Heat treatment and stress relief for solid-state welded nickel alloys

A joining method comprising:

• performing a first heat treatment step on a first superalloy workpiece and a second superalloy workpiece, at least one of the first and second superalloy workpieces comprising a gamma matrix phase and a gamma-prime precipitate phase, and further comprises a first constituent element operative to reduce a melting temperature of the gamma phase;
• metallurgically joining the first and second superalloy workpieces using at least one solid-state joining process;
• a second heat treatment step after the first heat treatment step and prior to the metallurgical joining step;
• and
• performing a post-weld stress relief operation on the joined first and second superalloy workpieces;
• wherein the first heat treatment step excludes an aging heat treatment and includes a solution heat treatment;
• wherein the first constituent element is entirely dispersed in the gamma phase after the first heat treatment step;
• and
• wherein the second heat treatment step excludes an aging heat treatment and includes a first partial stabilization step terminating prior to substantial accumulation of the first constituent element at or proximate a plurality of grain boundaries in an area of the first and second workpieces to be joined during the metallurgical joining step, substantial accumulation being less than an amount sufficient to cause overaging of the respective areas to be joined.