Mechanism of variation in high-temperature grain stability of aluminum in dissimilar friction stir welds

Kar, A and Kailas, SV and Suwas, S (2020) Mechanism of variation in high-temperature grain stability of aluminum in dissimilar friction stir welds. In: Materials Performance and Characterization, 9 (2).

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Abstract

In the dissimilar Friction Stir Welding (FSW) of aluminum to titanium, a large fraction of titanium particles is inhomogeneously distributed in the weld nugget and their distribution is highly complex. Such a distribution can have an immense influence on the grain stability of the weld nugget, which decides its mechanical properties at the high temperatures experienced in critical applications. The present investigation highlights the variation in grain structure at the top surface and center of the weld nugget. The results show that the microstructure at the surface of the weld contains a higher fraction of fine titanium particles, refined grains of aluminum and high-angle grain boundaries, and a lower intensity of shear texture components when compared to the center of the weld nugget. The variation in the grain stability of the weld was correlated with the qualitative variation in the strain rate and temperature in the weld. It is proposed that the formation and distribution of a high fraction of fine titanium particles results in superior grain stability of aluminum at the surface of the weld due to arrest of the grain boundary mobility against grain growth. This mechanism and methodology can be applied in developing metal matrix composites with superior mechanical properties as well.

Item Type:	Journal Article
Publication:	Materials Performance and Characterization
Publisher:	ASTM International
Additional Information:	The copyright of this article belongs to ASTM International
Keywords:	Aluminum; Friction; Grain boundaries; Grain growth; Grain size and shape; Metallic matrix composites; Research laboratories; Stability; Strain rate; Textures; Titanium; Welds, Dissimilar friction stir welding; Distribution of particles; Grain size; Grain stability; Grain-boundary mobility, Friction stir welding
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	19 Aug 2020 08:52
Last Modified:	19 Aug 2020 08:52
URI:	http://eprints.iisc.ac.in/id/eprint/64862

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