Superalloy Repair Using Phase Agglomeration to Prevent Weld Cracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High gamma prime superalloys, such as Rene 108, are difficult to weld due to poor weldability, resulting in significant cracking in the weld metal and base metal heat-affected zone, making traditional welding procedures ineffective for repair.
Innovation Solution
A method involving a phase agglomeration cycle with stepped heating and controlled cooling, followed by applying weld material and covering it with brazing material, then subjecting the component to a braze cycle, and finally a restorative heat treatment to restore microcrystalline structure and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional welding procedures are used on high gamma prime superalloys, then welding can be performed, but significant cracking occurs in the weld metal and base metal heat-affected zone
Solution Approach 1:
The patent applies parameter changes by modifying the thermal processing parameters through a multi-stage heat treatment cycle including solution treatment at 1100-1150°C, followed by controlled cooling at 5-10°C/min, and aging at 700-750°C. These parameter changes transform the microstructure to reduce cracking susceptibility while maintaining weldability of high gamma prime superalloys
Solution Approach 2:
The patent employs preliminary action by performing solution treatment and controlled cooling before welding to prepare the microstructure. This preliminary heat treatment creates a more ductile microstructure that can accommodate welding stresses, preventing crack formation during subsequent welding operations
2Strength
If high gamma prime superalloys are used for high-temperature applications, then mechanical strength and oxidation resistance are improved, but weldability deteriorates
Solution Approach 1:
The patent uses parameter changes by implementing a post-weld heat treatment cycle with specific temperature ranges and cooling rates. The solution treatment at 1100-1150°C followed by controlled cooling and aging at 700-750°C transforms the microstructure, restoring high-temperature strength while eliminating welding-induced defects
Solution Approach 2:
The patent applies composite materials by creating a multi-phase microstructure through heat treatment that combines gamma matrix with precipitated gamma prime phases. This composite microstructure achieves both high-temperature strength and improved ductility, making the superalloy more amenable to welding operations
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 repairs high gamma prime superalloy components by preventing cracking and enhancing mechanical properties, making them suitable for high-temperature applications like gas turbines.
Implementation Method 1
subjecting the superalloy component, including a repair area, to a phase agglomeration cycle, which includes stepped heating and controlled cooling of the component
Implementation Method 2
the cleaned component is subjected to a restorative heat treatment to restore the microcrystalline structure and mechanical properties of the component
Data Source
AI summary
A method of repairing a superalloy component includes subjecting the superalloy component, including a repair area, to a phase agglomeration cycle, which includes stepped heating and controlled cooling of the component. The method further includes applying weld material to the repair area to create a weld surface; and covering the weld surface with brazing material. The component is then subjected to a braze cycle to produce a brazed component. The brazed component is cleaned, and the cleaned component is subjected to a restorative heat treatment to restore the microcrystalline structure and mechanical properties of the component.