Single-Crystal Alloy Layered Manufacturing With Thermal Field Control
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Solution Overview
Problem
Existing additive manufacturing techniques cannot produce turbine components with a single-crystal microstructure throughout, as they lack the necessary control over temperature and cooling rates required for maintaining crystallographic orientation during the build process.
Innovation Solution
The use of an external heat control apparatus, including thermal insulation, heaters, and induction heating, to maintain a predetermined temperature profile and control the crystallographic properties of the solidifying powder during the additive manufacturing process, ensuring a single-crystal microstructure is achieved in turbine components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If additive manufacturing is used to build components layer-by-layer, then manufacturing flexibility and complexity are improved, but the ability to maintain single-crystal microstructure is lost
Solution Approach 1:
The invention changes the thermal parameters of the additive manufacturing process by implementing external heating zones that maintain elevated temperatures during layer deposition. This allows the build platform to be heated to temperatures that prevent premature solidification, enabling single-crystal growth throughout the entire component while maintaining the layer-by-layer manufacturing flexibility.
Solution Approach 2:
The invention introduces an intermediary thermal field between the laser energy source and the build platform. This thermal field, created by external heating zones and thermal insulation, acts as a mediator that maintains the necessary temperature conditions for single-crystal formation throughout the build volume, bridging the gap between rapid layer deposition and controlled crystallization.
2Manufacturing precision
If conventional casting is used to produce single-crystal microstructure, then crystallographic orientation is maintained, but manufacturing complexity and time increase
Solution Approach 1:
The invention replaces the complex mechanical and thermal control systems of conventional single-crystal casting with a simplified additive manufacturing approach. Instead of using elaborate mold systems and controlled cooling rates, the invention uses direct energy deposition with external thermal management to achieve single-crystal growth, dramatically reducing manufacturing time and complexity.
Solution Approach 2:
The invention performs preliminary heating of the build platform and surrounding zones before and during material deposition. This preliminary thermal preparation ensures that the temperature conditions are already optimal for single-crystal formation when each layer is deposited, eliminating the need for subsequent heat treatment or prolonged cooling periods required in conventional casting.
3Temperature
If laser heat input is increased to maintain solutioning temperatures, then high-temperature properties are improved, but single-crystal microstructure cannot be achieved throughout the component
Solution Approach 1:
The invention segments the thermal management into distinct zones: a localized high-temperature zone at the laser melt pool for solutioning, and extended lower-temperature zones throughout the build volume maintained by external heating. This segmentation allows the laser to provide sufficient heat input for solutioning at the deposition point while external heating maintains overall temperatures that prevent premature solidification and enable single-crystal growth throughout the component.
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 approach allows for the successful production of turbine components with a single-crystal microstructure, enhancing their high-temperature creep resistance and fatigue strength, while simplifying the manufacturing process and increasing yield compared to conventional casting methods.
Implementation Method 1
The external heat control apparatus comprises a layer of thermal insulation surrounding the component
Implementation Method 2
The external heat control apparatus comprises a heater surrounding the component
Implementation Method 3
a component is built up through repeated cycles of depositing metallic powder followed by laser melting
Implementation Method 4
The external heat control apparatus comprises a quartz lamp positioned near the component
Data Source
Figure 1
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Figure 4~5
AI summary
A method of making a component (C) includes: depositing a metallic powder (P) on a workplane (128); directing a beam from a directed energy source (124) to fuse the powder (P) in a pattern corresponding to a cross-sectional layer of the component (C); repeating in a cycle the steps of depositing and fusing to build up the component (C) in a layer-by layer fashion; and during the cycle of depositing and melting, using an external heat control apparatus (144, 146, 150, 154) separate from the directed energy source (124) to maintain a predetermined temperature profile of the component (C), such that the resulting component (C) has a directionally-solidified or single-crystal microstructure.