Single-Crystal Alloy Additive Manufacturing with External Heat Control

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Solution Overview

Problem

Existing additive manufacturing techniques cannot produce components with a single-crystal microstructure, which is essential for high-temperature turbine components to resist hot corrosion and oxidation.

Innovation Solution

The method involves using an external heat control apparatus separate from the directed energy source to maintain a predetermined temperature profile and heating rate during the layer-by-layer deposition of metallic powder, ensuring the component develops a directionally-solidified or single-crystal microstructure, employing a combination of thermal insulation, heaters, quartz lamps, and induction coils to control temperature and heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If additive manufacturing is used to build components layer-by-layer with directed energy source, then manufacturing flexibility and complexity are improved, but the component cannot achieve single-crystal microstructure throughout

Engineering Contradiction:

Improvemanufacturing flexibilityVSAvoidmicrostructure control

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The heating function is segmented into two independent systems: the directed energy source for melting powder and the external heat control apparatus for temperature maintenance. This segmentation allows each system to perform its specific function optimally without interfering with the other, enabling both manufacturing flexibility and microstructure control.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The external heat control apparatus acts as an intermediary between the directed energy source and the component. It mediates the thermal process by providing additional heating to maintain the component temperature between layers, ensuring single-crystal microstructure formation while the directed energy source continues to perform powder melting.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If conventional casting is used to produce single-crystal microstructure, then microstructure quality is improved, but manufacturing complexity and process requirements increase

Engineering Contradiction:

Improvemicrostructure qualityVSAvoidprocess requirements

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The additive manufacturing process inherently provides the layer-by-layer construction and directed energy melting functions. By adding external heat control, the system makes itself capable of producing single-crystal microstructure without requiring complete process redesign or complex seed crystal positioning mechanisms.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention changes the temperature parameter control by introducing external heating. Instead of relying solely on the directed energy source's thermal profile, the external heat control apparatus maintains the component at optimal temperatures between layers, transforming the thermal history to achieve single-crystal microstructure.

Inventive Principle:

Principle #35Parameter changes

3Temperature

If laser heat input is increased to maintain solutioning temperatures, then portion of component achieves required temperature, but single-crystal microstructure cannot be produced throughout the component

Engineering Contradiction:

Improvesolutioning temperatureVSAvoidmicrostructure uniformity

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The temperature maintenance function is extracted from the directed energy source and assigned to the external heat control apparatus. This allows the directed energy source to focus on powder melting while the external system handles bulk component heating, achieving uniform temperature distribution throughout the component.

Inventive Principle:

Principle #2Taking out (Extraction)

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 enables the production of components with single-crystal microstructures, enhancing their creep rupture and fatigue strengths while simplifying the manufacturing process and increasing yield compared to conventional casting methods.

Implementation Method 1

directing a beam from a directed energy source to fuse the powder

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

using an external heat control apparatus separate from the directed energy source to maintain a predetermined temperature profile of the component

Methodology Applied

Scientific EffectThermal control: Thermal Insulation

Implementation Method 3

such that the resulting component has a directionally-solidified or single-crystal microstructure

Methodology Applied

Scientific EffectDirectional solidification: Crystallisation

Data Source

PatentUS20220362886A1Layered manufacturing of single crystal alloy components

Publication Date: 2022.11.17 GENERAL ELECTRIC CO

AI summary

A method of making a component includes: depositing a metallic powder on a workplane; directing a beam from a directed energy source to fuse the powder in a pattern corresponding to a cross-sectional layer of the component; repeating in a cycle the steps of depositing and fusing to build up the component in a layer-by layer fashion; and during the cycle of depositing and melting, using an external heat control apparatus separate from the directed energy source to maintain a predetermined temperature profile of the component, such that the resulting component has a directionally-solidified or single-crystal microstructure.