Multi-Alloy Turbine Blade Joining With FAST Bonding

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Solution Overview

Problem

Current methods for manufacturing gas turbine engine blades, particularly in high-temperature sections, face challenges in effectively bonding multi-material blades without compromising structural integrity or causing thermal expansion issues due to abrupt compositional changes.

Innovation Solution

A method involving casting two portions of a turbine engine element, applying a load, and using field-assisted sintering technology (FAST) to fuse these portions by applying current across their junction, while optionally heating and using temperature feedback control to maintain the process below the alloy's melt point, ensuring a strong bond without thermal deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multi-material blades are manufactured using bi- and tri-casting methods, then the ability to use different alloys for high-temperature sections is improved, but thermal expansion issues and structural integrity are compromised due to abrupt compositional changes

Engineering Contradiction:
Improveability to use different alloysVSAvoidstructural integrity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by creating a gradient composition where the blade transitions from one alloy to another through intermediate compositions. This gradual change in material properties throughout the blade structure allows different sections to have locally optimized properties while maintaining overall structural integrity and compatible thermal expansion characteristics.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by continuously varying the chemical composition parameters along the blade length. By controlling the alloying element concentrations to change gradually rather than abruptly, the material properties such as thermal expansion coefficient transition smoothly, resolving the contradiction between material versatility and structural reliability.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If multi-material blades are manufactured using bi- and tri-casting methods, then the ability to use different alloys for high-temperature sections is improved, but thermal expansion issues arise due to abrupt compositional changes

Engineering Contradiction:
Improveability to use different alloysVSAvoidthermal expansion stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by creating a gradient composition where the blade transitions from one alloy to another through intermediate compositions. This gradual change in material properties throughout the blade structure allows different sections to have locally optimized properties while maintaining overall structural integrity and compatible thermal expansion characteristics.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by continuously varying the chemical composition parameters along the blade length. By controlling the alloying element concentrations to change gradually rather than abruptly, the material properties such as thermal expansion coefficient transition smoothly, resolving the contradiction between material versatility and structural reliability.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If field-assisted sintering technology is used to fuse cast portions, then manufacturing precision and bond strength are improved, but process complexity increases due to simultaneous application of load and current

Engineering Contradiction:
Improvebond strengthVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into a single integrated process by combining heating, pressing, and sintering operations into the field-assisted sintering technology. This consolidation achieves strong bonds and high manufacturing precision while managing process complexity through integration rather than separate sequential operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces conventional thermal diffusion bonding with field-assisted sintering that uses electrical current and mechanical pressure simultaneously. This substitution enables precise control of the bonding process with faster cycle times and superior bond strength, justifying the increased device complexity through enhanced process capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 fusion of blades with different alloys, maintaining structural integrity and minimizing thermal expansion issues, thereby enhancing the performance and reliability of gas turbine engine blades.

Implementation Method 1

applying current across a junction of the first cast portion and the second cast portion to fuse the second cast portion to the first cast portion

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

A recent technology in sintering of powder-formed bodies is field assisted sintering technology (FAST), also known as spark plasma sintering. This involves a combination of heat, pressure, and current.

Methodology Applied
Scientific EffectSpark plasma sintering: Spark Plasma Sintering

Data Source

PatentEP3865664A1Multi-zone blade fabrication
Publication Date: 2021.08.18 RTX CORP
  • EP3865664A1 patent drawingFigure 1
  • EP3865664A1 patent drawingFigure 2~3
  • EP3865664A1 patent drawingFigure 4

AI summary

In a method for manufacturing a turbine engine element such as a blade or vane, the element has an airfoil. The method includes: applying a load across an assembly of a first cast portion of the airfoil and a second cast portion of the airfoil; and applying current across a junction of the first cast portion and the second cast portion to fuse the second cast portion to the first cast portion.