Method for welding precipitation-hardened superalloys

A system for welding a precipitation-hardened superalloy article to produce a welded butt joint, the system comprising:

• a beam source for generating a power beam, the beam source being configured to vary an intensity of the generated power beam;
• an oscillation mechanism configured to at least one of (i) induce and (ii) vary an oscillation of the power beam;
• and
• a control unit configured to:
• define longitudinally at least one section within an entire length of the butt joint to be produced;
• control the oscillation mechanism to longitudinally oscillate the power beam with a selected frequency within said at least one section, and control the beam source to provide a selected intensity of the power beam, the selected intensity and the selected frequency being such that the superalloy material proximate the butt joint to be produced is caused to become uniformly heated and melt to thereby produce the butt joint from the consolidation of the superalloy material so melted;
• and
• control the beam source to gradually reduce an intensity of the power beam from the selected intensity while controlling the oscillation mechanism to longitudinally oscillate the power beam until a temperature of the butt joint within the at least one section reaches between 600° C. and 700° C. and solidify the butt joint;
• wherein said melting of the superalloy material to produce the butt joint and solidifying the butt joint by gradually reducing the intensity of the power beam while oscillating longitudinally the power beam within the at least one section are performed separately for sections of the butt joint to be produced to decrease cooling rates of the superalloy material to within a range of 1 to 1000 degC/s, lower gamma/gamma prime lattice misfit, and lower internal stresses at an interface between gamma prime particles and a gamma matrix in a microstructure of the superalloy material.