Composition optimization of welding wire and mechanical properties of joints of nickel-based superalloy containing high refractory elements

K465 nickel-based superalloy has been widely used in many fields due to its excellent high temperature performance. However, due to its high content of refractory elements, weldability is problematic. In order to solve this problem, three kinds of welding wires with different compositions were designed for K465 alloy, mainly by adjusting the contents of γ′-forming elements Al, Ti and solution strengthening element Co. The results show that adjusting the composition of the welding wire can effectively affect the weldability of K465 alloy. In particular, the precipitation of low melting point eutectic phases can be reduced by lowering the content of Al and Ti, while increasing the content of Co improves the thermal stability of the alloy and reduces the susceptibility to cracking. Among the three kinds of welding wires, the one with high Co and low Al + Ti showed the high weldability. The welded joints were of high quality, with a tensile strength of 822 MPa at room temperature, which is 84% of the performance of the base metal, and the elongation of the joints was close to that of the base metal. The results provide a new strategy and theoretical support for the welding of K465 nickel-based superalloy.