Interface investigations of 2A14Al/Nb explosively welded composites with 1060Al and Ag interlayers: Morphologies, grains, and mechanical properties

Abstract

Explosive welding (EW) with an interlayer is considered a suitable technology for producing Al/Nb layered composite, but the fundamental process behaviors of this method remain insufficient discussion. Here, contrast EW experiments respectively using 1060Al and Ag sheets as the interlayers were carried out to prepare 2A14Al/Nb composites, and the complex interfacial phenomena and the underlying mechanisms were thoroughly examined by advanced characterizations and theoretical analyses. The microstructure results indicated that the interlayer materials had significant influence on the bonding morphologies, but the defects of the two composites shared the same geometry and distribution characteristics. Combining the microstructures and thermodynamic history, the formation mechanisms of the different defects were revealed. The 2A14Al/Ag/Nb and 2A14Al/1060Al/Nb composites had the advantages of no intermetallic compounds and few defects, respectively, but the latter showed a higher bond strength, suggesting that the geometric defects had more negative effects on mechanical properties than intermetallic compounds. The multi-view EBSD data provided insights into the intricate grain evolutions induced by the EW process, including equiaxed 2A14Al grains and columnar 1060Al grains at the 2A14Al/1060Al interface, and nanoscale Al3Nb grains at the 1060Al/Nb interface. Finally, the correlations between the grain structures and mechanical properties were established by nanoindentation tests.