique The micro hardness and ultimate tensile strength (UTS) were determined and the sliding wear behaviour was estimated using a pin-on-disc apparatus. The effect of particle size and weight fraction of reinforcement on physical and mechanical properties were investigated and collated with unreinforced metal. Wear behaviour of the composite had a reasonably good correlation with composite mechanical properties were also observed. Validation of Experimental results with theoretical values were also discussed.

Effect of beryl and graphene nano platelets reinforcements on the wear behaviour of AL7075- beryl graphene particulate hybrid nano composites

The effect of beryl particles and graphene nano platelets (GNPs) on the wear behaviour of Al7075-beryl-graphene hybrid composites has been studied. The hybrid composites were developed containing Al7075 matrix as matrix materials and 6 weight percentage of beryl and varying 0.5 to 2 weight percentage of graphene by using novel two step stir casting technique and wear behaviour of the newly developed hybrid composites were studied. The dry sliding wear studies conducted using a pin-on-disc tribo-tester under atmospheric conditions revealed that the wear loss of Al7075-beryl-graphene hybrid composites are lower than that of the matrix Al7075 alloy and further with increasing weight percentage of graphene decreased the wear loss of the hybrid composites. The wear studies also showed that the increase in load, sliding speed and sliding distance, the wear loss of the composites increased. The microstructure of the worn out surface revealed that a huge amount of plastic deformation appeared on the unreinforced Al7075 alloy when compared to the reinforced hybrid composites. The incorporation of beryl and graphene into Al7075 showed worn out surface that is not smooth and grooves, scratches and parallel lines were observed. The addition of beryl and GNPs into the matrix reduces erosion and small grooves like structure were noticed in the hybrid composites which leads to a reduction in wear in Al7075-beryl-GNPs hybrid composites

The investigation of the effect of nano particles on dry sliding wear and corrosion behavior of Al-Mg/Al2O3 composites

Aluminum matrix composites were extensively used as structural material as it possesses good surface properties such as wear and corrosion resistance. The practical importance of nano particles in composite materials has triggered widespread attention towards the enhancement of its properties. In this study, Al-Mg/Al2O3 (0–8 wt%) metal matrix nano composites fabricated by two step stir casting route was investigated to comprehend its wear and corrosion behaviour. The Pin-on-Disc dry sliding wear test was performed on Al-Mg/Al2O3 (0–8 wt%) by adopting Design of Experiments under the action of different contact loads and sliding distance following the ASTM G99 Standard. The experimental results conveyed that specific wear rate decreases with increase in sliding distance. Statistical analysis was performed by Taguchi’s Technique and Analysis of Variance (ANOVA) to determine the most dominating factor that influences specific wear rate for the optimum weight percentage of reinforcement. Analysis revealed adequacy with the constructed model in predicting the wear behavior of composite and unreinforced Al-Mg alloy. The corrosion behaviour of the base alloy and composites was analysed by static immersion and electrochemical assessments, by immersing prepared specimens in aqueous sodium chloride (3.5%) solution. The dependance of corrosion rate of the composites with the weight percentage of Al2O3, exposure duration and temperature of the corrosive medium was studied in detail. Corrosion test results exhibit that corrosion rate decreases with increase in weight percentage of Al2O3 particles and exposure duration, whereas it follows reverse trend with increase in corrosion medium temperature.

Influence of Heat Treatment on Stress Intensity Factor of Nano Boron Carbide Hybrid Al2219 Composites with MoS2

The current work emphasizes on study of influence of heat treatment on Stress Intensity factor (KIC) of Al alloy matrix hybrid composites. Hybrid composites with a constant Nano B4C content of 3 weight % and MoS2 of 4 weight % as reinforcements to Al2219 alloy matrix are fabricated by using two step stir casting technique and tested for Stress Intensity factor and fracture toughness as per ASTM standards. One set of composites are subjected to T6 type heat treatment. Compact Tension (CT) Specimen were prepared using wire EDM process and tested in BISS Axial Universal Testing Machine to find Stress Intensity factor (KIC). From this study stability of crack propagation under mode-I failure is analyzed. Results show generous increment in energy required to open the crack and crack propagation is delayed in heat treated composites when compared to non-heat treated composites and furthermore improvement in fracture toughness of the heat treated specimen over non-heat treated specimen.

INVESTIGATION OF DRY SLIDING WEAR BEHAVIOR OF AL 7075–(SiC/TiC) HYBRID METAL MATRIX COMPOSITES

The main objective of present work focuses to investigate the tribological behavior of Al 7075 hybrid metal matrix composite. Al 7075 metal matrix composites has many potential applications especially in automotive and aerospace industries, due to their light weight to strength ratio and high wear resistance. The composite is fabricated using two step stir casting process by varying 5% to 15% volume fractions of Silicon Carbide and Titanium Carbide. Optical microstructure showed reinforcement distribution into Al 7075 matrix. The wear and frictional properties of the hybrid metal matrix composites was studied by performing dry sliding wear test using a pin-on-disc wear tester. Tribological behaviors were examined by applying different normal loads of 10[Formula: see text]N, 20[Formula: see text]N, 30[Formula: see text]N with different sliding velocities (1[Formula: see text]m/s, 2[Formula: see text]m/s, 3[Formula: see text]m/s) at room temperature without lubrication. Wear rate and coefficient of friction for different normal load and sliding velocities were plotted and studied. The micro hardness value of AST15 was higher by 18.8% than the AST0 Composites. The wear rate prediction indicated the wear rate for AST15 as [Formula: see text][Formula: see text]mm3/m as compared to AST0 which was [Formula: see text][Formula: see text]mm3/m. The wear rate increases with the increase in load and sliding velocities. Scanning electron microscopy micrographs of the worn surface are used to predict the nature of the wear mechanism.

Investigación sobre las propiedades mecánicas y de corrosión del compuesto de matriz metálica Al 7075/Redmud.

En el presente trabajo se realiza una investigación sobre las propiedades mecánicas y el comportamiento frente a corrosión del compuesto de matriz metálica Al 7075. El cual se preparó a partir de Al 7075 como matriz y lodo rojo como refuerzo, mediante el uso de un proceso de fundición por agitación en dos pasos. El porcentaje en volumen de refuerzo varía de 0% a 15%. La densidad del material compuesto se calculó mediante el principio de Arquímedes, mayor que la matriz básica. La distribución uniforme del refuerzo y la matriz en el material compuesto se estudió utilizando micrografías ópticas, y la microdureza del material se determinó utilizando una máquina de ensayo de dureza Vickers. La microdureza del compuesto aumentó, mientras que el refuerzo pasó del 0% al 15%. La resistencia a la tracción del material compuesto se elevó al 5% de la tolerancia de refuerzo (326 MPa), que es más alta que la matriz base. Los compuestos de matriz metálica Al 7075 presentan una velocidad de corrosión más baja en una solución de NaCl al 3,5% que la matriz base. A medida que aumenta el porcentaje en volumen en el lodo rojo, se reduce la velocidad de corrosión de los compuestos.

Machinability Analysis and ANFIS modelling on Advanced Machining of Hybrid Metal Matrix Composites for Aerospace Applications

ABSTRACTWire Electrical Discharge Machining (WEDM) is a competent method employed for machining intricate shapes in electrically conductive harder materials. Metal Matrix Composites (MMCs) possesses improved properties and considered as an alternate material for various engineering applications. An enduring issue with MMCs is that they are problematic for machining, because of abrasive nature of hard reinforcing phase. This current exploration is dealing the WEDM machinability analysis of LM6/SiC/Dunite Hybrid Metal Matrix Composites (HMMC) fabricated by two step stir casting process and to develop an artificial intelligence decision making model for WEDM the process parameters. The influence of input machining process variables namely Pulse ON, Pulse OFF, Flushing Pressure, Wire Feed and Servo Voltage against the desired output like Material Removal Rate (MRR), Surface finish, overcut, circularity error and perpendicularity error are investigated. Grey Relational Analysis (GRA) method is employed and grey relational coefficient values are given as input values for evolving the Adaptive Neuro Fuzzy Inference System (ANFIS) to predict the desired performance characteristic. A comparative study has been accomplished for validating the outcomes attained from evolved models and experimentation outcomes. The performance analysis of developed model proves that the developed model and this method are efficacious for predicting the desired performance measures.

Dry sliding and abrasive wear behaviour of Al-7075 reinforced with alumina and boron nitride particulates

Abstract Present research examination focuses on the surface morphology; mechanical properties and wear conduct of Al-7075 metal matrix composites reinforced with alumina and hexagonal boron nitride fillers. Particulate reinforced Al-7075 metal matrix composites were manufactured following the two step stir casting method with differing the weight percentage (2.5 and 5) of reinforcement. Uniform dispersion of alumina and hexagonal boron nitride in pure alloy was verified by optical microstructure. The fabricated samples were subjected to abrasion using dry sand rubber wheel abrasive wear test rig by varying the abrading distance and the applied normal load. Silica sand of particle size 350–400 µm was used as abrasive medium. Mechanical and dry sliding wear test results indicated that both alumina and hexagonal boron nitride fillers show improved mechanical properties and wear resistance. From the abrasive wear test results, it was recognized that the wear resistance of composites is increased by increasing the weight percentage of reinforcements and the reinforced composite gave better resistance against abrasion than the control sample (Al-7075). Further, it was adjudicated that 5 wt% micro hexagonal boron nitride reinforced Al-7075 composite prompts predominant abrasion resistance. Finally, it was presumed that hexagonal boron nitride and alumina fillers gracefully and successfully improved morphological, mechanical, and also the wear properties of Al-7075 alloy for various engineered load-bearing applications.

AWJM parametric investigation on hybrid composite produced through two step stir casting process

Abrasive Water Jet Machining (AWJM) is well known non-traditional machining process employed to machine difficult to cut materials with complex contours. The proposed research work deals with the machinability investigation of AA-2024-B4C-TiC hybrid composite through AWJM process. The machining characteristics as output responses for the analysis are Surface Roughness (SR), Material Removal Rate (MRR) and Kerf angle (KA). The effect of individual process parameters are water Jet Pressure (JP), Standoff Distance (SOD) and Traverse Speed (TS), these parameters holds higher degree of influence over output responses. The influence analysis shows the notable increment in the metal removal process with the increased SOD, TS and water pressure. Moreover, the optimal combination of process parameters and their contribution are determined through Grey Relational Analysis (GRA). The optimum parameters obtained from GRA are water jet pressure of 260 bar, stand-off distance at 1 mm and traverse speed of 20 mm min−1. Moreover, the most significant factor on affecting the responses were water jet pressure (82.17%) followed by the transverse speed (13.84%)

Synthesis and Mechanical Characterization of Micro B4C Particulates Reinforced AA2124 alloy Composites

In the current era of aerospace, automobile and other various industries, light weighed aluminium metal matrix composites plays a very major role. Metal matrix composites are composed of base material as metallic which is reinforced with ceramic particulate as reinforcement material. This paper consists of the preparation of micro composites by two step stir casting process by the addition of B4C particulates (80-90µm) into the AA2124 matrix by varying different weight percentages of 3% and 6% at a temperature of 730-750˚C. Further once the composites are prepared are subjected to characterization, the SEM revealed that there is good uniform distribution of micro particles in the aluminum by exhibiting a good bonding with matrix and EDS confirmed the presence of B and C elements. Different properties were evaluated like density, hardness, ultimate tensile strength and yield strength which revealed that there is an increase in the mechanical properties than compared to the base metal.

Dry-Sliding Wear Analysis of SiC Reinforced AA6063 As-Cast Aluminum Metal Matrix Composites

The pin-on-disc dry sliding wear analysis and metallurgical characterization of as-cast aluminum alloy AA6063 silicon carbide particulate (SiCp) composites of 400 mesh size (37µm), using magnesium metal powder as wetting agent produced by two step stir casting technique has been investigated and discussed here. The composition of reinforcement was being varied by varying the weight fraction of silicon carbide particles (0%, 3.5%, 7% and 10.5%). The dry slippery wear behavior at room temperature has been studied through wear rate analysis over a weight range of 20N-40N along a total sliding distance of 1570m at a constant speed of 500rpm.The results revealed that the wear in micrometer decreases and also there is decrement in wear rate with the increase in wt. % SiC, while the wear in µm and wear rate has increased with the increase in the value of load in N. The vicker’s microhardness values at a load of 0.05kgf have shown a sharp increase in the hardness values of the matrix composites

Mechanical Behaviour and Morphology of A356/SiC Nanocomposites Using Stir Casting

In this research an attempt has been made to explore the experimental investigation of A356/SiC nanocomposites using two step stir casting process. A356 alloy ingot was selected for the matrix and the reinforcement (aluminium fine powder (99.9%) plus nano size SiC mechanically forged by using ball mill at 100 rpm for duration of 10 hours). Ball milling process enhances the wettability of the particles. Reinforcement was varied from 1% to 5% with a step of 1% by weight. The stirring process was carried out at 500±50 rpm with stirring duration 10 minutes in two steps. The melt composites were poured at 680±20° C into the die to fabricate the composites. In this process of fabrication, less oxides/segregations were depicted. Tensile strengths of fabricated composites were evaluated by using UTM and toughness was calculated from area under stress-strain curve. To identify the involvement and presence of the nanoreinforcement into the matrix alloy (A356), fractured surfaces of the fabricated nanocomposites were examined using SEM and EDX. Tensile test results have shown the fracture mechanism and enhanced mechanical properties with the addition of forged nanoreinforcements. Yield tensile strength (YTS) and ultimate tensile strength (UTS) of A356 parent alloy found as 212.76 MPa and 219.90 MPa respectively. The improvement of 41% in YTS and 45% in UTS in case of A356/SiC nanocomposites were investigated. Decrease in % elongation and toughness with increase in forged nanoreinforcement were predicted. Proper distribution of reinforcement was attributed by SEM micrographs. EDX spectrum disclosed the presence of the constituents in the parent alloy (A356) and stir cast nanocomposites.

Degradation of Hybrid Metal Matrix Composites Reinforced with Boron Carbide and Graphite Particles due to Pit Corrosion

In the present study, the corrosion behaviour of the Al2219, Boron carbide and Graphite has been investigated. The Aluminium Metal Matrix Hybrid Composites were fabricated by two step stir casting technique. Corrosion tests were carried out with the natural sea water (3.5 wt % NaCl) according to standard procedure. The tests were conducted at room temperature by cyclic polarization technique for a definite time interval. After the test, material loss was calculated by weight loss method. The surface morphology of the specimen before and after corrosion was studied using the optical microscope images. The test result reviles that, the corrosion rate of the composite was greater than the base alloy, but the corrosion of the hybrid composite is the most compared to the alloy and monolithic composite.