Experimental and Numerical Study of Formation Mechanism of Dual-Phase (AlCoCrFeNi)X HEAs Brazed Joints by Reactive Ni/Al Nano-Multilayers

The FCC + BCC dual-phase solid solution structure was obtained in the Al0.1CoCrFeNi/304SS brazed joints using Ni/Al reactive multilayer nano-foils, which was proved by combining experiments with simulation. In this study, Finite Element Analysis was achieved to analyze the diffusion behavior across brazing joints, which were subsequently interrelated with the formation mechanism of the brazed micro-structures during the brazing process. During brazing, the joint interface is tightly bonded, and the atoms are diffused sufficiently to form the solid solution zone. The representative microstructure of the joint mainly comprised hard BCC (Al-Ni) + ductile FCC (Co-Fe-Cr) dual-phase. The successful use of nano-multilayer foils as a HEAs filler design can broaden the application range of HEAs and provide a novel procedure for brazing 304SS and Al0.1CoCrFeNi HEAs, and developing a novel field in the manufacture of HEAs-related joints.