DISTINCTIONS OF STRUCTURE FORMING OF WELDED JOINTS PRODUCED BY FRICTION STIR WELDING
In this paper the characteristics of the process of friction stir welding are discussed. The analysis of the basic mechanisms of the structural state in the material after being exposed to severe plastic deformation and temperature. In the study the formation mechanisms of the structure of the welded joint is proposed to use approaches that describe the behavior of metals and alloys, subjected to thermo-mechanical effects in the process of sliding friction. Implementation of FSW technology in sectors there is an important task to study the mechanisms and identify the physical laws and the formation of the structural state of the factors leading to the formation of structural inhomogeneities and discontinuities in the metal during intensive plastic deformation and thermal stresses to which the material is exposed in the area of welded joint formation during friction stir welding. Having knowledge about the mechanisms of formation of the structural state in the weld zone and heat affected zone and the causes of defects generation in material and their connection with the terms of the thermomechanical effect can be selectively controlled welding parameters to produce defect-free welded joints produced by modern and cost-effective way of welding.