Prediction and optimization of mechanical properties of PA6/NBR/graphene nanocomposites fabricated by friction stir processing

2021 ◽  
pp. 009524432110200
Author(s):  
Ali Ghorbankhan ◽  
Mohammad Reza Nakhaei ◽  
Ghasem Naderi

The friction stir process (FSP) method used to prepare polyamide 6 (PA6)/nitrile-butadiene rubber (NBR) nanocomposites with 1 wt% Graphene nanoparticles. Response surface methodology (RSM) and Box-Behnken design were used to study the effects of four input variables including tool rotational speed (ω), shoulder temperature (T), traverse speed (S), and the number of passes (N) on tensile strength and impact strength of PA6/NBR/Graphene nanocomposite. In order to investigate the dispersion state of Graphene and the morphology of the PA6/NBR blend in the presence of Graphene, wide x-ray patterns (WAX), scanning electron microscopy (SEM) were performed. Furthermore and differential scanning calorimetric (DSC) was used to investigate the thermal properties of PA6/NBR containing 1 wt% Graphene nanoparticles. The results confirmed that at the optimum range of input variables, PA6/NBR/Graphene nanocomposite provided good thermal stability as well as the highest tensile strength, and impact strength. This is caused by the large surface area to volume ratio of the dispersed layered Graphene in PA6/NBR blends. Under optimal conditions of the rotational speed of 1200 rpm, traverse speed of 20 mm/min, shoulder temperature of 125°C, and number pass of 3, the maximum tensile strength and impact strength are 70.4 MPa and 70.3 J/m, respectively.

Author(s):  
Sumit Jain ◽  
R.S. Mishra

In this research, a defect-free dissimilar weld joint of AA7075-T6 and AA6061-T6 reinforced with Al2O3 nanoparticles was fabricated via friction stir welding (FSW). The influence of tool rotational speed (700, 900 and 1100 rpm), traverse speed (40, 50 and 60 mm/min) with varying volume fractions of Al2O3 nanoparticles (4%, 7% and 10%) on microstructural evolution and mechanical properties were investigated. The augmentation of various mechanical properties is based on the homogeneity of particle dispersion and grains refinement in the SZ of the FSWed joint. The findings revealed that the remarkable reduction in grain size in the SZ was observed owing to the incorporation of Al2O3 nanoparticles produces the pinning effect, which prevents the growth of grain boundaries by dynamic recrystallization (DRX). The increasing volume fraction of Al2O3 nanoparticles enhanced the mechanical properties such as tensile strength, % elongation and micro-hardness. Agglomeration of particles was observed in the SZ of the FSWed joints produced at lower tool rotational speed of 700 rpm and higher traverse speed of 60 mm/min due to unusual material flow. Homogenous particle dispersion and enhanced material mixing ensue at higher rotational speed of 1100 rpm and lower traverse speed of 40 mm/min exhibit higher tensile strength and micro-hardness.


2020 ◽  
Vol 17 (4) ◽  
pp. 491-507 ◽  
Author(s):  
Nitin Panaskar ◽  
Ravi Prakash Terkar

Purpose Recently, several studies have been performed on lap welding of aluminum and copper using friction stir welding (FSW). The formation of intermetallic compounds at the weld interface hampers the weld quality. The use of an intermediate layer of a compatible material during welding reduces the formation of intermetallic compounds. The purpose of this paper is to optimize the FSW process parameters for AA6063-ETP copper weld, using a compatible zinc intermediate filler metal. Design/methodology/approach In the present study, a three-level, three-factor central composite design (CCD) has been used to determine the effect of various process parameters, namely, tool rotational speed, tool traverse speed and thickness of inter-filler zinc foil on ultimate tensile strength of the weld. A total of 60 experimental data were fitted in the CCD. The experiments were performed with tool rotational speeds of 1,000, 1,200 and 1,400 rpm each of them with tool traverse speeds of 5, 10 and 15 mm/min. A zinc inter-filler foil of 0.2 and 0.4 mm was also used. The macrograph of the weld surface under different process parameters and the tensile strength of the weld have been investigated. Findings The feasibility of joining 3 mm thick AA6063-ETP copper using zinc inter-filler is established. The regression analysis showed a good fit of the experimental data to the second-order polynomial model with a coefficient of determination (R2) value of 0.9759 and model F-value of 240.33. A good agreement between the prediction model and experimental findings validates the reliability of the developed model. The tool rotational speed, tool traverse speed and thickness of inter-filler zinc foil significantly affected the tensile strength of the weld. The optimal conditions found for the weld were, rotational speed of 1,212.83 rpm and traverse speed of 9.63 mm/min and zinc foil thickness is 0.157 mm; by using optimized values, ultimate tensile strength of 122.87 MPa was achieved, from the desirability function. Originality/value Aluminium and copper sheets could be joined feasibly using a zinc inter-filler. The maximum tensile strength of joints formed by inter-filler (122.87 MPa) was significantly better as compared to those without using inter-filler (83.78 MPa). The optimum process parameters to achieve maximum tensile strength were found by CCD.


Author(s):  
Nasir Khan ◽  
Sandeep Rathee ◽  
Manu Srivastav

Al-Mg-Si alloys have wide applications in industries such as aerospace, marine, automobile, construction. In this work, newly developed friction stir welding (FSW) was utilized for joining of AA6082-T6 alloy. The effect of major FSW process variables like rotational speed, traverse speed, and shoulder diameter of tool is studied over microstructural and mechanical characteristics of friction stir welded (FSWed) joints. Experimental design was done using Taguchi method (L9 orthogonal array). Three factors viz. rotational speed, welding speed, and diameter of tool shoulder were taken at three levels each. Mathematical modelling was developed in order to optimize the tensile strength of weld joints. Analysis of variance (ANOVA) was utilized to determine the percentage contribution of input variables. The results of present study exhibits that shoulder diameter, rotation, and welding speed of tool significantly affect the mechanical strength of FSWed joints.


2018 ◽  
Vol 877 ◽  
pp. 163-176 ◽  
Author(s):  
Devuri Venkateswarulu ◽  
Muralimohan Cheepu ◽  
Devireddy Krishnaja ◽  
S. Muthukumaran

A 6061-T6 aluminium alloy was friction stir welded in submerged water as well as in air cool at a constant traverse speed and different rotational speed in order to investigate the microstructural characterization and mechanical behaviour of the joints. In order to improve the tensile strength of the joints, weldments were studied at different heat treatment processes such as post weld aged condition and solutionized condition. It is observed that, water cooled joints are resulted in enhancing of both strength and ductility with the lower strain hardening ability than the air cooled joints. The width of the hardness distribution varies with the different cooling process of the joints. The highest hardness peak observed to be located in the heat affected zone of the joints. The maximum tensile strength of the joints achieved for welds under water cooled conditions in contrast to air cooled conditions. Moreover, a combination of water cooling and post weld ageing is proven to be the optimal path to improving the microstructural and mechanical properties of the joints with a maximum efficiency of 89.87% of the base metal strength. The microstructural observations of the joints revealed the presence of voids defects for the low rotational speed joints due to the insufficient heat input. The nugget of the higher tensile strength joints were free from defects and showed the fine grained material flow patterns which are constructive to obtain better mechanical properties.


2020 ◽  
Vol 17 (4) ◽  
pp. 519-526 ◽  
Author(s):  
Senthilnathan T. ◽  
Sujay Aadithya B. ◽  
Balachandar K.

Purpose This study aims to predict the mechanical properties such as equivalent tensile strength and micro-hardness of friction-stir-welded dissimilar aluminium alloy plates AA 6063-O and AA 2014-T6, using artificial neural network (ANN). Design/methodology/approach The ANN model used for the experiment was developed through back propagation algorithm. The input parameter of the model consisted of tool rotational speed and weld-traverse speed whereas the output of the model consisted of mechanical properties (tensile strength and hardness) of the joint formed by friction-stir welding (FSW) process. The ANN was trained for 60% of the experimental data. In addition, the impact of the process parameters (tool rotational speed and weld-traverse speed) on the mechanical properties of the joint was determined by Taguchi Grey relational analysis. Findings Subsequently, testing and validation of the ANN were done using experimental data, which were not used for training the network. From the experiment, it was inferred that the outcomes of the ANN are in good agreement with the experimental data. The result of the analyses showed that the tool rotational speed has more impact than the weld-traverse speed. Originality/value The developed neural network can be used to predict the mechanical properties of the weld. Results indicate that the network prediction is similar to the experiment results. Overall regression value computed for training, validation and testing is greater than 0.9900 for both tensile strength and microhardness. In addition, the percentage error between experimental and predicted values was found to be minimal for the mechanical properties of the weldments. Therefore, it can be concluded that ANN is a potential tool for predicting the mechanical properties of the weld formed by FSW process. Similarly, the results of Taguchi Grey relational analysis can be used to optimize the process parameters of the weld process and it can be applied extensively to ascertain the most prominent factor. The results of which indicates that rotational speed of 1,270 rpm and traverse speed of 30 mm/min are to be the optimized process parameters. The result also shows that tool rotational speed has more impact on the mechanical properties of the weld than that of traverse speed.


Author(s):  
Ravi Butola ◽  
Ranganath M. Singari ◽  
Qasim Murtaza ◽  
Lakshay Tyagi

In the present work, nanoboron carbide is integrated in the aluminum matrix using friction stir processing: by varying process parameters, that is, tool pin profile, tool rotational speed and tool traverse speed, based on Taguchi L16 design of experiment. A self-assembled monolayer is successfully developed on the substrate to homogeneously and uniformly distribute the reinforcement particles. Response surface methodology and artificial neural network models are developed using ultimate tensile strength and total elongation as responses. Percentage absolute error between the experimental and predicted values of ultimate tensile strength and total elongation for the response surface methodology model is 3.537 and 2.865, respectively, and for artificial neural network is 2.788 and 2.578, respectively. For both the developed models experimental and forecasted values are in close approximation. The artificial neural network model showed slightly better predictive capacity compared to the response surface methodology model. From the scanning electron microscopy micrograph, it is evident that throughout the matrix B4C reinforcement particles are well distributed also; with increasing tool rotational speed grain size decreases up to 1200 r/min; on further increasing the tool rotational speed particles starts clustering.


2017 ◽  
pp. 1293-1305
Author(s):  
G. Venkateswarlu ◽  
M.J. Davidson ◽  
G.R.N. Tagore ◽  
P. Sammaiah

Friction stir processing (FSP) has been developed on the principles of friction stir welding (FSW) as an effective and efficien new method for grain refinement and microstructural modification, providing intense plastic deformation as well as higher strain rates than other conventional severe plastic deformation methods. FSP produces an equiaxed homogeneous microstructure consisting of fine grains, resulting in the enhancement of the properties of the material at room temperature. The objective of the present paper is to examine the influence of friction stir processing (FSP) parameters namely tool rotational speed (RS), tool traverse speed (TS) and tool tilt angle (TA) on the microstructures of friction stir processed AZ31B-O magnesium alloy. This investigation has focused on the microstructural changes occurred in the dynamically recrystallised nugget zone/ stir zone and the thermo mechanically affected zone during FSP. The results presented in this work indicate that all the three FSP process parameters have a significant effect on the resulting microstructure and also found that the rotational speed has greatly influenced the homogenization of the material. The grain refinement is higher at intermediate rotational speed (1150 rpm), traverse speed (32 mm / min and tilt angle (10). It is established that FSP can be a good grain refinement method for improving the properties of the material.


2013 ◽  
Vol 818 ◽  
pp. 14-19 ◽  
Author(s):  
Vahid Rezazadeh ◽  
Ali Sharbatzadeh ◽  
Ali Hosseinzadeh ◽  
Amir Safari ◽  
Salar Salahi

mproving ductility in metals using friction stir processing (FSP) is a challenging effort and is made by means of a rotating tool inserted in a work piece providing heat transfer and plastic deformation. In this investigation, improving ductility during FSP was determined as a purpose and the microstructure and mechanical properties of nugget zone were investigated during friction stir processing (FSP) of pure copper. Ductility was measured using tensile elongations at a temperature of 20 °C. By varying the traverse speed from 40 to 100 mm/min at rotation speeds of 300 and 600 rpm, the ultrafine grain microstructure was achieved .Defects were observed in rotational speed of 300 rpm. By increasing traverse speed at constant rotational speed of 600 rpm grain size of the nugget zone decreased and ductility increased. Achievable ductility was limited by cavity formation due to lower heat input and deformation in samples with defects.


Author(s):  
Jicheng Gao ◽  
Chao Li ◽  
Yifu Shen

The aim of this work is to fabricate the high-density polyethylene–copper composites by submerged friction stir processing at different traverse speeds. The scanning electron microscopy is used to analyze the distribution of microstructure and particles. The experimental results indicated that the macrostructure morphology, microstructure and tensile strength vary depending on the traverse speed. Compared with the pure high-density polyethylene, Cu-filled polymer composites showed lower tensile strength and higher microhardness. The maximal values of the tensile strength and microhardness were achieved at traverse speeds of 30 and 15 mm/min, respectively. The thermal properties of Cu-filled high-density polyethylene composites were studied by differential scanning calorimetry. The crystalline content of the composites was decreased due to the addition of copper. From the experimental tests, it can be concluded that submerged fiction stir processing has a great potential for producing polymer–metal composites.


2020 ◽  
Vol 18 (1) ◽  
pp. 157-166
Author(s):  
Anas Islam ◽  
Shashi Prakash Dwivedi ◽  
Vijay Kumar Dwivedi

Purpose This study aims to minimize pollution and enhance the mechanical properties of SiC- reinforced aluminum- based composite by utilizing waste eggshell. Pollution is increasing at an exponential rate across the globe. Every nation is struggling to have strong control over the rise in pollution. Many countries are even successful in this regard, but only up to a certain extent; also, a lot of capital investment is required just to make arrangements for making and taking care of dedicated dump yards. An alternative approach in this regard could be using the unwanted wastes in some constructive works by recycling them. Novel strategies and dedicated cells for the research and development regarding the recycling of various kinds of wastes are continuously being developed by various nations. Design/methodology/approach This study attempts to make a hybrid composite of AA6101 alloy through the friction stir process (FSP) technique in which waste eggshells and SiC have been used as reinforcement particles. As the densities of eggshells, SiC show different values of densities to make them a single entity, they were subjected to ball milling for around 75 h. After ball milling, the reinforcement particles (eggshells and SiC) were distributed uniformly in the metal matrix (Al), and they appear as a single entity in the metal matrix composite. Findings The main objective of this study is to obtain an enhanced value of tensile strength of the final composite. Concerning this, the parameters of FSP, i.e. rotational speed and transverse speed, have been optimized through the Box–Behnken design approach. The optimized values of FSP parameters came out to be as 935.92 rpm of rotational speed and 22.48 mm/min as transverse speed value. Originality/value The results showed that the tensile strength and hardness of the composite developed at an optimum combination of FSP parameters enhanced by about 47.14 and 45.45%, respectively.


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