@incollection{GolubevDoynovHantelmannetal., author = {Golubev, Iurii and Doynov, Nikolay and Hantelmann, Cord and Michailov, Vesselin}, title = {W{\"a}rmequellemodell und FE-Temperaturfeldsimulation f{\"u}r das R{\"u}hrreibschweißen}, series = {DVS Congress 2017 : Große Schweißtechnische Tagung : DVS-Studentenkongress : Vortr{\"a}ge der Veranstaltungen in D{\"u}sseldorf vom 26. bis 29. September 2017}, booktitle = {DVS Congress 2017 : Große Schweißtechnische Tagung : DVS-Studentenkongress : Vortr{\"a}ge der Veranstaltungen in D{\"u}sseldorf vom 26. bis 29. September 2017}, publisher = {DVS Media}, address = {D{\"u}sseldorf}, isbn = {978-3-96144-008-5}, pages = {112}, language = {de} } @inproceedings{GolubevMorozovaNaumovetal., author = {Golubev, Iurii and Morozova, Iuliia and Naumov, Anton and Hantelmann, Cord and Doynov, Nikolay and Michailov, Vesselin}, title = {Numerical simulation and experimental investigation on Numerical simulation of 6082-T6 aluminum alloy}, series = {Materials Science and Technology 2017, (MS\&T17), Pittsburgh, Pennsylvania, USA, October 8-12, 2017, volume 2}, booktitle = {Materials Science and Technology 2017, (MS\&T17), Pittsburgh, Pennsylvania, USA, October 8-12, 2017, volume 2}, publisher = {Curran Associates, Inc.}, address = {Red Hook, NY}, isbn = {978-1-5108-5058-3}, pages = {987 -- 994}, abstract = {The series of impulse friction stir welding (IFSW) experiments for aluminum alloy 6082-T6 butt joints was performed to obtain micrographs, tensile and hardness test samples and to receive the validation data for a numerical model of the process. Impulse force and frequency were varied to determine the effect of individual process parameters on microstructure evolution and mechanical properties of the welded butt joints. A three-dimensional model was established to simulate temperature distribution, heat generation and contact state between the tool and the workpiece during IFSW. Based on the numerical simulation, the influence of the impulses on heat input, maximum weld temperatures and contact state was found. The combination of impulse force and frequency effected the grain refinement. The influence of impulses on the elongation and hardness of the welded joints during IFSW were determined.}, language = {en} } @misc{GolubevMorozovaNaumovetal., author = {Golubev, Iurii and Morozova, Iuliia and Naumov, Anton and Hantelmann, Cord and Doynov, Nikolay and Michailov, Vesselin}, title = {Numerical Simulation and Experimental Investigation on Impulse Friction Stir Welding of 6082-T6 Aluminum Alloy}, series = {Papers from Materials Science and Technology 2017 (MS\&T17), October 8 - 12, 2017, David L. Lawrence Convention Center, Pittsburgh, Pennsylvania USA}, journal = {Papers from Materials Science and Technology 2017 (MS\&T17), October 8 - 12, 2017, David L. Lawrence Convention Center, Pittsburgh, Pennsylvania USA}, doi = {10.7449/2017/mst_2017_987_994}, pages = {987 -- 994}, abstract = {The series of impulse friction stir welding (IFSW) experiments for aluminum alloy 6082-T6 butt joints was performed to obtain micrographs, tensile and hardness test samples and to receive the validation data for a numerical model of the process. Impulse force and frequency were varied to determine the effect of individual process parameters on microstructure evolution and mechanical properties of the welded butt joints. A three-dimensional model was established to simulate temperature distribution, heat generation and contact state between the tool and the workpiece during IFSW. Based on the numerical simulation, the influence of the impulses on heat input, maximum weld temperatures and contact state was found. The combination of impulse force and frequency effected the grain refinement. The influence of impulses on the elongation and hardness of the welded joints during IFSW were determined.}, language = {en} } @misc{MorozovaObrosovNaumovetal., author = {Morozova, Iuliia and Obrosov, Aleksei and Naumov, Anton and Kr{\´o}licka, Aleksandra and Golubev, Iurii and Bokov, Dmitry O. and Doynov, Nikolay and Weiß, Sabine and Michailov, Vesselin}, title = {Impact of Impulses on Microstructural Evolution and Mechanical Performance of Al-Mg-Si Alloy Joined by Impulse Friction Stir Welding}, series = {Materials}, volume = {14}, journal = {Materials}, number = {2}, issn = {1996-1944}, doi = {https://doi.org/10.3390/ma14020347}, abstract = {Impulse Friction Stir Welding (IFSW) was utilized to join 6082-T6 alloy plates at various impulse frequencies. A distinctive feature of IFSW is the generation of mechanical impulses that enhances the forging action of the tool, and thereby, alters the weld microstructure. The microstructural evolution in the Stir Zone (SZ) with special focus on the strengthening precipitation behavior, and overall mechanical properties of the IFSW joints have been investigated. It was demonstrated that the strengthening β″ precipitates reprecipitated in the SZ of the IFSW joints during natural aging. In contrast, no precipitates were found in the SZ of the Friction Stir Welding (FSW) weld. Partial reversion of β″ after IFSW is supposed to occur due to more developed subgrain network and higher dislocation density introduced by impulses that accelerated precipitation kinetics. Dynamic recrystallisation was facilitated by impulses resulting in a fine, homogeneous structure. There was no significant difference between the microhardness in the SZ, tensile and yield strength of the FSW and IFSW joints. However, the application of impulses demonstrated the smoothing of the hardness reduction in the transition region at the advancing side. The shift of the fracture location from the Heat-Affected Zone (HAZ) by FSW to the SZ as well as higher elongation of the joints by IFSW of lower frequencies could be related to the grain refinement and the change of the grain orientation.}, language = {en} }