Diffusion-Bonded Turbomachine Blades With Less Machining Waste

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Solution Overview

Problem

Current methods for manufacturing solid turbomachine blades, particularly those made from Titanium Aluminide, face challenges such as complex machining requirements, high material waste, and long manufacturing cycles due to the fragility of the material and the need for multiple operation steps, which are exacerbated by the high cost and low machinability of Titanium Aluminide.

Innovation Solution

A method involving the production of turbomachine blades from at least two assembled parts using a diffusion connection technique without fusion, where the parts are cut from a metal alloy or ceramic-based material bar, allowing for efficient material use and reduced recycling needs, and incorporating machining to achieve a defined profile, while utilizing ceramic-based materials for enhanced robustness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If solid machining is used to manufacture turbine blades from Titanium Aluminide, then the blade profile can be precisely achieved, but the manufacturing cycle becomes long and material waste increases due to the fragility and low machinability of the material

Engineering Contradiction:
Improveblade profile precisionVSAvoidmanufacturing cycle time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The blade manufacturing process is segmented into two distinct phases: (1) near-net-shape forming by diffusion bonding of multiple pre-formed parts, and (2) selective precision machining only of critical surfaces. This segmentation avoids the inefficiency of machining the entire blade from solid material while maintaining precision where required.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The blade components are pre-formed into near-final shapes through diffusion bonding of pre-machined or pre-formed parts before final assembly. This preliminary action reduces the amount of material removal and machining time required in the final production stage.

Inventive Principle:
Principle #10Preliminary action

2Strength

If forged blanks are used to produce turbine blades, then the material strength is improved, but the manufacturing complexity increases due to the need for multiple operations including material preparation, forging, and machining

Engineering Contradiction:
Improveblade material strengthVSAvoidmanufacturing process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention merges multiple manufacturing operations into a unified diffusion bonding process. Instead of separate forging and assembly operations, multiple blade components are simultaneously joined through diffusion bonding in a single process step, reducing manufacturing complexity while maintaining material strength.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The blade is constructed as a composite structure made from multiple materials or processed states of the same material, joined through diffusion bonding. This allows optimization of each component's properties while simplifying the overall manufacturing process by eliminating traditional forging steps.

Inventive Principle:
Principle #40Composite materials

3Adaptability or versatility

If casting blanks are used to manufacture turbine blades, then the manufacturing flexibility is improved, but the scrap rate increases due to casting defects emerging after machining

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidmaterial scrap rate
Core Design Contradiction:
Adaptability or versatilityVSLoss of substance

Solution Approach 1:

Critical blade components are pre-formed with near-net-shape geometry before diffusion bonding assembly. This preliminary forming action minimizes the amount of material that needs to be removed during final machining, thereby reducing scrap from casting defects while maintaining manufacturing flexibility.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the material state and processing parameters by using diffusion bonding instead of traditional melting and casting. This allows the use of pre-formed parts with controlled microstructures, reducing casting defects and scrap rate while maintaining the ability to produce complex blade geometries.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If mechanical interlocking is used to assemble blade parts, then the assembly process is simplified, but the blade reliability decreases due to stress concentration at the joint interfaces

Engineering Contradiction:
Improveassembly easeVSAvoidblade joint reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention replaces mechanical interlocking systems with diffusion bonding, a metallurgical joining process. This substitution eliminates stress concentration at mechanical joint interfaces while maintaining ease of manufacture through a controlled bonding process that can join multiple components in a single operation.

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

Solution Approach 2:

The joining method transitions from mechanical (macro-scale) to metallurgical (micro-scale) by changing the physical and chemical parameters of the joint interface. Diffusion bonding creates a continuous metal-to-metal bond at the atomic level, eliminating the discontinuities and stress concentrations inherent in mechanical interlocking while maintaining manufacturing feasibility.

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 simplifies the manufacturing process, reduces material usage and recycling needs, maintains robustness, and minimizes material waste, making it suitable for both fixed and moving blades by leveraging the properties of ceramic-based materials and diffusion assembly techniques.

Implementation Method 1

a step of producing a rough draft from at least two parts, at least one of them being a solid part obtained by cutting a bar from a metal alloy or a ceramic-based material, said at least two parts being joined by a diffusion-bonding technique without fusion

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3595842B1Method for producing metal alloy parts with complex shape
Publication Date: 2023.10.25 MECACHROME FRANCE
  • EP3595842B1 patent drawingFigure 1~2B
  • EP3595842B1 patent drawingFigure 2C~2D
  • EP3595842B1 patent drawingFigure 3A~3B

AI summary

The present invention relates to a method for obtaining a solid blade of a turbomachine, comprising a core, a tip and a root, the method comprising: - a step of producing a blank from at least two parts (50, 51), at least one of which is a solid part, the at least two parts being assembled by a diffusion connection technique and without melting, and - a step of machining this blank in order to produce a blade with a defined profile.