Sacrificial Backing for DED Repair of Thin-Walled Aerospace Parts
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Solution Overview
Problem
Existing repair techniques for aerospace components, such as gas turbine engine components, are inadequate for components lacking sufficient substrate material or suitable substrate material, preventing effective directed energy deposition (DED) repairs.
Innovation Solution
A sacrificial backing material is attached to the aerospace component to provide a platform for DED repair layers, with controlled residual stress state and microstructure achieved by adjusting DED process parameters like powder feed rate, energy intensity, traversal speed, and auxiliary heating/cooling, allowing repairs to extend across through holes or separated sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If traditional repair techniques are used on aerospace components with insufficient substrate material, then the repair process cannot be performed, but the component requires repair to extend its service life
Solution Approach 1:
A sacrificial backing material is introduced as an intermediary substrate to enable DED repair processes on components with insufficient substrate material. The backing material provides a stable platform for depositing repair layers, allowing the repair to proceed without compromising the structural integrity of the original component. After repair, the sacrificial backing is removed, leaving the repaired component with restored structural integrity.
Solution Approach 2:
The repair process is segmented into distinct phases: attaching the sacrificial backing material, performing the DED repair process in controlled steps, and removing the sacrificial backing. This segmentation allows each phase to be optimized independently, ensuring both ease of repair and structural integrity are maintained throughout the process.
2Productivity
If DED repair layers are deposited without controlled parameters, then the repair can be completed quickly, but the residual stress state and microstructure are uncontrolled
Solution Approach 1:
The DED process parameters (powder feed rate, energy intensity, traversal speed, auxiliary heating/cooling) are systematically adjusted and controlled to achieve the desired residual stress state and microstructure in each repair layer. By optimizing these parameters, the process maintains high productivity while ensuring precise control over the mechanical and functional properties of the repaired component.
Solution Approach 2:
The repair process incorporates monitoring and control mechanisms that provide feedback on the deposition process, allowing real-time adjustments to maintain optimal parameter ranges. This feedback loop ensures consistent microstructure and residual stress control across all repair layers while maintaining efficient repair speeds.
3Adaptability or versatility
If the aerospace component lacks sufficient substrate material at the repair site, then conventional repair methods cannot be applied, but the component needs repair to remain in service
Solution Approach 1:
The sacrificial backing material serves as a mediator that enables DED repair on components with insufficient substrate. It provides the necessary substrate surface for powder deposition and melting, allowing the repair process to proceed on components that would otherwise be unrepairable. The backing material is temporarily attached, enables the repair, and is then removed, adding minimal complexity to the overall manufacturing process.
Solution Approach 2:
The sacrificial backing material is attached to the component before the DED repair process begins. This preliminary action prepares the repair site in advance, ensuring that the substrate conditions are suitable for DED deposition. By performing this preparation step beforehand, the actual repair process can proceed efficiently without interruptions or additional complexity during the deposition phase.
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
Enables DED repairs in components previously unsuitable for such methods, extending the life of the repaired aerospace parts by providing controlled mechanical and functional properties.
Implementation Method 1
depositing, using the DED energy/powder head, a first layer of DED powder material in the repair region; melting and consolidating, using energy from the DED energy/powder head, the first layer of DED powder material
Implementation Method 2
auxiliary heating and/or cooling provided to the repair region
Data Source
Figure 1
Figure 2
AI summary
A method of repairing an aerospace part (10) including inspecting the aerospace part (10), made from a base material, to identify a worn or defective repair region (20) that requires repair. A sacrificial backing material (24), which serves as a platform for deposition of repair layers (14) during a repair procedure, is attached to the aerospace part (10). A repair procedure is performed on the repair region (20) using a directed energy deposition (DED) energy/powder head (18) after which the sacrificial backing material (24) is removed from the aerospace part (10) and the aerospace part (10) is returned to service. The repair procedure includes depositing, using the DED energy/powder head (18), a first layer of DED powder material in the repair region (20); melting and consolidating, using energy from the DED energy/powder head (18), the first layer of DED powder material to form a first repair layer (14) having a pre-determined residual stress state and/or microstructure; and repeating the depositing and melting and consolidating steps to create a desired plurality of repair layers (14).