This present work investigates the effect of adding novel biochar microparticle into the welding zone of dissimilar friction stir welding of AISI-SAE 1010 (steel)–CDA 101 (copper) alloys. The primary ...aim of this work was to produce efficient weld joints in AISI-SAE 1010–CDA 101 alloys using biochar as solid lubricant via friction stir welding process. The biochar particles were prepared from rice husk biomass via carbonization process. The welding was performed using tapered pin profiled tool with rotational speed of 900 rpm, traverse speed of 30 mm/min, axial load of 5 KN, dwell time of 5s, plunging depth of 0.2mm, and biochar additions of 0.5, 1, 2, and 4wt%. The highest tensile strength of 205 MPa, elongation of 44%, yield strength of 177MPa, strain value of 36, and Vickers hardness of 121 were observed for FSW joints made using 2wt% of biochar content. Large addition of biochar up to 4wt% marginally affects the properties. Similarly, the fatigue strength of 157MPa was observed for weld made using 2wt% of biochar. The microstructure of biochar-assisted weld nugget shows highly refined less thermally affected grains. The grains were in equiaxial with distortion-free. The EDAX report confirms the presence of copper, iron, and carbon on the weld nugget, which indicates fine mixing of parent metals with solid lubricant. These mechanical properties improved environmental friendly dissimilar welding method could be used in industrial applications such as automobile, aerospace, construction, defense, medical, energy where high strength with high durable weld joints are required to meet the current technology demand, and process economy.
Heat generated during the friction stir welding (FSW) process is of complex nature and plays a vital role in influencing the quality of the fabricated joints. In this experimental research, an thermo ...mechanical process model was formulated to estimate the values of peak temperatures generated during the employment of FSW tools with four different pin geometries (namely cylindrical, taper cylindrical, square and triangle) for joining of AZ80A Mg alloy flat plates, to understand their significant role in influencing the size of the grains, their mechanical strength and in the quality of the joints. The peak temperature values of the formulated thermo mechanical process model are found to be consistent with that of the actual experimental results and exhibited relatively very small variation It was observed that the joints fabricated by taper cylindrical pin geometry was found to possess very fine sized grains, due to the generation of ideal peak temperature (i.e., 348 °C which is nearly 81–82% of the melting temperature of AZ80A Workpiece).
Experimental investigation was conducted to find out microstructural characteristic changes arising in the weldments AZ80A Mg alloys obtained using the friction stir welding. Tools with three ...different pin profile geometries were employed during this investigation at constant tool rotational speed and feed rate. Tensile tests are performed and the tensile fracture surfaces are examined using the Scanning Electron Microscope (SEM) and the obtained SEM images are used for microstructural investigations. From the experimental results, it was observed that the geometry of the tool pin plays a significant role in producing essential stirring action there by regulating the flow of the plasticized material and leading to the formation of small sized grains having equally distributed fine strengthening precipitates. These structured grains have a direct reflecting impact in increasing the hardness and mechanical properties of the fabricated joints at the nugget zone of the friction stir welded AZ80A Mg alloy joints.
The main objective of this paper is to produce defect free weldments with improved properties during friction stir welding of dissimilar Mg alloys. The influence of the anisotropic arrangement of ...materials when AZ80A Mg alloy is taken as advancing side and AZ91C Mg alloy as retreating side and vice versa with respect to their mechanical properties and microstructural characteristics were investigated. The effects of various FSW parameters on the quality of these joints were also analyzed and best optimized FSW parameters were suggested. Defect free sound joints with excellent mechanical properties were produced when AZ80A Mg alloy was positioned at retreating side. At the same time, it seems a little bit difficult to obtain good quality joints with the contrary arrangement of materials. These investigations revealed that materials having inferior plastic deformability must be kept at the advancing side to obtain sound joints during FSW of dissimilar alloys of Magnesium.
Abstract
In this experimental work, 6 mm thick plates of distinctive metal alloys namely AZ91C Mg alloy and AA6061 Al alloy were joined using the FSW process, and fabricated joints were investigated ...to apprehend the impact of convoluted interfaces and their distribution in the nugget zone and the role of intermetallic aggregates in impacting the mechanical properties of the joints. Employment of tool rotational speeds higher than 1100 rpm has fabricated AZ91C Mg–AA6061 Al joints possessing inter–infiltrating structures along with curved junctures, promoting micro-void unification (MCU) on the fractured regions owing to mechanical-related interlocking. AZ91C Mg–AA6061 Al joints have experienced tensile-related failure along the layer of intermetallic and in the regions of inter–infiltrating components nearer to the side of Al parent metal. Joints exhibiting superior strength have been attained due to the generation of intricate interfaces at the joint region, which in turn has contributed to the mechanical-based interlocking. Highest tensile strength exhibited by the joint was 242 MPa, which is nearly 78% of the strength of the parent 6061 Al alloy (310 MPa).
Abstract
In this research paper, an endeavour was made to devise empirical relations amidst the process parameters of friction stir welding (FSW) and tensile relevant strength of AZ80A Mg alloy ...joints, based on a 6 parameters—5 levels based central composite design (CCD). Mathematical equations illustrating the impact of process parameters of FSW were formulated based on quadratic regression based analysis to optimize the parameters for attaining superior tensile strength and sensitivity related equations were established from these numerical models. A detailed sensitivity characteristic relevant map for the FSW of AZ80A Mg alloys was established forecasting the fine tuning related prerequisites of the employed FSW parameters. Coefficient of determinant (R
2
) announced that 99.062% of the overall variability was described by the formulated model and only lower than 1% of the overall variations was not justified by the model. Predicted R
2
was also in perfect agreement with the adjusted R
2
and announced the model’s capability to demonstrate 95.43% of the variability in the generated data. Highest value of tensile relevant strength (80.77% of the parent metal) was exhibited by the AZ80A Mg alloy joint fabricated under optimized parameters. Tensile relevant strength of AZ80A Mg joints was observed to be highly sensitive to traverse speed of the employed tool.
A quadratic equation has been developed based on experimental measurements to estimate the peak temperature in the friction stir welding (FSW) process during the joining of AZ80A Mg alloys. The ...numerical simulation of the FSW process was performed by employing COMSOL software to predict and calculate the distribution of temperature on the various regions of the parent metal and the welded joints. The predicted and finite element analysis (FEA) simulating the results of the distribution of peak temperatures were found to be consistent with the experimental values. In addition to this, a parametric experimental investigation was conducted to identify the most influential process parameter that plays a significant role in the peak temperature distribution during FSW of AZ80A Mg alloy. Linear contributions by the input process parameters of FSW, namely, traversing speed, rotating tool speed and axial force on the peak temperature were observed to be 32.82 %, 41.65 % and 21.76 %, respectively.
The high degree of inhomogeneity in material and intricacies created by machining of carbon fiber reinforced plastic (CFRP) composites hinder the accurate prediction of residual strength of the ...adhesive bond joint using analytical models. Recently, artificial intelligence techniques are effectively utilized as an alternative method for predicting the results of complex phenomena. In this paper, attempts were made to predict the bond strength of laser surface treated and adhesively bonded CFRP composite specimens using the artificial neural network (ANN) from the acoustic emission (AE) parameter recorded during the shear test. Twelve adhesively bonded specimens whose surfaces were pre-processed with 3W Nd:YAG laser at different processing parameters. ANN was trained using segregated AE data according to the failure mechanism and the percentage of failure load (5 to 100%). Predicted values were compared with experimental values and the results were analysed for the suitability of ANN with AE in the application.
FDM (Fused deposition Modeling) is a unique technique ofAM (additive manufacturing) where computers are used to build successive layers to produce a complete 3D entity. The major constraint of FDM ...technique is its narrow range of industrial applications, where the usage of components produced by FDM is limited to either demonstrational part or as a conceptual model rather than to be used as a fully functional component. Many studies are being continuously carried out to enlarge the spectrum of materials used which could result in increased usage of FDM in various production scenarios. Greater cost efficiencies and material process ability have drawn greater focus toward this extrusion-based technique. Many researchers have focused on developing various composite materials such as ceramic based composites, metal matrix, fiber-reinforced and polymer composites. This paper focuses to review the major developments that have taken place in developing the various samples and parameter optimization for FDM.
Fruit rot disease is a serious, emerging problem in butternut squash (Cucurbita moschata) cultivation in Northern and Eastern Provinces of Sri Lanka. Aim of the present study was to identify the ...causative agent of the fruit rot in the Trincomalee District and find a suitable fungicide to control the disease. Diseased fruit samples were collected randomly from four fields in Nilaveli, Morawewa, Kinniya and Thambalagamam. Fruit rots appeared brown colour, sunken and water-soaked spots which later turned black, enlarged rots with moldy appearance. The pathogen was isolated on Potato Dextrose Agar (PDA) medium. Cultural and morphological characteristics were studied. On PDA, cultures initially appeared white, cottony with heavy aerial mycelium which later became flat. Younger hyphae had swollen tips, while matured hyphae were hyaline, aseptate and dichotomously branched. Aplerotic oospores were surrounded by terminal oogonia. Zoospores arose from globose sporangia. There was no morphological variation among isolates, collected from the four different villages in the Trincomalee district. Internal transcribed spacer (ITS) region of the genome was PCR amplified. PCR products were subjected to DNA sequencing. Based on morphological features and analysis of ITS region of the genome, the pathogen was identified as Pythium aphanidermatum. Koch’s postulates confirmed the pathogenicity of P. aphanidermatum. Four concentrations (10, 100, 1,000 and 10,000 ppm) of commercial fungicides (Captan 50 WP, Mancozeb 80 WP, Homai 80 WP and Topsin 70 WP) were tested against the isolate in vitro. Fungicides, namely Homai or Captan (>1000 mg l-1), can be used to reduce the pathogen growth.
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