An experimental insight of friction stir welding of dissimilar AA 6061/Mg AZ 31 B joints

In the present scenario, aerospace and automobile industries depend on lightweight materials such as magnesium and aluminum alloys because of their great balance between mechanical properties and weight ratio. Despite these benefits during the joining process of these dissimilar materials by welding, many challenges arises. The prominent one is related to the low melting points of these lightweight metals which make it almost impossible the joining using conventional arc welding techniques. To tackle this challenge, Friction Stir Welding (FSW) can be considered as a promising candidate tool. In this study, to demonstrate the FSW performances of joining two dissimilar materials we have investigated the joining of AA 6061 and Mg AZ 31 B using a built-in house a modified milling machine. The dissimilar combinations of AA 6061 and Mg AZ 31 B joints were successfully joined by embedding different welding conditions and varying the offset distance. The mechanical performances were evaluated by conducting specific mechanical tests such as micro-hardness, tensile, and impact tests, respectively. To explain the mechanical results, we have applied optical microscopy observation on the microstructure associated with the bonding location. The results prove that the strength of the Friction Stir Welded joints is much higher as compared to other techniques especially in terms of dissimilar metals

Effect of stacking sequence of fibre metal laminates with carbon fibre reinforced composites on mechanical attributes : numerical simulations and experimental validation

Fibre Metal Laminates are structures used primarily in aerospace applications because of their principal advantages such as high strength, lower density, and impact resistance. In the present work, a systematic assessment has been made to evaluate two different stacking sequences of FMLs (Type – I (AA 6061/Carbon Fibre/AA 6061/Carbon Fibre/AA 6061), and Type – II (Carbon Fibre/AA 6061/Carbon Fibre/AA 6061/Carbon Fibre)) against a pure carbon composite (Type - III) as baseline for improvement. The investigations are made for enhanced impact resistance, improved tensile strength, increased flexural capability, microstructural evolution, and surface composition. Mechanical-based testing resulted that Type – I shows significant performance followed by Type – II. The maximum values of tensile strength, impact test, and ultimate load bearing capacity of during flexural test were around 192.92 MPa, 9.3 J, and 155 N, respectively. Correlations of experimental results were drawn against numerical simulation to validate the tensile and flexural results. Microstructural evolution indicated good bonding capability of Type – I FML with the carbon fibre. EDX analysis was carried out analyse surface chemistry. Selected Fibre Metal Laminate sequence can help in improving aeronautical industry's structural applications because of good ductile properties together with fatigue strength and impact resistance

Joining of hybrid AA6063-6SiCp-3Grp composite and AISI 1030 steel by friction welding

Joining of metals and aluminium hybrid metal matrix composites has significant applications in aviation, ship building and automotive industries. In the present work, investigation is carried out on Friction Welding of AISI 1030 steel and hybrid AA6063-6SiCp-3Grpcomposite, that are difficult to weld by fusion welding technique. Silicon carbide and graphite particle reinforced AA6063 matrix hybrid composite was developed successfully using stir casting method and the joining feasibility of AISI1030 steel with AA6063-6SiCp-3Grp hybrid composite was tried out by friction stud welding technique. During friction stage of welding process, the particulates (SiC & Graphite) used for reinforcement, tend to increase the viscosity and lead to improper mixing of matrix and reinforcement. This eventually results in lower strength in dissimilar joints. To overcome this difficulty AA1100 interlayer is used while joining hybrid composite to AISI 1030 steel. Experimentation was carried out using Taguchi based design of experiments (DOE) technique. Multiple regression methods were applied to understand the relationship between process parameters of the friction stud welding process. Micro structural examination reveals three separate zones namely fully plasticized zone, partially deformed zone and unaffected base material zone. Ultra fine dynamically recrystallized grains of about 341 nm were observed at the fully plasticized zone. EDX analysis confirms the presence of intermetallic compound Fe2Al5 at the joint interface. According to the experimental analysis using DOE, rotational speed and interlayer sheet thickness contribute about 39% and 36% respectively in determining the impact strength of the welded joints. It is found that joining with 0.5 mm interlayer sheet provides efficient joints. Developed regression model could be used to predict the axial shortening distance and impact strength of the welded joint with reasonable accuracy

Physicochemical and Thermal Properties of Ceiba pentandra Bark Fiber

Owing to their low weight-to-high strength ratio and recyclable features, the natural fibers are the most potential choice in place of synthetic fibers and been used as reinforcement materials in polymer matrix composites. Characterization of Ceiba pentandra bark fibers (CPFs) such chemical analysis, Fourier Transform-Infrared Analysis (FTIR), X-ray diffraction, thermogravimetric analysis, and Differential thermogravimetric analysis (DTG) analysis has analyzed. CPFs contain 60.9% (w/w) of cellulose, 17.5% (w/w) of hemicellulose, and 23.5% (w/w) of lignin. Besides, its density and crystallinity index are 682 kg m−3 and 57.94%, respectively. TG and DTG analysis discovered that CPFs are thermally stable up to 342.1°C. Further, all the resources of CPFs ensured that it can be an excellent alternative for synthetic fibers in polymer matrix composites

Review of research on friction riveting of polymer/metal light weight multi-material structures

The present transportation industry has been challenged by cost-saving requirements, ever-stronger environmental protection regulations and the significant growth of transport volume. One approach for tackling these challenges is the development of new improved transportation vehicles using new materials and innovative joining technologies. In the recent decade, the use of fiber-reinforced plastics-metal structures has increased significantly in bridge, automotive and aircraft structures, and friction riveting has evolved as a new and promising candidate for joining fiber-reinforced plastics to metals. Friction riveting bridges the gap between mechanical fastening and welding, and offers advantages such as short joining cycle times and a minimum of surface pre-treatment of the joining partners. The present work provides a comprehensive understanding of joining mechanism and behavior of friction riveted multi-material joint structures. Friction riveting has full potential to grow as an ecofriendly, economical and reliable joining method for developing polymer-metal multi-material structures