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Recent Trends and Advances in Friction Stir Welding and Friction Stir Processing of Metals
Published in T. S. Srivatsan, T. S. Sudarshan, K. Manigandan, Manufacturing Techniques for Materials, 2018
Puthuveettil Sreedharan Robi, Sukhomay Pal, Biswajit Parida
An improved continuum finite element model was developed for successful prediction and simulation of material flow and distribution and other relevant field variables using temperature, strain, and strain rate–dependent flow stress (Fratini et al. 2010). The effect of shoulder size on temperature distribution and material deformation during friction stir welding of an aluminum alloy was studied using a fully coupled thermomechanical model (Zhang et al. 2009). The study indicated that increasing the shoulder size increased the maximum temperature and resulted in a uniform distribution of temperature under the tool shoulder. Using a three-dimensional finite element model, the welding heat input (Aval et al. 2011a) was predicted. The frictional power had a major effect on both heat generation and temperature distribution within the metal. The study also revealed that the temperature during friction stir welding was asymmetrically distributed and the peak temperatures were higher on the advancing side when compared to the retreating side. Investigation of the thermomechanical and microstructural issues during dissimilar friction stir welding of AA5086–AA6061 by Aval et al. (2011b) revealed finer grains and a large thermally affected region on the AA6061 side compared to the AA5086 side. For the AA5086, the microhardness was found to be higher than the base metal due to the presence of refined grains as a result of recrystallization in the weld nugget. On the AA6061 side, softening by dissolution of hardening phases in the thermomechanically affected zone was observed.
Heat generation and steel fragment effects on friction stir welding of aluminum alloy with steel
Published in Materials and Manufacturing Processes, 2023
Pankaj Kaushik, Dheerendra Kumar Dwivedi
The friction stir welds formed at different parameters and heat inputs showed different joint morphology and defects. The strength of joints depends on the coalescence between two metals and the soundness of their weld nugget area. In the case of dissimilar friction stir welding, the weld nugget area or stir zone should be free from defects and voids to attain high strength and better life of the welded structure. The present study investigates the effect of steel fragments or voids on joint strength. The joint strength may also be correlated with the heat generated due to process parameter variations. So, a combined effect of defects and heat input is explored on the weld strength. The details of different parameters used, their heat input, defective area, and joint strength are presented in Table 2.
Evaluation of mechanical properties of dissimilar aluminium alloys during friction stir welding using tapered tool
Published in Cogent Engineering, 2021
Benjamin I. Attah, Sunday A. Lawal, Esther T Akinlabi, Katsina C. Bala
The effect of input parameters on the material characteristics of dissimilar friction stir welded AA7075-T651 and AA1200-H19 using the tapered tool was analyzed and the accompanying evidences have been found: Dissimilar friction stir welding between AA 7075-T6 and AA 1200-H19 was successfulThe overall tensile strength of the friction stir welded joints increased with rotational speed from 128.79 MPa at 1150 rpm to 151.54 MPa at 1500 rpm and decreased to 122.47 MPa at 1850 rpm.The average hardness of the two alloys is higher than that of the softer 1200-H19 but lower than that of the harder AA 7075-T651 aluminium alloysFrom the analysis of results, medium welding speed (60 mm/min) encourages material coalescence better than higher welding speed of 90 mm/min.There was a decrease in hardness from 98.58 to 77 HV when the welding speed was decreased from 90 mm/min to 60 mm/min which is also an indication that higher welding speed does to encourage material coalescence and consequently does not favour hardness.Proper bonding of alloys can be achieved at 60 mm/min hence higher impact energy of 21.4 J as against impact energy of 5.4 J obtained at 90 mm/min and 12.9 J obtained at 30 mm/min.