Stir Casting Route Research Articles

Optimization of stir casting process parameter on copper aluminium composite

Stir casting technique is playing an essential role in synthesize of metal matrix composites with different compositions. In present investigation, the titanium carbide based copper aluminium 5052 composite is fabricated through stir casting route. The methodology of the work is to optimize the stir casting process parameters and surface analysis on copper aluminium composite. The various control factors were used to evaluate the tensile strength of the composite such as stirrer speed, time and furnace temperature. The compositions of alloying elements were validated through Energy Dispersive X-Ray Analysis (EDAX). The synthesized copper aluminium composite has hardness of 240HV and density of 7.82 g/cc. The casting surface was analyzed by scanning force microscopy (SFM). Taguchi optimization was used to found the desirable factor of stir casting process factors. The variance analysis was used to found the effect and contribution of different factors. The optimal tensile strength was validated at 700 °C of furnace temperature, 800 rpm of stirrer speed and 15 min of stirrer time. The average roughness of the surface is 57.75 nm.

Central composite design and optimization of selected stir casting parameters on flexural strength and fracture toughness mTiO2p/Al 7075 composites

Ceramic particulate like titanium dioxide play major role in enhancement of properties of aluminium composites for high strength-low weight applications. The major process used in the dispersion of the particles in the melt is the stir casting route. There is need for incremental studies on the modelling and optimization of the procedure. This study reports the influence of stirring temperature, speed, and time on the flexural strength and fracture toughness of Al 7075 reinforced with 10 wt% micro titanium dioxide of average size 13 µm, produced via stir casting. Central composite design (CCD) was employed in the design of experiment and specimen were produced according to the experimental runs. The result of the analysis of variance (ANOVA) showed that the parameters contributed significantly to the responses and satisfactory models were obtained for the properties under investigation. The interaction between the parameters revealed that increasing speed and time ensued improvement in the properties. An uptrend in temperature was observed to enhance the flexural strength but reduce fracture toughness. Response surface optimization revealed combined parameters for optimal performance as 643.4 ˚C, 423 rpm, and 30 mins for temperature, speed and time respectively yielding 470.4 MPa and 34.7 MPa.m1/2 for flexural strength and fracture toughness in that order. Model validation experiment was carried out using the combined parameters and deviation of −0.024 and + 0.014 were obtained for the flexural strength and fracture toughness respectivelyectively. Since the values were less than 0.05, the models were concluded to be statistically fit for resposne prediction.

Nano reinforcement technique as a tool for enhancement the mechanical and fatigue properties

Abstract For the past three decades, AA7075 based metal matrix composite materials showed more attraction due to their enhanced mechanical and fatigue properties. The mechanical and fatigue behaviour of nano composites needs more investigation for their applications. In the present study, stir casting route based AA7075 reinforced with nano – sized, Al2O3 particles (average size 35 nm). The evaluation of mechanical and fatigue properties in the nano cast composites and matrix were carried out at room temperature (RT). The composites and base metalwere subjected to high and low cycle fatigue. Scanning Electron Microscope was used to estimate fatigue behaviour of nano composites samples. The mechanical and fatigue properties was enhanced by the nano Al2O3, when compared to the matrix. The microsite evaluation showed uniform distribution of Al2O3 particles into the matrix and few porosity was recorded. The improvement of the properties above is attributed to the grain refinement and to the distribution of the Al2O3.

Study on fabrication and mechanical characterization of aluminium hybrid nanocomposites

This work focussed on fabrication and mechanical characterization of AA8011 alloy based hybrid nanocomposites prepared via stir casting route. The effect of relative fractions of Al2O3 and B4C nanoparticles of average particles size of < 50 nm and < 60 nm respectively in three blends of the composites viz., AA8011 + 1.0 wt% Al2O3 + 2.0 wt% B4C (Hybrid-a), AA8011 + 1.5 wt% Al2O3 + 1.5 wt% B4C (Hybrid-b) and AA8011 + 2.0 wt% Al2O3 + 1.0 wt% B4C (Hybrid-c) on crystallite size, microstructure, microhardness, impact and tensile properties is investigated. The remarkable decrease in crystallite size observed in Hybrid-c in comparison to other two composite blends after XRD analysis. The significant improvement in hardness and tensile strength exhibited by the hybrid nanocomposites over the AA8011 alloy matrix, maximum of these values were possessed by Hybrid-c in this study. After the notch impact tests by Charpy and Izod, the Hybrid-c with AA8011 + 2.0 wt% Al2O3 + 1.0 wt% B4C blend exhibited higher values but not shown much difference in comparison to Hybrid-b and Hybrid-a. From this work it come to know that the synthesized hybrid nanocomposites have shown excellent mechanical properties for the case of structural applications seeking high performance.

Microstructure and mechanical behavior of Al6061/Ni/Cr hybrid nano metal matrix composites with addition of graphene and magnesium

The present work emphasizes the micro structural and mechanical behavior of Al6061 hybrid nano-metal matrix composite (HNMMCs) reinforced with variable wt% (0, 0.6, and 1.2) of nickel and chromium nanoparticles with a fixed amount of 0.6 wt% of graphene and 0.5 wt% Magnesium oxide nano particles. The advanced stir-casting route fabricates the HNMMCs. Tensile and micro hardness tests as per ASTM standards were conducted to analyze the mechanical behavior of samples of advanced composites. The micro structural behavior of advanced composites was investigated by the field emission scanning electron microscope (FESEM). The SEM micrographs and energy dispersive spectroscopy (EDS) mapping analyses confirmed the uniform distribution and presence of reinforced particles within the Al6061 matrix. The study of this work revealed significant improvement in tensile strength and microhardness of developed composite with respect to Al6061.

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.

EVALUATION OF MATERIAL REMOVAL RATE AND SURFACE ROUGHNESS IN WIRE ELECTRO-DISCHARGE MACHINING OF 10-WT.% ZrO2-REINFORCED AL ALLOY COMPOSITE

In this study, we optimize the wire electro-discharge machining (WEDM) parameters in zirconia ([Formula: see text] ceramic particulates-filled Al7075 alloy composite by using the Taguchi-combined Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method. The Al7075 alloy composite was synthesized via the stir casting route by the addition of 10[Formula: see text]wt.% of ZrO2 particulates. Scanning electron microscopy (SEM) was used to analyze the microstructure of fabricated composite. Experimental work was executed as per the [Formula: see text]([Formula: see text] orthogonal array design by considering three input machining parameters like pulse current ([Formula: see text], pulse on-time ([Formula: see text] and pulse off-time ([Formula: see text], respectively. The material removal rate (MRR) and surface roughness (SR) were chosen as the output responses for machining of the developed composite. The signal-to-noise (S/N) ratio was employed to determine the optimum levels of machining parameters for the output responses. Moreover, analysis of variance (ANOVA) was used to find the significant contribution of parameters. The main effect plot explored that [Formula: see text] of 25 A, [Formula: see text] of 115[Formula: see text][Formula: see text]s and [Formula: see text] of 60[Formula: see text][Formula: see text]s were identified as the optimum levels of machining parameters which provide the maximum MRR (0.36757[Formula: see text]g/min) and minimum SR (3.826[Formula: see text][Formula: see text]m) for the proposed composite during the WEDM process. ANOVA results revealed that [Formula: see text] was the most dominant factor regarding MRR and SR followed by [Formula: see text] with contributions of 74.05% and 14.48%, respectively.

Study on Dry Sliding Wear and Friction Behaviour of Al7068/Si3N4/BN Hybrid Composites.

Hybrid aluminium metal matrix composites have the potential to replace single reinforced aluminium metal matrix composites due to improved properties. Moreover, tribological performance is critical for these composites, as they have extensive application areas, such as the automotive, aerospace, marine and defence industries. The present work aims to establish the tribological characteristics of Al7068/Si3N4/BN hybrid metal matrix composites prepared by stir casting route and studied using a pin-on-disc apparatus under dry sliding conditions. The hybrid composite samples were prepared at various weight percentages (0, 5, 10) of Si3N4 and BN particles. To investigate the tribological performance of the prepared composites, the wear experiments were conducted by varying the load (20, 40 and 60 N), sliding velocity (1.5, 2.5 and 3.5 m/s) and sliding distance (500, 1000 and 1500 m). Wear experimental runs were carried out based on the plan of experiments proposed by Taguchi. The minimum wear rate was found with the composite material reinforced with 10 wt. % of Si3N4 and 5 wt. % of BN. Analysis of Variance (ANOVA) was employed to analyse the effect of process parameters on wear rate and coefficient of friction (COF). The ANOVA test revealed that the weight fraction of Si3N4 has more of a contribution percentage (36.60%) on wear rate, and load has more of a contribution percentage (29.73%) on COF. The worn-out surface of the wear test specimens was studied using its corresponding SEM micrograph and correlated with the dry sliding wear experiment results.

A Contemporary Review of Aluminium MMC Developed through Stir-Casting Route.

The growing demand for composite materials with improved properties is attracting a lot of attention from industries such as automotive, aerospace, military, aviation, and other manufacturing. Aluminium metal matrix composites (AMMCs), with various reinforcements such as continuous/discontinuous fibers, whiskers, and particulates, have captured the attention due to their superior tribological, mechanical, and microstructural characteristics as compared to bare Al alloy. AMMCs have undergone extensive research and development with different reinforcements in order to obtain the materials with the desired characteristics. In this paper, we present a review on AMMCs produced through stir casting routes. This review focuses on the following aspects: (i) different reinforcing materials in AMMCs; (ii) microstructural study of reinforced metal matrix composites (MMCs) through stir casting. Both reinforcing micro- and nanoparticles are focused. Micro- and nanoreinforced AMMCs have the attractive properties of combination such asthe low-weight-to-high-strength rati and, low density; (iii) various tribological and mechanical properties with the consideration of different input parameters; (iv) outlook and perspective.

An overview on the synthesis of aluminium matrix composites using stir casting technique

Aluminum alloys are popular materials in industrial applications because of their higher specific strength to weight ratio and excellent mechanical properties. Various ceramics are added as reinforcement to improve mechanical characterizations of pure aluminum alloys and the newly synthesized material is recognized by aluminum matrix composites. Aluminum alloys have been used as matrix materials and materials such as aluminum oxide, magnesium oxide, boron carbide, silicon carbide, graphite, and fly-ash, and many more ceramics used as particulate reinforcements. The stir casting route is the most suitable, and ease of handling and economical methodology to develop the composites. In this review article, the influence of particle embedment and the predominant factors attributed to mechanical stirring during the processing of aluminum matrix composites are explored. Furthermore, the recent development and various parameters and related constraints that are also considered for improving the performance of aluminum matrix composites to be achieved in the future are also to be detailed in this study.

A study on microstructure and mechanical behaviour of AA6063 metal matrix composite reinforced with areca sheath ash (ASA) and rice husk ash (RHA)

Now a day’s composite materials can also prepared with the addition of agricultural by products ash as a reinforcement which gives an effective result. The Rice Husk Ash (RHA) and Areca Sheath Ash (ASA) ranged from 0% to 8 % increased by 2% with the molten aluminium alloy individually using stir cast route hence evaluate performance of reinforcement. Microstructural characterization and mechanical properties have been used to evaluate the performance of the composites. SEM and EDS analyses were analysed for microstructure characterizations of composites. In this paper Hardness, Tensile strength, Compression strength properties were investigated. Results obtained from experiments that the hardness, compression strength and tensile strength of the composites increased with an increase in the weight percentage of Rice husk ash (RHA) and Areca sheath ash (ASA).From the results Areca sheath ash can also used as a alternative reinforcement which leads to increase properties of composites.

Mechanical characterization and fractography of 100 micron sized silicon carbide particles reinforced Al6061 alloy composites

In the current exploration, the impact of the 100 to 125 micron size addition of silicon carbide (SiC) on the mechanical performance of Al6061 alloy has been studied. The Al6061 alloy dispersed with 6, 9, and 12 wt.% of SiC particles were synthesized by a two-step stir cast route. Two-step addition of the preheated particles into the melt helps avoid the agglomeration of the particles, which further contributes to enhancing the properties of composites. The orchestrated composites were exposed to microstructural examines and mechanical properties evaluation. Microstructural portrayals of acquired examples were completed by SEM microscopy, EDS, and XRD patterns. The event of SiC particles were affirmed by the XRD patterns. The density of the Al6061-SiC composites was increased with the addition of high-density silicon carbide particles. The hardness, ultimate, and yield qualities of metal composites have been improved with the increase in the content of SiC support. The ductility of SiC reinforced composites decreased with hard ceramic particles' incorporation in the Al matrix alloy. Various fracture mechanisms were observed in the Al6061-SiC composites using SEM.

Mechanical and tribological behavior of Al composites containing varying beryllium aluminum silicate and constant CeO2

The main aim of the present work is to see the performance of “Al–Beryl” composites processed via stir casting route with or without CeO2 on their mechanical, wear and corrosive properties for structural applications in heavy machinery and watercrafts. Hardness and ultimate tensile strength increased with 36% and 43%, respectively, with 9% Beryl addition. Further, effect of addition of constant 0.5 wt.% CeO2 in “Al–Beryl” composite was evaluated and remarkably improvement in corrosion resistance was observed. Tribological performance of the composites was investigated by conducting sliding wear tests against steel at different loads in dry and wet conditions. Characteristic features of adhesion, fracture and delamination were observed in SEM micrograph of the worn composite having low beryl content slid in air whereas abrasive wear predominates in water or oil. Addition of increased wt.% of beryl particles led in reduced wear of the composite at all loads. Increase in corrosion resistance by 45% decrease in weight loss with 0.5% CeO2 addition was observed. “Al6061–9% Beryl–0.5% CeO2” composite with high hardness, wear and corrosion resistance is found most promising for structural applications.Article HighlightsAn increase of 36% in hardness and 43% in ultimate tensile strength was found in Al composites with 9% Beryl addition;Coefficient of friction was found least for “Beryl–CeO2” added composites in wet sliding conditions;A transition in wear mechanism occurred with adhesion, fracture and delamination of the worn composite with low beryl content slid in air;Corrosion resistance increased by 45% with 0.5% CeO2 addition in Al composites.

Fabrication and Modelling of Tribological Performance of Al-Si/12Al2O3/2MoS2 Composite using Taguchi Technique

This paper investigates the effect of mechanical, microstructural and dry sliding wear behaviour of Al-Si/2wt%MoS2, Al-Si/12wt%Al2O3, and Al-Si/12wt% Al2O3/2wt%MoS2 composites that prepared using the stir-casting route. To avoid friction and wear at the interfaces of materials, an attempt has been made by adding solid lubricant MoS2 to build such a self-lubricating composite with Al-matrix. The tribological analysis has been described based on the Taguchi orthogonal array (L27). Three variables combination such as sliding velocity, sliding distance and contact pressure are used for this study to determine the tribological responses, i.e. wear rate and coefficient of friction. The properties of composites were improved by increasing the weight % of MoS2 and Al2O3. The tensile strength of Al-Si/2MoS2, Al-Si/12Al2O3, and Al-Si/12 Al2O3/2MoS2 composites is 6.02%, 12.46%, and 2.44% compared to the base matrix. The addition of MoS2 helps the hybrid composite to attain better tribological properties with a slightly lower specific strength. Analysis of variance showed that the composites such as Al-Si/2 MoS2 and Al-Si/12Al2O3/2MoS2 were strongly influenced by the pressure in wear rate. Similarly, sliding velocity affects the coefficient of friction for Al-Si/2MoS2. Wear tracks formed during the dry slide process were analysed using optical and SEM with an EDS. It was discovered that pressure plays a vital effect in the wear mechanism. The hybrid composite (Al-Si/12 Al2O3/2MoS2) material can be utilised in place of conventional materials in tribological demanding automotive applications

Tribological Analysis and Characterization of Zinc Rich Al/Si3N4 Composites Fabricated Via Ultrasonic Assisted Stir Casting Technique

ABSTRACT In the present word, there is a need to minimise the fuel consumption because of the limited resources to beat this demand of aluminium metal matrix composite tremendously performing in the automobile sector, aircraft and various industry. In the present research, an attempt has been made to develop a composite using silicon nitride as a reinforcement (2 wt.%, 4 wt.%, 6 wt.%) in aluminium alloy matrix via ultrasonic stir casting route. After characterisation of composite and optimising the wear parameter, the conclusion was drawn as the maximum ultimate tensile strength (UTS) obtained 6 wt.% composite was tested as 157 MPa. There was 23.15% improvement in UTS when addition of 2 wt.% particle in Al alloy and 65.26% increment in strength when compare 6 wt. % composite UTS to pure alloy. The minimum wear rate was found to be 0.0011 mm3/m at the load of 10 N, 6 wt.% Si3N4 reinforcement, 2.094 m/s sliding velocity and sliding distance as 700 m.

A novel Cu-Gr composite electrode development for electric discharge machining of Inconel 718 alloy

Requirement of processes with high productivity leads to the development of new tools and machining technique. One such attempt was made to develop a Copper Composite (CC) tool reinforced with graphite particles through the stir casting route. The CC tool was utilized to machine the Inconel 718 alloy using Electric Discharge Machining (EDM) technique by varying input variables viz tool material, discharge current, pulse on time, pulse off time and gap distance. Brass, Copper, Copper—5% Graphite (CG5), Copper—10% Graphite (CG10), Copper—15% Graphite (CG15) are the various used tool material whereas Material Removal Rate (MRR), Tool Wear Ratio (TWR) and Surface Roughness (Ra) were recorded as responses. The results revealed that using the CG10 and CG15 tools causes arcing and open circuit under some parametric conditions. CG5 offers best MRR and least TWR owing to the bridging effect, high thermal conductivity and lesser density which was suitable for roughing operation whereas brass offers least Ra which was recommended for finishing operation. The surface topography was analyzed with the aid of Scanning Electron Microscope (SEM). Micro crack, pock marks, globules and remelted layers are some of the defects observed in surface morphology. The process parameters was optimized using VIKOR technique.

Distinct heat treatments and powder size ratios affecting mechanical responses of Al/Si/Cu composites

The aim in this investigation is focused on the evaluation of two distinctive powder size ratios of pure elements (Al, Si and Cu) powders. Heat treatments (T4 and T6) affecting the mechanical strengths of Al/Si/Cu composites are also investigated. The novelty concerns to pure elements to constituting the composites and no melting or stir casting route are used. It is found that the densifications and tensile strengths are similar when distinct powder size ratios are used. It is also found that T4 and T6 treatments increases and decreases the mechanical strengths, respectively. The Si content indicates a deleterious effect in mechanical behavior. The T6 aging provides θ-Al2Cu incoherent with Al matrix, and the compressive strength is decreased. This suggests that the examined Al/Cu composites (using pure powders) are potential materials considering economical and environmentally friendly aspects.

Investigations on the effect of electrical discharge machining process parameters on the machining behavior of aluminium matrix composites

Extensive applications are found in aluminum matrix composites, where high strength to weight ratio, low weight and high corrosion resistance are needed. One of the categories of such materials is the SiC reinforced aluminum matrix composite. This reinforcing material belongs to ceramic group of materials and can withstand high temperature and improve several properties when incorporating in the grain structure of the base matrix. The introduction of SiC enhances wear resistance, hardness value and tensile strength. However, the use of high percentage of SiC material reduces the machinability (ductility) and toughness resistance and the machining of such material becomes difficult. In this current study, an attempt is made to develop an aluminum (LM25 alloy) matrix composite, which is reinforced with 7%SiC and 3%Gr particulates through stir casting route. The fabrication of composite is followed by evaluating the machining behavior of hybrid composite through electric discharge machining. During machining, current, voltage, pulse on time and pulse off time are selected as input controllable variables while material removal rate (MRR), tool wear rate (TWR) and over cut are chosen as responses. The experiments are carried out as per Taguchi's L9 OA, with the aid of ANOVA and significant parameters effecting responses are identified. Main effects plots are drawn and optimum set of input machining conditions are determined.

Microstructural and mechanical characterization of novel AA7075 composites reinforced with rice husk ash and carbonized eggshells

This paper investigates microstructural and mechanical characteristics of novel AA7075 composites supplemented with agricultural waste, i.e. rice husk ash and poultry waste, i.e. carbonized eggshells. Both these wastes possess important constituents which make them potential reinforcement material for composites, and their utilization also reduces the problem of disposal to a certain extent. AA7075 composites with varying weight percentages of rice husk ash and carbonized eggshells were prepared through stir casting route. The sum of weight percentages of both reinforcements was kept constant at 5 wt.%. Composites were tested for density and different mechanical properties. Prior to these tests, composites were examined through scanning electron microscopy and energy-dispersive X-ray spectroscopy techniques, wherein uniform distribution of reinforcements was observed. Inclusion of light weight reinforcements decreased the density of composites. Among these composites, highest hardness value was shown by composite having 5 wt.% of rice husk ash with 24.47% enhancement over unreinforced AA7075. Maximum tensile strength and compression strength were exhibited by hybrid composite with 3.75 wt.% rice husk ash and 1.25 wt.% carbonized eggshells. This increment is 28.20% and 16%, respectively, over base composition. Impact strength decreased as the weight percentage of CES increased, thereby indicating brittleness in behaviour. Fractography analysis of tensile and impact test specimens was done through scanning electron microscopy to determine failure mode wherein presence of cracks, voids, dimples, debonding, etc. was observed. Hence, these light weight and low cost green AA7075 composites showed improved properties making them as an alternative as well as sustainable material for automotive and aerospace applications.

Effect of micro graphite particles on the microstructure and mechanical behavior of aluminium 6061 (Al-Mg-Si) alloy composites developed by novel two step casting technique

In the present research, the effect of micron sized graphite addition on the microstructure and tensile failure of Al6061 alloy has been studied. The Al6061 alloy metal matrix composites reinforced with 6, 9 and 12 varying weight percentages of graphite particles were fabricated by novel two step stir cast route which helps in improving the wettability of Al6061 alloy matrix with graphite particles. The synthesized composites were subjected to microstructural studies, density, hardness and tensile properties testing. Microstructural characterizations of obtained samples were carried out by SEM microscopy, EDS and XRD patterns. The occurrence of graphite particles were confirmed by the XRD patterns. The density and hardness of metal composites have been decreased with adding of graphite reinforcement, while the ultimate tensile strength and yield strengths were improved with the addition of graphite particles. There was increase in the elongation of the Al6061 alloy composite after the incorporation of the reinforcement. Various fracture mechanisms were observed in the Al6061-graphite composites using SEM.