Superalloy Repair Using Refractory Metal Blocking Elements
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Solution Overview
Problem
Existing methods for restoring and remanufacturing nickel- or cobalt-based superalloy parts in gas turbine engines, such as turbine blades and vanes, face limitations in achieving structural properties comparable to the base material, particularly in building up replacement material for larger defects and preserving cooling passageways.
Innovation Solution
A method involving the use of a refractory metal blocking element formed in situ, with diffusion brazing and laser cladding, where a refractory metal powder and binder combination is applied to block entry into internal spaces, allowing for the infiltration of repair material that replaces lost material and enhances structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding or laser cladding is used to build up replacement material for larger defects, then the structural integrity is improved, but the structural properties of the replacement material are substantially limited relative to those of the base material
Solution Approach 1:
A blocking element is inserted into the internal space before the diffusion brazing process. This preliminary action prevents repair material from entering the internal space (such as cooling passageways) while allowing the diffusion brazing to proceed. The blocking element is removed after the repair material has been properly deposited and bonded, ensuring clean internal spaces and optimal structural properties without contamination.
Solution Approach 2:
The blocking element serves as an intermediary tool during the repair process. It temporarily occupies the internal space to control material flow during diffusion brazing, then is removed to reveal the properly repaired component. This intermediary approach enables the use of diffusion brazing for build-up repairs while maintaining the integrity of internal passages and achieving structural properties comparable to base material.
2Stability of the object's composition
If diffusion brazing is used for build-up repairs, then the microstructure approaches that of base metal, but the repair material may enter and block internal cooling passageways
Solution Approach 1:
The blocking element is inserted into the internal space before initiating the diffusion brazing process. This preliminary placement ensures that repair material cannot enter the internal cooling passageways during the material flow phase of diffusion brazing, while still allowing the process to achieve its beneficial microstructural effects in the repair zone.
Solution Approach 2:
The blocking element acts as a temporary intermediary that facilitates the diffusion brazing process by controlling material flow. It enables the use of diffusion brazing (which produces superior microstructure) while protecting internal passages from contamination. The blocking element is removed after serving its protective function, leaving both the internal space and repair zone in optimal condition.
3Loss of substance
If traditional welding or laser cladding is used to restore material, then material loss is compensated, but the internal cooling passageways may be compromised or blocked
Solution Approach 1:
The blocking element is placed in the internal space before material restoration begins. This preliminary action creates a physical barrier that prevents repair material from entering cooling passageways during the welding or laser cladding process, while still allowing these traditional methods to effectively restore material loss at the component surface.
Solution Approach 2:
The blocking element serves as a temporary intermediary structure that enables material restoration without compromising internal passages. It blocks the entry of repair material into cooling passageways during welding or laser cladding, then is removed afterward to reveal intact internal spaces and successfully restored external geometry.
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 method effectively restores the structural integrity of damaged components by achieving a microstructure similar to the base metal, improving resistance to thermal-mechanical fatigue and preserving internal cooling passageways, while maintaining the aerodynamic efficiency of the engine components.
Implementation Method 1
A refractory metal blocking element is formed, in situ, with at least a portion to be within the internal space... the blocking element at least partially blocking entry of the material to the internal space
Implementation Method 2
the blocking element is removed. The adding may comprise diffusion brazing using a powdered material comprising a mixture of first and second component powders
Implementation Method 3
A material is added by at least one of welding (e.g., gas tungsten arc welding), laser cladding and diffusion brazing
Data Source
AI summary
A method for forming or remanufacturing a component to have an internal space. A refractory metal blocking element is formed, in situ, with at least a portion to be within the internal space. A material is added by at least one of welding, laser cladding, and diffusion brazing, the blocking element at least partially blocking entry of the material to the internal space. The blocking element is removed.