WAAM Titanium Repair With Hybrid Microstructure Control
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Solution Overview
Problem
Wire arc additive manufacturing (WAAM) processes typically produce components with non-isotropic mechanical properties due to columnar microstructures, leading to poor fatigue properties.
Innovation Solution
A method and system for controlling WAAM processes by calculating structural transition points and adjusting parameters to achieve equiaxed or hybrid microstructures, using phase field modeling and finite element analysis to predict and control microstructure and residual stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional WAAM process is used to build bulk components, then production speed is improved, but microstructure becomes columnar leading to non-isotropic mechanical properties
Solution Approach 1:
The patent applies periodic action by alternating between columnar and equiaxed structure formation in different layers during the WAAM process. The system periodically transitions between different build parameters to create alternating microstructure patterns, which resolves the contradiction by maintaining production speed while achieving isotropic mechanical properties through the alternating microstructure architecture.
Solution Approach 2:
The patent utilizes parameter changes by dynamically adjusting WAAM build parameters (such as wire feed speed, arc current, and travel speed) to control microstructure formation. By changing parameters between layers, the system transitions between columnar and equiaxed structures, thereby achieving isotropic mechanical properties while maintaining high production efficiency.
2Stability of the object's composition
If post processing treatments are applied to change microstructure, then microstructure transformation is attempted, but inability to transform from columnar to equiaxed microstructure persists
Solution Approach 1:
The patent applies preliminary action by controlling microstructure formation during the additive manufacturing process itself, rather than attempting transformation after manufacturing. By pre-programming the alternating columnar and equiaxed structure formation through parameter control during WAAM, the system eliminates the need for post-processing treatments to transform microstructure.
3Productivity
If columnar microstructure is produced in WAAM, then bulk component fabrication is enabled, but fatigue properties deteriorate due to non-isotropic characteristics
Solution Approach 1:
The patent applies local quality by creating different microstructure types (columnar and equiaxed) in different locations/layers of the component. The alternating microstructure pattern ensures that no single columnar region dominates, thereby improving overall fatigue properties while maintaining bulk component fabrication capability. Each local region has optimized microstructure for its specific functional requirements.
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 the fabrication of components with isotropic strength characteristics by alternating between columnar and equiaxed structures, improving fatigue strength and reducing residual stress.
Implementation Method 1
Wire arc additive manufacturing (WAAM) is an important class of directed energy deposition (DED)-based additive manufacturing process where wire feedstock is fed into a plasma, or other heat source, to melt and fuse the wire feedstock into a substrate
Implementation Method 2
calculating solidification parameters for a material being used for the WAAM process, the solidification parameters including a temperature gradient, a solidification velocity, and a cooling rate of the material
Data Source
AI summary
A method for determining build parameters for a wire arc additive manufacture machine (WAAM) is disclosed herein. The method includes receiving, by a processor, a plurality of input parameters for a WAAM process for building a component, calculating a melt pool size for the WAAM process based at least in part on the plurality of input parameters, calculating solidification parameters for a material being used for the WAAM process, determining one or more structural transition points during WAAM process for building the component, the one or more structural transition points indicating an internal microstructure of the component, generating a build file in response to the one or more structural transition points indicating that the internal microstructure of the component meets a threshold, the build file including build parameters for use by a WAAM machine, and instructing, the WAAM machine to build the component using the build file.