Modeling of Processes and Study of Structure During FSW of Magnesium Alloy of the Mg-Al-Zn System

Experimental laboratory equipment for friction stir welding (FSW) after working out the optimal welding modes at different linear speeds allows to obtain high-quality butt joints from thin ductile metals. With the development of new mathematical tools for modeling of thermo-deformation processes, it became possible to analyze the stress-deformation state and thermomechanical processes occurring in the joint zone of FSW, and this is necessary to predict the operational properties, strength and service life of welded structures. Using mathematical models and fi-nite-element analysis, the temperature distributions from the volume source of heating during FSW were visualized, and the residual deformations and stresses in the zone of butt-welded joints of thin sheets of magnesium alloys were numerically determined. Modeling of the kinetics of changes in temperature fields during the FSW process showed that the width of the HAZ decreases with an increase in the linear speed. It was established that with an increase in the linear speed of welding, the maximum residual stresses increase by 10...15%. Residual plastic deformations de-crease with an increase in the linear speed of welding. In the future, it is advisable to determine the effective balance of linear speed and rotation speed of the FSW tool to obtain greater uniformity of the weld structure and reduce heat transfer to the metal during welding.