Affiliation:
1. Astrakhan State University
2. Don State Technical University
Abstract
This article is devoted to the study of the mechanism of formation of dissimilar welded joints Ti-2Al-1.5Mn, pure titanium (Ti35A) and aluminum (Аl (pure), Аl-6Mg-0.5Mn) alloys obtained by friction stir welding (FSW). The investigated microstructure of the weld joint nugget (WN), zones of thermo mechanically affected zone (TMAZ) and heat affected zone (HAZ) formed at FSW between Ti-2Al-1.5Mn, Ti35A and aluminum (Аl (pure), Аl-6Mg-0.5Mn) alloys. Zones of welded joints at FSW are formed in the mode of structural superplasticity (SP) with a specific shear-band layered structure with alternating layers. The achievement of superplastic state (SPS) in the formation of WN, TMAZ, HAZ is provided by the step–by–step transformation of various mechanisms of plastic deformation in the mode of simple, collective, abnormal dynamic recrystallization, prepared by the processes of dynamic return, polygonization with the transition to post-dynamic recrystallization by the mechanisms of Bailey–Hirsch, Kahn-Burgers-Taylor. At FSW aluminum and titanium alloys with polymorphism, SPS is supported additionally due to recrystallization by twinning and as a result of phase transformations of alpha-gamma or alpha-beta phases.
Publisher
Trans Tech Publications, Ltd.
Subject
Mechanical Engineering,Mechanics of Materials,General Materials Science
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