Solid-State Welded Nickel Alloys Without Base Metal Over-Aging
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Solution Overview
Problem
The existing heat treatment and welding processes for nickel-based superalloys result in over-aging of the base metal near the weld region, leading to a reduction in strength due to multiple stabilization and aging processes, which affects the design and operational parameters of components like turbine engine parts.
Innovation Solution
A method involving a first heat treatment step on superalloy workpieces with a gamma matrix and gamma-prime precipitate phase, followed by solid-state joining and a post-weld stress relief operation, without initial full stabilization and aging, to minimize over-aging and maintain mechanical properties of the base material adjacent to the heat-affected zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If post-weld stress relief is performed on welded superalloy components, then residual stresses are reduced, but the base material undergoes over-aging and strength is reduced
Solution Approach 1:
The patent applies local quality by differentiating the heat treatment approach between the weld region and the base material. The weld region receives stress relief treatment while the base material is protected from over-aging through controlled heat exposure, maintaining different thermal histories for different zones to achieve both stress reduction and strength preservation
Solution Approach 2:
The patent segments the heat treatment process into distinct phases: pre-weld heat treatment of base material, welding operation, and post-weld stress relief of only the weld region. This segmentation allows selective application of thermal processes to different components, preventing blanket over-aging while achieving stress relief where needed
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach prevents over-aging of the base material near the weld region, maintaining comparable mechanical properties to the unwelded areas, thus enhancing the structural integrity and performance of welded superalloy components such as rotor and bladed disk components.
Implementation Method 1
The first and second superalloy workpieces are joined using a solid state joining process
Implementation Method 2
at least one of the first and second superalloy workpieces include a gamma matrix phase and a gamma-prime precipitate phase
Implementation Method 3
subjected to a post-weld stress relief operation
Data Source
AI summary
A joining method includes performing a first heat treatment step on a first superalloy workpiece and a second superalloy workpiece wherein at least one of the first and second superalloy workpieces include a gamma matrix phase and a gamma-prime precipitate phase. The first and second superalloy workpieces are joined using a solid state joining process, subjected to a post-weld stress relief operation and a final aging heat treatment.