Turbomachine Components with Differential Grain Structures

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Solution Overview

Problem

Current methods for producing turbine disks and other turbomachine components often result in uniform microstructures, which compromise between the different mechanical properties required for the rim and bore regions, such as creep and stress-rupture versus tensile strength and low cycle fatigue resistance, due to the limitations of single-alloy monolithic structures.

Innovation Solution

A process involving the fabrication of preforms from different precipitation-strengthened alloys with varying solvus temperatures or grain refiner content, which are joined and subjected to supersolvus heat treatments to achieve distinct grain sizes and properties in the rim and bore regions, allowing for tailored microstructures and properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a uniform microstructure is used throughout the component, then manufacturing simplicity is maintained, but mechanical properties cannot be optimized for different regions with different operating conditions

Engineering Contradiction:

Improvemechanical properties optimizationVSAvoidmicrostructure uniformity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating different microstructures in different regions of the component. The rim region receives a first heat treatment to produce a first microstructure optimized for high-temperature creep resistance, while the bore region receives a second heat treatment to produce a second microstructure optimized for tensile strength and fatigue resistance. This allows each region to have properties tailored to its specific operating conditions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the component into distinct regions (rim and bore) with different microstructural characteristics. By dividing the component into zones that receive different heat treatments, the invention enables independent optimization of mechanical properties for each segment based on its functional requirements.

Inventive Principle:

Principle #1Segmentation

2Reliability

If different heat treatments are applied to different regions, then region-specific mechanical properties are achieved, but processing complexity increases

Engineering Contradiction:

Improvemechanical propertiesVSAvoidheat treatment process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by forming the component with a non-uniform microstructure before the final heat treatment stage. This is achieved by controlling the cooling rates during solidification or forging to create regions with different grain structures, which then respond differently to subsequent heat treatments, reducing the complexity of achieving region-specific properties.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by varying heat treatment parameters (temperature, time, atmosphere) applied to different regions of the component. The rim region is subjected to heat treatment parameters that promote grain growth and creep resistance, while the bore region receives parameters that maintain finer grains for strength, thereby achieving differentiated mechanical properties through controlled parameter variation.

Inventive Principle:

Principle #35Parameter changes

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 regions having finer grains in the bore and coarser grains in the rim, optimizing their mechanical properties for specific operating conditions, thereby enhancing the performance and reliability of turbomachine components.

Implementation Method 1

The first and second preforms are joined together to form an article comprising first and second portions formed by the first and second preforms, respectively, and corresponding to first and second regions of the component, respectively, and so that the interface surfaces of the first and second preforms form a solid-state joint located between the first and second portions of the article

Methodology Applied

Scientific EffectSolid-state diffusion: Diffusion

Implementation Method 2

A supersolvus heat treatment is then performed on the article so that greater grain growth occurs in the second portion than in the first portion

Methodology Applied

Scientific EffectGrain growth:

Data Source

PatentUS8918996B2Components and processes of producing components with regions having different grain structures

Publication Date: 2014.12.30 GENERAL ELECTRIC CO

AI summary

Processes for fabricating components to have two or more regions with different grain structures, and components produced by such processes. First and second preforms are fabricated to comprise interface surfaces at which the preforms can be joined together. The first and second preforms are formed of first and second precipitation-strengthened alloys, respectively, and the first alloy differs from the second alloy by having a higher solvus temperature or a higher grain refiner content. The preforms are joined together to form an article comprising first and second portions formed by the first and second preforms, respectively, and corresponding to first and second regions of the component, respectively, and the interface surfaces of the preforms form a joint between the first and second portions of the article. A supersolvus heat treatment is performed on the article so that greater grain growth occurs in the second portion than in the first portion.