M. Anthony Xavior

Effect of non-ionic surfactant assisted modification of hexagonal boron nitride nanoplatelets on the mechanical and thermal properties of epoxy nanocomposites

Hexagonal boron nitride (hBN) nanoplatelets have attracted considerable interest recently. In this work, hBN nanoplatelets have been prepared using chemical exfoliation route. The exfoliation of hBN nanoplatelets takes place along the (0 0 2) plane without destroying the crystal structure. The hBN nanoplatelets are modified using polyvinylpyrrolidone (PVP), a non-ionic surfactant in order to achieve finer dispersion of hBN nanoplatelets in ethyl alcohol, and subsequently in the epoxy matrix. The enhanced dispersion of hBN nanoplatelets achieved using PVP is due to the adsorption of PVP over the hBN nanoplatelets, and PVP miscibility with epoxy resin in an uncured state. Due to the finer dispersion of hBN nanoplatelets in the epoxy matrix, the flexural properties are higher as compared to pure epoxy. PVP assisted dispersed hBN nanoplatelets reinforced with epoxy nanocomposites have higher flexural properties as compared to pure hBN nanoplatelets-reinforced epoxy nanocomposites. The enhanced dispersion of hBN nanoplatelets using PVA also limits the decrease in glass transition temperature (Tg). Further, thermal stability of the epoxy increase with an addition of PVP modified and unmodified hBN nanoplatelets in the epoxy matrix as compared to pure epoxy. Fractography studies reveal that addition of PVP modified and unmodified hBN nanoplatelets in the epoxy matrix depict rough surface with many small facets due to resistance offered by the dispersed nanoplatelets.

Evaluating the performance of cutting fluids in machining of AISI 304 austenitic stainless steel

In this paper, an attempt was made to determine the influence of coconut oil (vegetable based oil) on tool-shim interface temperature and the cutting force developed during turning of AISI 304 stainless steel material with coated carbide tool. Experimentation was conducted as per Taguchis orthogonal array and the observations were used to conduct the analysis of variance and to perform a graphical analysis. The analysis shows that cutting fluid had some influence on the process parameters and in general coconut oil outperformed the other cutting fluids in terms of reducing the cutting force and tool-shim interface temperature. A mathematical model was developed using Minitab-15 software to predict the cutting force and temperature. Chi-square test was performed to check the validity of the developed model and it was found that there is no significant difference between the predicted and observed value at a significance level of 0.05.

Effect of ceramic reinforcements on microwave sintered metal matrix composites

ABSTRACT Metal matrix composites (MMCs) using Aluminum Alloy 2900 and 2024 as matrix material with silicon carbide and alumina as reinforcement have been fabricated through powder metallurgy route for investigation. The average particle size of matrix metal and reinforcement material considered in this research is 10 µm. AA-SiC and AA-Al2O3 composites with 3, 6, and 9 weight percentage (wt%) of SiC and Al2O3 are fabricated. The Rockwell hardness and Compressive strength of AA-SiC and AA-Al2O3 composites were found to increase with an increase in the wt% of reinforcement when the samples were microwave sintered. AA 2024 with 6 wt% Al2O3 reinforced MMCs samples were exhibiting improved hardness results, strength behavior, and stress-strain behavior when the samples are microwave sintered. AA 2900 with 6 wt% Al2O3 exhibited good ductility and formability properties. Good Microstructural bonding was observed in the MMCs, which is attributed to finer Al2O3 particulate used as reinforcement and the microwave sintering.

Evaluation of parametric models in predicting the machining performance

The performance of the machining (turning) process is evaluated in terms of tool life, surface roughness, tool-shim interface temperature developed and metal removal rate during the process. It is very important for the manufacturing engineers to know the performance of the turning process for a set of cutting (input) parameters. In this paper, parametric models based on multiple regression analysis (MRA), neural networks (NNs) and case-based reasoning (CBR) are developed for predicting the machining performance, i.e. the output parameters. An experimental database containing 114 data sets are used for developing the three models. Each data set contains nine input and four output parameters. About 20 machining trials are exclusively conducted with various combinations of input parameters, and their corresponding output values are compared with the predicted values of the developed models. Descriptive statistics of the errors are calculated for the three models and it was found that the CBR model provided better prediction capability than MRA and NN models.

Encapsulation and microwave hybrid processing of Al 6061–Graphene–SiC composites

ABSTRACTThe demand for new aluminum alloy–based metal matrix composites with combinations of novel reinforcements, processed through innovative methods are very much needed for critical engineering applications. With this perspective, the current research work is aimed at the development of Al 6061 composites reinforced with two-dimensional Graphene nanoflake-encapsulated SiC. Ultrasonic liquid processing method is used to disperse the Graphene flake and the mixture is ball milled by adding SiC to achieve the encapsulation. Subsequently, the Al 6061 powder is added to the milled mixture and consolidated through uniaxial vacuum hot press followed by microwave hybrid sintering. Scanning electron microscope (SEM) analysis, X-ray diffraction analysis, hardness, density, and microstructure analysis were carried out on developed composites. Raman analysis was carried out to analyze the distortion on Graphene physical structure during various processing stages. Further, effects on novel combination of material w...ABSTRACT The demand for new aluminum alloy–based metal matrix composites with combinations of novel reinforcements, processed through innovative methods are very much needed for critical engineering applications. With this perspective, the current research work is aimed at the development of Al 6061 composites reinforced with two-dimensional Graphene nanoflake-encapsulated SiC. Ultrasonic liquid processing method is used to disperse the Graphene flake and the mixture is ball milled by adding SiC to achieve the encapsulation. Subsequently, the Al 6061 powder is added to the milled mixture and consolidated through uniaxial vacuum hot press followed by microwave hybrid sintering. Scanning electron microscope (SEM) analysis, X-ray diffraction analysis, hardness, density, and microstructure analysis were carried out on developed composites. Raman analysis was carried out to analyze the distortion on Graphene physical structure during various processing stages. Further, effects on novel combination of material with combined processing approach on flexural and tribological behavior have been analyzed.

Effect of graphene addition and tribological performance of Al 6061/graphene flake composite

Abstract Graphene, no wonder has attracted a significant research interest due to its extensive physical properties at its single atomic thickness and 2D morphology. The current studies focus on the role of graphene in reducing the wear and frictional coefficient of Al 6061–graphene-reinforced metal–matrix composites (MMC’s). Reinforcement chosen is 0.3, 0.6 and 0.9 wt% of graphene to investigate the self-lubricating property under dry wear condition and processed through the ultrasonic liquid processor. The dry frictional wear test was carried out using pin-on-disc tribometer to evaluate the effect of graphene content in the composites under various normal load (5, 10, 15 N) and disc sliding speed (0.4, 0.8, 1.2 m/s) conditions. The results show that there is a significant increase in the hardness and wear resistance and a reduction in the coefficient of friction (μ) values compared to pure alloys. Arithmetic mean surface roughness values (Ra), max profile peak (Rp) and max valley depth (Rv) are found to be comparatively lower than the pure alloy. Due to the tribological potential coupled with improved strength and surface roughness values, Al 6061–graphene composite are excellent candidates for all applications where it is subjected to Friction and wear.

A Heuristic toward Minimizing Waiting Time of Critical Jobs in a Flow Shop

This paper deals with scheduling in permutation flow shop that is considered with the objective of minimizing the waiting time of priority based or critical jobs. Generally, priority based jobs are few in nature in all the flow shops. Hence, it is utmost important that we minimize the waiting time of critical or priority based jobs. All the existing heuristics are developed to minimize parameters like makespan time, flow time, etc. While processing jobs through machines, all machines are considered equally important. In this work, an attempt is made to improve the existing utilization of one or more jobs during processing. The above aim was achieved by reducing the waiting time of the critical or priority based jobs under consideration, and hence achieving zero waiting time for the same. The heuristic is proposed to improve the utilization of such critical jobs. The proposed heuristic was compared with the results of CDS method and validated.

Effect of microwave heat treating processing on frictional behaviour of aluminium alloy 2900 composites

Abstract The sliding wear behaviour of microwave processed, SiCp and Al2O3p reinforced aluminium alloy 2900 and 2024 metal matrix composites prepared by powder metallurgy method was investigated in a pin on disc system. The objective is to determine the effects of novel alloying elements of AA 2900, ceramic addition and microwave aging process on the strength to tribological properties. This composite is evaluated to be an effective replacement for conventionally available AA 2024 composites in brake applications. Compared to conventional heat treating processes, microwave processing used for heat treating the samples is observed to be novel method in improving the strength–microstructural–tribological properties. AA 2900 with 6 wt-% Al2O3 exhibited good strength to microstructure relationship with excellent wear characteristics compared to AA 2024 composites which are governed by alloying elements in AA 2900. 2 H aged AA 2900 with 6 wt-% Al2O3 sample exhibited good frictional coefficient values with good density and strength characteristics. Hence, it is observed that alloying elements in AA 2900 and microwave processing have enhanced the strength to tribological behaviour where the property enhancement is achieved only through ceramic reinforcements.

Workload Assessment for a Sustainable Manufacturing Paradigm Using Social Network Analysis Method

In this paper, focus is on the sustainable manufacturing systems functionalities, i.e., process planning and scheduling for effective and efficient performance of the system to achieve the desired objectives. The desired objectives for this research work have been considered according to the above-mentioned situation. Hence, makespan, throughput time, and energy consumption were identified as the most appropriate performance measures in line with the context of the problem. Mathematical model will be formulated for the performance measures by considering the realistic constraints. Unpredictable events such as machine breakdown or scheduled maintenance are most common in any manufacturing unit. Workload assignment with these disruptions is a challenge, and therefore, a new methodology has been developed for effective and efficient solutions. In this paper, a new social network analysis-based method is being proposed to identify the key machines that should not be disturbed due to its contribution toward achieving the best system’s performance. Moreover, an illustrative example along with three different configurations will be presented to demonstrate the feasibility of the proposed approach. For execution, a Flexsim-based simulation approach will be followed, and with different instances, the proposed methodology can be executed. The validation of the proposed approach and its effectiveness will be evaluated through comparison with different instances, and finally the efficiency of the proposed approach will be confirmed with the results.

Ultrasonication and microwave processing of aluminum alloy- Graphene - Al2O3 nanocomposite

ABSTRACT Nanocomposites with Graphene and Al2O3 (particulates) as reinforcement combinations with various proportions (weight percentage) in aluminum alloy AA 2024 and AA 2219 matrix with 30 to 40 µm are processed through vacuum hot press and microwave processing approach. X-ray diffraction and Raman spectroscopy analysis was done on developed nanocomposites to study the Graphene peaks, carbide formation, and other deformation on added Graphene in the nanocomposites during microwave processing. Microstructural, compressive, and diametrical tensile strength analyses were also carried out on developed composites. Effect of Graphene addition in combination with Al2O3, on strengthening mechanism during microwave sintering, had been discussed.