Investigation on the coupling interaction in electron beam welded Al–Cu bimetallic sheet

Abstract

Two sound joints of Al–Cu bimetallic sheet with 6.5 mm in thickness were obtained in Cu (upper)–Al (lower) and Al (upper)–Cu (lower) welding configurations via the electron beam welding and their distinct coupling models were developed to well understand their flow behavior of the molten pool and microstructure evolution mechanisms during the electron beam welding. For the electron beam welding of the Cu–Al bimetallic sheet, liquid Al and Cu flowed into each other and fully combined in the fusion zone and the interface zone under high-temperature environment, forming large amount of intermetallic compounds. For the electron beam welding of the Al–Cu bimetallic sheet, liquid Al was floating on the Cu substrate, while liquid Cu was flowing at the bottom of the molten pool and mutually combined with liquid Al at the interface, forming a relatively small amount of intermetallic compounds. Moreover, a part of liquid Al flowed back to the seam root under the influence of the Marangoni effect. Therefore, the fusion zone and the interface zone with various phase compositions were formed in these two Al–Cu bimetallic joints and the mechanical properties of the corresponding joints were determined. Furthermore, the average tensile strengths of Cu–Al and Al–Cu bimetallic joints were 59 MPa and 67 MPa, respectively. The fracture locations of these two joints were both at the edge of the fusion zone along the Al2Cu intermetallic compound interlayer. Moreover, the fracture characteristics of these joints were mainly cleavage fracture.

Dissimilar P-TIG welding between Inconel 718 and commercially pure Titanium using niobium interlayer

“…This has encouraged a number of researchers to delve into the joining of various dissimilar alloys. [1][2][3][4][5] Ni-based superalloys possess unique mechanical properties at high temperatures due to the presence of strengthening elements such as Cr, Fe and Nb and these alloys are widely used in manufacturing of gas turbine components, rocket and aircraft engine components. 6,7 Commercially pure titanium's (CpTi) exceptional biocompatibility, high specific strength, and corrosion resistance make it an attractive choice for applications in the biomedical engineering, aerospace and automobile industries.…”