Scientific journal
Scientific Review. Technical science
ISSN 2500-0799
ПИ №ФС77-57440

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DISTINCTIONS OF STRUCTURE FORMING OF WELDED JOINTS PRODUCED BY FRICTION STIR WELDING

Morhat T.V. 1 Kolubaev E.A. 1, 2
1 Institute of Strength Physics and Materials Science of the Siberian Branch of the Russian Academy of Sciences
2 National Research Tomsk Polytechnic University
The features of the microstructure of not hardenable aluminum-magnesium alloy, formed by friction stir welding are discussed. The morphology of the welded joint alloy near the interface of the base metal and weld was discussed. It is shown that as a result of friction stir welding a graded structure with ultrafine grains in the center of the weld joint is formed. It is shown that the formation of the joint structure is carried out on the mechanism of formation of a layered structure of ultrafine plastic deformation due to translation and rotation of structural fragments. It was suggested that the reason for the formation of layers is competition processes of strain hardening and softening due to frictional heating and heat-induced deformation. There is an analogy between the microstructure of the weld formed by friction stir welding and the microstructure formed during sliding friction.