Multi-element boron-free high-temperature brazing filler metal and seal welding application method

The invention designs a multi-element boron-free high-temperature brazing filler metal, which comprises the following chemical components in percentage by weight: 5.5 to 7.5 percent of Al, 5.0 to 7.0 percent of Ti, 12.0 to 16.0 percent of Cr, 4.0 to 8.0 percent of Co, 4.0 to 7.0 percent of Nb, 2.0 to 6.0 percent of Mo, 7.0 to 10.0 percent of Ta, 0.05 to 0.1 percent of W, 0.01 to 0.03 percent of B, 0.07 to 0.2 percent of Zr, 0.001 to 0.004 percent of La and the balance of Ni. The invention introduces a high-temperature brazing filler metal for a nickel-based high-temperature alloy, develops a reliable powder metallurgy process hole sealing and welding method, and adopts the method to replace a boron-containing brazing filler metal, so that the required precision of an assembly gap is reduced, and the mismatching between a sealing and welding process and a solution treatment process is solved. Compared with traditional brazing, the method is more stable, the structures of a welding area and an influence area ar