Seven-element medium-entropy alloy brazing filler metal and preparation method and brazing method thereof

The invention relates to the technical field of brazing, and provides Zr-Ti-Nb-Hf-Ni-Cu-Co seven-element medium-entropy alloy brazing filler metal for pure titanium and titanium alloy brazing and a using method of the Zr-Ti-Nb-Hf-Ni-Cu-Co seven-element medium-entropy alloy brazing filler metal. The invention provides Zr-Ti-Nb-Hf-Ni-Cu-Co seven-element medium-entropy alloy brazing filler metal, which is characterized by comprising the following components in percentage by weight: 10.0-16.0% of Ti, 10.0-16.0% of Hf, 10.0-16.0% of Ni, 10.0-10.0% of Cu and the balance of Zr. 1.0 to 8.0 parts of Nb; 0.2 to 5.0 parts of Hf; 5.0 to 9.0 parts of Ni; 4.0 to 9.0 parts of Cu; 1.0 to 6.5 parts of Co; zr: the balance. The brazing filler metal has the following technical effects that the melting point of the brazing filler metal ranges from 780 DEG C to 810 DEG C along with different components, the brazing filler metal can be easily prepared into an amorphous foil belt, pure titanium-pure titanium and pure titanium-titani