Vacuum brazing of Al0.3CoCrFeNi high-entropy alloys with CoCrFeNiNb0.5 eutectic filler metal for wide-temperature range application

The service conditions of high-entropy alloys (HEAs) joints brazed with conventional filler metals (FMs) can be confined because few HEAs phases generate in the braze zone. In this study, a multicomponent CoCrFeNiNb0.5 eutectic HEAs (EHEAs) FM was developed to braze Al0.3CoCrFeNi HEAs in vacuum, the braze zone mainly consisted of face-centered cubic (FCC) and Laves lamellar structure, exhibiting a superior metallurgical compatibility with the Al0.3CoCrFeNi base metals (BMs). The shear strength and shear displacement of brazed joints reached 461 MPa/1.35 mm at room temperature (RT), 741 MPa/1.42 mm at -196 degrees C and 380 MPa/1.62 mm at 700 degrees C, respectively. This strategy can stimulate the fabrication and wide-temperature range applications of HEAs brazed components by exploiting the structural and performance merits of EHEAs FMs.