Damaged Surface Repair with Solid-State Metallurgical Bonding
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Solution Overview
Problem
Conventional repair methods for high-temperature components in gas turbine engines, such as brazing, fail to form a microstructural bond with the base material and introduce undesirable phases like silicides and borides, limiting their effectiveness and durability.
Innovation Solution
A repair method involving a feedstock mixture of base material particles and a binder, with optional melting point depressant, formed into a preform that is subjected to thermal cycles below the melting temperature to create a metallurgical bond in a solid state, avoiding fusion and thus minimizing the formation of unwanted phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional brazing techniques are used to repair high temperature components, then the repair process can be completed, but the brazing material does not form a microstructural bond with the base material and introduces undesirable phases such as silicides and borides
Solution Approach 1:
The invention changes the fundamental parameters of the repair process by using solid state diffusion bonding instead of brazing, operating below the melting temperature of the base material to avoid formation of brittle silicide and boride phases while achieving metallurgical bond
Solution Approach 2:
The invention extracts and eliminates the harmful brazing material from the repair process, using only base material particles that diffuse into the damaged area without introducing foreign phases like silicides and borides
2Reliability
If brazing material is used to fill damaged portions, then the damaged area can be filled, but the brazing material may not withstand the operating conditions of the component
Solution Approach 1:
The invention uses base material particles that are homogeneous with the component material, ensuring the repaired area has the same properties as the original material and can withstand the same operating conditions without microstructural degradation
3Productivity
If thermal cycles above melting temperature are used to form a bond, then rapid bonding can be achieved, but fusion occurs which introduces undesirable phases
Solution Approach 1:
The invention changes the temperature parameter range to solid state diffusion bonding conditions, achieving metallurgical bond through atomic diffusion at temperatures below melting point, thus avoiding fusion and formation of brittle phases
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 enhances the mechanical strength and durability of the repaired components by forming a metallurgical bond that matches the properties of the base material, extending the service life of high-temperature components without introducing brittle microstructures.
Implementation Method 1
heating and homogenizing the feedstock mixture to obtain a fluid feedstock mixture, pouring the fluid feedstock mixture on the damaged portion of the surface of the component, solidifying the fluid feedstock mixture to obtain a solidified feedstock mixture
Implementation Method 2
subjecting the component and the preform to at least one thermal cycle for forming a metallurgical bond in a solid state between the preform and the surface of the component after the at least one thermal cycle, the at least one thermal cycle occurring below a melting temperature of the component and the preform
Implementation Method 3
The obtaining of the feedstock mixture includes applying a vacuum, mixing and heating the feedstock mixture above a melting point of the binder
Data Source
AI summary
A repair method for a component having a damaged portion on a surface thereof includes obtaining a feedstock mixture comprising base material particles and a binder, forming a preform with the feedstock mixture, placing the preform on the damaged portion of the surface of the component, and subjecting the component and the preform to at least one thermal cycle for forming a metallurgical bond in a solid state between the preform and the surface of the component after the at least one thermal cycle, the at least one thermal cycle occurring below a melting temperature of the component and the preform. A repair method involving pouring fluid feedstock mixture on a damaged portion of the surface of the component is also disclosed.