Effect of niobium interlayer in dissimilar friction stir welding of aluminum to titanium

Journal Article · Thu Nov 15 04:00:00 EST 2018 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2018.09.007· OSTI ID:22805875

Kar, Amlan ^[1]; Choudhury, Sounak K. ^[2]; Suwas, Satyam; Kailas, Satish V. ^[1]

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1. Indian Institute of Science, Bengaluru 560012 (India)
2. Indian Institute of Technology, Kanpur 208016 (India)

Highlights: • In the present study, FSW of Al to Ti with Nb interlayer has been characterized. • Fragmentation and distribution of Nb and Ti have been correlated with properties. • Ternary mixing and chemical reaction reduced the brittleness of the joint. • Al in the weld nugget showed a gradient in microstructural features. • The weld with Nb interlayer exhibited higher ductility. - Abstract: The most important issue associated with dissimilar welding is the formation of detrimental intermetallics and consequent reduction in mechanical properties of the weld. It was expected that addition of an interlayer would modify the pattern of the intermetallic formation. The present investigation deals with Friction Stir Welding of aluminum (Al) to titanium (Ti) in presence of niobium (Nb) interlayer. X-ray Computed Tomography results highlighted that fine particles of both Ti and Nb are homogeneously distributed. Large Ti particles are substantially fragmented whereas large Nb particles remain as flakes. Microstructural features of the nugget zone indicated a complex mixing of materials. Jointing had been perceived through elemental diffusion at the interfaces of Al/Ti and Ti/Nb. However, Nb restricted the reaction between Al and Ti, and acted as an efficient interlayer to retard the formation of brittle Al{sub 3}Ti intermetallic phase. Mechanisms of microstructural evolution in Al side of the weld have been identified as Dynamic Recovery, Dynamic Recrystallization and particle stimulated nucleation. Significant improvement in the tensile ductility had been observed due to the presence of finer particles. The presence of Nb in the weld nugget influences the microstructural evolution and tensile properties of the weld by reducing the formation of intermetallics.

• OSTI ID: 22805875
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Vol. 145; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM
COMPUTERIZED TOMOGRAPHY
DIFFUSION
DISTRIBUTION
DUCTILITY
INTERMETALLIC COMPOUNDS
MICROSTRUCTURE
NIOBIUM
NUCLEATION
RECRYSTALLIZATION
TITANIUM
WELDING